Hello Pines, both of you, pleased to meet you. It's the 9th of January 2024. The cold, really cold weather has changed into plus degrees, so the snow in your crown is melting and dripping on me here when I sit on this bolder. There is a sign on the other side of the bolder that it's brought here from the area around Viborg by the ice during the ice age. Well, the area of Viborg was not the aerea of Viborg by then, but anyway it comes from the east, and is very ancient. But you, if we think of you as a family, are much much more ancient than that. You came here at the time of the dinosaurs, or even before. I decided - well I hope you don't mind, but - I decided I needed to study a little bit more about pine trees, to know more about pine trees, and what best way to do that to do it together with you. Since I met some of the other pine trees in the same park I decided I need to read a little bit also, so I found a book. And the other pines here in the park, they have their own specific character, but I guess most people walking by here would think of you as the real landmark, because you grow here, the two of you, on the... near the road and near the shore. So you're sort of easily recognisable. There are a lot of people walking and also skiing now in the park even though it's wet but never mind. So back to the book. I found a book by, written or compiled by, a huge book, by somebody called David Richardson, and it's called The Ecology and Biogeography of Pinus. So there is a lot of information of all kinds and I began by reading the introduction, or part of the introduction and I'm going to, yeah. And that's where I learned that you are a part of the so-called gymnosperms and not the angiosperms like most plants or flowers and so on, and that you're very ancient. And yes, so maybe I should quote the text so I don't invent something. So yes, when the earliest angiosperms were appearing in the early Cretaceous, that's 120 million years ago, you were already here. So gymnosperms arose much earlier in the middle Devonian, 365 million years ago. And I quote: "Evidence from fossilised cones shows that ancestors of Pinaceae", that's your family however that's pronounced "had evolved by the Mid Jurassic and that Pinus", your kind " had evolved by the lower Cretaceous." So you really, your ancestors really are ancient. No wonder that you're so strong. So now I quote further: "By the end of the Mesozoic, pines had diversified into two major groups, or subgenera; representatives of both subgenera, Strobus (... or soft pines, with one fibrovascular bundle in the needle) and Pinus", that is your kind "(... or hard pines with two fibrovascular bundles in the needle), survive today." So I understand you're probably part of this second branch of the family. But where did I find, there was... There was a beautiful passage describing why it is that you are so strong and have survived so long and are so widespread around the world, especially in the northern hemisphere. So now I quote: "Among the factors that have contributed to the rapid migration and population increases of pines in the Holocene are: their abundant output of seeds from an early age; their ability to recruit dense daughter stands on exposed sites soon after disturbance; effective mechanisms for long-distance seed dispersal; a mating system that permits inbreeding and selfing in isolated trees; and various life-history traits that confer resilience at the population level under a wide range of disturbance regimes; and the ability to colonize nutrient-poor sites." So yes, that I've noticed when I've met other pines elsewhere that you really thrive there were nobody else wants to live, tree-wise I mean. And you can take both damp and dry conditions as long as there is light. Yeah, but my purpose is not to preach to you or just to read aloud stuff, but I would like to somehow have some sort of support or refutal or confirmation of this knowledge. I understand that you can't know by heart everything that happened to your distant ancestors, but I hope you could somehow inform me, if you agree with this knowledge or not, or if it's relevant at all. Or yes, why, if it's relevant for you, I wonder, does it make a difference if your ancestors are ancient or not. But on the other hand, if we think of the genetic legacy as some sort of accumulated knowledge over millennia and so on, then you must be really really wise. I don't know what else I could, what can I expect from you except tolerance and patience with me. Even though you might not be able to teach me directly or engage in this conversation, literally through language or even comment on the text I read to you, somehow I think it makes sense to learn about you together with you. So thank you for this new start at the beginning of the New Year and see you soon again. Take care.
Hello Pines, it's a while, more than a month since I was here. I spoke with you in January. Now I will try to continue my pine studies with you again. I looked a little bit on the next section in the book by Richardson, about the whole species Pinus, and one small section of the introduction is called Morphological traits of pines. And of course that's about beginning with the growth form and size and size, and then also there the whole-tree longevity, so how long the pine trees live. And that's of course always interesting. So I quote here, from page ten onwards: "Pines, like many other conifers, have the characteristics of monopodial growth and large size. The largest species of pines in the world are centred in distribution in California and the Pacific Northwest of the USA." End of quote. So monopodial, I suppose means like having one trunk. That's why we in Finland grow so many pines too. Of course the pines a part of the natural flora here, but they also are a staple of the forestry industry. But anyway, I quote from Richardson, again: "The largest species of pine in both height and girth is Pinus lambertiana, which reaches over 75 m in height and more than 5 meters in diameter in the Sierra Nevada of California." End of quote. There are other big pines, too, but those are the very biggest. That's absolutely amazing. Then about the longevity of pines. I quote: "Many pines are very long-lived, and the two bristlecone pines, Pinus aristata and Pinus longaeva are the oldest living organisms in the world" - well, that's what they claim at least in this book, alright that was a side remark from the quote, I continue quoting: "with the latter reaching documented ages of nearly 5000 years (according to Currey in 1968). The oldest living Pinus aristata was aged to 2435 years (by Brunstein & Yamaguchi in 1992). And NOoden (in 1988) lists two other pine species, Pinus cembra, which is about 1200 years and Pinus sylvestris 500 years. That's our common pine here in the north. And Nooden lists them as among the longest-lived plants in the world, but several other pines could also make this list, claims Richardson. And of course this made me interested in looking up what is the oldest pine in Finland. And they have found one almost by accident in the very north-east in the Urho Kekkonen National Park. And the pine at the time of measuring it or taking, making a hole and looking at that tree rings, they counted it's age to 764, so that's quite amazing. And what I think is most amazing is that it didn't look so very old. It was not exceptionally big or, but it was growing in the far north in harsh circumstances and the tree rings where minute, very very very small. And that's good to remember that the tallest pines are not always the oldest ones. I also looked for the tallest pine and then tall you can mean either by height or then bye girth, and sort of the fattest, the broadest trunk of a pine they had found quite nearby, 120 km or so from here, in a place called Pikku Parola, in today part of Hämeenlinna city. And it's actually quite near my childhood summer house in Kalvola, which is also now part of Hämeenlinna, so I should go and try to find it sometimes. And it was like 4 m and something, almost 5 m around the 'waist'. But back to the book. One more thing is interesting, and that's the role that Pine trees have played in the dendrochronology, that is, counting the tree rings and understanding, for instance, climate change through changes in the tree trunks. And I quote: "Pines have played a fundamental role in the development of the modern science of dendrochronology, beginning with the pioneering work of Andrew Douglas, in the American Southwest. Douglas, who was an astronomer became director of the Lowell Astronomical Observatory in Flagstaff in Arizona in 1894. And with research interest in sunspot activity and possible related impacts on climate, Douglas was drawn to the possibility that tree rings might contain climatic records that would not otherwise be available from existing weather stations. Working with the Pinus ponderosa in the Flagstaff area, Douglas developed the concept of cross-dating to compare and extend these tree ring measures over broad regional areas to identify year-to-year variation in climate. It was this pine research that led him to establish the Laboratory of Tree Ring Research at the University of Arizona in 1906." End of quote. Then one more quote, so I quote: "Although the field of dendrochronology has expanded greatly in scope and depth since these early studies and involves work with many tree genera throughout the world, research with pines still forms the heart of this field. Pines contain the longest single chronologies available and some of the most sensitive chronologies for evaluating regional patterns of climate." And the reference here is Brunstein 1996. End of quote. So this is actually fascinating to think of that especially pine trees are important for this tree research. I always used to think that you had to cut down a tree and then count the tree rings, but luckily you don't have to do that but you can sort of stick in, like in the same way that they do with ice, actually thousands of metres, hundred of metres down in the ice in the Antarctic. You can sort of take a small slice of the whole tree trunk, and obviously that doesn't damage the pine tree too much. Anyway, I wouldn't like that. It sounds like a visit to a dentist or something, but of course it's interesting to think that pine trees can help us sort out climate change. But now it can be measured so obviously, because the climate has changed so drastically during the recent years that we don't need tree ring evidence for that, because there are measurements already. But nevertheless, I think it's nice to think of pines as our allies, not only with storing carbon, taking it away from the atmosphere, but also in the early days in finding out about the changes. But now when I look at you here, I realise I don't understand how old you are, because in some sense you look, well, as in your best years, vigorous and healthy and thriving, so it's very difficult to think that you would be very old. But there's actually in some of the text that old pine trees have their crown sort of bent downwards so they become like rounded almost like mushrooms. And there is a little bit of that turning at least in you, the one of the two of you that is nearest to me. But then again the one that is further away, although it looks like it's thinner, it has a bark that characterises old pines, shield bark, which is found on pines that are in the minimum of a certain age, which I have forgotten, which I have to read again. Yeah so this is sort of basic. No news for you, of course. But maybe you can be proud of thinking that the very oldest plants on this planet actually are your relatives. Well, thanks for this lesson with you again, and I hope you have a nice rest of the February and see you again in March. Thank you.
