UNP1292SD_David_Mladenoff_WordPress

- Good evening everyone. I'm Jane Elder, and I'm the Executive Director for the Academy of Sciences, Arts and Letters. And I'd like to welcome you all to our academy talk, "The State of Wisconsin's Forests." At the Wisconsin Academy we're known for programs and publications that explore, explain, and sustain Wisconsin thought and culture. 

The work that we do and the events that we host, like the one you're attending tonight, are all designed to bring people together at the intersection of the sciences, arts and letters to inspire discovery, illuminate creative work, and foster civil dialogue on important issues. 

Though we can't do this work alone, I'd like to thank those who make this evening possible: the Wisconsin Academy members and donors who support our work, the Great Performance Fund at the Madison Community Foundation and its generous donors who make our programming at Overture Center possible, and Isthmus Publishing. So tonight I'm very happy to present Dr. David Mladenoff, professor of forest and landscape ecology at UW-Madison. 

For 30 years, he has examined how both natural and historical disturbances have affected our forests. And how we can ensure the sustainability of our forests into the future. And now, without further ado, please welcome David Mladenoff. 
(audience applauding)

- Well, thanks for coming, everybody. I hope you find it enjoyable and a little bit informative evening, anyway.

One disclaimer I guess I want to make: I'm a university faculty member. I can present facts and I can also state my interpretation and some of my opinions. But as wise as they may be, they're really only mine, and they don't represent either my department or the university as a whole. Somehow I give myself license.

Don't worry, Mark.

Also, several people have asked me, if this was going to be a Wisconsin forestry talk. And, well, the simple answer is "no." It's not a forestry talk. It's a forest talk. So it's about the forest ecosystems. Certainly forestry and forest management, it's a part of that. And I'll talk about that a little bit. But it's a forest talk. And, I guess it will be a kind of, a little idiosyncratic, maybe. It will be the things that amaze me, the things that I would like to convey and tell to you.

And so, yeah. That's what it will be.

So we're going to talk about quite a bit of history, actually. Because I think it's important. I think it really matters. And then we're going to talk also about the present and about the past. But two really important things are, I think, the idea that change happens all the time. It's always happening in ecological systems. I know that it seems obvious. I think we don't always think about it. 

When we go out to a favorite forest, for example, I think we expect it to be, you know, kind of the same. I mean, that's what we like about it. And so we don't really expect change. And the other thing is that forests can change, sometimes, in ways that are unexpected. For example, this pine forest up here on the left, it had some old trees, that's partially old-growth forest. Let's assume it changed into this young aspen forest, over here on the right. 

So well, I mean historically then we might say we have a pretty good idea that, well, that pine forest had to be cut; it had to have been logged. And then it must have really burned, very, very, very severely. Enough so that it killed all the young seedlings and pine saplings that were in the understory. And made a great seed bed for young aspen trees. Well, that's one probable outcome. But there can be other outcomes, as well. And so, things are not always predictable. 

Although there may be you know a higher likelihood of one thing happening, other than another. But, the important thing is, the history, what something was beforehand, is really important. And it really matters on what we end up with, either in the present or in the future. So, how far back to go with this history, thing? Well, a little bit, at least, pretty far back. 

And that is to mention that the glaciers covered, the last glaciation that covered most of the state, probably over half of the state, I think you can see here. Some of the state was glaciated earlier than this, right here. And some areas were not. And there was an awful lot of very large rivers. Melt water flowing off the glaciers. And those had a really big effect as well. And what the glacier and all this water flowing did. It left on the state what we call soil substrates. 

And what do we mean by that? Well...

Depending upon what happened, and there's a kind of a map of general soils in the state. And this is important, so just pay attention.

So, in these really yellow areas here, those are very, very sandy areas. And so what that means is when the glacier was receding further north, all this melt water coming off the glaciers deposited. Lots of coarse sand and gravel, so it's really sandy soil. Poor soil is what we would call it. And it's, down here, where Glacier Lake, Wisconsin was. And it's generally in these 3 locations. And then this red, we've got very very heavy red clay soils. 

