Today’s Forest: Ecology & Management
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Today’s Forest: Ecology & Management


[music] I spent lots and lots of time in the Black Hills in fact most of the most of my research in the past 20 years has has been up in the Black Hills. I’ve done things like work work on Jasper, so I’ve, with Wayne Shepherd, who some of you may and founded in the world of forestry he was with the Rocky Mountain Experiment Station. He was a Collaborator, of graduate student a collaborator of mine, and we, we’ve just completed a 10-year remeasurement of the post fire recovery in Jasper, and so we’ve got, We followed it, every every year for the past 10 years, so we’ve got great, great information on how jasper is coming back. We’ve looked at, I’ve had a couple, of a couple of phd students that have done their dissertations in Jasper. I’ve worked on fire, use of fire in the hills, and prescribed fire, and how we use that. What opportunities that represents to manage stands worked on growth and yield of of pine forests and so, So the Black Hills has been been great to me for for 20 years, given me all sorts of opportunities. I’ve worked with the Forest Service. I’ve done landscape assessments in McVeigh and Norback and other places for the forest service and so I got the other side. I’ve got kind of the management side of the Hills in my, in my background up here. So it’s been a it’s been a wonderful place for me. My vehicles all get get taught like, like horses when I, as soon as I buy them I, I teach them where Lusk is and where to make the turns. And then they they just do it. They like going back to the barn. They just they just come here, so What, uh, what I’m going to talk about today are some I some of the aspects of the Ecology of Ponderosa pine systems, I’m going to like a used watch salesman, I’m going to convince you that managing forests density is really, really important in the context of a way forests grow in the black hills that if there’s one take-home message, and I quote from a good friend here that bad things happen at high densities, and that’s, there and and we’re live a, we lived through that in terms of fire. We lived through that in terms, of in terms of beetles now. So, so if there’s one take-home message for trees bad as far as living with living with trees and forests in, in close proximity but bad things happen at high density. The end and I’ll give you some examples. We’ll talk about about some fuels management and then from some aspects of regenerating Ponderosa pine and Aspen. So that’s my tasks for today and We’re going to start with kind of what, what what it what makes the Black Hills the place that I come to every year for 20 years, or 20 years. Well, it’s, it’s this this island that rises out of the sea of grass of the Northern Great Plains. So, so millions of years ago some, some granite pushed up and then lifted lifted the Black Hills up and it determines that kind of physiography and therefore, therefore the the way that plant communities play out across the landscape of the Black Hills and so the Southern Hills, Bell Fourche, Spearfish, and Wyoming. So the, Hill City for scale, and so so this this core of granite, it’s pushed up, And so that a central part, central part of the black hills are these granitic derive soils and high elevations, and they’ve given us the Needles Highway and the heads, and and surrounding that is is this belt of Limestone. Limestone Plateau, so most of the area North, its broadest kind of little east and going up in a band north of Custer and then and then around the outside, is is are some sandstones and then around there is is a ring of the hog backs. And it’s that physiography that makes the hills what they are and where we see plant communities. Now the uplift the uplift means, it’s higher than the, if, if it wasn’t higher we wouldn’t have Ponderosa pine here. So, so because because of that push up, that when when storms come through either, either this way, or this way they’re lifted up and and that moisture, then condenses and comes down as rain or snow and and so there’s more rainfall cooler temperatures up here less, evaporation less evaporative demand and that makes the difference between having trees and grass. So the Black Hills, just because of that because there’s there’s there’s more rain that comes here then then the evaporative demand over the course of the year means that the ecological balance falls out in favor of trees. Now, I’m also a department head, and I have forestry and range in my, in my department, and so trees are the superior plant and and grass is inferior and and so, so the Black Hills for me is a really special place because it’s, it’s, it’s an example of trees winning and, And there, there’s these wonderful environmental gradients that therefore care because of the prevailing directions and the elevation trends across the Hills. That there’s difference of different amounts of moisture that falls and different amounts of evaporation so we even within the context of the hills we see different sort of plant communities and different sorts of growth and and so in general as you go from as you go from the outside in and from the South – North, you get more moisture and and so if you you know whenever you’re driving into the hills from from where the inferior plants live that, that you start off, and you see this mixture and you see this this sparse, short pines and and lots of grass in between and So that’s where the battle is is being tipped and in terms that moisture balance. Now some people would say that well those are cowshed trees and they’re they’re short because they don’t grow it enough density to force their height. Well, well they’re short because that’s a really bad place for trees to grow and and it’s and there aren’t very many of them so that that’s why they’re short and stubby and, And as you as you gain elevation that you get more moisture, and the trees just grow better, and then they form dense closed canopy forest and the trees clearly have won the battle of the environment there and, and that would be that, that would be where we see dense forest where we see timber production and and things like that. So rainfall kind of in this outer belts about 16 inches a year. When we get up