Hello Pines, nice to see you. It's windy but not so bad and the wind is behind my back so maybe we can have a conversation. It's the 20th of March and this morning, early, around five, it was the spring equinox, meaning that the day and night are equally long. Spring equinox here in the north and of course autumn equinox in the southern hemisphere. To continue our studies or my studies about you with you, I looked up another section in the introduction to the book of Ecology and Biogeography of Pinus edited by David Richardson. And I chose one that speaks about pines in landscape, sort of what kind of areas pines live in. I quote: "Pines are found in a remarkably wide range of environments from near the Arctic where the winters are very cold and growing seasons are short to the tropics, where frost never occurs and growth continues through the year." (end of quote) Then they continue that (I quote) "Some pine species form virtually monospecific forests over very large areas whereas others form mixed forest with other conifers ... and broadleaf trees... or form savannas or open woodlands. Pines are the dominant trees over large parts of the boreal forest" (end of quote). So in some sence, although we are now in the middle of the city of Helsinki and in a park, this is in the area of the boreal forest of course; we are at the border of Siberia if you wish, or taiga. Well, Richardson further writes that, (I quote) "In boreal type forest pines (especially banksiana and contorta and ... pumila, and sibirica and also pinus sylvestris in Fennoscandia and the former USSR) occur with other conifers (like Abies, Larix and Picea); Abies, that's the spruce trees and Larix is what we call the 'leaf spruces' but I don't remember its proper name, the spruces that loose their needles for the winter, and then Picea and also several broad leaf genera, especially birches and aspen trees. Well, this was not a proper quote, but anyway. Now I try to read so I don't transform the text too much. (I quote) "Pines possess a range of specialised mechanisms that enable them to thrive (and usually attain dominance) in these harsh environments. Although the northern coniferous forest contain the greatest area of pine forest many more species occur in temperate regions. The ranges of the temperate pine species are generally much smaller than those of higher latitudes ....; in temperate regions, and even more so in the tropics, pines are usually associated with acidic, nutrient-poor soils." (end of quote) And of course that's true also for the boreal forest. So for instance in Finland where we have most of our forests today are forest plantations, the main trees cultivated are pine trees and spruce trees. And usually pine trees, I think, they thrive better when there is less humidity, so higher up on the slopes or where the soil is less rich, sometimes like in mires or bog-like areas, whereas spruces are more, they need better soil but they also transform the landscape very much; well, more of that later. Richardson continues (I quote) "That pines are not restricted to such sites, with nutrient-poor soil, is clearly shown by their ability to spread into more productive sites, both within and outside their natural ranges, following disturbance that reduces the competitive superiority of vigorous angiosperms. The disturbance regime is thus an important determinant of pine distribution and abundance in the landscape." And fire is the main ingredient or the main form of disturbance and an important part of the life of pine trees in nearly all pine habitats, they claim. Well, nowadays in these managed forests of course any fire that occurs would be put down as quickly as possible, but as we've seen now with climate change, it was not many years ago, there were huge fires, for instance in north of Sweden nearby that were difficult to extinguish when it was a very dry and hot summer. And of course further south in Europe this is occuring even more. This question of disturbance is interesting because of course man-made disturbances are more and more common these days. (I quote) "Several authors have defined 'ecological groups' of pines based on their response to disturbance." For instance there has been described five groups for the pines of North America, like one group is "thick-barked species tolerant of surface fires"; another group is "species that become established rapidly from seed after fires"; a third group is "species with moderate tolerance to shade"; the fourth species, the fourth group of species "found in unusually dry or cold environments, which have wingless, animal-dispersed seed"; and then the fifth group, "species of warm, humid environments with rapid growth and short leaf duration" (end of quote or reference). And then based on these traits we can distinguish the propensity of different pines to different landscapes. So they often form savannas but become dense forest if fires are suppressed. Like group one forms seral even-aged stands, and group two occur in association with other conifers and broadleaved trees, group 3 form savannas or open woodlands rather than forests, and group four form dense, usually seral forests. Well excuse me, actually I said the numbers wrong, so I repeat: Group one form seral even-aged stands - No I don't, I'm sorry because the numbers occur after the group. So, one group form savannas but become dense forest if fires are suppressed and that's the group one. And then there is a group that forms seral even-aged stands, and that's group 2. And then there is the third group that occurs in association with other conifers and broadleaved trees; a fourth group that form savannas or open woodlands rather than forests and a fifth group that form dense, usually seral forests. Based on, of course disturbance is only one aspect that influences the landscape that pines thrive in, but Richardson nevertheless and his colleagues, they discuss "the major pine habitats beginning with the coldest and moving to warmer climatic regimes" and they are the "boreal forest habitats", the "subalpine and timberline habitats", the "temperate forest habitats", the "mediterranean coastal habitats, arid habitats and finally lowland and montane tropical habitats." (That was end of quote). So if I now think of what I associate with pine landscape here in Finland based on the reproductions - of course also walking in pine forest but that's a limited experience, I'm a city girl - but still, there is like the pine landscapes are an important part of the national landscape in the country. The first, of course we are all part of the boreal forest have habitats, even the forestry pine trees, but the difference between the pine trees in the archipelago, the so-called 'martallar' or pines that look a little bit like you but might be even much more bent like really twisted and like dwarfs. They are very special to the archipelago and the rocky islands and cubs, not cubs but like cobs that you can find at sea. And pines are among the first to come after the spruce [I mean birch!] and the rowans there. Then a similar type of twisted pine trees, which I think are very beautiful, so I apologise, I don't mean that in a pejorative sense at all, they occur also high up in the north, in Lapland and closer to the tree line. And then small pines, and of course the twists are partly produced by the wind. Then other type of like dwarf pines, small pines, not necessarily twisted, can be found on bogland everywhere or not really bog but like sour soil as was mentioned before. But somehow the national landscape is formed of the the tall straight pine trees up on the higher slopes, so not on rocky hills but on the sort of not really mountainous but on higher ground, where there is still sufficient soil but not like that much water so the spruces are not competing, and there the pine trees form beautiful landscapes. Why, what makes them, why do I say they're beautiful? Of course because pine trees are very beautiful when they're tall and straight and have their crowns high up and the trunks of Pinus sylvestris are reddish and shine in the sunlight. Because the pine forests are so pleasant because they allow some sunlight; the crowns are high up and there is not that much shrubs and vegetation under the pines because the pines like to keep the world for themselves. I don't know if their needles are poisonous or they make that specific acidic soil, but compared to spruce trees, spruce forests, which are more dense and dark and difficult to walk through, like traditional, what I call traditional pine forests, are more open and beautiful in many ways. But of course what they don't speak about now, Richardson and colleagues here in the introduction, is something that I remember from the book by philosopher Emanuele Coccia, The Life of Plants, where he agrees that all plants not only respond to their environment but they produce their environment. And that's very true for the pine trees as well. So maybe it's not so obvious here, where you two are here alone among all the deciduous trees in the park; there are a few more pine trees further up, but anyway this is a park environment and you don't have the chance to really produce your environment here, humans intervene. But when you have the chance you create your own kind of world and that's a world that many humans at least here find also very pleasant. Yeah you're not, you are the major landscape architects around in these areas. Well I thought about talking about another text I encountered about dead pine trees that are called 'kelohonka' or 'kelo' in Finnish and that can remain without rotting and standing up like grey sculptures in the forest. I encountered an interesting text about that, but maybe that will be for another time. I thank you for your patience with me and with all these basic stuff that I'm sort of learning with you, but yeah. We're heading towards warmer times and now already the light increases so let's enjoy the spring season, which now begins. Thank you and see you again in a month or so.
(Hello pines, nice to see you again. It's the tenth of April and finally the spring is here. Today even the geese.) Probably they were here before but we had a lot of snow and what we call back winter last week, so it's only now it feels like spring. Today it's like a mixture of mist and sun, there is a forecast for wind in the afternoon but right now there is no wind and it's really, really pleasant. And you look great. And I was reminded of, looking at you two as somehow separate and individuals, too, by a talk I listened to or a conversation, interview with Keith Williams, organised by the Networking with plants community, and he mentioned, he spoke about gift economy and indigenous ideas of reciprocity and so on, but he also emphasised the need for attending to specificities. So not to consider plants or trees too, I guess, only in terms of species, but to recognise that you have your special preferences depending on your life history and your place of growth and so on. Nevertheless I'm going to continue with a little bit of studying pine trees together with you, the pine trees, by going back to the book by Richardson and others about the biogeography and ecology of pinus. And to begin with I can tell you, if you didn't know already, that you or your species Pinus sylvestris is the most widespread European pine and you extend from boreal habitat southwards into the deciduous forests of both the Atlantic and central European forest regions. I quote: "For the Atlantic forest region along the west coast of Europe Pinus sylvestris is native only in Scandinavia and Scotland but it has been extensively planted and become naturalised in areas to the south in England and western France." End of quote. Yes I remember many years ago in Ireland people were very unhappy with the plantations of Scots pine which were not at all native there, and a forest that was completely different in character, no actually not Scots pines but spruces, which created a forest completely different from the woodlands they were used to, which were mostly deciduous trees. And of course spruce forests and pine forests are very different, so excuse me for mixing them up. Back to the home areas of Pinus sylvestris, so you are again the most dominant species in the forest regions and mountains of central Europe. So I quote: "Scots pine woodlands characteristically occcur on sandy soils across the lowlands of northern Germany and Poland with or without associated hardwoods", such as Betula, Alnus, birch and aspen and so on, "and often with the ericaceous shrubs in the understory." End of quote. Ericaceous, I think it refers to Erica, which is heather, and at least the heather that grows here in Finland, it could well be thriving together with pines because it's on poor soils. And then Richardson calls you a plastic species, plastic not in the sense of created of artificial material produced from oil, but plastic in the sense of adaptable or formable. So I quote: "This plastic species is successful in montane habitats as well, however, forming woodlands on dry calcareous gravels up to subalpine in levels in the Alps. Nutrient-poor acid soil at elevations of 1400 to 2500 m in the Alps and the Carpathians support sparse forests of Pinus cembra, often growing with Larix decidua", leaf spruce we call it. "Dry dolomitic soils in the mountains of Austria and southwards into Croatia support the typical subspecies of Pinus nigra, the black pine. The dwarf mountain pine, Pinus mugo, forms the highest subalpine community in central Europe, as previously discussed." So these your relatives, Pinus nigra and Pinus mugo, they are sometimes planted as park trees even here. I think that the small shrub-like pines that look like bushes or hedges, they are probably Pinus mugo. And Pinus nigra, I don't know, maybe Pinus cembra more than that. Later in the in the chapter there is a sequence with the title Widespread versus narrowly-endemic pines. And that's of course an interesting question I've never thought of, but of course there can be diversity not only between different species but diversity within a species. I quote: "Relatively little direct attention has been given to considerations of the historical, ecological and genetic factors that have interacted to determine the limits of distribution of individual pine species. The extremes of patterns of distribution can be shown by contrasting such widespread and ecologically plastic species as Pinus contorta and Pinus sylvestris with highly localised endemics such as Pinus peuce and Pinus radiata." And here are some Homo sapiens of the touristic variety, I suppose, but that's no problem. Anyway, it might be interesting for you to know that "Pinus sylvestris has the largest geographic distribution of any pine, ranging in its occurrence from the Scottish Highlands along the Atlantic to the Pacific coast of eastern Siberia," so across the whole Asian continent actually in the north, "with a relic population throughout the northern Mediterranean Basin" as well. "It reaches latitudes from 70° N in Norway to 37° N in Spain and elevations from sea level to 2600 m. The ecological range of Pinus sylvestris is equally broad." So not only geographic distribution but also the ecological range. I quote: "It is common in boreal forests in northern Europe and across Asia where it shows strong dominance of the most xeric slopes and sandy soils. In western Siberia and Mongolia it is a species of the arid steppes and is largely restricted to river courses and the margins of lakes." Well, they also suggest that what remains of Pinus sylvestris in the Mediterranean region and in Central Europe that they are relics from the Pleistocene. That shows how really, really old you are. So "here Pinus sylvestris occurs in the montane and subalpin habitats in the mountains of northern Portugal and central and northern Spain across the Pyrenees to the Alps and Apennines, and then on to the Balkan Peninsula and southwards through the former Yugoslavia to northern Greece. It is also common in the mountains across Turkey and in the Caucasus where it may be found from the coastal to subalpine habitats." So that's a huge area, but then "with such a wide range of biogeographic and ecological distribution, it is not surprising to find that Pinus sylvestris is highly plastic and contains considerable genetic diversity." So now we come finally to this idea of diversity. And they write that, I quote: "This genetic diversity is particularly high at the intra-population level, but lower between populations and races, suggesting that there may have been a blending of genetically diverse populations during the Pleistocene when the range of this species was much more restricted." I'm not sure I completely understand, but I think intra-population level means probably the pines in a specific area and then between populations would be like some forest with pines in Spain and some forest with pines in Greece and that it's within specific populations that the genetic variety is bigger, which seems somehow surprising. Anyway, they write: "Much of the ecological success of Pinus sylvestris appears to result from its strong ability to disperse and colonize disturbed sites. Populations of this species in refugia in the Mediterranean Basin were important sources for dispersal and recolonization of glaciated terrain in Europe and northern Asia in the early Holocene." So the early Holocene, that's a period we live in now, even though they have suggested that we've entered the Anthropocene, but they haven't agreed on that so we're still in the Holocene. So when after the Ice Age the pines came back on soil that was freed from ice, they came from populations in the Mediterranean Basin. So you're probably coming from the Mediterranean after all; no wonder you look so Mediterranean. Alright, jokes aside, I didn't know that Pinus sylvestris was the most widely distributed pine species, but a few years ago I didn't know that there were so many other pines, I thought that all pines were like you. Well, now I know this is not true and that you're a very special species, but thinking of Keith Williams' point, you two are also very different. Although you're probably, very probably close relatives, although not necessarily, but I think especially your bark is very different. So you, the one nearer to me here, don't have a shield bark like your neighbour behind you, which has much more poignant shielded bark. Well, anyway, I don't know about your differences further than that your roots might be very, very different and probably they're also entangled very tightly. But maybe that's enough for today and I will come back again in May and let's see what topic we find to study then. Meanwhile enjoy the spring and take care.