That's from when the Great Lakes were higher, in the past. And then we have, what we call loamy soil. It's kind of just-right soil. It's what we call, maybe, good garden soil. But, still, there's also a difference between loamy soils in the south and in the north. The ones down here are a lot better. So, if you can remember at least part of those general patterns, I'll repeat them. But we'll be coming back to that.

So, after the glacier, forest trees had to reinvade. I mean, during glaciation, they were out of here. So, take for example, this map. It's a reconstruction of how beech reinvaded the state. And this was solved by a paleoecologist that study fossil pollen deposited in lake sediments. And you can see in that diagram that from 10,000 years ago where it was, had its refuge down, really near Florida or Georgia. And then it took really about 7,000 years to get close to the Midwest. 

And then it really took even a couple thousand years more to move just a little bit further to its, the furthest west that it went in eastern Wisconsin. So it took a long time. You have to think that, you know. The forests didn't move back up here as whole communities, as we think of them now. You know, the pine and oak and paper birch forest didn't all come up together, for example. They came one at a time. You know, they all have, they have their own environmental preferences. 

They have different life cycles. You know, they have different kinds of seeds. They can move, they will move at different rates. And they also found their refuge in different places in the eastern US. And so it had different distances to cover. So this whole thing took from about 10,000 years ago, up until about 2,000 years ago, when finally beech, and then actually hemlock, also made it to the northern part of the state. It was really about the last one.

There was a lot of really big change in those first 7-8,000 years. The climate was oscillating. Species were still coming back. Then things kind of settled down. At least in the relative sense.

Now because, in part, we have one hour instead of three, we're going to make a big leap from a couple of thousand years ago, up to this picture here. And so this is a picture that we reconstructed from a data source I'll tell you about, of what we think the vegetation, the soils, the forests of the state looked like in the 1800s. And this picture we get from reconstructing and mapping information from the original, the federal government land surveyors, that surveyed the whole state. 

And meticulously recorded an awful lot of information about the trees they saw, the size of those trees, a lot of information. And so, from 2,000 years ago to this point, certainly things changed. But, you know, the general pattern was not too far off. I mean, to some degree, the south here, these are all oaks, for example, these brown colors. And while the line between the oaks and the northern forest, it sort of oscillated, a little bit, you know, with climate changes. 

And on the sands here, the oranges are pine, for example. And along here. And well, you know, there was thing going on between oaks and pines depending upon really what the climate was doing. But the basic pattern was pretty subtle. And the other main pattern I want you to notice is the pines, first of all on the sand. 

But then this arc right here, the dark green and then the slightly lighter green, this was all hemlock, another conifer, and what we call northern hardwoods: sugar maple, yellow birch, basswood in some locations, things like that. So the pines and the oaks were on the sands. And in the north, the hemlock and the hardwoods that like a better soil, you remember those? Those northern loamy soils. That's where they were. But in the south it was unusual. 

As I said, this is basically all oaks, except for right here, and right here. And so that tells us, along with this other map from the same data source, something pretty important. So this is a reconstruction of what the forest density was at that time. 

So, how closely together were the trees growing? Were they growing really, with a really thick, close forest? Or was it open, woodland, very open savanna, maybe just scattered trees? And so, not only the, what we call the composition, what species were present, is important, but the density is really important too. It tells us a whole lot of other information. And what this does tell us is that all of southern Wisconsin burned, really a lot. Because that was the only was it was kept so open. 

And oaks would be the only trees that could survive under that kind of condition. This was both natural fire and lots of fire, probably, by Native American causes as well. In the north, you'd have a really hard time getting these areas, these loamy areas, moist soils to burn. But these areas with pine and oak, in here, these did burn. So this is the first thing that will be on the test. 
(audience laughing)

Well, now we'll take a quick, quick trip through some change.

