Impacts of Deer Browse on Hardwood Species in Michigan Farm Woodlots and Forests

March 9, 2022

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Video Transcript

 - [Lyndon] There he is. - [Michael] Hi. - [Lyndon] Dr. Walters is a famous in my household. I have two young foresters that went to MSU. Neither are their primary careers, but it impressed both of them with a discussion about how the deer population is affecting our hardwood species. So to lead right into it, tell us about this. - Thanks, and I wanna thank you, Lyndon, for the invitation for today and sending your sons to my class and very much enjoyed them both. I teach silviculture at Michigan State University. I have an extension appointment. I do extension work, but almost all of that is with the Department of Natural Resources on management problems that they have, and then doing research and then bringing the results of that research to them so that they can improve their management. So this audience and the extension I do is oftentimes a little bit different than this. I am hoping that I have this talk cued on to what you guys would, is useful to your audience. And if you need some clarification, just please ask me questions via email or at the end of this. I'm gonna focus on Northern hardwood systems for this talk. That's where I do virtually all of my work, but it has some clear parallels to central hardwood systems that a lot of the folks on this meeting are probably more familiar with, try to illustrate some of those similarities as I get into this, talk about the basics of the forests, their management, some challenges with their management, and then some things that individual landowners can do to overcome some of those challenges, centered upon deer but other factors as well. It shows you Northern hardwoods forest in Northern Michigan. Can I do it here; there we go. Okay, just a brief description of the forest I do most of my work in. There's this area called, if you look up in the upper left of this slide called the tension zone that goes across the middle of the mitt of Michigan. North of that tension zone, cooler summers, cold winters, sandier soils, more acidic soils and different forest composition than what you see south of that line. South of that line, you have broadleaved forests and the Northernmost distribution of hickories, walnuts, tulip poplars and lots of trees that are distributed further south. North of that zone, you get mixed broadleaved-conifer forest are more common. You get the southernmost distribution of many boreal species such as red and jack pines, spruces, balsam fir and the like. I'm gonna focus most of my talk on that region that's north of the tension zone. Just some basic differences though, I'm gonna talk about mesic, rich, Northern hardwood forest, beech, maple forest much like you have further south, but you tend to have mixtures of things like basswood, yellow birch and hemlock within those forests that you don't see further south. Some of the same challenges in terms of management. I have several consulting foresters that I keep in contact with that I know from outside of work, but also that have been my students. And they say in Southern Michigan, the central hardwood forests of Southern Michigan are usually wood lots rather than expansive contiguous forests. Main challenge is markets for poorer, less valuable products, pulp chips and things like that that prevent silviculture from getting done. But that heavy deer browsing is a major issue too, but also invasives and other things as well, much of the same factors that affect Northern hardwood forests as well, heavy deer browse being a large, a big issue, limited markets not being as big of an issue in some areas, but being an issue in some, and invasives being less of an issue in the Northern hardwood forest as well. So in the Northern hardwood forest, the north, basically land use and soils have shaped current composition. Here south of that tension zone in the central hardwood forest, again, this is primarily agriculture with wood lots. In the north it's nearly all forest. The great cut over that began with white pine in the 1860s and 1870s, and got into the Northern hardwoods as late as the 1920s was completed by about the 1920s with the cutting of those vast Northern hardwood forests. And much of this area has rebounded from these areas being cut over at that time. The soils are shaped by glaciers, and you have these upland finer-textured soils that are on glacial moraines where you have more mesic forest, and those are sugar maple, mesic Northern hardwood forest dominated by sugar maple. And then on the other end of the spectrum, you have these sandy outwash plains that are dominated by conifers, jack pine being the extreme. And kind of in the middle of that, you've got these oak-red maple forests much like you have the oak-hickory forests further south that are being invaded by red maple. We have very similar forest in Northern Michigan to those as well. This Northern hardwood forest, if you look at this map, all these areas in light green on this map really coincide with areas that are dominated by Northern hardwood forests. Again, these are associated with these large morainal systems that go across Northern Michigan