Hello Pine, nice to see you again. There's a lot of traffic today but not so much wind, luckily. Now it's springtime and growth-time and you too, will have some small candles, or what those sprouts are called, but I can't see so many of them. So I was tempted to read about seed dispersal and pollination and all that kind of reproduction activity, but then I decided that I should continue in an orderly fashion, according to the book that I'm studying by Richardson and others, the biography, the biology and echo-geography and ecology of Pinus [Ecology and Biogeography of Pinus], the whole broad spectrum of different type of pine trees. So the section I am going to talk about today and maybe read some excerpts from is called Pines and Humans. So I quote: "People have interacted with pines since early hominids first encountered these trees in the Mediterranean Basin, probably about a million years ago. Human activities throughout the Holocene at least, and especially over the past few thousand years, have had a major influence on the behaviour of pines. The present-day distributions of pines over large parts of their range in the Old World are the net result of numerous expansions and contractions caused directly or indirectly by human activities." (End of quote) And they list important human-induced changes to many factors, such as changes in fire regimes or changes in grazing or browsing intensity, harvesting and construction activities, the abandonment of agricultural land, purposeful manipulation like in forestry, and also the alteration of biotas and last, but not least air pollution. And now I look at some of these aspects or some fragments of them, which they discuss. And of course one is the changes in fire-regimes. Because fire has played a pivotal role, as they say, in the evolution and spread of pines since they evolved from their precursor gymnosperms. Human-induced changes to natural fire regimes have had a major impact on vegetation in most fire-prone systems and have had a dramatic effect on pines throughout their range, they say. In many parts of the natural range of pines human activities have led to increased fire frequency, they write, and this has often arisen thorough the agency of slash-and-burn agriculture. In Finland that was very much practiced in the eastern parts of Finland, 'kaskikulttuuri' they called it. And this practice has benefited pines, at least temporarily, in some areas but in most cases this form of land use has devastated forests, of course. Heavy grazing of rangelands has reduced fire frequency in many parts of the American West by reducing fuel loads and this has had a major impact on vegetation. But fires have importantly, being purposefully excluded from pine forests in several parts of the northern hemisphere. Although in recent years we read and heard about the huge fires, a few years ago in Sweden, but also in the whole north of Russia, the Siberian forest fires, and in Canada, of course. Okay, but back to the book. So fire exclusion, I quote, "fire exclusion has allowed pines to spread to some areas where the natural fire regime excluded them, and has changed the forest composition in areas where the natural fire regime allowed pines to grow, but where changed fire characteristics have altered processes affecting vegetation dynamics." So fire is an important agent and any changes to the fire regimes will have a change on pines, too. And there are impacts of fire suppression in pine forests through the disruption of the complex relationships between pines, fire, pathogens and insects. And these different relationships vary in different biogas and habitats. Well, then they write about grazing and browsing. And changes in grazing pressure has triggered changes in pine distribution in many regions. I quote: "Interactions between grazing and fire-regimes (and often alien plants) are complex, and the relative importance of each factor is often not clear" (end of quote). Moreover, I quote: "Grazing at moderate to heavy intensities frequently enhances seedling establishment which sometimes leads to range expansions" (end of quote). On the other hand, I quote, "grazing also facilitates pine establishment by opening up vegetation in abandoned fields" and "grazing reduces the cover of vigorous grasses and thus competition with pine seedlings" (end of quote). And they also note that areas subjected to heavy grazing may remain susceptible to colonization by pines long after grazing pressure has been greatly reduced or eliminated. And then they mention examples with rabbits that have influenced pine regeneration, and also introduced goats that have had severe impacts on pine regeneration and so on. They also note that browsers do most damage to young trees rather than mature ones and most pines are long-lived. And that's why the primary effect of changes such as increased moose densities in Pinus sylvestris forests in Sweden are therefore on rates of recruitment to adult growth stages. So it's difficult to approximate the exact effect, but of course moose in Finland, too, they can destroy young pines easily. But humans have also interacted with pines directly through harvesting activities. I quote: "Humans have harvested pines and their products for thousands of years" (end of quote), so they consider four categories of harvesting that have actively influenced pine forests. And one is harvesting of nuts, another is fuelwood gathering, and then of course, logging of pines and also logging of broadleaved trees, their competitors. The harvesting of pine seeds or pine nuts for human consumption has a very long history in Europe and in Asia. Your pines [nuts], the pines [nuts] of Pinus sylvestris are not harvested but rather for instance Pinus cembra or Pinus koraiensis or Pinus pinea or Pinus sibirica, their nuts. I can go to the shop here and by pine nuts, of course. But here, what is or has been more important is bark, because bark has been harvested from at least eight Pinus species, the authors claim, for human consumption, but usually only in times of famine. And they also note that it has not taken place on such a scale that it would have influenced pine growth specifically. But pines have been cut for fuelwood for many centuries, and that has had much more impact. And the need for fuelwood in many parts of the natural range of pines still accounts for a large part of the total area of pine forest cleared every year, they write. The situation with respect to fuelwood resources in some developing countries is desperate actually, still. A wide range of influences of pine-logging, including a case where selective logging for one pine species benefits another species, have been studied. And in many areas the logging of trees other than pines have had a major influence on pine forest. For example, as already mentioned, the clearing of broadleaved forests in parts of Asia has created suitable conditions for pines. Other human activities, like construction and mining activities, which replicate the effects of natural disturbances such as floods, glaciations and landslides, and thus create areas of disturbed ground for recolonization by plants, including pines then, which often like.. Or you, because you like light so much, so when an area is cleared you are among the first to go there. Well here the birches might be first. They also mention abandonment of agricultural land; often pines are quick to re-colonise there. But of course, then there is the purposeful manipulation, which we could call forestry industry, and that's of course most evident. Of course, we could think of planting pine trees in parks, but that's not so common, and yeah, in many places pines are not considered park trees in the same way as lindens or maple trees or sycamores and so on. But anyway, the pines have been widely used and planted by humans, and large-scale afforestation started in the second half of the 19th century in Europe. But sustained, large-scale forestry was, however, not widespread in Europe until the early 20th century, and only expanded to other parts of the world in the second half of the 20th century. The development of forestry with alien species in different parts of the world is widespread and some places have proved highly successful, some pines have proved highly successful for use in plantations outside their natural range. Well, I quote: "Reasons for the widespread use of pines in exotic forestry plantations include: their simple design, with straight trunks, and an almost geometrical branching habitat makes them ideal for timber production; as mentioned previously, the fact that LAI values can be doubled or trebled, trippled, through silviculture contributes to their high productivity; they grow faster - you grow faster - they grow faster than many other potential species; they are relatively easy to manage in plantations; their seeds are easy to collect, store and germinate; and they are ideally suited for planting in grasslands or scrublands (marginal forest lands) where most afforestation is required" (end of quote). Well, easy to germinate? I've tried to germinate one of your cones or not your cones but a cone of your relative and have not succeeded yet, but that's another story. Anyway, I continue quoting: "Large-scale afforestation with pines outside the natural range of Pinus has transformed large tracts of former grassland and shrubland to forest. The obvious impact of this form of land transformation on native biodiversity and ecosystem functioning in these areas is causing problems in some areas." Moreover, I quote, "in the last few decades several pine taxa have spread from plantations outside their natural range, and in several areas invasive pines have major impacts on the functioning of invaded ecasystems." And partly related to this there is the question of altered biota, because introduced diseases, insects and plants have had detrimental effects on native pine taxa in many areas. And the various human activities have exacerbated, made worse, the problems of diseases in pine forests. And these include the replacement of disease- resistant species with more susceptible species and fire suppression which favours alternate hosts over disease-resistant and fire-tolerant species and so on. And on the other hand, the impacts of invasive alien plants on native pines have probably been much worse than is currently reflected. The detrimental impacts of invasive alien grasses on pine regeneration in many parts of the northern hemisphere are understated, they claim. Of course "the widespread movement of insects and disease agents on logs and shipping materials is a very serious threat. Fungi and subcortical insects like bark beetles and horntails and so on are likely to cause major damage to pine ecosystems in the future" (end of quote). And this is of course with the increased globalisation and the increased traffic this becomes more and more a problem, but especially the climate catastrophy, because the warming climate makes the conditions suitable for a broader range of insects here, too. And that has been noted by forestry people already, because the winters are warmer and many larvae, for sinatnce, they don't die any longer, they don't freeze tpo death, and so on. Okay, but that's a whole problematic of its own. The authors also mention air pollution and refer to the large-scale damage to conifer forests caused by acid rain, which was first observed in Europe in the early 1970s. But air pollution also enhances the likelihood of insect attack and pine mortality due to diseases such as Armillaria root rot, which is increased by pollution, or any factors that induce stress in the trees, also periods of drought, even though they don't mention it, but which come with climate catastrophe. Then they go on to speak about the genetic diversity of Pinus and the ecosystem functioning, but that's a topic for another day. But I think this scale of human impact on the life of pines is quite important, although, so that there are other areas except this forestry business that we're used to. And just to, if you think why do I speak to you about this, so of course we could say that humans impact your life here, extensively by their presence, but I guess that you might be planted here by humans, or if not, at least your continuous growth is supported and preserved by humans, because you're in the middle of the city. Well, I don't know, I guess I'm somehow, or I hope I'm not boring you too much with this talk. But for me it's personally important that I somehow try to learn from you and with you, not only about you. So thanks for your patience again and see you next time. Thank you.