North and at the higher elevations, it’s about 29 inches a year so it’s a really huge difference, a really huge difference, but you all know that because you, you probably vacation like some people go to Florida you go to Hot Springs. The, so so the and the Black Hills is also neat because this was a this was a refugee, this is a refuge for vegetation in, in, in past ice ages and climate changes and, and so the vegetation that we have in the Black Hills is a mix of what comes from the south and what comes from the north. They both kind of got stranded here in the past, so Ponderosa pine is comes from the South and the West and Species Like Spruce and Birch are Aboreal species from Canada and and so this is a real, Understory the same way we’ve got aboreal species that really are characteristic of places way up north and then then species that are characteristic of Colorado and Arizona and places like that. and So, so these all got stranded here, and they’ve mixed and they’ve sorted out in, And in some really pretty from an ecological standpoint some very neat plant communities and. So Ponderosa pine is the dominant tree species, so if you counted all the trees in the Black Hills probably 90 some odd percent would be ponderosa pine trees. It, that, that dominates the landscape. But because there’s all this variation in rainfall and soil types and things like that that not all ponderosa pine is equal. So they’re not all the same just because it’s ponderosa pine in terms of how they behave in an ecological sense and therefore, how we approach them in a management sense, It’s not all the same just because it’s ponderosa pine from from a forest management standpoint that the underlying ecology can be different, and then we have to approach the management in different ways and so, so there’s communities where we have Ponderosa pine and we might have something like burberry arctostaphylos in the understory and on the kind of on the Prairie Fringe. This is a Ponderosa pine over story with a sedge sun sedge understory and this would be Ponderosa pine with juniper, common juniper as as an understory that you’d see on the limestone plateau a lot and out into the sand stones .and Then up North primarily this would be ponderosa pine with Baroque in in the understory. Now first what’s in the understory tells us something about how wet it is, how productive it is, and It also tells us gives us some insights in terms of what, what what challenges we might face in terms of regeneration and things like that so if a forester is looking at a piece of ground, this is what they’re going to do they’re going to take this that this holistic view and they’re going to assess what, what the nature of the plant community is in both the overstory in the understory and what that means in terms of the environment. How wet it is? How productive it is? How hard it is to get regenerated? How fast trees will grow? What sort of what sort of opportunities we we might have? What sort of fire hazards would, be would be represented by the different complex of communities. There’s trees other than Ponderosa pine and so Spruce, white Spruce is one of these and this is aboreal species. This is one, this is one from the north and so, so picea Glauca, White Spruce, is, is a species that’s very shade tolerant, so in the world, in the world of foresters we break out trees, and we describe how they behave with this concept of shade tolerance. And it’s a it’s a big driver in and setting the way that we manage different species and so ponderosa pine in the in that parlance of shade tolerance is intermediate, is intermediate in shade tolerant. So in the simplest sense If you went into a really shaded area and as species was shade intolerant you wouldn’t expect it to regenerate and if you went into a more open area and more open, it you would need to have a really open area maybe up to the point of having a clear felling it for really shade Intolerant species like Lodgepole pine in order to get regeneration and growth. Ponderosa pine is intermediate it can it can go it can do okay over on the open edge? It can do okay over on the closed canopy edge. So it spans a big range in terms of where it’s able to regenerate and grow. Engelmann Spruce is very shade tolerant. It isn’t going to do very well in terms of regenerating out in the open or growing when its young out in the open it’s going to need a shaded environment, so if you see young Engelmann. You know you see kind of dense, half dense forest and that’s where that’s where I Engelman, yeah, I come from Colorado. I slipped up didn’t I? White Spruce, White Spruce is going to regenerate out in, in, in, the in, the open or out the enclosed areas. And and you typically see associated with with more moist areas. So drainage is north-facing slopes and places like that. Aspen, Aspen shade tolerant, shade, shade Intolerant, it doesn’t grow well beneath canopies. So aspen is shade Intolerant, but it doesn’t regenerate from seed. It regenerates from root sprouts. And so the kind of the ecology of how it plays out what we do from afar from a management standpoint is very different. So, so those are the species. The Black Hills is a great place for out for forestry students. They have to dendrology plant tree identite, tree identification is a big course that we make all students suffer through to be foresters. They got to be really good identifying trees the Black Hills a great place because you only got to know like five or six and, And so, so while, while the environment is a great environment. It’s it’s got a lot of moisture. It’s got you know rapid growth rates, very productive in terms of producing, producing wood for good or bad the Black Hills environment produces lots of wood per acre every year and but it doesn’t have very many species that live here and in terms of trees. Now when the, the, the big thing, the big the big thing we’re going to talk about today is managing stand density and so there’s a great world, word model that I’m going to work through that people have developed to lay a foundation for, for talking about you know what we want to accomplish. How we take a landowners objective. I want to grow a lot of wood because 20 Years from now my kids going to go to Colorado State University and you want to give me