Some change from the 1800s. Set the stage a little bit more. Well during the early to mid-1800s, Euro-American settlers quickly settled southern Wisconsin. And it was converted to farms pretty quickly. The land was great, the prairie soils were great for farms, the climate was great. This happened, really, 1830s, '40s, '50s, in the southern part of the state. And this preceded from the very south, as Native Americans were forced off their land, progressively, but with trees.

Now, another interesting thing that happened, when all this land was being settled and the prairies and savannas were being converted to farms, is that it resulted in more forest. I think some of you know why that is, but it sounds kind of funny, I know. It resulted in more forests. Because, some of these areas, small ones, of what was oak savanna, scattered open oak trees, didn't get plowed. So, they grew up into forests. 

Sprouts came up, more acorns took root, and that's really the legacy that you see in this area here, of part of southern Wisconsin, a little east, a little west of Madison. Those are the forest woodlots that we have now in the southern part of the state. And those oak forests, becoming in a lot of cases maple forests, but mostly oak forests. Those are our legacy of that original settlement pattern. 

Some of you who've read John Muir will recall that he actually described that phenomenon in their family farm, north of Madison. And these oak forests, although they occur in relatively smaller pieces than forests of the north. This is a really important component in the fact of the total forests in the state. Those oak woods are important. I have to say that because I believe it, but I'm going to talk mostly about the north. 

So, as the survey proceeded north, again, with Indian removal treaties, obviously in the north timber and logging was really the dominant initial effect on the land. And I know many of you know the basic story, because pine logs float so well, the early logging in the 1840s, '50s, before railroads in the north, followed the large rivers and tributaries. And it just so happen that that's where a lot of the good pine was too, here. Up the Wisconsin and the Black and the St. Croix. 

Up the river valleys is where a lot of the pine was taken out. And I think a lot of you also know, too, that there was, an absolutely astronomical amount of timber that was cut. The whole north was basically what we would call old growth and mature forest, with a lesser component of young forest. Maybe a third, or so, in very rough terms. And the effect on the forest was, of course, unprecedented, really. I want to point out one particular thing. 

And this is not a great photograph, I'm sorry, not a great photograph, I realize, but it illustrates something important. And that is that not only was it the terrestrial habitats, the forests themselves that were treated in such a destructive way, but the aquatic habitat as well, had very bad treatment. And especially the streams, which you can see here. Basically, the habitat structure of the streams, the banks, the streams themselves were filled with silt.

All the habitats were really just about destroyed, I mean, both aquatic and terrestrial. And lakes too had a rough treatment. Maybe not as bad as streams. So it's important to keep that in mind. You can't really do such big things on the land without also affecting aquatic systems.

So again, just to point out and remind you for that test question, where the hemlock is and what we call the northern hardwoods, the maple, birch, in this area here, those areas were logged pretty much after the pines, in part because they really weren't on rivers, as much. They weren't on the big rivers for moving logs. And also, they didn't, the hemlock was lower value, and it wasn't cut so quickly. And the hardwoods didn't really float very well. 

So it took a little while for those areas to be logged. And here you can see an example, in fact. This is from '80s, the 1880s, to the early 1900s, even into the 1940s in some locations, not until WWII, that all of the hardwood forests get logged. And in fact this is a train in northern Wisconsin being loaded with yellow birch logs.

So, there was not logging only. There was what we call slash fires. And some of you know about this as well. So it wasn't just the logging of the fire, but the fact that conditions following logging with an awful lot of what we call slash. That is, these are lots of big old trees, right? So there were tree tops, big branches, even some wasted trees left behind on the ground. And this was the situation over miles of territory. 

And when these dried, of course, it was an incredible conditions for fire. They were highly flammable, and there really was no fire suppression. Fire suppression didn't become effective until well into the 1900s. Railroads and general human activities were a common source of ignition in these slash. And, the thing is, that these fires were extensive and severe and repeated. Though the heat of these fires was really unprecedented. 

They were not a kind of fire that had ever really happened in these systems before. Because they just weren't such, such a situation created for that to occur.