here. These drumlin fields and moraines in Northern Michigan are also found really close to the Great Lakes, even areas of sandy soils. Over 7 million acres in Michigan is Northern hardwood forest. Sugar maple's a dominant player. In slightly poorer soils, red maple can be a dominant species, and then, like I mentioned mixed with basswood, beech, yellow birch and hemlock. If these forests are simply cut rather than partial harvesting as you see in a lot of your woodlots down south, and clearcut, oftentimes they come back to early successional species and primarily aspen, paper birch and things like that. Now, Northern hardwood forests in the system are a mix of public industry and private ownership. It's much more in public and in industry ownership than your central hardwood forest that you see in Southern Michigan, Northern Indiana, Northern Ohio. Timber management in the private forest of Southern Michigan is certainly much more geared towards wildlife, but of course there being many valuable tree species in Southern Michigan forests that are both the targets of management and exploitation as was well covered in the talk before with regard to unscrupulous harvesters. The timber management in the north tends to be aimed in the Northern hardwood forest for high value sugar maple logs and pulp. There's markets for both. And single tree selection and group selection dominate their management. And that is much the same as you see in woodlots in the south. And that's where you simply have a sort of a partial harvest, relatively low intensity harvest in which individual dispersed trees are marked through a stand. Sometimes trees are marked in small groups. And the objective, if you do that silviculture right is to maintain ad infinitum, forever, basically a system in which you can go back into that stand every 15 years and harvest valuable stems of valuable tree species, like I said, from now until the end of time if it works. It's not exploitation. It's not supposed to be, and it's not geared towards simply removal of the most valuable species, but to remove trees that are ready for harvest, but then also thin in the smaller classes such that you're promoting younger, smaller trees into larger size classes to harvest in the future. Okay, how that worked, that single tree group selection system has dominated about the last 60 years or so. It's when it was implemented in these forests. And it entails that forest are harvested every 10 to 20 years, and like I said, dispersed trees removed from the forest. You can hopefully see that over here on the right, but this is a 30 acre square. Inside of that area, it has recently been subject to single tree selection harvesting, plus the addition of some small gaps here and there. And that matrix outside that square hasn't been harvested, partially harvested lately. And it looks considerably different. And yet you still have near complete canopy cover in that forest. Okay, this backdrop's important, 'cause it kind of sets things up for what we're seeing are the results of deer browsing in these forests. What do we expect single tree selection stands to look like after they've been managed by single tree selection silviculture for decades and decades? What you expect, and this shows a diagram, pardon, it's a little fuzzy down here, what you expect is that you'll have pockets of dense, small trees. You'll have equal size pockets in the stand. So these might represent areas. We see the little trees down here where you were just in that stand five years ago. Trees responded to it. Little saplings and things like that came into that space that you opened by the removal of a tree. All these little saplings grow up and they're happy as can be. Then you have some areas that you might have been into 30 years ago in the partial harvest that occurred before that. They're larger saplings. There's fewer of them 'cause you can't fit as many larger trees in the same amount of area that's been devoted to harvesting, et cetera. Now this might be an area you were into 60 years ago and it has fewer larger trees in it. And finally you have maybe some trees that are 100 years old in here. And how that looks, what that looks like basically is if you made a plot of diameter in the stand of the trees, in number of trees per acre, you've got lots and lots of little ones. They fill little space, right? And you've got fewer and fewer trees as their size gets larger in the stand. And you have this, what is called an inverse J-shaped distribution. If you measure the diameter of all your trees in the stand and then you plot them in a graph, that's what it would look like basically. And so this diameter's expected to reflect age in here too. So this age class four, this is the youngest age class. Like I said, there's lots of them in there, right? So they comprise quite a few. Their frequency is high. Their number of trees per acre is high. This is the next youngest age class, the next youngest age class, and the oldest, so four different age classes, four different harvest increasing to the stand. Okay, that's just a short sort of silviculture lesson, but it kind of sets up what I'm gonna talk about right here. If you took, so let me go back to this graph for a second here. People have