the tuition and so, so I want to I want to produce some big saw a lot of volume of big saw logs or, or you know I just don’t want the, I don’t want the homestead to burn down next year if a fire comes through. So there’s all sorts of things we care about in terms of how we want a forest to be structured and the foundation for that is is largely how we manage stand density over time so it’s just this, this word model where we attach a lot of the ecological, the ecological happenings that are related to, to density and so It’s going to have five, we’re going to talk about starting off a stand and moving it through time in order to illustrate, illustrate this and and so five stages A through E and So if we started out, if we started out a stand of trees. They were all really small even if there were lots of them, even if there were lots of them out there because they were really small Than any one of those trees wouldn’t know that it had a neighbor That its growth rate what it was doing in terms of growth would be totally controlled by the site. How much rain fall there was, how much, how much was available in terms of nutrients and things like that. So it’s the growth rate of each of those individual trees through, through a stand at this point would be just a site thing, just a site thing. how much rain fall there was. How much, How much sunlight happened there. What the growing season length was. You know all the things farmers care about. That would that would determine the growth and every one of those trees would grow just about the same because, It would they be independent and wouldn’t know there were any neighbors. Now so no competitive interaction tree growth would be just as fast on individual tree basis as it could possibly be and would be with him would be just determined by the site. But if we added up all of the volume increment on all of the trees we had out there it wouldn’t be so much. There’d be some sunlight that would hit the ground for the inferior plants to use. There’d be some water that wouldn’t be taken up by the roots and put in the atmosphere and so forth so, so we if, we if, If we were just looking at how, much how much volume growth was being produced here. There wouldn’t be as much as if we added some trees. So we could stick more trees out there, use more sunlight, use more water, use more nutrients and get more volume growth. Get more biomass produced on that site. So that’s what a stand that this stage looks like so this is there are lots and lots and lots of trees out there but none of them know they have a neighbor. Don’t know they have a neighbor. They’re just growing just as fast as that site can make them grow. There’d be no sense to thin this because taking out some trees wouldn’t cause any faster growth on the ones that remained. Putting more trees out there would give us more growth but the other thing that’s going to give us more growth is letting them get bigger, so So if we go away, we come back, and we’ve let them all get bigger. There’s the same count we had before But all that’s happened is that all of them have gotten bigger. There’s going to be this magic point where given that combination of how many there are and how big they are. Now they suddenly know they have a neighbor now trees look slow and benign. They don’t move, they don’t move, they did, they just exist for their whole life with it, but but they’re vicious with respect to each other, that their competition is a huge deal with trees. With trees you’re either you’re either bigger and better than your neighbors or your dead. And, and so competition is is a real driver in, in stand development and so we get to the point where in mesic forest systems where, where sunlight is, is really the limiting ultimate limiting factor in how much, how much, you how much tree density you can have out there that, that trees start to compete without each other and and primarily it’s when canopies close. When you start to see those branches get really close to one another and systems are doing the same thing underground for water and nutrients and so forth and and so once this happens, once this happens, once this combination of how many trees are with how big how big they are get to the point where competition happens, all those trees are growing a little bit less now and and so if you when you look at a stump and I, and you see big fat rings in the middle, and then suddenly you see them start to shrink down. That’s what’s happened, That’s what’s happened. They know they got a neighbor now. So individual trees are starting to slow down and in how they’re how they’re growing. But now we got a whole bunch more leaves their these canopies start to come together and, and so the sunlight that that’s coming down is now most of it is being intercepted by the leaves or the needles of pine trees and, and photosynthesis is making biomass happen and in fact. We’re getting close to using all the sunlight water and nutrients on the site. When competition starts, when competition starts some trees are a little bit bigger than others and, and, and one of the neat things about talking about competition and forest stands is that if you, if you’re competing and We got one tree that’s this big an one tree that’s this big that, that competition is not equal is not is not equal and this little bit taller tree has grown a little faster And it’s going to get more nutrients and water and sunlight than this neighbor that’s next to it and So the growth rates are going to get like compound interest this one’s going to grow lots, lots faster than this one. And it’s going to just it’s going to grow and live but very, very slowly and so the relative difference in size is going to be enhanced over time and So if you go into stands where this has happened forest stands where this competition is going on you see some big trees, and you see some smaller trees. They win. Some of these trees have a big L on their forehead because if you’re smaller than your neighbor when you start to compete that’s just going to get exacerbated over time and those differences are going to become more and more pronounced and this is going to be the foundation when we talk about thinning for picking winners and losers that you want to pick those trees that are really superior in terms