Hello Pines, it's a great to see you again. It's a great day but a little bit windy, let's see how this works. It's the 11th of June and I plan to study with you the second chapter of the book Ecology and Biography of Pinus and this chapter is called Phylogeny and systematics of Pinus and it's written by Robert A. Price, Aaron Liston and Steven H. Strauss and most of the stuff is quite on the one hand difficult because they discuss classification based on molecular biology and chemistry and all kind of stuff like that, but also some of it is not so interesting for us or for me, because it's about the history of different types of classifications and so on, so it's more the history of the study of Pines. But nevertheless there are some things that might be interesting to know and in the introduction they begin with something that we already know. I quote: "Pinus with more than 100 species, is the largest genus of conifers and the most widespread genus of trees in the northern hemisphere. Its natural distribution ranges from arctic and subarctic regions of North America and Eurasia south to subtropical and tropical (though usually montane) regions of Central America and Asia." Well, end of quote. And then I further quote: "The greatest centre of pine species diversity is in North and Central America (with c. 70 species, with particular concentrations of species in Mexico, California and the southeastern USA) and in eastern Asia (c. 25 species, with particular concentrations in China). And because of its great economic and ecological importance, the systematics of the genus has received considerable attention from the perspectives of morphology, cytology, crossability, secondary product chemistry, protein electrophoresis, and most recently from restriction site and sequence comparisons of chloroplast and nuclear ribosomal DNA." End of quote, wow. So, but nevertheless they say that "comprehensive studies utilising both morphological and molecular data must be completed before a definitive worldwide treatment of the genus will be possible." End of quote. Allright. And they explain that in this chapter they present an overview of the history of pine classification, and they also discuss the types of characters that have been used in delimiting groups of species, and the progress towards a phylogenetic classification of the genus from recent molecular systematic studies. And I'm not going to give you an overview of the chapter, not at all, but I picked a few details from the beginning, first of all from Pinus in relation to other Pinaceae, other relatives. So the Pinaceae is a very distinct family of conifers, comprising ten or eleven genera distributed widely throughout the northern hemisphere. And the family is supported as monophyletic, I have to say that I'm not sure what monophytetic means, by a series of shared-derived features that are unique among the conifers. And these features include, and now I quote "a specialised pattern of proembryogeny, protein-type sieve cell plastids and the absence of biflavonoids. Other distinctive morphological features of the family are: the regular occurrence of two ovules per cone scale, each seed usually with a prominent terminal wing derived from the surface of the cone scale (but poorly developed or rudimentary in some pine species); the lack of fusion of the bracts and cone scales in early development; and the presence of two saccae on the pollen grains of most genera." Well, that's so microscopic so I can't see it, but the features of the seeds might be possible. They further write that "pines form a distinctive natural group within the pine family, supported as monophyletic by a form of shoot dimorphism in which the highly condensed short shoots (or 'needle clusters' or fascicles) bear one to eight (usually two to five) needle-like leaves sheathed at the base by series of bud scales. The genus is also distinguished from other members of the family by its often highly woody cone scales with specialised apical regions, the umbo and apophysis, which represent the areas left exposed in the first-year conelet and the mature cone, respectively." Wow, that's hard to understand but this idea of needle clusters or fascicles I remember when trying to classify some other pine trees. If I remember correctly you have, Pinus sylvestris, you have like two needles in each fascicle, but that I must check, but I think I believe that. Well, then there is a lot of talk of early classification of the genus, beginning with Linnaeus, so I quote: "Pinus is a classical Latin name for pines, and was applied by Linnaeus (in 1753) in his species is Species Plantarum to a group of ten species, including five species of pine and five species now placed in other genera of the family." And then, in another sub-chapter called Twentieth century classifications they begin by stating, I quote: "Many classifications of pines have been proposed since 1900, of which four of the most influential treatments covering the entire genus are discussed in detail in this section." But I'm not going to go into those here, but rather finish by a few observations about the morphological characters important to pine classification. And that sub-chapter they begin by stating, I quote: "Delimitation of species and higher-order groups within Pinus has traditionally been primarily based upon certain foliar (that is needle and needle fascicle) and reproductive (that is ovulate cone and seed) characters. The number of needles per fascicle is nearly constant within many species of pines, and has frequently been used as a diagnostic character for various sectional or subsectional groups in the genus. On the other hand, some species fairly regularly exhibit variation in the number of needles per fascicle within and among individuals. Most needle numbers are in the Fibonacci series of one, two, three, and five (and rarely up to eight, which is infrequently found in some Mexican species)." End of quote. And they also write that needles can vary substantially in length among and within species, ranging from as little as 2-4 cm to as much as 40 to 45 cm
depending on the species. And internal and external anatomical characters of the needles can also be very useful in separation of species, and in documentation of interspecific hybridisation. The number and position of resin canals in the needle cross-section can vary considerably among species of pines and has often been used in classification as well. The number of layers of cells in the hypodermis of the leaf can also vary significantly among species. In some species the cells are relatively uniform in wall thickness, while others have thicker walls on the inner cell layers. The morphology of the stomatal complexes and patterns of wax deposition on the needles have been surveyed for 51 species of pines, and so on. I thought I'd stop with these needles here, because that's somehow something that I've been, that I've acquainted recently. I was up in a workshop in the north of Finland in Äkäslompolo near Kittilä and there I performed with a beautiful pine. But also, we had a workshop where we made natural pigments from plants and then made a brush of a kind, or a mixture of brush and pen of pine needles. And that was quite funny, because taking sort of a bundle or a few fascicles and tying them with a thread or a thin rope to a small branch to make it more compact, rather than using a branch as it is. It made quite a nice brush. Of course the needles are not soft as in real paint brushes but it was possible to paint with your needles and that was very fun. I even thought about the option that trying to boil some of your needles and see if they could make a pigment or so, I mean some colour. Because we boiled some lingo berry leaves and if they were boiled long enough they made a beautiful brownish yellow. Anyway, I also earlier tried to work with your needles, then with dry needles, and trying to somehow use, create letters by placing your needles and trying to glue them there, but it was rather complicated. So maybe this paint brush is better. But anyway, thank you for helping me study again. I hope you have a nice Midsummer and rest of June. See you sometime in July. Take care.
Hello Pines, good to see you. It is the end of July, the 20th of July. A little bit windy, but basically the sun is out; sometimes a little bit of clouds. It feels like ages I was here, but speaking of ages when it's about weeks, not even a full month, is of course a little bit crazy because I'm going to study with you now very old times. It's a chapter called Early Evolution of Pines by Constance I. Millar and I didn't realise that it's really so ancient, I mean you are so ancient, your ancestry. So in the introduction Millar notes that there has been "an explosion of information on the palaeohistory of the Earth." And "physical and biological evidence has been used to infer palaeoclimates with increasingly finer resolution in time and space. New fossil discoveries have added to the record of past vegetation, and new diagnostics for identifying taxa have led to systematic revisions of many fossil floras. The improved methods and widespread use of radioisotope dating have added precision to determining the ages of fossil floras. This information ... has contributed new insights and a revised understanding of evolution for many plant groups." And for "pines, major synthesis have focused on two time periods in the history of the genus. Studies on the Mesozoic history of the pine family and especially Pinus, have significantly changed our understanding of the origin of the genus. Similarly, studies on the Quaternary history of pines have led to new interpretations about the impact of recent palaeohistoric events on the genetic structure and evolutionary relationships of extant species." It's difficult to somehow understand the timescale that's relevant and I'll come back to that later, I had to look it up, but anyway Millar writes that "the broad-scale events that influenced the evolution of the genus, that is pines, between its origins in the Mesozoic and its present diversity remain obscure." So we don't really know, but "the impact of the Palaeogene, both Palaeocene and Oligocene events, especially the Eocene, on the evolution of the genus as a whole has only begun to be analysed. When recent information on plate tectonics, climate, fossils, and biogeography of pines is brought together, the Eocene emerges as one of the most important phases in pine evolution." All right Eocene... there is later in the text a lot of discussion and comparison between changes in the Pleistocene and then the Eocene. That is the most recent period before Holocene where we are now living, if not in the Anthropocene. That is, the Pleistocene, if I understood it correctly, began about 1,8 million years ago, so less than 2 million years ago. That's what we think of as the ice age, or the ice ages. Whereas the Eocene is much much earlier; and its 54.8 million years ago, so instead of 1.8 million years 54.8 million years ago, so it's a really ancient period of the Earth. Anyway, in the subchapter Origin of pines Millar writes: "The prevailing hypothesis until the mid-1970s on the origin of the genus relied on the contemporary interpretation of Mesozoic fossil flora and the prevailing theories of the origin of cool-temperate vegetation. Fossil pines had been described from Triassic, Jurassic, and abundant Cretaceous locals, with pines especially abundant and diverse at high northern palaeolatitudes. Mirov's widely cited interpretation dated the genus to the late Palaeozoic or earliest Mesozoic with its origin centred in a far-northern circumpolar continent known as Beringia", so a continent that existed then. And "according to Mirov, the subsequent evolution of pines unfolded in a steady and progressive migration southwards during the Mesozoic and the Tertiary, culminating in a final southward thrust toward the equator during the Pleistocene", that is the ice age. This interpretation, however, was cast into doubt, according Millar, by systematic revisions of Mesozoic coniferous fossils. And "the revisions, combined with new fossil discoveries in the last two decades", result in a new understanding. So I quote: "Although geographic biases may be expected due to unequal distribution of sediments and proximity of fossil locations to active palaeobotanists, fossil pines occur at middle and few high latitudes, widely spread east and west, with apparent centres in northeastern United States, Japan and western Europe. The earliest known pine, Pinus Belgica, from the Early Cretaceous (about 130 million years ago) was found in Belgium", or what is now Belgium, or it was found in Belgium. What it was then 130 million years ago, that's hard to say, or I don't know. Alright so 130 million years ago; that's a humbling number. I know that, what does it matter if your ancestors were alive 130 million years ago, you live here now, but still, something in the idea of sort of the time you have had to adjust to changes and developments, it's incredible. Anyway, Millar writes that I quote: "Most importantly, no fossil evidence exists for a high-latitude Mesozoic centre of origin for pines." So "hence, a circumpolar origin for Pinus is unsupported, and pine origins in middle latitudes are more likely. The regions of northeastern United States and western Europe, which would have been contiguous, so in contact, in the early and middle Mesozoic are the current candidates for the centre of origin of the genus. Alternatively, the diversity of Cretaceous pines and Pityostrobus, a relative of pines, in Japan suggests that pines might have evolved in eastern Asia." Then there is a lot of descriptions of the different periods and the changes over time referencing specific data, but I will jump to the end of the text, to the summarising the findings. And in a section called Pleistocene versus Eocene Impacts Millar writes: "This chapter emphasises that tectonic, climatic, and biogeographic events of the Eocene had a major impact on pine distributions and evolution." And Eocene was the 54.8 million years ago, period, or the period starting by then. "The Pleistocene differed in lasting less than 2 million years (compared to 20 million years for the Eocene), in having many more cycles and in having alternating periods of unequal duration with glacials longer than interglacials. The events of the Pleistocene had enormous effects on vegetation, including pines. In northern latitudes, pine distributions were displaced by continental ice sheets; in mountainous regions elsewhere, species migrated up or down in elevation. Along coasts and in other lowlands, pine populations shifted north and south in response to the climate cycles. In general, however, Miller continues, "the Pleistocene does not appear to have completely reshuffled the genus in the way that the Eocene did, and many of the Tertiary patterns and the evolutionary events that date to that period have been maintained. Pleistocene events primarily affected Pinus in a gradient from north to south, with the effect that species and populations shifted south then north (or down then up in elevation), following the cycle of glacial and interglacial periods. The impact of the Eocene, by contrast, the longer, earlier period, was greatest in the latitudinal centre of the genus and had the effect of dissecting the genus and concentrating pines into widely disjunct regions." So disjunct meaning separated. Millar writes that "insufficient time has elapsed since the close of the Pleistocene for its full impact to be felt on evolution in Pinus. Patterns initiated by the Pleistocene appear minor compared with the effects of the Eocene and are insufficient to erase the evolutionary impacts of the early Tertiary. Thus, many of the major evolutionary patterns of the early Tertiary can still be traced in the biogeography and relationships to extant pines." So the early Tertiary, that's the Eocene. Well, it sounds funny to say that insufficient time has elapsed since the close of the Pleistocene, but of course when we speak of this kind of evolutionary processes of millions of years a few thousand years is not enough. Alright, so what can I say. I expected to sort of learn about the early evolution but I was taken away to the early history of the Earth. But what I learned from this is that you belong to the Earth since 50 million years and that's so beautiful and humbling to think of it. And I'm so grateful that you're still here, I mean of course there are new species evolving all the time and we humans spread you and other species everywhere in weird places, but the idea that you or your relatives still thrive makes me happy. So that's all for today and enjoy the rest of the high summer. Take care and thank you.