foresters that figure out how many trees you need per areas to make the forest sustainable into the future. Like I said, you should be able to go in this forest every 20 years, harvest the trees that are ready to harvest, that are over and above a certain diameter, then in these smaller size classes to maintain this diameter distribution. That's the whole goal. Forest researchers have figured out the exact number of trees you ought to have in certain diameter classes decreases the number of trees as the trees get larger that you need to have in each class after you harvest for that stand to be sustainable from now until the end of time. And what they figured out, and this is what we drew from to come up with this sort of diagram here is that this accepted selection silviculture stocking criteria, that's a mouthful, but these are stocking guides that foresters use, have been developed by forest researchers, it says the number of small trees you needed to have in the stand in order to make a go of it. The bare minimum value of 171 per acre is a value that we grabbed right from these stocking guides that were developed in the 1950s. Those are for trees in what's called the breast height. That means they're that tall to two inches at breast height, two inches in diameter if I measured it at breast height. So trees that just get up to chest high up to trees that are two inches in diameter at breast height, that is considered by researchers and managers to be a very bare minimum number of trees that is acceptable for this kind of system to be sustainable for forest management. This shows in oodles of plots that we established as researchers across Northern Michigan, and shows the number of stands that exceeded this value, that is they're sufficiently stocked in trees that are that big around, pretty small. And you can see there's a clear pattern to this. The green means they're well stocked. The red means we don't have enough trees in that size classes. And the Xs mean we didn't have any trees at all in those size classes in the sample plots that we used. You can see across this Northern tier kind of hugs Lake Superior in the UP, most of our stands were well stocked in that size class. In the Southern UP, that was most uniformly low stocking of any area. Lots of stands had few sugar maple stems. Sugar maple, again, is 70% plus of the overstory, and has been the objective for management in these stands for decades basically. And there are fewer than are sustainable or none at all. And the Northern Lower Peninsula in general is also fairly challenged in that regard. If we threw in a whole bunch of other species, not just sugar maple, but if we also considered along with sugar maple all these other species that're desirable for management, red maple, black cherry, basswood, white pine, yellow birch, red oak, hemlock, American elm, all those, it doesn't improve the situation very much. So that's summing the stems that are between breast height and two inches in diameter. Across all these species, we still have large number of stands that are understocked for bare minimum number of stems in that size class for sustainable management. That's not a good picture. Okay, and on the flip side of that and this really stinks, beech and ironwood, that's 171 stems per acre in that size class. These are stands in green, a couple in the UP, this entire Southern tier of stands in the Northern Lower Peninsula exceed 2,000 stems per acre in the same size class of beech and ironwood, which is not a forester's dream and ash too, but it's almost all beech and ironwood. Beech, ironwood and ash exceed 2,000 stems per acre in many stands, and lots of stands are 500 stems per acre plus. The problem with these species is that beech and ash are both heavily compromised by insect and disease problems from becoming mature trees. And ironwood has a low timber value basically. So it's not what managers have been trying to regenerate in these forests. So we have this pattern that we have low sugar maple generation, and then regeneration is dominated by beech and ironwood in lots of areas. This shows you an area, this is in Emmett County, Michigan where we actually stem-applied Garlon to all this beech and ironwood that's over here. You can see it's like a line along here. We stem-applied Garlon in this area where it's clear. We were able to eliminate the ironwood and beech. But it really shows strikingly just how dense that beech-ironwood understory is. This shows the same forest right up the hill. And this regeneration of these species occupies growing space, and can outcompete some of the saplings that we're trying to promote in those forests. Okay, so we know, and this is work that we did out of our lab, and smaller classes are in short supply now. And really these stems that are breast height up to two inches in diameter, that's the future, right? Those should be young saplings that have responded to these partial harvests that are the future for these stands. We know they're in short supply now when we go out and measure 'em in the woods, but is this a recent problem or has it been a problem since we've started to use selection silviculture in these stands? Now, what we'd expect to see is that we'd expect to see that the Northern