of competition and growth and vigor and so forth and get rid of the losers. Stand growth is going to be when we add up the growth on all the trees now while, that while they’re all slowing down a little bit when we add them all up we’re near turning, we’re near high efficiency or in terms of turning sunlight water and nutrients into biomass on that site. We could add we could add some more trees and get a little bit more or we could take trees and take some of that away By thinning, but we’re in this kind of this this almost, almost to the point where we’re getting all of the biomass growth we can get and then then there’s some other things that are going on that we see happen to trees at this point that, that are important because sunlight is, is not getting all the way to the ground because there’s so much foliage up there the lower branches on these trees aren’t getting enough sunlight to stay alive and and so the lower branches start to die and stand self prune and so if you’re going to be selling logs, if you’re going to be selling logs you want that to have happened to your trees because when the branches die and fall off the wood the Annual increments of wood to get put on are don’t have any knots in it and and so the wood becomes more valuable. So, so there’s, there’s this, this idea of competition and its effect on trees is fundamental to the way and underlies these things that we want to accomplish what we’re going to do is manage, we’re going to manage the effect of competition by controlling density and when we manage the effect of competition the The big, the big deal is that trees are plastic. With respect to competition so they change what they look like depending on how much competition they grow under. Trees that grow under not so much competition have branches all the way down to the ground and they’re big and so they get lots of knots There if you look at their stem form they look like upside-down ice cream cones, and so if you try to saw a log out of them you know, you you kind of run out of, you run out of wood and you get in and Trees aren’t square. They’re round but but they also are skinnier at the top then at the bottom and so trees that don’t grow under a lot of competition tend to tend to have a lot of taper to them and aren’t as valuable for wood production. And the, certainly and most importantly the size of the rings that the more competition there is for an individual on a tree, the more competition it grows under the thinner those rims are So the longer it takes to get big. So it’s that play, that idea that trees are plastic with respect to competition and by modifying the density of a stand we can control the outcome of how fast they get big, what they look like in terms of stem form and crowns and branches and all those kind of things and then how much total volume increment how much of the site production potential that we capture and turn into biomass. So when a forester looks at a stand to control density all those things are going around in your head and they’re balancing those things out. So this is a stand that’s just started competition and, and you can see you can see these placidus start of these plastic effects how trees respond to competition and so, so these these trees are skinnier than they could have been because they’ve been competing for a little bit and, And the branches have basil branches have started to prune up even at this very small, small tree size because they were so very very dense. Now we go away, we go away from this stand again, and we come back. There’s still the same number of trees, Theyre’s still the same number of trees we started with at the beginning. All it’s happened is that all of them have gotten bigger. Now they haven’t all gotten bigger at the same rate because some of them had the L on your forehead and, and, and had bigger neighbors that were superior competitors and and so forth so there’s a lot of size differentiation in the stand and the degree of crowdedness of this stand is is now getting pretty intense. So it’s, it’s when we’re going to have to come up with and where we’re headed is a way to numerically quantify this degree of crowdedness so that we can pick what’s happening in stands and in terms of the level of competition. Now in and incomp… and this is going to be, this is going to be a combination of how many there are and how big they are they trade off against each other. So if if you’re you know, if you’re going to get in an elevator with with the Rapid City T-ball team and, and there were 12, 12 kids from the T-ball team, it’d be a pretty comfortable ride up You know to the 12th floor of the Hilton. But if you happen to get in the elevator and you had the offensive and defensive line of the Minnesota Vikings, It’d be a different experience the same, the same count in terms of people but but the amount of crowdedness you felt would be really different and your experience going up the elevator would would be a bad one. So, So what what we’re headed for here, you know this foundation is that we’re going to have to come up with something that takes both? How many there are and how big they are together to tell us how much competition is in it stand and and the nature of these ecological processes that are happening. So we’ve got to the point now where this degree of crowdedness these individual trees if we look at the rings on these trees they’ve shrunk down quite a bit. But when we add up how much biomass increment is happening on all those trees It’s as much as we can possibly get in this stand. We couldn’t get any more we could add more trees to the stand we could increase this degree of crowdedness, but we couldn’t get any more volume increment, and that’s because really what, what, what the biomass production of a stand is related to is how much sunlight is captured, is how many needles that we have an how they are displayed to capture sunlight and and how much of a soil volume we occupy with roots to pick up water and nutrients. And so now we’ve reached the point where we’re doing, We’re getting all of that, that we can and turning it into you know through photosynthesis, we’re turning it in to fixed Carbon, and it’s it’s happening and on the stem of all the trees in the stand taken together as much as it possibly can so at