Hello Pines. Strange weather today, it was raining heavily just a few minutes ago and it might rain again soon but I thought I'd have a chat with you, briefly here in between, and hope for the rain not to start. The topic for today is The late Quaternary dynamics of pines in Europe. It's a text written by Katherine J. Willis, Keith D. Bennett and H. John B. Birks. I'm quoting just a few parts of it but it's chapter 5 in the book that I've been reading together with you before. And why I found it interesting is that it speaks about Europe especially, and they write that "Pines occur as native components of the tree flora in most parts of Europe." And they mention 12 native species, on the one hand in the subgenus pinus, the diploxylon pines and in the subgenus strobus, the haploxylon pines. And I had to check what these mean, so there are these two subgenera and haploxylon are the soft pines, which have one fibrovascular bundle, in the needles I suppose, and diploxylon or hard pines have two. And yeah, so Pinus sylvestris, you, is "the most widespread diploxylon species and occurs from Spain to the Urals and from the Arctic Ocean to northern Greece", and "occurs on a variety of soils and in extremely diverse climates. It is most abundant as a forest tree in northern Europe as one of the dominant species of the boreal forest", as we know. I mean the Finnish basic boreal forest but also the whole or large parts of western Siberia or western Russia today, northwestern. Well, "the eight other diploxylon pines" or hard pines "are all southern European and/or montane in distribution." And "the most common of these is Pinus nigra which is widespread southern Europe" and is important in the Mediterranean basin and also in central Europe. And then other pines that are wildly distributed in the Mediterranean area are Pinus brutia and Pinus halepensis, which are sometimes combined but here they are different species - and now there is some rain, I think. Part of it comes from your needles but let's see. "Pines that show a distinctive altitudinal zonation", meaning that they prefer certain heights in terms of altitude above sea level, "they include Pinus mugo which grows at the treeline in the mountains of the Balkans and Central Europe" and then "Pinus heldreichii, a small tree distributed in the Balkans and at mid-altitudes." Then there is Pinus uncinata, I hope I pronounce it correctly, "a small tree of the Pyrenees and the western Alps. Finally, pines that are predominantly coastal in their distribution include Pinus pinaster, which occurs in the Iberian peninsula", Spain and Portugal, "and eastwards to northern Italy, and Pinus pinea in the Mediterranean Basin." "Two of the three haploxylon species", the soft pines, "are endemic to Europe: Pinus cembra, which forms open woodlands on acidic soils at or near the treeline at altitudes of 1400 to 2500 m in the Alps and Carpathians" and "Pinus peuce, which is a rare pine of the Balkan mountains." And these two are actually sometimes used in parks here in Finland, in southern Finland especially. "The third species, Pinus sibirica, is a northern Asian species that extends through Russia as far west 50° East" or 50 Meridian and I checked that and it's really far east because Finland is located between the 20° and 30° so there are only small parts of eastern Finland at 30°, so 50 that's quite a bit into Ural and further. "In western Siberia", Pinus sibirica "occurs at low elevations, forming forests on swampy plains" together with Pinus sylvestris and spruce, different types of spruces, Picea. "Pines generally occupy marginal habitats in Europe such as mountain and boreal environments and dry sandy soils, shallow rendzina-like soils on limestone, ranker soils on rock outcrops, blocky beach ridges, stable screes and boulder fields, and peats" I mean bogs. "They are not confined to acid soils. Pinus sylvestris occurs locally on shallow limestone soils in Scandinavia". "Pines commonly form a surface layer of needle litter up to 5 to 10 cm thick, even on dry limestone rocks. They avoid waterlogged soils but they can grow on drained or naturally dry or damp peats, for example on bogs in Britain, Fennoscandia and the Pyrenees." And this is very clear that although they never become tall but in the mires or bogs you can find pine trees because they get the light there. So "although pines can grow vigorously more favourable habitats", its not that you like poor soil, but the problem is that "they are usually excluded from such areas because of competition from more shade-tolerant trees." And then they also write that "pines frequently dominate the vegetation in which they occur." So now this is very special for you here in the park, although there are several pines but you're not like the dominating species here but in the natural pine forests, sure, both inland and in the archipelago. And then they write that "pines now also occur as secondary colonizers of abandoned cultivated areas, especially in the Mediterranean Basin, and of derelict grasslands and heaths on shallow soils following changes in land use and reductions in grazing pressure." Then they speak a lot of pine pollen and note that "the pollen of the individual species cannot be recognized. But "pine pollen is usually considered to be over-represented in the pollen rain relative to other species of forest trees", for instance in sediments, and "it is also notoriously well-dispersed. For this reason", they write, "Palaeoecological records of Pinus pollen have often been disregarded as evidence for presence or absence in a region because of the high production and long-distance dispersal capabilities of the taxon." So just the fact that there is a lot of pine pollen in an area doesn't mean that there has been a lot of pine trees growing there, because the pollen might have been coming with the wind or in other manner. Well, but then there is a lot of scientific details of these fossil remains but I jump to the section where they summarise, which is called Full-glacial and late-glacial distribution. Because the Quaternary, as I forgot to mention, is the period that we normally speak of as the ice ages. So "pine was present in Europe throughout the Quaternary in all known glacials and interglacials." And "the landscape of central and southern Europe, although not glaciated, would have been undergoing considerable transformation. In the northernmost parts of central Europe permafrost developed", while Finland for instance was covered with kilometre-thick ice, and "further south in central Europe vast swathes of glacial outwash sands were being deposited by the wind, creating sand dunes, which are still visible in many regions today." And of course this influenced the pines. One interesting detail is that "limited precipitation would have affected not only the amount of moisture available to plants but also the protective effect of snow-cover against roots and shoots. However, drought-tolerant species such as Pinus nigra and you, Pinus sylvestris could have survived much drier conditions than those predicted" in the glacials and the interglacials. "In comparison with other temperate trees, shrubs and herbs, therefore, many species of Pinus could have survived the full-glacial climatic and environmental conditions. Arguments about long-distance transport or local presence will continue until further macrofossil evidence is found." Well, but now I lost where I am, here, because I chose some sequences that I wanted to quote for you, so they note that "pine was probably present 11 200 years ago in all but a few parts of Fennoscandia and Britain and by 10 000 years ago, pine had reached much of the Scandinavian uplands, and had begun to increase in the British Isles." "By 9000 years ago pine had reached Finland and had become locally dominant for the first time in northwest Scotland. Continued northward expansion at 7800 years ago brought pine to the northernmost Fennoscandia." "By 5700 years ago it remained dominant in the extreme north of Finland but occurred only locally further south", interestingly. "The northward extension of pine was almost certainly a response to climatic warming." Well, this is something to think about in today's climatic warming. "However, only in northeastern Europe and Fennoscandia was pine able to continue its northward migration unchecked. In western Europe its northward spread was checked soon after 11 200 years ago by the expansion of Corylus and the deciduous Quercus", that is hazel and oak tree. "Pine survived longest in areas either with poor soils or far from refugia of deciduous taxa. Ultimately Pinus sylvestris remained only in the northern boreal forests, sparsely on dry soils in the central European mountains, and in small isolated pockets in the northern European lowlands and northern Britain, where edaphic factors were of primary importance in excluding other taxa. So what is edaphic factors, however you pronounce it, factors related to soil, whether by human influence or other type of influence. But now I have some wind, that's not so nice. But then, I'm not going into the details of the investigations about the spread of pine but jump directly to the summary, or not the summary but the end of this section, where they write that "in northern Scandinavia, macrofossil remains of pine occur abundantly in lake sediments as well as peats beyond the present latitudinal limit of the tree." But in in Britain "Pinus sylvestris reached its maximum distribution between circa 8000", no sorry not in Britain, I jump here, in northern Scandinavia, so "Pinus sylvestris reached its maximum distribution between about 8000 to 7000 years ago but between 5700 and 3200 years ago the northern limit gradually retreated to about its present position." They spend also a lot of time discussing an abrupt decline in the British Isles at about 4400 years ago and "it appears to be a phenomenon peculiar to that region" only. "It is, however, possible that the difference in the records from the two areas is due to circumstances of preservation," which are more, there are more information preserved in Scandinavian lake sediments. But now to conclusions, just to end with. So they write that "from the palaeoecological evidence it would appear that pine has been present in Europe throughout the Quaternary. In periods of maximum glaciation pines were restricted to southern and central Europe but rapidly expanded northwards during interglacials. Pinus sylvestris is the only species known to have spread into northern Europe during the interglacials and is thus the only species of pine in Europe to demonstrate invasive behaviour on these broad scales of time and space." So you're the traveller here. "The record of Pinus sylvestris in northern Europe is particularly well known because of the abundance of pollen and macrofossils. It is unusual in this respect relative to other trees of the north temperate zone and provides an opportunity for modelling rates and mechanisms of change which is not available for other species. The behaviour of Pinus sylvestris during the postglacial is unexpectedly complex in time and space and it is likely that other pine species have been similarly dynamic. In the Holocene", that is the period up until now and even now, even though some people say we are in the Anthropocene, but then officially Holocene, "it is clear that anthropogenic", that is human based, "activity has had a major effect on the behaviour of pines and their present-day distributions in Europe. For example, Pinus sylvestris expanded its range during the early Neolithic in Scotland, and in central Europe one or more pine species increased during the Neolithic and Roman occupations. It is rare to find examples where pines have decreased their range through anthropogenic activity." So you have not suffered so much from human intervention. "The Pinus sylvestris decline in northern Europe", especially British Isles "at 4400 years ago maybe the exception." That's where they end. So although you're called, Pinus sylvestris is called Scots Pine, you're not so prominent in Scotland any longer, but more prominent in the boreal forest. I'm very happy that you are here in this park now as a reminder that these cliffs by the sea probably were covered with a lot more pines before Helsinki was built when there were some fishermen or seal hunters only. Thanks again for this chat with you and thank you for assisting me in trying to learn about you with you. Have a nice August. Take care.