hardwood stands would be dominated by about 100-year-old cohort. We expect a lot of the forest stands out there in Northern Michigan to be 100 years old. Why do we expect that? We expect that because they should correspond to that great cut over that occurred in the early 1920s. Being the 2020s now, forests that responded to that great cut over should be about 100 years now. But then we expect to see about three younger cohorts that responded to partial cuttings that have occurred since the 1960s. When I've asked, like I've asked some geezer foresters that are retired from DNR, like 90 years old now or so, and they said, "Well, we started doing this partial cuttings in Northern hardwood stands in the early '60s." And with those partial cuttings where there was stand improvement or a selection silviculture harvest like the system I introduced to you, we've been in there three or four times since the 1960s. So we should expect to see that 100-year cohort. And we should expect to see three or four cohorts, age groups of trees younger that responded to those partial cuttings. So if I partially cut a stand in 1960, I should expect to see a 60-year-old cohort of trees that responded to that partial cutting. Well, we asked that question, is this a recent phenomenon? Or have we not been able to be successful with this system since the '60s? I had a student that went out, and there we go, and she went into these recently harvested areas, and she collected cut stumps from all the trees, crossed a range of sizes and developed an age structure is what we call it for these 51 stands. What she found, I'll try to be brief here with this is that the dominant cohort age was about what we expected. Now the dominant cohort, what I mean by that is like the overstory trees. The main canopy of trees you have in the forest, lots of 'em were about a 100 years old, just like we thought, right? Some of 'em are younger. Some of these stands in the Upper Peninsula were entered the first time for forest products later than the 1920s. And then some are quite old. And these are ones like near Traverse City, 125 years old. Some of these are associated, now this is near Munising, this is near Holton. This is pretty, oh, I have an itchy trigger finger here. Sorry about that. These guys down here are near Traverse City. They're close to areas that were settled early. Maybe they were subject to silviculture, or agriculture and cleared, who knows, but they're older along those long ways. So this part fits. This is what we thought we'd see. This is the part that we were afraid of, unfortunately. The dominant cohort in these stands is the black circles. I'm gonna try to go pretty fast with this to just get the point across. What we expect to see is you expect to see that dominant cohort, but then you expect to see, remember those three or four younger cohorts in the forest that are younger than 60, 65 years old when they first started to enter these stands. And really if you stack these one on top of another, and you could see 'em right here, what you expect to see is the dominant cohort should be smaller than each successive cohort that's younger, much like that plot I showed you earlier. You expect to have a lot more younger, smaller trees than larger older trees, right? That's not what we see at all. And this is our 51 stands. And they're just shown as to whether they have a single age class, two age classes, three, up to five plus, okay? Lots of our stands don't have anything that is younger than that canopy cohort. They don't have any trees in them that are younger than 100 years old, none, zero. That means that those stands have never responded since we started partial cutting in there 60 years ago, in terms of regeneration. Nothing was able to come up with those stands. Some have two. And this red line indicates less 65 years old. Some have three, some have four. The ones that have five, some of those have older age classes in them. Some it's older than 200 years old, indicating that they were never clear cut basically. They were probably old growth stands that some folks, managers started partially cutting from the get go. Almost all of these are in the Northern Upper Peninsula of these stands, but the glaring part of this is that there's very few well represented, that is, at high density. Remember those circles are supposed to be big below that line that says 65 years. Very few of the stands have well represented younger cohorts in them. Then I'll try to just cut to the chase on this. If we're successful at recruiting trees or developing new trees in response to our partial cutting 60, 40, 60 years ago, 60 years ago is when we started partially cutting these stands, then, this is some work that Catherine Henry, who did this work came up with, you should expect a four inch diameter sugar maple stem, as four inches at chest height, again, should be about 40 to 60 years old. That's about how old a four-inch stem should be if we're successful at regenerating these forests with the silviculture system. Well, what we found, unfortunately, there are some areas where that's true, 40 to 60 would be green, green, yellow. This area close to Lake Superior, we're seeing that. All of the areas, again, same pattern, South Central