The fires did a couple of important things. They killed what we call the advanced reproduction: so the seedling and saplings, if it was pine forest, for example, that are underneath. And it would have grown up and resulted in a new forest that would have been at least partly pine, for example. They were also so hot that they burned off all the organic matter on the forest floor. And it even, really, burned the topsoil as well. 

So, again, this was an unprecedented condition that had never really occurred before. It meant, well, you can see the two photographs here. It meant that it really wasn't suitable for very many things. And if anything tried to grow, it often would burn again. But it did create a certain set of conditions: this bare mineral soil over very large areas, very high light conditions. Obviously it was very open. And this really favored the seeds of aspen, and to some degree, paper birch. 

Aspen has seeds that, they're like dandelion fluff. If you've ever seen them when they're really shedding, they're all over and they travel really long distances. And so this was the one thing that was really able to fill this niche. The other thing that happened was near the end of this period, by the 1930s, fire suppression was becoming effective. So finally all the burning stopped.

Another way to kind of look at this picture is through time, is compressed in this graph here. And this really, this really tells the whole story of our forests.

Obviously from the mid-1800s that great big mass of pine, lumber, that was removed. Kind of a little bit later and not quite so massive, is the hemlock in the north. And here's the oak and other hardwoods, starting in the south. As the pine is dropping off, and the hemlock is being harvested. Also, those other hardwoods: the birch and the sugar maple, for example, until a big crash in the depression. And then, a little bit of a rally, again, because of World War II. 

And they came and got really what was left of that hemlock and the hardwoods, as well. And that was pretty much the story of what happened to our original forest. I mean, this was just blazingly fast.

Well, by this time, say the '20s and the '30s, many farms in the north that had been established had failed due to really poor, rocky soil, too sandy. The climate was really too cold. There was poor transportation. The whole promotion of the north for farms. And, in fact, there was a big political fight in the state in the early 1900s, between whether it would be, was it going to be farms or was it going to be forest. It was just really a bloody fight. And the farm people won out for awhile. 

And it just turned out to not be a very practical idea. So finally at this point, the state really began to grapple with, with just what had happened over these decades, and you know, what we had left, and just what were we going to do with it.

Well, one really important effort in resource inventory, which, that may not sound too interesting, but this really is. In the 1930s, the state funded a very large effort to essentially, intensively map the whole state. And I mean intensively. I mean, go out into the field and walk every quarter-mile with crews. And record everything that was there. This was called the Bordner Land Economic Inventory. 

It was really to see, "Well, what is really out there?" You know, what's really left? What can we do with this? This was when, after the '20s when court cases and laws had changed so that finally, it was just really clear that states, in fact, have authority for land-use planning, as it related to private land. So this was really important. Because before the '20s, that really wasn't the case. So now we have information and they're going to see just what's out there and what can be done. 

Well, we use this information to look at change.

What's really key, then, about this 1930s period? It's key actually for the whole state, but for the forests for sure. The big logging was over. It was the peak of cleared land in the north. It was a peak of farm abandonment, both, this is both economic and environmental situation. And fire suppression became important. So forests finally were able to regrow. And the land was able to start healing. This is a really important period in time. This also, definitely, on the exam.

So, we did some mapping. From the early maps that we did from the land survey dated in the 1800s. And also, then, from the Bordner reports in the 1930s. And then I'll show you a little bit about the, close to the present, in the 2000s. So, we're going to be from

the original conditions in 1800, to the most extreme change in the 1930s, and then start to see, well then what happened after that? We'll look at a few key species that we've map, based on how important they were on the landscape. So for white pine, here's the mid-1800s. And the darker the color, means that more of those locations was dominated by white pine. It doesn't mean only white pine. Just that that was the most important thing in those areas. Here's what it looked like in the 1930s. 

I think this is really an incredible view of what you see in your old photographs and the graph that we just looked at before. But if you try to think of the big picture of what was happening to the state, it's pretty amazing how that was accomplished in a short period of time and with the available technology.

By the 2000s there actually is some pine regeneration happening. But, probably still at this time, maybe white pine is less than 5% of what it was in the 1800s. Quite a dramatic change.