this point we’ve got full site occupancy and all the volume production we can possibly have. So stand growth is equal to production But we still have the same number of trees all that’s happened and from here to here to here is that we’ve gotten, gotten bigger but there’s been some of these key points in the changes of the ecological processes that are going on and the implications they have for what we want to accomplish in terms of forest management and so this is a stand that you know what kind of a mature Black Hills stand that would be right, right, right about there. At full, full site occupancy, so this stand is producing all of the all of the volume that it can produce. This stand is at the same place, So this stand and this stand are the same density. They’re doing the same thing, but the trees look a lot different. Okay, you got all these gnarly branches on here. Those trees, just I mean if forester, kind of, if you were trying to sell these to a forester, I mean, so you got it look at all those gnarly knots and so forth because if you saw if you saw a board out of those. They’re just going to have big darn black knots in them. They’re going to fall out. That’s all shop grade wood, I mean, that’s that’s not that that’s not value. That’s not nearly as valuable per unit as these stems that have all of this clear wood in them in the nice stem form and so forth. Now what happened? Why, why, did this happen? Well these trees got here because earlier in the and they are the same age, same age, same site productivity. I mean, they’re within a stone’s throw one of these got here growing their youth and they spent their youth at higher density so all those plastic effects on stem growth played out over time here, and so these these stems are a little skinnier. There’s a little skinnier because they grew longer at high density, but the branches pruned up and the stems are nice and straight and, and, And they don’t taper very much and so forth. These, these stems grew with without much crowdedness when they were young and so those lower branches didn’t prune up as early and, and, and so forth so they that’s that plastic response to density played out over time. So what we do with with thinning regimes when we talk about thinning is that’s what we’re trying to figure out. How we control these outcomes? Now, we go away, we come back, in one of these stands, But something really different is happened now the trees have all gotten bigger. They’ve all gotten bigger, but now there’s fewer of them. Some of them have died and so we’ve reached a point where self thinning happens so in order we’ve reached kind of a carrying capacity in terms of that density concept we’ve been talking about and so given the number of trees we have and how big their they are. That they’ve reached the point where we can’t have any more density in the stand somebody’s got to go, somebody’s got to go for the trees to continue to get bigger, so trees always get bigger. I mean that’s they have two fates in life get bigger or die as individuals that’s all they can do get bigger or die and, And so now we’ve reached the point where if they all got bigger we exceed a carrying capacity for that forest site. So somebody’s got to go, somebody’s got to go and it’s going to be the losers. Okay, so that we’ve had that continuous differential growth where the slower, slower growing trees are falling further and further behind the faster growing trees and, And so now we walk into when he stands we see. Oh yeah, that’s a dominant tree really got a nice long crown, and it really looks vigorous, really healthy. And then we see these small suppressed trees that that look sickly and so forth well, they’re the ones that are going to die. So that the other ones can go on and continue to get bigger so self thinning, and this is a really, really high a density Individual tree growth of rain widths on these streets are really, really tiny at this point. We’re still getting all the volume growth, We can get in the stand all the biomass growth, but now we go through from here in ever more For tree, for this stand to go from this year to next year to the year after for, for the big trees to get bigger the little trees are going to dying to make room for them to get bigger, so so this would be, this would be a stand that’s at this at that point now. When stands get at this point they are hard to take pictures of because they’re so crowded But there’s there’s trees if you got up to where I am you can see a bunch of little dead trees out there. We let this process go on for longer But that let that stand grow longer some trees are dying, but when they die at this stage they’re small they die and the ones that are left living the big ones, the vigorous ones that are left figure, fill in that space. They fill in that space and take that water, light, and nutrients that the dead tree had just given up and, and they fill it in now there might be little trees, especially With Ponderosa pine in the Black Hills given the way pon region happens here you can see little trees out there. You could even see trees get this big, but they look really spindly and sickly and so forth There’s not enough left over for them. They’re they’re like, like grasses, they’re inferior in terms of competition at this point. And they can’t grow up into the overstory because those big trees are superior competitors, but if things go on for a long time. Some big trees really big trees die at this point and the trees around it can’t, can’t grow their branches can’t grow in to fill that canopy gap and grab up that available sunlight and so forth and so sunlights hitting the ground and that regeneration then can grow up into the overstory. And that’s where multi-age stands come from, so regeneration happens, it doesn’t get shaded and crowded out and it grows up into the overstory and new age classes come to be and you have uneven-aged multi-age or uneven-aged stands and Ponderosa pine here in the Black Hills used to probably be like that a lot and fire was was certainly part of the system that created that. So, so this is you know this is a stand. Where now this is human-caused, so so trees were cut in here at a big enough gap to in order to produce an open enough environment. Enough water light nutrients available for