Upper Peninsula and much of the Northern Lower Peninsula, the age of a four-inch sapling in these stands can exceed 80 years old. So trees that are that big around are 80 years old actually. That's astounding to me. So that shows that we're really not doing the job with that silviculture system. And just to take you back to this pattern, this pattern is not coincidental but it's associated with, now this is February mean snow depth across Northern Michigan. These areas, this is lake effect snow. You've probably seen that pole along the highway near Holton, and it shows we have 300 inches of snow this year sort of thing. Well, that's lake effect snow off of Lake Superior. All these areas up close to Lake Superior get oodles of snow. It pushes the deer out. All the deer migrate into Southern Upper Peninsula that time of year. And this pattern for sugar maple and stands that are well stocked and poorly stocked, remember poorly stocked is red, no stems at all is X, well stocked is green, is that the only place and just focus on the Upper Peninsula where it's really clear here, where almost all those green stands are in areas of deep snow. It's really the clearest sort of indication that much of this is associated, at least some of it is associated with persistent, chronic deer browsing, preventing the growth and recruitment of sugar maple stems beyond the seedling stage. So the current silviculture is not working in some areas. We've shown that clearly. And here we're getting very little in the way of new cohorts that are moving up from seedlings into smaller saplings, into trees that are four inches over the course of the last 60 years. Poor regeneration of desirable trees over 60 plus years, high density of less desirable competitors like beech and ironwood. That's no coincidence they're also two of the least desirable trees from a deer's perspective in terms of providing good browse is beech and ironwood. In some other work that we've done, beech is dead last in terms of preferability by deer, by browsing deer. So those are able to punch through the deer layer, the ironwood and the beech. Sugar maple is not. Well, deer are the problem. That's pretty clear, and there's some cameras that we have in some of our experimental stands. But there are other things too that are problematic, and they warrant addressing very briefly. Okay, now this is a summary of 20 years of our research and various projects. I'm just gonna kind of fling through it fast here. Deer eat seedlings. So there's a factor that's responsible for these patterns we see. There's how they limit and how they change things. But then there's also, this is the part that is more sunny, there's some silviculture that we can do or some management we can do to change things around for the better. Well, deer of course, eat seedlings. You could kill the deer, which is unfeasible, all the deer, but just not socially acceptable. Then you have your factor being advanced regeneration, that which has been caused by long-term deer densities. The problem there is this competition for desirable stems. You could conceivably brush that, get rid of it with herbicide and things like that. Seed can be limiting. We've found this in our studies. Oftentimes these stands, they're managed so intensively with lots of the larger trees pulled out of the stand that there aren't lots of large seed trees, even of sugar maple, but definitely of more minor species in the stand. They're there to supply seed. Substrate can be a factor for some tree species. There are many, several small-seeded small species such as hemlock and yellow birch, where the surface needs to be disturbed. Either you need to have rotten wood for the seedlings to get going on or disturbed soil. And we're so careful with soil impacts these days and a lot of harvesting in these stands takes place in the winter, such that there's very little creation of mineral soil for some of these small-seeded species to get started on. So lots of these things conspire to these poor regeneration patterns we're seeing. But then these are the two we found that are probably the most important things. It's the combination of small gaps and deer. Now by small gaps, when we are harvesting individual trees dispersed through the stand, we're creating very small pre-fall gaps, the let a little bit of light down to the forest floor for tree seedlings to get started. The light levels are low enough. Those trees don't grow very quickly. And then the crowns from the trees that are still there, so here's the gap in the middle, and here's the tree that was removed, and here's the trees that are still there. Their crowns coalesce over time such that it reshades the understory pretty quickly. You might have something that develops and becomes four or five feet tall and then it just stalls out because the light is again low in the forest. That's a problem in and of itself. But when you add deer to that combination, it's a particularly deadly combination because those small gaps focus deer browsing, and things don't grow quickly enough in those gaps to escape deer in height. If those seedlings developing into saplings are able to grow, again up above breast height approximately, that's just coincidental if that's the case, then they're