Let's look at another important species: that eastern hemlock, another conifer. Another very large-statured conifer. The pines and the hemlock are really our biggest trees, longest lives. And here you can see where hemlock is most important. And it was even more dominant where it occurred. And I'll tell you more about that later. But notice, as we've seen from those other maps, is that where the hemlock is important, is where the pines were not important. 

Here's where the pines were most important.

So they only partly get along together. In the 1930s, another extremely dramatic change. Some left. And for hemlock, the pattern is a little different than pine. Because instead of some recovery, we see, in fact, there's even still less hemlock. So, even, you know, less conifer, fewer conifer trees on the landscape. This is because, remember those last trees were cut in the '40s, and didn't show up in the 1930's map. 

And because where there was some regeneration of hemlock, often high deer populations eliminated it. Because hemlock is very sensitive to deer browsing. And that's really been, with ups and downs, really a continuing issue over time.

Well, there really was a winner out there right? With all this, we talked about it a little bit. We'll fess up and show you what was happening. Here you can see aspen from the mid-1800s. This is, you know, a very short-lived, pioneer species. It grows really quickly but it really doesn't live more than about 60 years in Wisconsin. And yet, in the 1930s, after all those fires, it really just exploded on the landscape. 

And we'll talk later about, this had all kinds of effects, both economic and ecological.

By the 2000s, again, aspen doesn't live too long. If it's cut, if you clear-cut aspen, it'll sprout back. It grows, it'll pop up again, like corn. It's one of the few tree species that will actually do that. And even with a lot of cutting of aspen in recent decades, some of it is not on good sites, and for other reasons, there's been somewhat of a decline of aspen since about the 1950s. 

So those again are the big species composition changes, right? But there's another kind of change that's really important. And that's something you see reflected here. And here we group data about, well, what was the size of the trees on the landscape? So here, three classes of trees: bigger than 20 inches in diameter, so more than a foot and a half, about one of my shoes.

Pretty big trees: 10 to 20 inches in diameter. And small trees. So, in the 1850s, really, a lot of big trees. And well that's born out by the kind of timber that was removed, right? The volume and the size of the trees that you see in all the old photographs. That's what most of the landscape was. Of course, there are small trees. Because trees are always dying, there are fires and windstorms that happen. And there are small trees as well as big trees. 

Well, by the 1930s, again, the dramatic change we saw in the change of the species, we see it happening in here in what we call structure, in the size of the trees that are on the landscape. Now, really, very much most of the trees are all in this very young category we can see here. Very little happening out here. By the 2000s, kind of interesting, really. It's changed somewhat, but really not that much. We really still have a pretty young forest. 

Even there's been almost a century of recovery, since the '30s, obviously some of the forest we use and it's harvested and remains young that way. And so it's interesting. We're still in a recovering state with the forest. There are more trees, certainly, in a somewhat mid-range, large size, that you see here. So these two important things are jointly of great importance: both composition, the species, what they were, and the structure. 

And we'll talk a little bit about what some of the ecological consequences of all that was.

So, still talking, you know pretty much about the '30s here or so. Where are the major changes then, that we see have happened? Well, this really broad dominance of what were old conifer trees on the landscape is gone. And I think what's important is that it wasn't just pine, which covered a lot of the landscape, but all this old hemlock as well. That covered at least, in fact, a bigger part of the landscape. And of course it was mostly old and old forest. And that's lost. 

And that was both conifer and hardwoods as well. So, I think there's something that for me this was striking, quite some time ago, is that this really, I think all those are concept of what was lost historically. So it wasn't just that there was, you know, a lot of pine in some places. And it wasn't that there was pine all over the north, either. And I think those are two, maybe different ideas that a lot of people have. But there was a lot of pine in some places. 

And there was a lot of hemlock in the other places. And together, the northern forest was really a conifer, an old conifer dominated ecosystem. Other conifers were also much more important than today. Things like white cedar, tamarack. Tamarack in the 1800s was actually the 5th most abundant tree species in the survey. And I think we just really, we wouldn't really expect that to be the case.