Hello pines, good to see you. It's beginning of September but it feels like summer still, although a lot of the deciduous trees are dropping some of their leaves or at least part of them are yellow, but that cannot be because the nights would be chilly. I think it's more because of the drought. But on the other hand there have been some showers so I don't know. Anyway, the chapter I thought I'd study with you today is called Pines of the Mediterranean Basin and it is written by Marcel Barbero, Roger Loisel, Pierre Quézel, if I pronounce it correctly, David M. Richardson and François Romane. And it's really about the Mediterranean pines. So, they start by saying that they define the Mediterranean Basin as the area around the Mediterranean Sea that experiences a true Mediterranean-type bioclimate, so on both sides. And they suggest that the region can be divided into four parts, northwest, northeast, southwest and southeast, by lines running east west, so southern Anatolia-Malta-Strait of Gibraltar and then north to south, Adriatic Sea-Malta-Tunisia. And these create sort of zones that are reasonably discreet in terms of at least the following factors: features of soil and climate; impacts of human cultures; skills in resource management; obstacles of poverty; deep-rooted traditions; economic forces; and political events. So in the Mediterranean area the pine populations have been heavily influenced by human populations, as everywhere. And they write that, I quote, "conditions in the northwest of the region favour a more settled human society, with more stable traditions, individual title to property and inheritance of land." While "in the east, however, the arid environment, together with exposure to waves of immigration from Arabia and Asia, has mitigated against settled life, and a pastoral society still predominates over considerable areas." End of quote. This text was written 25 years ago, even more than 25 but reprinted in 2000, so this might have partly changed but only to some extent. They further write, I quote, "the marked cultural differences between west and east continue to play a major role in defining contrasts in land use, with the former being increasingly characterized by the development of industry, urbanization and tourism, and a concurrent decrease of agriculture and pastoralism." Anyway, pines are important components of many landscapes in this region and have played major roles in the origin of its flora and vegetation, they write. And as I already mentioned, the biography of pines in the region has been greatly influenced by humans. In no other part of the natural range of Pinus, they write, has there been such a complex interplay between pines and humans. And in this chapter they discuss the Mediterranean pine resource, the ecology and biogeography of the different taxa, their roles in the vegetation history of the region since the last glaciation, that is, the ice age, and the parts they have played in recent vegetation history. But, they emphasise that changing patterns of land use are still having major effects on the dynamics of the Mediterranean pine forest. Of course most of the pines in the Mediterranean region are foreign to us here in the north, but when they discuss the Mediterranean pine resource they write, I quote: "The extant pine flora of the Mediterranean Basin comprises 10 Pinus species. Included in this list is Pinus sylvestris which, although widespread in the region, is more characteristic of extra-mediterranean Europe." So that's you, so it's good to know now that we are here in the extra-mediterranean part of Europe. I never thought about that but this is a question of perspective of course. Well, the area of forests in the Mediterranean Basin and adjoining areas has fluctuated dramatically over many centuries, especially in the last two centuries. And "given these circumstances, and many large-scale afforestation programmes in many parts of the region it is difficult to give a precise assessment of the area covered by each Pinus species in the Mediterranean Basin", they write. And they further note that "although pine forests cover only 5% of the total area of the Mediterranean Basin, they comprise about 25% of the forested area." And like in North Africa and Anatolia 75% of the forested area comprises pine forests. The Mediterranean pines can be divided into several groups on the basis of their distribution and general ecology. And the two most common species, Pinus brutia and Pinus halepensis, occupy large parts of the eastern and western part of the Mediterranean Basin, respectively. So Pinus halepensis being the only pine with a considerable part of its natural range in North Africa. Although some of the other species also occur there. And I must say that I have never, as far as I know, I've never met at least consciously Pinus brutia or Pinus halepensis, because I don't think they are grown in the parks here as some other of the Mediterranean pines. Well anyway, "isolated populations of Pinis halepensis in Asia Minor and the Near East, at the eastern limit of the Mediterranean Basin, pose intriguing questions regarding past distribution patterns and migration pathways." So we don't know where they sort of began. "Two species, Pinus pine and Pinus pinaster, occur at low and medium altitudes. Pinus pinea, whose natural range is difficult to define because it has been planted so widely for so long, now occurs in scattered populations throughout the Mediterranean Basin except in North Africa." And Pinus pinea, that's the famous pines in Rome as well and in Italy. "Pinus pinaster is restricted to the western part of the Mediterranean where many subspecific taxa have been recognized but which are difficult to distinguish," so I suppose the Iberian peninsula. Then there is "another group, found especially in the mountains, and that is represented principally by Pinus nigra whose populations, from the Pif mountains of Morocco to the eastern Taurus mountains of Turkey, are divided into several subspecies and numerous varieties." And Pinus nigra can also be found in arboretums and parks here. I've met some, if I remember correctly. And "Pinus sylvestris, although not a truly
Mediterranean pine, has some populations that are very well adapted to the Mediterranean mountain environment, particularly in Spain and southern France." And then there is "the last group that comprises the high mountain pines, Pinus heldreichii, including variation leucodermis, which is confined to southern Italy, the northwestern Balkans and eastern Greece, and Pinus uncinata, a vicariant species of Pinus mugo, which occurs in the western Alps, the Pyrenees and the Sierra de Javalambre." Well, anyway, pines have been widely used and planted by human inhabitants of the Mediterranean Basin since prehistoric times. "Since the second half of the 19th century, reafforestation programmes have been undertaken in most parts parts of the region, notably in Italy, France, Spain and Turkey, often in order to control erosion." And "such plantings have undoubtedly had a major influence on the distribution of these species in the region" because of course then they spread. "Only relatively recently", however, "has any systematic thought been given to ecology and genetics when selecting species for use in reafforestation. So what pine trees are suitable for planting where. And then I jump towards the next section, but they conclude this one by noting that "the preceeding paragraphs point to an intricate tapestry of pine taxonomy within the Mediterranean Basin - much of it the result of the long history of human occupation and manipulation of genotypes in the course of cultivation and translocation within the region." But "much work remains to be done" with this. Then they introduce something they call the étage concept or concept of floors or levels, which "although not well established in the English language ecological literature, is widely used in the Mediterranean Basin", and "étages are essentially belts or zones of vegetation described on the basis of topography, altitude and regional climate." And also they distinguish the following étages in the Mediterranean Basin: They call them infra-Mediterranean; thermo-Mediterranean; meso-Mediterranean; supra-Mediterranean; mountain-Mediterranean; oro-Mediterranean and alti-Mediterranean. And this is difficult to understand what they mean, except the mountain-Mediterranean, but importantly "pines occur in all these zones where they exhibit a wide range of behaviours. And most subspecies, so different types, are found in the mountain-Mediterranean étage. Then there is a lot of discussion about the historical developments, but let's jump to recent vegetation history.
And the writers note that "as knowledge of the Mediterranean vegetation has accrued, it has become clear that pine-dominated 'climax' communities, or stable, pine-dominated vegetation arising from 'pine climax' formations that have been irreversibly modified by long periods of human influence are very common." So these 'climax' means that it's like the end point, because in some places pines are like an intermediate stage; when there has been disturbance or fires or something, then pines come in and then broadleaved trees take over. But there are also these 'climax communities' of pines. They explain, I quote, "the pine paraclimaxes are very frequent, particularly in the northern part of the Mediterranean Basin, where the 'pine stage' is an essential phase in the succession leading to the climax. Thus, it is possible to associate a pine with each broadleaved tree of a climax formation, at least for the vegetation of low or medium altitude." And then, I'm not going through all these combinations but the interesting thing is that you, Pinus sylvestris, have your companion is
Quercus pubescens, a specific type of oak tree, which then takes over when you have prepared the ground, if I understood it correctly. Then there is a lot of talk about change scenarios and I jump to the present situation with the models of dynamics. So the writers again emphasise that "the trends differ markedly between the northern and the southern parts of the Mediterranean Basin. For example around the western Mediterranean Sea, the area under pines has decreased drastically in the Maghreb area (particularly Pinus halepensis), whereas in Europe the area of pine forests has generally increased." "The reason for this is the large increase in the extent of human activities, including clearing of the forest for cultivation, cutting for various purposes (to feed livestock, build houses, obtain charcoal), overgrazing and frequent fires. Trends in southwestern Europe are totally different, and the area of pine forests is increasing rapidly." "The overall increase in the area under pines is essentially attributable to aspects of the biology of pines and changes in land use." So "the biology and ecology of (some) pine species allows them to become 'weedy' within their natural range." Well, weedy, I suppose that they act like weeds. "The pines, which often behave like invaders, produce large numbers of seeds at an early age (less than 10 years in some cases)" and "these seeds can germinate in various vegetation types like abandoned fields, grasslands, matorral and burned areas." So "the area of abandoned fields, grasslands and matorral has generally increased over the past few decades, particularly in the European Union where a policy of setting aside land has prevailed." "These trends are also increasing the fires and the burned areas that leads to vegetation types where pine germination easily occurs." Well, this was written 25 years ago, so it would be interesting to know what the situation is now, but I would assume that there is even more sort of efforts in afforestation and letting land return to natural habitats, so to speak. But as concluding remarks they write that "the role of human-induced changes to disturbance regimes in structuring pine forests is quite different in northern (mainly Europe) and southern parts of the Basin (North Africa). In western Europe (France and Spain) pines are often invaders occupying the abandoned fields induced by the 'set-aside' policy of the European Union", as already mentioned. "On the contrary, in many areas of the southern part of the Basin, where the shortage of fuel and timber is most severe (for instance in Algeria and Morocco), the area under pines is often decreasing drastically." "The most important problem in pine forests of the Mediterranean Basin is probably fire," they note, "particularly in the warmest étages where forest fires cause major damage, and where means to reduce fire hazard are urgently sought." "In most cases, it is not practical to replace pines with other non-coniferous (and less flammable species), since few of the latter grow well where pines thrive." So this idea that pines - I've always thought that pines are very well resisting fires, but that's of course only some species, particularly the ones that grow on Canary Islands, if I remember correctly, but also of course as coniferous trees pines create environments that are easily flammable. Well, the idea of the Mediterranean Basin is fascinating and I'm reminded of a map I saw on Facebook or somewhere, which was placed in a different angle than the normal one, where Spain and Gibraltar is in the west and the Bosphorus and Anatolia and Sinai are to the right, the Alps in the north and Sahara in the south and the Mediterranean Roman Mare Nostrum is there in the middle. But this one was like placed vertically, so Gibraltar and the opening to the Atlantic was up in the north, and Sinai down to the left and then the Black Sea down to the right and the whole Mediterranean looked like a huge sack, like a vertical format with Europe to the right and Africa to the left. And that reminded me of the importance of maps but also our ways of speaking, and the concepts we use, how they really do influence our understanding. And for instance, the fact that almost all the pines in Finland are of the same species, Pinus sylvestris, despite the great variety in how you look and grow, except then some of the park trees, makes it so strange to think that there can be so many pine species already in a rather limited area like the Mediterranean. But anyway, thank you for listening to me today and thank you for studying with me today. And I wish you a nice autumn and yeah, enjoy the last months of light. See you again in October.