able to escape the reach of deer browse, and they're good to go. If you're in a small gap, that takes longer to do. The deer are focusing their browsing on you. Your chances are slim, basically if you're in that kind of environment. Okay, so we see all these things going on. So I'm gonna be brief with this, and then I'm gonna suggest some things that I imagine several of you who are are woodlot owners might do to overcome some of these problems. What we're trying to do to overcome this problem, so the DNR in Michigan has about 4 million acres that it manages, really a big swath of forest. Lots of it is in Northern hardwood forest. I'm guessing they would wish that were even higher instead of some of the bottomland cedar swamps they have and things like that. But they have lots and lots of Northern hardwood stands, and they're trying to figure out how to manage these better. So we set up an experiment with them whose goal is to try to find a management system, new management that can improve tree regeneration. The management we're using right now, selection silviculture is not working. The deer are interacting with this and creating a big problem. So we came up with four different overstory treatments, one of them being business as usual, the selection silviculture, but others being more intensive overstory harvest because those more intensive overstory harvests are allowing seedlings to grow faster. They often result in a big mix of junk, including blackberry that deer don't want, like I don't like to walk through. Neither do deer, such that ceilings might be protected from deer and be able to punch up through them. So we have these more intensive overstory harvests. And then we did two things in the understory. We leave tops that are greater than eight inches in half the stands and that's to prevent all crisscrossing to prevent deer from going through. And then we have the herbicide scarification treatments to get rid of that advanced regeneration layer, advanced tree layer, that competition that the ironwood and the beech stems give to the desirable trees we're trying to raise. I'm gonna show you more pictures of those in just a minute. We got 140 stands. Each of them is 30 acres. It' a long-term project we're doing with them. These are pictorially our treatments. This is our business as usual, our single tree selection system. We're cutting much larger gaps in the forest too than what's typically caused by removal of the single tree. We do that by cutting multiple groups of trees together. Then we're imposing what's called a shelterwood system where we remove more uniformly, more than 50% of the trees in this. We wanna leave about 50% of the overstory cover in the stand and that necessitates removing a greater fraction of those trees 'cause we're removing lots of the smaller ones. And we're leaving ones that are desirable for shading the understory and providing seed for tree regeneration. And then we have these seed tree harvests where we're just leaving 60 trees per acre, essentially almost a clear cut. And then these are our understory treatments. We have these leave tops that we're trying to prevent deer from walking through. And then we're doing herbicide and scarification in the understory as well. And basically just real quickly, so this shows one of our seed tree systems down here on the bottom. This shows it from the air on Google Earth up here in this area I'm circling. And this has this overlay of all these plots that we have, these permanent plots that we have that we're looking at vegetation and deer use over time. We have this timeline. First couple years, we're looking at the impacts of harvest. We're looking at deer browsing directly in these stands over time. And then we figure after about 10 years, we'll know what's going on because we're gonna be able to assess the saplings, tree saplings that are able to grow up above the height that deer can browse. We call those free to grow saplings. This shows one of the large gaps in one of our treatments; it's the large gap treatment. Okay, so the problem with this for you folks and for the DNR too is that this takes a long time to do. And it's not the be all and end all. It's an attempt to try to find different manage techniques to get around the problem of having high deer populations. It's unlikely we're gonna reduce deer populations greatly. They might become reduced naturally, but it's just not socially tenable for us as forest managers to push for greatly reduced deer populations. So we're trying to raise trees with deer on the landscape. It's gonna take a while. And we're not sure where we're gonna get with this. And it's, like I say, it's not the be all and end all. And so what we're doing is we're encouraging DNR foresters to go out there and start dinking around with options themselves and considering options that fit the stands, fit societal pressures, limitations and things like that. And these are the things that I think that you all could potentially consider if you have similarly challenged woodlots and forests that you're interested in managing. So I came up with five of these that I think are worthy of trying, or are truly options. We're not gonna know really what works best. I have a feeling that some of our more