So evergreen trees, large trees, also when there were deciduous trees, hardwoods, they were large, too. So very distinctive habitat. And different in many ecosystem processes than young forests, than all-deciduous forests. And important habitat differences for soil organisms, for nutrient cycling. The forms in which, you know, nitrogen for example, is made available to plants, is very, very different under conifers under evergreens than it is under deciduous species. 

It profoundly influences how productive, how much it can grow, and what kind of things can grow. So, really big differences in a lot of ways. And a very distinctive habitat, actually for a lot of mammals, birds, and in particular, forest plants really like sort of one place or the other, pretty much.

In the interest of time, I've picked a few examples of some forest birds that I'm going to show you. And this is some work done with some colleagues of mine. So we have three forest birds: Pine Warbler, Blackburnian and Black-throated Green. Some of you I know are familiar with those. 

And what my colleagues did, they took our vegetation data and they created maps of, well, of the suitability of habitat, in the first case, for the Blackburnian on the landscape, based on what kind of forest there is. And here you see on the map on the left, is the current suitable habitat is based on the color. The darker the color, the more suitable, the better it is. And then of course the extent is obvious in the map. 

And then you see the suitable habitat for a Blackburnian in the 1800s forest, on the right. So I think I don't have to tell you that currently it's really only a fraction, a small fraction of what it was in the 1800s. And if we look at Pine Warbler, it's not quite as extreme, because it is really is more key towards pine.

But it's still several times different. And then the Black-throated Green Warbler, again, it's a very, very extreme example. So these differences are large. 

And we have to ask, if these in fact also reflect, then this is the breeding territory, right? I think we have to wonder, does that actually mean that these are telling us about parallel declines in populations as well? I mean I think that would be a pretty remarkably different baseline in bird populations than what we typically use from the 1960s.

So, I want to talk about another aspect of change. And this, again, is due to the fact that both the species changes and the size of the trees. And that is forest carbon that's stored in the forest. And this was something that no one was probably thinking about in the 1800s. But in the 1800s, because we had all this old forest with big trees and big logs and again, lots of conifers. And they tend to last for quite a long time, even after they die. 

There was an awful lot of carbon stored in these forests in northern Wisconsin. And excuse me, that I, I missed changing this one slide, into English units. In megagrams per hectare, instead of tons per acre. I think a hundred megagrams per hectare is maybe, like, 45 tons per acre. So I don't know if that's actually any more help or not. 

(laughs)

 Maybe not. This kind of stuff we think about, you know. So this big change, what did it look like in the 1930s? Well, yeah, you know, all that carbon is gone. And, you know where it's gone? I mean, there's some in buildings, there are 2x4s for sure. Remember all this destructive burning that happened after the logging? All the waste that was left behind. So all of that carbon was released into the air, into the atmosphere. 

And really, as part of the problem, now, that we think about, in this century, with climate warming, about which we will return.

And if we look at the 2000s, and we saw in some other diagrams, you know, there's been some recovery. But really, not so much. We have somewhat older forests, for sure. But, you know, this is the hand we were dealt in the 1930s. And even though we do continue to use the forest, nevertheless, even if we weren't using it, it's going to take a long time to recover. The other winners you can see here in this old picture, I think from the 50's, a report in the 1950's. 

I should have the citation on there. But there were animal and bird winners, along with the aspen as well. And the obvious ones, of course, are deer and grouse. Aspen is obviously very important, especially with deer hunters. And we have to mention that there are other species that live in aspen forests. And there are, for example, other forest bird species that live in aspen forests. And there's some concern, we saw, in the previous maps, that well aspen is declining since the 30's. 

But, it's still really one of the dominant forest types on the landscape. And so I think, you know, the kinds of other species or forest birds that are in aspen forests, it may be declining in the near term, but there's just so much more, still, of that habitat on the landscape, than there was in the 1800s. It just hasn't had that kind of collapse that our other conifer forests and hardwood forests have had.