Hello Pines. Good to see you this October afternoon. There is not much wind but strange gusts from various directions. Maybe that's why it's relatively calm now because the wind is changing direction. It's more than a month since I was here because we met last time in the beginning of September and I realise that there is only two months left after this meeting, because I come to you once in a month, so November and December. But what I thought I would study with you this time is a chapter called Genetic Variations in Pinus, written by Thomas Ledig or I don't know, Ledig sounds like Swedish. It has a lot of complicated sections about genetics really like chromosomes and all that, but I thought that I could read sort of the beginning and the end the major... the outlines of the chapter. And in the introduction Ledig writes that "Pines are, on average, among the most variable of organisms, both among and within populations, as revealed by measures of quantitative genetic variation, and by diversity at isozyme loci", whatever that means. "The high level of diversity within populations is a result of a genetic system that effectively provides for the creation, storage and release of genetic variation. The observed level and pattern of variation within species of the genus Pinus, and therefore their ecological role, depend to a great extent on their genetic system. Wind-borne pollen provides cohesiveness among populations and guarantees that most patterns of geographic variation will be clinal", or sloping. "On the other hand, systems of seed dispersal are conducive to rare colonization events that provide opportunities for the action of genetic drift and protect the genetic integrity of founding populations during race formation." So, if I understand it correctly, if some seeds are taken into places where there are no pine trees before, there is an opportunity for those few seeds to start a new colony in a way. Well, another, I continue quoting, so "Another paradox is that ecotypes separated by less than a kilometre can coexist because the tremendous seed output of pines results in net fitness despite high selection intensities." So you pines are producing enormous amounts of seeds, that's clear. "The genetic system that allows for the storage and release of such high levels of genetic variation makes pines ideal material for breeders and facilitates their domestication, with the result that several species have entered world commerce because of their adaptability to plantation culture." Well, as we know here in Finland pine plantations, even though they're not called pine plantations, but they are a major source of economic wealth. So "High levels of genetic variation, tremendous reproductive capacity, and facultative selfing also contribute to the success of pines as invaders when introduced into the southern hemisphere where they are not native." Yeah, so you're your native of the northern hemisphere and this idea of selfing is that if you, that you can sort of reproduce with your own pollen, your own female and male parts can sort of combine even though less successfully than with sort of foreign mates, because, I jump a bit and quote: "The reproductive system of pines is exclusively sexual. A few species will sprout from the stump after harvest or from the root collar when the top is killed by fire. - However, this is not a method of multiplication. The branches of a few species may layer (or form roots) if brought into contact with the soil while still attached to the tree but this is very rare and of negligible importance in the reproduction of pines. Neither is there any evidence of apomixis", whatever that means. "When pollination is prevented by isolating the megasporangiate strobili, whatever that means, with suitable barriers, no seeds are set and cones failed to mature. So, for instance, if we compare with some deciduous trees where you can coppice the trees and a lot of young branches grow out from the trunk, this is not the case with pines. And yeah that's clear, Pines are either sort of sown or then planted and preferably planted; they grow better as far as I understand. Ok, back to the study text. So Thomas Ledig writes: "I will refer to the reproductive structures as megasporangiate strobilus and microsporangiate strobilus", excuse my pronunciation. "These are often referred to as female and male flowers." OK, so female would then be megasporangiate strobilus and male would be microsporangiate strobilus if I understand correctly. "However, they are not morphologically flowers, which is why the gymnosperms in general and the pines in particular are distinguished from the angiosperms, the flowering plants." Yeah, that's clear. And you gymnosperms are the older ones, as fa as I understand. The interval, I continue, "the interval between initiation of strobili and maturation of seeds is two years in most species. In brief: the primordia are initiated within the buds in late summer; the strobili emerge from the buds the following spring; within a period of days or weeks, anthesis occurs in the male or pollen strobili and the female strobili reach a receptive stage and are pollinated; fertilization occurs one year after pollination, in the second spring; after fertilization seeds develop and mature over a period of several months and are shed from the cone in the autumn, about two years after the primordial were first visible within the bud." So that's quite a long time actually, two years, I didn't know that. Well, there is then a more detailed description of the reproductive cycle, but I'm not going to go into that here nor into the segregation and linkage and organelle inheritance nor the summary of the reproductive system, but a few words about the mating system. So, I quote: "The mating system usually refers to the levels of inbreeding (selfing and consanguineous mating) and outcrossing. The mating system is affected by mechanisms of self-incompatibility and self-sterility, and also by population structure and the temporal and spatial distribution of relatives." Of course in-breeding is not beneficial in the long run, but in cases isolation it might be helpful. Anyway, I continue: "Spacial and temporal separation of the sexes should favour outcrossing and, therefore, recombination. Pines are monoecious, meaning that the male and female reproductive structures are borne on the same tree but separated. The megasporangiate strobili occur predominantly high in the crown and near the ends of branches in the mid- or lower crown, and the microsproangiate strobili are borne predominantly on the interior and lower portions of the crown." And now I think that actually, the microsproangiates are then the females and the megasporangiates are the males, so the opposite as what I interpreted before. "However, substantial overlap occurs, creating the opportunity for geitonogamy." So, temporal separation of the sexes, or dichogamy, is observed in some species but not in others," meaning that the pollen and the females are sort of mature at different times in the same tree. But then I jump and conclude, I quote: "Given that neither spatial nor temporal separation of sexes is strong, that relatives tend to be clustered, and that self-incompatibility seems to be lacking in most species of pines, a high level of outcrossing must be maintained by some other mechanism. Partial self-sterility resulting from inbreeding depression seems to be a major part of the explanation." So inbreeding depression means sort of hindrance of in-breeding as I understand it. Further, later in the section Ledig explains: "Even if selfed zygotes pass all the hurdles of embryonic development, inbreeding depression continues to act, reducing the chances that they will survive and reproduce. In general, germination of seeds from self-pollination is only 89% that of seeds from cross-pollination; seedling mortality is 31% greater for selfs than for outcrosses; and height growth (which affects competitive ability, crown size and, therefore, reproductive output) of selfs is 10% less than that of outcrosses. Nevertheless, the pine mating system is flexible enough to permit inbreeding and selfing in isolated trees. This flexibility is important for colonizing species and facilitates invasion of new habitat. Pines in exotic locales often escape, establishing colonies at some distance from the seed source. - The predominant pattern for pines is one of outcrossing. Outcrossing promotes recombination, and it maintains variation because new recessive alleles are shielded from exposure to selection. The barriers to selfing are largely postzygotic and are fully effective only when the opportunity exists for competition with outcrossed siblings. The barrier does not preclude selfing and, therefore, pines can be successful colonizers. The ability to self may have enabled pines to migrate successfully to new habitat as glaciers waxed and wayned." Allright, so you are highly adaptable to circumstances, choosing your mode of reproduction accordingly. But now I jump far, far down in the chapter and leave all the details and statistics for another time. Also, I don't speak of the mutation system, which is of course very important and which is whole a section here, too, but continue with Patterns of variation in pines. "Common garden studies (usually called provenance tests or seed source tests in the forestry literature) have shown pronounced patterns of geographic variation in most pine species that have been investigated. - In common garden studies, the local provenance usually seems to be among the best adapted (i.e. has the fastest growth rate and often the best survival). - Another common trend is that trees from southern sources grow more rapidly than those from northern ones, and those from an elevation slightly lower than the planting site perform as well as the local provenance. Populations from southern latitudes or low elevations are usually adapted to longer growing seasons than those from northern latitudes or high elevations. The effects of elevation are especially striking," Ledig writes. "However, adaptation is conservative. Selection for tolerance to extreme conditions is more likely than selection for the mean. Therefore, for growth and yield, optimum seed sources for a given planting site are often from slightly milder climates. One exception is Pinus sylvestris in Scandinavia. Because this pine entered southern Sweden from the north after migrating around the Baltic Sea through Russia and Finland, populations in southern Sweden are adapted to growing seasons much shorter than the ambient. However, Scots pine from Germany, across the Baltic Sea, grow more rapidly in southern Sweden than do the local trees, conforming to the rule. Most patterns of variation in pines are clinal because they reflect the underlying pattern in the environmental factors that exert selection pressure. Temperature precipitation, length of the growing season etc. are continuously distributed variables. - As mentioned above, many growth traits (height, diameter, volume) vary continuously with latitude or elevation, surrogates for length of the growing season and correlated climatic variables." Well, this detail about the pines in Sweden is funny, but anyway. "Migration history as well as selection may influence the patterns of variation within pine species", he writes and "Genetic variation within populations is generally high. Usually above 90% of the variation detected at isozyme loci is within populations. Variation for quantitative traits is also high. - In summary, geographic patterns of variation in pines can be either clinal or ecotypic. Clinal patterns predominate because environmental variables are usually continuously distributed and because dispersal mechanisms and gene flow through pollen flight are highly effective in pines. However, discontinuous, or ecotypic, patterns are known and are maintained by intensive selection or because insufficient time has elapsed to erase the effects of past isolation." Then there is a lot about domestication but I jump to the conclusions. So, "The genetic system of pines, in general, favours the creation and recombination of genetic variation. The creation of genetic variation, or mutation, is probably higher in long-lived woody perennials than in any other organisms because of the opportunity for the accumulation of somatic mutations in cell lines that give rise to reproductive structures. - Thus, it is not surprising that pines are among the most genetically diverse of organisms. Diversity has permitted pines to evolve in concert with environmental change over the 200 million years since they diverged from ancestral forms. However, diversity has its negative aspects; most mutations are deleterious, not so good, and recombinants may be so unlike their parents that many are maladapted, especially in a constant environment. These effects are offset by the high fecundity of pines. - Furthermore, some species are wind-dispersed and others animal-dispersed, mainly by birds. Both wind- and bird- dispersed species are capable of being transported long distances. The best direct evidence is (1) the occurrence of colonists at some distance from planted stands in countries where pines have been introduced, and (2) observations of birds that cache seeds, many kilometres from the source. Indirect evidence is provided by the rapid rates at which pines migrated northwards during the current interglacial and by patterns of genetic diversity that are best explained as 'foot prints' of founder effects left by long-distance colonists. Because pines lack self-incompatibility systems, facultative selfing is possible and they can colonize new habitat after long-distance dispersal. Genetic drift is likely to have influenced patterns of genetic variation in new colonies. Pollen output in pines can be tremendous and wind-dispersed pollen can cover great distances. Therefore, gene flow can counteract drift in all but the most extreme colonization events and maintain genetic variation at levels characteristic of the species. - Because of effective gene flow, it should be anticipated that most variation in pines will be clinal. However, ecotypic variation is also known, usually a response to edaphic factors", whatever edaphic factors means. "Extreme selection pressures can be effective in establishing and maintaining ecotypic differentiation because of the high fecundity of pines. Differences among populations have evolved over distances as short as a few kilometres. Because of their high diversity, many species of pine respond rapidly to selection and are easily domesticated (and may, incidentally, be aggressive invaders). All right, so two sides of the same coin; you can easily adapt to new circumstances, but because you easily adapt to new circumstances you also adapt to ... places where you are not wanted by humans or by plants that already live there. Yeah, this idea of a two year reproductive cycle I think is fascinating as well as the idea that you have both male and female flowers, although they are not flowers, on the same tree, but try to maintain some difference in the timing. So this was a long session. I thought I would just read a few excerts but it was maybe too much so I hope I haven't bored you. And I wish you a nice coming autumn; it's getting darker now and colder, obviously very much colder. And let's hope there are no bad storm. So thanks again for your patience in listening to me and take care.
Hello, Pines. Nice to see you again. I was here yesterday, but there was too much wind so the camera tripod toppled over and parts of the our conversation was also hard to follow. Today there is a little bit less wind but a lot less sun. The weather was beautiful yesterday but now we have a grey day and instead of the heavy wind gusts we have the leaf blowers and machines transporting all the old leaves away. They would be good nourishment for the soil of course, but the park department wants to keep the park looking decent, so it's understandable. Well, the text that I thought that I would be reading to you is the same one that I already started with yesterday, so I hope you don't mind the repetition. But it's about seed dispersal in Pinus and it's written by Ronald M. Lanner and it's chapter 14 in the same book that we've been studying, the Ecology and Biogeography of Pinus edited by David M. Richardson. And so Lanner writes that "the dispersal of diaspores has had a profound effect on the biography, indeed on all aspects of the population biology of pines". And diaspores means, I checked that, it means not only the seeds but everything that is around it, for instance the wings or the whole parcel. And Lanner further writes that "dispersal at a distance allows diaspores to sample a much wider range of conditions than those experienced by their parents, thus being exposed to a nexus of natural selective factors new to the line. Once outlying populations have become established, and have begun to differentiate genetically, long-distance dispersal makes gene flow possible between central and marginal stands. Thus seed dispersal is a major determinant not only of a species' geographic occurrence and successional behaviour, but of its genetic structure as well." End of quote. In a section called context of seed dispersal Lanner emphasizes that "the dispersal of pine seeds has both temporal and spatial contexts." And "in this chapter dispersal to a 'safe site' where the seed will germinate will be considered the final act in a chain of events that begins with cone initiation." And of course the first moment is then readiness produce seed. "The minimum age at which seeds are borne is quite variable among pines." And then "once readiness-to-bear has been achieved the initiation of cone primordia becomes the next critical step." So - And when discussing cone and seed development Lanner writes that "there are numerous post-initiation factors that can constrain the magnitude of future seed dispersal. For example, lack of pollination in Pinus sylvestris, (that is you), Pinus sylvestris conelets leads to conelet absission. In a cone in which many of the ovules have been pollinated, those that have not received pollen fail to develop as seeds, producing wings only." So "low levels of pollination may occur in years when the crop is small, as between mast years, or because of pollen washout in a rainy spring". Moreover, "isolated trees self-pollinate at a higher frequency than stand-grown trees, and thus bear many empty seeds."