intense overstory harvests are gonna be successful. Our leaving treetops definitely works in some areas. We've found that that does keep the deer out. It does become a bit of a problem of what do you have there to respond to being protected by those treetops. That might be a beech or an ironwood sapling that got leveled during the logging operation and then resprouts and shoots right through that mess. But it could be a maple seedling too. Okay, so these are the five. Number one, you can continue managing the overstory. So again, silviculture has been done in these forests, has not been working, hasn't worked for 60 years. That's not everywhere. That's not along the Lake Superior watershed. It works there. But in the Southern Central Upper Peninsula and much of the Northern Lower Peninsula, it ain't working. But you could continue to manage the overstory with partial harvesting, like has been done, because in lots of those, in many stands, there is an ample supply of growing stock of pole-sized and saw timber-sized trees that could be subject to at least a few partial harvests moving into the future over the next few decades. There are enough trees in the overstory. You might not run out of those trees for a while. So really you might not have to worry necessarily about regenerating full stands yet. Another option is to try and we've been encouraged by some of these options so far, and certainly small gaps are part of the problem, try more intense harvests aimed at regeneration. Current selection system harvests are not intense enough to promote regeneration up into larger size classes, into sapling size classes and beyond, and reach the overstory eventually. You can do this by doing larger gaps, by removing groups of trees in your stand. Or dispersed heavier, by dispersed I mean dispersed trees, individual trees, but heavier harvests such that the residual overstory lets more light into the forest floor might also do this for you. In addition to this, and this goes back to some of the earlier research that we did, maintain large seed trees of species that you want on site. They gotta be local. They have to be in your stand really to get the kinds of densities of those trees that you expect. And we regenerate these stands primarily naturally. So that's what, you have to have those nice big seed trees, 12 inches plus, in order to supply enough seed to really get things going in there. And don't be afraid about disturbing the soil surface. Some small-seeded things, if you have birch and hemlock, virtually every species benefits from scarification, even oaks. And then by scarification, I mean disturbance of the soil surface such that you just expose Merrill soil, maybe you're burying some of the seeds as you're doing it and things like that. All those things benefit tree regeneration. Leaving tree tops to discourage deer can be a really valuable thing too. Leave those treetops in gaps in areas where you expect tree regeneration to occur. It doesn't do any good to leave them in the closed forest understories where the canopy is closed, where you don't expect tree regeneration, where light's not high enough to allow trees to grow up into larger size classes. Leave those tree tops crissy-crossy in the middle of the gap, such that they can promote trees. Real quickly, this is things that DNR is considering doing in some areas that they have chronic regeneration problems in. Intense harvest that promote what's called even-aged cohorts of seedlings. That is all these new tree seedlings that are popping up here are all the same age, as you would expect in this seed tree system. This one of the sites that we're studying right now. This area might become an aspen stand. So? It doesn't mean it won't become a sugar maple stand again one day; it just won't be for several decades. So you might have to convert some areas to aspen areas where timeframe for continued management of that overstory is ending. And you wanna try to continue to manage those areas. Of course, planting seedlings protected from deer with fences, tubes, et cetera. I would say, and I found this slide, it does not look like they're actually managing the stand over inside the fence there. Combining this with partial overstory removal is important if you want to promote new cohorts of trees in your woodlots. And so I would say that instead of putting this fence inside the forest understory as it was done here, put it in the middle of a large gap formed by the harvesting of several trees together in order to make this happen. And finally, do nothing at all. So these stands are 100 years old approximately now in Northern Michigan. I think that varies quite a bit more in the central hardwood biome. I know that again, the area settled in Southern Michigan in the 1830s, some woodlots are that old. Some are younger. Some got slipped back to some point, came back from old fields, but more far more variable than Northern Michigan and in the Northern hardwood system. But in the Northern hardwood system, doing nothing might be just fine for the next hundred years plus if growing high value wood at medium rotation say 100, 120 years for sugar maple is not your goal. Sugar maple, yellow birch, hemlock live 200 to 300 years. I always tell my students, hemlock is particularly an example of this. If you can't grow it, don't cut it. Hemlock is the poster tree example of this. It has probably more sensitive to deer browsing than virtually anything else, yellow birches too, so is yew, in Michigan, but is so sensitive it regenerates poorly everywhere except along the Lake Superior snowshed that I showed you earlier. So if you have it in a stand, just let it be basically. 