Well we're not done yet. But, we need to check in a little bit now at this next juncture and think about where we are on this story. Because with what we've gone through, it's important not to minimize, you know, the successes that have occurred with the forests. Because it is regrown in a very large extent. And that really is a success story. I mean, compared to the turn of the century a hundred years ago, it's pretty dramatic. It's largely forested. 

And these forests are still growing, still recovering. This isn't something that happens in just a few decades. They're still not as diverse as they were, in the past. They provide a lot of economic value. But that's different than it was in the past as well. I mean, certainly you know recreation is really the big use of forests now.

We want to look a little bit closer now at those forest changes. And here now, it's not from the 1800s, but it's from the 1930s into the 2000s. We've aggregated trees into a few general types. So here's those aspens forests from the '30s to the 2000s. Here are those northern hardwoods: the sugar maple, the yellow birch, things like that. Mostly sugar maple now, that's been a big change. And, here are the oak forests, also increasing. The differences here are really not so much. 

I mean, it sort of depends on how you group the species.

The sampling error and this little blip here, actually is maybe a sampling artifact. But the main point is though, that these two have increased, this one has decreased, and now they're pretty similar in the amount of area that they dominate on the landscape. And so, I don't really think that's really a bad thing. I don't think that that's a big negative change for example in aspen. I think it's good to have a little more of these others on the landscape. 

And there's also species that can get older than aspen and bring some of that big structure back. Big trees are also ultimately more valuable, right? You can make lumber out of big trees. You go and buy a maple board, you know what that's like. It's much different than what goes into paper pulp, for example. But now look at our conifers. By now you know, I think, that I like conifers. We do have a gradual increase in white pine, you can see here. Pretty interesting. It's been pretty steady. 

It's got a long ways to go. But really, the other conifer forests, really, not much at all. I mean, there's some red pine but lots of it is plantation. There is some regeneration, but it's, again, in the relative sense, compared to what the situation was, it's not that much. This is, I think, a striking map. It's not about forests per se, it's about forest land ownership. Different classes. And these are private land classes. 

And there's lots of privately owned forest land here that is just in brown and not in an actively managed category. But it's pretty interesting, because each of these agencies, and the different private owners, they all manage their lands in a little different way. Agencies do it differently than private individuals, than corporations. And so this means that it is important to have different strategies for different ownerships. And in part, what one does can sort of compensate one for the other. 

You can't draw everything and do everything the same. And that's probably a good thing.

Forests are generally well-managed in this state. But I would say not by all. The state DNR and the US Forest Service, they have a really tough job. They have a tough job and they do a good job of balancing incredibly competitive needs and desires on the part of people.

Counties and private industry often cut their forests more aggressively and have narrower goals, more production oriented. And of course all the agencies, and in fact all the owners, are constrained by what lands they inherited, what was there. That's, again that historical legacy thing, is a really big factor, and a great limitation.

Some challenges now from here. What might they be?

Well, there's a whole suite of them. Certainly, the really big one, and just the backdrop for everything that happens from here on out is human-driven climate change. This is really a critical issue, and it just forms the template upon which everything else is going to happen from here on out. This is also the context in which anything that we can do to respond has to be taken into account. 

In other words, we can't think about how we're going to manage the forests without taking climate change into account.

So current models suggest that there's likely to be a four to nine degree Fahrenheit warming for Wisconsin in about a hundred years. An average, let's say, of about six degrees Fahrenheit. So let's think about what that means exactly. Kind of while no one was noticing, average temperatures have warmed in the state already in the last 100 years by 1.4 degrees. Not a trivial amount, really, you'll see why. 

And it's interesting, so far a lot of this change has been mostly that nighttime temperatures in the winter are not so low anymore. This might seem like a good deal if you're from northern Wisconsin.

But this has consequences as well for all aspects of forest health and sustainability. And just for one example, economically, it's already resulting in the situation that there's several three to four weeks per year, where the ground in the winter has not frozen. Even under some snow cover. There's less snow cover and it's not as cold. So this means that conditions just aren't suitable for logging that minimizes damage to the soil. And then on some wet sites it can't happen at all. 