new trees to happen and grow up, and this is another human-caused, human-caused, example of that this is a shelter wood with a lot of regeneration. Yeah. [Off camera – Would you associate a time line for us as far as that stand is concerned?] That’s a great question, but I’m going to go in a completely different way because, because each of those stages was a combination of how many trees there were, and how big they were it’s totally our choice. There, there is, there is no timeline because we can make it whatever we want. We could have we could have ten trees. We could have 50 trees. We can have 500 or 5,000 trees and the time for each of those numbers of trees to get to those stages differs, and that’s the basis for our choices of manager. That’s exactly what we do with management. You choose what stage we want to be in how fast, We move to stage two stage by other PPL. Great question! [Off camera – I’ve got a related one. Seems like everything you told us does not speak well for these Areas they sit aside virgin quarter and every touched. They, if you’re willing to wait a very long time they can produce great trees in Europe and Northern Europe they grow, They grow their spruce on 300 year rotations to produce really, really great trees for lumber but you have to wait three hundred years. If practically here in the Black Hills you’re exactly right that that you’d want to open that, That by having very, very dense stands it just makes the time to get to a decent size for timber harvest impractical. I talked so fast I wore the batteries out. I’m not married to, I’m not married to anything that I’ve gotten slides, and I’ll I’ll degress at a drop of a hat. I’m known in students as the EE Cummings of lecturing. So I I just I can be really random. Yeah, sure Yeah. [Off camera – You’re talking about how you’re suited for growing these nice plants around here.] Yes, yeah. [Off camera – We got these two huge areas Reynolds Prairie an Gillette Prairie. It seems like it has all the characteristics its high] So it was a combination of soils and disturbance history that there were places where soils weren’t great for trees. Even though the moisture and so forth was it’s a different soil type and that that’s not suitable for pine trees, but then when you exclude fire you see, you see trees encroaching and moving into those areas, so it’s a combination of the two. Now that this this isn’t from the Black Hills this happens to be based on data from Scotland, But, But, but anyway it, It’s an illustration of that effect. So, so what they did was they went out and they planted trees at different densities, let him grow for a long period of time and then plotted out what the ring widths look like over time for 35 years of growth and so the I, it’s metric units, But this is about a this is over a thousand trees per acre. Right here, and so so to age 12 no no competition They were all the same but then things started the more dense stands started competing at age 12 and so their ring widths are less than Then where there were fewer trees and so the accumulated effect over time was after 35 years at a thousand trees per acre we only got trees this big. At, at half that at five hundred trees per acre, competition didn’t start til later and and when it did it wasn’t as severe for longer and so these trees at half the density got this big in 35 years. At at seven hundred do quick division, divide by 2.5. About 15 years ago I gave up doing a long division on my feet because students just are vicious and. So I progressively lower densities the time at which competition starts, the time at which full site occupant is the time at what self thinning starts, occurs later in stand development occurs at an older age and And so the effect would be that, that in this, in this stand that these trees aren’t very big but boy we stacked a lot of biomass in that stand and we probably had some self thinning going on So this stand might have might have more more biomass or more tree volume in it then then this stand, but these trees are really big. So there’s going to be this trade-off you can’t you can’t have your cake and eat it too in forestry. That you can have big trees or you can have lots of volume ,lots of biomass or some combination of the two, but you can’t have both you can’t have the most of both and So when thinning regimes get rid design, that’s what we trade off. What’s the right density to give us the outcome we want in terms of how big the trees are? How much volume we have there. How many board feet we have there and then what’s the, what’s the value of the stem in terms of how knotty is it? How branchy is it? What’s the stem form and things like that. So those are the underpinnings of coming up with a kind of a commercial thinning regime and That’s a, that’s a real tree and again that’s not here that’s New Zealand. That’s Radiata Pine in New Zealand, so it’s got really fat rings to it. But so you can see it so, so you can you can see those, those stages of development happen, and then you can see here that thinning happened that, that we went in and we change that structural stage, we changed it from full site occupancy with small rings, to effectively open grown. By taking out a bunch of trees, so with management we can we can choose at any time which of those structural stages we want to be and what sort of ecological processes go on. And trees are going to respond to it and change the way they grow because they’re plastic with respect to density, changeable with respect to density. There’s other things that happens with respect to density and so I’d very at very high densities there’s not a lot of water like nutrients left over for grasses, forbs, and shrubs at low tree densities, would open essentially stage A. All that water a lot of the water, sunlight, nutrients that are available on the site. Don’t get used by trees and, and, and my man in the range, in my range group is really happy because we produce lots of grass and so, so in forest not only can we choose what we want to see in terms of tree response and volume and, and, diameter growth and things like that, but we can make decisions about how we allocate resources and production between trees and understory. So we could produce and in this case, and in this case a lot of grass