And "seed dispersal from a closed stand of pines is biologically more meaningful than dispersal from a woodland of widely scattered trees, because the latter would produce a much larger proportion of selfied progeny, leading to greater mortality." And this idea of course, has consequences for forestry practices. How dense should the remaining seed trees be? Or how much of them should be left standing when felling trees. Well, then there is a chapter on timing of seed dispersal. And Lanner distinguishes between masting and non-masting species, masting is this occurrence of all the trees in the same species producing enormous amounts of seeds in one year. And then Lanner writes about the the phenology of cone opening. I quote: "The commonly held stereotype is that pine cones mature in late summer to early autumn, that they dry and open almost immediately, and that they then shed their winged seeds on the wind. The cones then cease to function. This pattern is perhaps typified by Pinus strobus, reported to have a period of seed-fall extending from early September to late November, most of which occurred during a one-week period in late September to early October" in one study. But "the actual situation is far more complex. For example, serotinous pines can retain their seeds in closed cones for several years." Serotinous in this context means reacting to fire, so speaking of cone serotiny Lanner writes that "trees bearing serotinous cones will disperse seeds in whatever year a facilitating fire occurs. Thus dispersal is determined not by plant characteristics so much as by unpredictable environmental events." So they need the fire, the heat of the fire to open the cones. There is also mention about variation in non-serotinous species that "even among pines whose cones apparently open promptly on maturity to disperse winged seeds, there is a wide variety of dispersal dates." Well, one of the most interesting parts is the chapter on pine seed morphology, the forms of the pine seeds. And there are beautiful illustrations, which I can't share with you, unfortunately. But Lanner writes that "Pinus is far more diverse in the morphology of its seeds than all other Pinaceae species combined." "Pine seeds may be fully winged, equipped with rudimentary wings, or have no attached structure. Wings may be removable, that is, articulate or firmly integrated, that is, adnate. Seedcoats can vary in thickness over a wide range. Seed length can vary by a factor of 10, and seed mass by the factor of 270 among species of the genus. Shapes vary from ellipsoid through pear-shaped and cylindrical to almost triangular. Coats may be reddish, purplish, greyish, brown, black or mottled." Usually "the winged condition is viewed an adaptation to wind dispersal, and winglessness as an adaptation to dispersal by jays and nutcrackers" that is, birds. "Countering this idea", however, there is a "report that chipmunks were more efficient in gathering winged seeds, than experimentally de-winged seeds." And "this implies the winged seeds were more visible to the rodents, in effect acting as 'flags'. Since the chipmunks are agents of regeneration, this raises the possibility that the wing has evolved as more than just a device to facilitate wind dispersal." Then there are discussions on latitudinal effects on seed mass and altitudinal effects on seed soundness, and also agents of pine seed dispersal. As already mentioned birds, rodents. First of all there is the wind and when it comes to the wind the rate of fall and the height of release has some importance as well as wind speed and turbulence. And then there are the birds, especially the family Corvidae, like crows and jays. And then also some discussion about avian dispersal in different species of pines. And then seed dispersal by mammals such as North American red pine squirrel, the old world red squirrel, probably the squirrel we have here, the white-footed mouse or chipmunks. In conclusion Lanner writes that "the data reviewed here suggest that dispersal of winged pine seeds can be a multi-level process. Initial dispersal of seeds that are moved laterally by normal winds leads to the negative exponential distribution." That means that "the result is a high concentration of seeds on the ground close to their source, diminishing exponentially with distance." But, "these seeds can then be redistributed by rodents attracted to the concentration of nutritious food and if properly cached and left uneaten and unrecovered, can become germinants. This process results in augmentation and perpetuation of existing pine populations, and establishment of pines in nearby patches of proven environment. The unknown fraction of seeds carried long distances in turbulent atmospheric structures may have an important genetic impact." "Long distance dispersal is riskier than local dispersal, but can lead to new populations in new places, giving evolution a spatial as well as a temporal dimension. Among wingless-seeded pines, avian seed dispersal allows the construction of large seeds filled with large quantities of nutrient, surely an advantage to species growing in stressful habitats." So "dispersal is both local and long-distance and much of it is into habitats chosen for their openness. Seeds are placed in good germination sites, and over-caching, normal bird mortality, and forgetfulness guarantee some will always be available to sprout." So, to finish Lanner writes, I quote: "More of the 'Bird Pines' and their dispersers need to be studied, to deepen our understanding of this phenomenon. And finally, the positive role of rodents needs far more attention than it has received in the past. How important are rodents to pines? Are there unsuspected mutualisms awaiting discovery? Careful seed-by-seed investigation is needed in order to forge a stronger understanding of the regenerative process of which seed dispersal is but one essential step." Well, thinking of avian seed dispersal, when I came here to lean on this rock there were some crows or maybe they're called jays, 'naakka', some birds picking in the ground, because the park cleaners when they stir up the soil blowing the leaves, they also stir up some of the cones of course. But the cones on the ground here they are now closed because it's been so wet and so much rain. Well, this was our next to last conversation because there is only one session left in December. I hope you will have a reasonably pleasant November. I know it's getting darker and maybe you can rest a little bit although you continue your photosynthesis. And yeah, thank you for listening to me again and for helping me study you here next to you. So see you soon again. Take care.
Hello pines, good afternoon, or well, it’s just a little past twelve and it's raining. The snowfall this morning has turned into water, but not too bad, more like a drizzle. And now, today is the 14th of December, and I'm coming to you for the last time this year to talk about, study the pines, the Ecology and Biogeography of Pinus, the book that we've been reading. And I've chosen one of the last chapters, chapter number 20, Pines in cultivation: a global view by D.C. Le Maitre to introduce to you today. And I'm only going to read briefly a little bit from the beginning and then from the end of the text. And I hope the wind won't be too bad nor the traffic or the raindrops, but anyway. And I'm not going to, it’s quite a detailed description so I’m only going to introduce it very briefly. But in the introduction Le Maitre writes that “people and pines have had a long association. Recent findings in China suggest that hominids emigrated from Africa about 2 million years ago.” And “the first evidence of hominid habitation within the natural range of Pinus has been dated to about 1.4 million years ago on the eastern shore of the Mediterranean Sea (the Levant).” “The first encounters with pines would probably have been in North Africa or in the Middle East, the natural bridge between Africa and Eurasia.” “During this long period people have learned to obtain many products from pine trees, ranging from firewood to medicinal compounds, for use in daily activities ranging from utilitarian to religious ritual.” And in this chapter, he will review “the history of pines in cultivation” asking questions such as “When did people begin to feel the need to cultivate pines? What were pines and their products used for?” and “How did technological developments… alter patterns of use?” And of course, the “chapter must necessarily take a broad view” you know. “Much of the information is drawn from the temperate regions of Europe and the Mediterranean Basin because of their well-documented history and because reviews are available of the forest cultivation and uses.” And Le Maitre also mentions that “the word ‘cultivate’ is derived from the Latin word cultus, which means to till the ground and has strong associations with ‘improve’, and ‘develop’ and ‘pay attention to’ and ‘cherish’.” And he notes that he has “adopted this broad interpretation for cultivate in this chapter because of the varying role pines have played in human history and culture in the northern hemisphere.” And of course, “cultivation is also directly linked to [the] trade: once there is a surplus to sell and someone who needs it trade will begin. Most of the known history of people and pines has been a story of exploitation and trade. So much for the introduction. And then he speaks of the prehistory, from prehistory to classical Greece and some of the subtitles he then uses for other eras like from medieval times and so on. So, one aspect is solid wood for construction and domestic use, and another aspect has been resin and derived products like turpentine and stuff like that and then also seeds and other minor products. Of course, pine seeds are not used here, your seeds are very small, but in the Mediterranean area pine seeds are used very much. And Le Maitre actually quotes “an idiom used by inhabitants of Kunawar in India” where they have another type of pine so “one tree, one man's life in winter”. I guess that could mean both firewood and nourishment. And then there is of course the human impact on species distributions. And before that he mentions religious and ceremonial uses, so “burning of rosin, the hard fraction of the resin” is still common in religious practices, and also medicinal uses. And he also notes in passing that “humans have consistently over-exploited natural resources for a variety of reasons, including the assumption that they were inexhaustible”, already in prehistoric times. But then I will jump to the last section, which is … of course, there have been huge changes for instance in the 20th century but some of them are summarized in the very concluding notes, which he calls Synthesis. And there he writes as follows: “The ingenuity of people is clearly shown in the multiplicity of uses that have been found for pine trees from prehistory to today. Many of the earliest uses of pines”, for instance construction and medicinal extracts, “have remained important throughout this period. Others have disappeared as they have been replaced by other products, for example the replacement of pine by steel in shipbuilding. Wood-fibre and products derived from wood-fibres are a recent innovation. Numerous products, for example rayon, were developed in the last 100-200 years. Others, like paper, were invented in the more distant past but large-scale use of wood fiber in paper only began in the 20th century.” I continue quoting, so: “For almost all of the many millennia since people first encountered pines the central theme has been one of continual and intensive exploitation. Some would argue that this is simply a lack of forethought, especially among [so-called] ‘primitive’ societies. This is fallacious and simplistic. Research into the dynamics of hunter-gatherer and agro-pastoral societies, their knowledge of and relationships with natural resources, and their responses to resource availability, has shown that the ecological, social, ethical and economic factors that drive resource exploitation are far more complex than was thought, even a couple of decades ago.” “There certainly is little reason to assume that Neolithic societies would have had less knowledge of their resources, and their impacts on them, than similar societies do today. The basic driving factors in the unprecedented increase in forest cultivation during the last 300, and especially the last [200 or] 100, years have been: the increasing shortage of raw timber, the recognition that utilization rates were not sustainable and, at least in some countries, acknowledgement that the costs of restoring and establishing forests are far higher than the costs of sustainable harvesting of existing forests. But why are pines only now emerging from their Cinderella role and entering center stage?” Le Maitre asks. “The history of the cultivation of pines suggests at least three reasons why attitudes to pine cultivation have changed over the last 600 or so years.” And “the first step seems to have been the recognition that pines will grow relatively rapidly where many other trees, including more valuable ones, fail.” “The second step was the realization that only pines could meet the need for rapid growth and an acceptable quality of easily worked timber on marginal and agriculturally inferior land.” And then, “it's only in the 20th century that pines took the third step into the limelight. The key factor now for favouring pines is their long fibers”, typical of conifers and “this makes them ideal for the production of pulp for paper and paper products”, which has been “their primary use in the 20th century.” “For modern western culture, the utter dependence of people upon wood as a basic requirement for existence before the industrial age is hard to imagine. Just picture a world in which the social and economic functions of oil, steel, plastics and other synthetics and electricity were all supplied by one material resource - wood.” That's amazing actually and very difficult to understand, but that was the reality of the history of human societies until the last 200 years or so. “Conifers, [and] particularly pines, are still the major source of the world's wood pulp for paper. This need alone will ensure that pines will continue to play a significant role in the affairs of human societies in the future”, Le Maitre claims. And yes, I think it's fascinating this idea to think of how dependent we have been on wood, and of course, here in the north well pine wood but also spruces and all conifers. So, that's a great note to end our conversations with, to remind myself and you as well, about the very, very important role you have played in human history. So, thank you for that, as representative of pines, but also thank you for these moments together studying pines with pines, so to speak. So, thanks for your patience and well, good winter solstice, which is coming up and then a happy new year as well. Take care.