People are noticing this that live in the north. What else does this mean, this temperature difference? Well, the current annual temperature for Madison averages over the year is 46 degrees. For Park Falls it's 40 degrees. Six degrees, right? That's the difference that warming is supposed to happen. We really experience the temperature in these two places in a very different way, I think. 

When you're in Madison, at least for me, I want to be up there in the summer, because there's a big difference in the temperature. The forests are different. The environment is different in a lot of ways. This is six degrees. If every place goes up in the state another six degrees, then things adapt. When using predictions of climate change in several labs, including my own, we've been using simulation models to see how the forests might change. 

The ones that will be most affected will be northern species like spruce, balsam fir, aspen, paper birch. They're likely to decline. Some other species like pines and even sugar maple, might be vulnerable. So if we look at a couple of examples. For example, quaking aspen. Here's the situation today. Here's mild warming. And here's extreme warming. And you see a big drop in the area suitable for aspen. 

And now even this more extreme warming scenario, the A1FI, it may not, it actually may be more than that, that will ultimately occurs. If you look at sugar maple and other important species, a similar kind of pattern. Quite a bit of decline. And we might think that, "Well, if those northern species are going to decline, "things are going to get warmer, "maybe our southern oaks, "well maybe they can just move up, "and do well in northern Wisconsin.

 And let's take a look at, for example, white oak, and look at that idea. And you see white oak in southern Wisconsin. And, although there's a quite an increase in northern Wisconsin in a 100 years, it's nothing like what is in southern Wisconsin now. But this is what might be suitable for oak. This isn't how much oak actually gets there. And that's really key. Because you have to think about, it takes a really long time for these species to move. 

And the whole landscape now is much more fragmented. You know, there's this big band of agriculture across the north. And it just isn't so easy for southern oaks to move from down here into the north. What we might have is a situation of empty niches in the north. And then an actual decline in the amount of forest, meaning in terms of the size of the trees and the number of the trees, for example. This could mean important changes ecologically as well as economically.

There's one more set of threats I need to talk about, I'm afraid. And these are things like exotic invaders of plants, diseases. And a lot of this is due to global trade and unregulated movement of plants and soils and things like that. Overbrowsing by deer could actually be a problem because it can inhibit regeneration and actually establishment in movement of southern species. And even something like intensive harvesting of biomass may not be a positive thing for our forests. 

Because you can't remove everything from the forest. The trees and the branches and top and everything, and continue to have productive soils into the future.

So, what now? Well, I apologize if I presented a lot of problems and a lot of sort of hard history.

You know, Aldo Leopold said one of the penalties of an ecological education is that one lives alone in a world of wounds. You see things out there besides just the green. My wife is always telling me not to point out things that I see out there in the green. She says, "How did you..."

Well, what about all these problems and scenarios? Not all of these things will happen. And some of them will be compensating factors. But a lot of these things will happen. This is something I think that we will have to confront and something that we can plan about. There are things that we can do. We can manage forests in a way that is, involves adaptation. In other words, to the extent of climate change, some of it is going to happen. 

We manage in a little bit different way about planning what we're going to do on the forests. And thinking about potential outcomes of species in the context of different climate scenarios. This is something that's been done. The forest service, DNR, the Nature Conservancy. It's staring already. And of course, there's things in the broader society that we can do to mitigate future climate change. And that's about reducing fossil fuel development, fossil fuel use. 

So it's about scientific probabilities but all of these bad things are probably not going to happen. But, and nevertheless, some things will happen. There's going to be a lot of change. But there are things that we can do. And it's really important, I think, that we have the kind of research that we need to figure out an even better way of what those things are. So we really need to support, I would say, more scientific research in this state and not less. 

And in that way, we can still have forests. We will have forests in a hundred years. Actually, forests do fine without people. We know that from in the past, you know? They don't really need us. But there are things that we can do. And we will have forests if we do some of those things and take some action. For both the people and all the other species that will need those forests in the future. Thank you. 

(audience applauding)