growth and fob and shrub growth for for either Wildlife or for domestic cattle by having lower tree density. So agroforestry is built on built on those principles. And then and, then and then a real take home message, bad things happen at high density that, that, when we, as we go to higher and higher densities, And we see these these competition effects kick in in trees That their vigor goes down and and so their resistance to insects and disease becomes compromised. Mountain pine beetle, part of the issue with Mountain pine beetle dense forest of sufficiently big trees is is what Mountain pine beetles key on. So we tend to see, we tend to see these these impacts of associated with forest health exacerbated by, by high density and fire that when we have closed, closed canopies very high, high densities of needles and small branches together across the canopy that represents a lot of continuity with fuels with respect to fire and that’s where crown fires happen. So how do we figure out? How do we take that combination of how many trees are and how big they are and put that together in a way that we can talk about how dense the stand is or how dense do we want it to be to get one of these outcomes that we want? For small trees, for small trees We just count them because size doesn’t matter and it gets in it gets in a way of thinking about it. So, so when we talk about seedling sort of stands and in small tree stands We just measure how many there are so,so what we do is go out and put in some small plots out there, so we could put in plot there was about a hundredth of an acre in size count how many little seedlings were on it do that on ten plots add them up, that’s how many we’d have per acre. Now when we think about that we’re really thinking about what the future of that’s going to be is 500 trees going to be the right number to have when this stand for example closes canopy? Are the trees going to be the right size? When we want to do our first thinning are they going to be big enough that we can sell them for posting poles? But at this point. We’re just going to count them. We’re just going to count them and tell you we got 200 an acre. We got a thousand an acre. We got five thousand an acre. But we’re going to we’re going to think about that in terms of what that means for the future, do we have enough for when these trees get big to make a to make a good stand and, and, and, we’re going to move back and forth between how many there are and how far apart they are so that’s, that’s Math that’s Algebra, that’s Algebra so a hundred trees per acre if we had a hundred trees per acre in they were evenly spaced. That would mean the distance between each of those trees would be 21 feet. So when you think about when you you know that that in in in terms of thinings and so forth, We walk back and forth between these these two ways of expressing tree density and, and they’re just, they’re just Algebra between them and so 435, if we wanted trees to be spaced 10 feet apart that would mean we’d have 435 trees an acre and, and if we wanted them six by six, so often you’ll hear people talk about thinning. We want six by six. We want 12 x 12, 15 you know something if we’re going to shelter would we want about 21 feet apart and really that translates to it to a tree count. When we have big trees, We don’t have little trees, when we have big trees the problem is different, what we’re trying to accomplish is that elevator problem. We want to know If we’re getting on an elevator with 12 people is it the t-ball team or the Minnesota offensive line? Okay, because that’s going to make a real different, that’s, that’s the key difference being able to take those two and put them together in, in some way to, Now so, so we have a lot of small trees, you know relatively these are two mature stands of Ponderosa pine. There’s a there’s a big number of tree count here per acre. But they’re not so big. There’s not so many trees here, but they’re really big so what’s the difference in the density of these two populations of trees? So, so putting that together putting that how many there are and how big they are together in one package and one number is what we’ve got to do. Because this is going to be then we’re going to take that and relate it back to those structural stages. So we know what’s going on in those stands and, and So, so what we’re going to have to we’re going to start off around, How do we, how do we know how much density is in a tree? Based on its size So fundamentally where you know for one of these trees. How much density does that mean relative to one of these trees? We want this we want to come up first of all with this tree to tree comparison. That is, Is this tree, is is this tree worth two of these trees, four of these trees, six of these trees? What’s the what’s the rate of exchange based on tree size in terms of what that means in terms of competition and crowdedness? Yes, [Can you back to that slide you were just on?] yeah No, [That tree you were just pointing to.] yeah. [If you wanted to let that, have that tree grow because you knew that you were going to be harvesting it, and that the competition isn’t there, so the self grooming isn’t going to happen. Could you not help the tree by pruning it, you know what I’m saying?] Yeah, yeah You can enter if ah and there are lots of places now because we used to get a clear wood from from old trees and, and old trees aren’t so available to cut anymore. And so pruning is, is becoming much more common to do that at an early age to cut these lower branches off. So that the wood that produced doesn’t have branches in it and therefore doesn’t create knots. Exactly yeah, and If, if at home, that’d be a great thing to do for the forest service probably not so much, but If I, if I had a, if I had a woodlot my back 40 here in the book in the Hills I’d be out pruning, because I enjoy that kind of stuff. Aspen, Aspen as opposed to Ponderosa pine does not, does not come from seed, it is not seeds that make new new Aspens. Here in any significant or real number Aspen does produce viable seed, Absolutely the seed that aspen produces is is viable and if you if you took it in your house and you put it in a pot, and you treated it right it would produce a little aspen. But, but it just doesn’t