'Cause if it's 100 years old, it may well make it to 250. And over that length of time, the deer problem could fix itself. I hope that hit on some things you'd be interested in. Sorry for the emphasis on Northern hardwood systems. I hope there's still some time, I didn't go too long on this, for your questions. I'd be happy to answer any that would come up. - [Lyndon] Yeah, there is at least one question here. Please type in, if you're out there and have questions, please type them in the questions and answers. - Yeah, I can see that. - [Lyndon] Good. - "What about different cutting shapes left such as cross another wild neighboring woodlot?" - [Lyndon] Is he talking about deterring the population to the neighbors? - Yeah, it looks like. So how I interpret that is, the question pertains to connectivity of tree cover for wildlife travel. You know, it's something that the state thinks about quite a bit because they're trying to manage at the ecosystem level for a lot of these properties. And they can coordinate the management of adjacent stands. One of the ways that they do this and they assure sort of connectivity of forest cover across stands and across the landscape is that they manage riparian areas as such, right? So riparian areas are often, those would be like stream sides and things like that. They have some fairly strict guidance, not necessarily rules but guidance regarding harvesting in such areas such that those stream sides are almost always these sort of contiguous forests. Now another thing that may have come up in that question too is this questioner probably sees that we have all these squares that we're cutting up here in this experiment. We do that just for scientific purposes. We're not really putting any value or suggesting that people should conduct their harvest as squares on the landscape, but rather use of natural breaks and features, stand boundaries that basically are defined by composition and size of trees are more likely to dictate how that harvest gets laid out, out there on the land. I hope that covers it. - [Lyndon] Yeah. Is the idea of the competition, if your neighbors is more favorable to the deer population than yours, that maybe you'll have some success in regenerating. In general, we think about that not being such a successful, but as we see more and more homes go up in the rural areas and a lot of woodlots, small woodlots around those homes, maybe that's true. Maybe if we get enough enough options for deer, that they won't be as hard on the mature forest regeneration. - Yeah, I think that that might be true. So we went out. We're getting at some of this. I should have prefaced, this whole research stuff that we're doing, I am doing this with Gary Roloff, who's in the Department of Fisheries and wildlife at MSU. He's got a good chunk of our study sites set up with motion cameras. He's catching deer on it for years basically. And he's looking at the effect of areas that are next to our forest in terms of, does it increase deer browse damage, decrease deer browse damage based on what those neighboring areas are like? I don't know. I don't know what to expect with some of that. My guess, what I have noticed of this and we've been out looking at monitoring browse, we were out like last summer, all summer long doing that, is that they're really uninterested in forest understories that where it's been a while since there's been a partial harvest or almost never has there been a partial harvest. The understory, even if there's sugar maple in the understory, or if there's beech and ironwood, that is just not desirable to them to eat. Whereas if you have a recently harvested area, they like glom right onto that big time in even smaller gaps. And I think it's just because there's so little new growth on those understory seedlings and saplings for them to take anything off of the seedlings and saplings, They're just little teeny tips they put on of new growth. So anything that grows up in that open area, they're highly interested in. We did notice 'cause we like count deer pellets, deer poop. That's how we assess on all of our sites, how we've changed deer by harvesting. Our harvesting increased deer use big time at all our sites. And the more intensely we harvested, say that seed tree system you saw where we just leave some trees here and there out there, those are hit more by deer browsing. They're hit the most, the ones that we harvested the most intensely. What we're hoping for is that we create just such a flush of stuff in there, including trees and everything else, that it overwhelms the increased use that those sites are seeing. I hope that makes sense. But they really glom onto areas that have just been harvested in the first few years, changes the whole thing. - [Lyndon] That's interesting. I need to say thank you so much for presenting today.