outside that the conditions under which Aspen seeds become aspen seedlings the environmental conditions that make that happen don’t exist here in a, in a way that makes that a reliable or significant producer of new Aspens. So that’s the wester, by now in Canada and up in the midwest that’s different aspen does come from seed there. As well as from root suckers, but not here, not so much. Where, where new Aspens primarily come from is the roots of old Aspen. So, so the root systems of existing Aspen near their dirt the root systems of Aspen tend to be concentrated very near the surface of the soil and, and roots that are maybe half the diameter of my little finger or so have buds all along them and, and, and, when conditions are right these buds Like like a bud on the branch of a tree. These these buds burst and and new Aspen happen and and so this is an aspen that’s connected to an old root. So there was a bud here at the at a node on this root very near the surface and when things were right this bud burst and this new Aspen stem happened. Now the conditions that make this right are, are first it’s a temperature thing, It’s a temperature, sunlight thing and so, so these buds burst went when there’s a heat in the soil from the sun. So are closed for his canopy is a bad place for these spouts to happen. The other thing that has to happen is that that the sprout,that the sprouting is suppressed by a chemical balance in a plant so as long as the top of an Aspen root system is there and alive and it’s, it’s, it’s auctions and gibberellins for those that care. But, but, but, but the top of the plant produces one and the roots produce another and as long as the top is there that the action of the one produced by the root is suppressed you cut the top away or fire kills the top and you’re not producing the oxen, more and then the Gibberellin kicks in and causes the sprouting to happen. So to get new aspect to get new Aspen you got to take the tops away, you got it you got to kill the old ones to get the new ones. Most of the time now sometimes you’ll see existing clones where you get a little sprouting but if you want to see a lot of sprouting got to take the tops off to get this process to go on and then you got to take the canopy off to get enough heat to promote it. So this is this is Jasper and and so a lot of places in Jasper the fire burned through Aspen and the Aspen has a very very thin bark and just a little bit of fire heat, whacks it and they don’t they don’t survive fire at all and, and so these stems are all dead these are these are right? This is like this a year after jas, Jasper burned, and these stems are every one of them is dead and that’s the response that happened, Now you could go there today, and you may or may not see aspen because the cows came back to Jasper very soon. Pardon? The cows came back to Jasper very very quickly after it burned. And so there’s a lot of places where this happened that you won’t see aspen today. Now others will tell you it was the elk but. Pardon? No, no that the cows were turned back into aspen,the the the grazing permits were made active again. Very very quickly after Jasper burned when when the suckers were very susceptible to browsing and and for elk and for cows. This is the haagen-dazs of the plant world. Not so much deer, but certainly certainly elk elk will, will just zero in on this. Yes, yep that the the new shoots and the leaves are, are desirable there’s some discussion with cattle when they’ll use it and under what conditions, and so forth so it’s elk certainly will hammer it and and cows under the right conditions will. Yep, yep But I have pictures I have pictures of cows walking through places like this with Aspen Plants dripping out of their mouths. Yeah, and they’ll and I’ll show you some browsing effects, but, but that fire that fire, which killed the overstory triggered that imbalance and Auxins and gibberellins. Created no over story canopy, a black surface with all that soil heat and boom all those aspen sprouts happen, that’s Nirvana. That’s regeneration nirvana for Aspen. We can simulate that with mechanical treatments by cutting the stems and so reducing canopy cover in shifting the Hormone balance. Sometimes it just happens, so it is there there’s clonal variation and and so forth so you can see places where the overstory wasn’t cut that new aspen happens. And it seems to be a characteristic of clone some some clones of Aspirin will do this and some just won’t. So there’s variability And and then one of the issues that certainly and in the, in aspen in the Black Hills that we worry about is is Invasion by Pine or overtopping by pine and We’ll talk about this a little bit when we go out there’s a nice area up the hill where where it’s been where the pine had been cut off the aspen. But here’s where fire has done it so, so these pine trees are much taller than the aspen trees and, and so the pine grow there they grow bigger they grow taller than the Aspen. They suppress and kill the aspen because remember the aspen is shade intolerant, it doesn’t do good growing under shade. and if this were to have just continued to grow so the black stems are pine the white stems are dead Aspen and, and so the new sprouts if the elk don’t eat them are going to do great here because because that pine overstories been removed. And then that’s the and that’s the key word I didn’t think I saw it before. Because it was there I guarantee you it was there, but it was small just enough to keep that root system going. So you’d have a tree You know a little skinny aspen tree over here and a little skinny one over there, And those roots would have existed under the soil. Take the pine away kill those aspen trigger the suckering response in there everywhere and that’s the way aspirin persist, and that’s why fire was so important in keeping in here that’s why you see some, that’s why if if we could go in a time if we were either old enough or could be in a time machine and go back to like 1860 you would have seen a lot more aspen than are here today because fire has not caused this to happen very often. But it’s still it’s still lurking out there in a lot of places. It’s still hanging, it’s still hanging and with enough disturbance. You can see it kick in. And, and the other thing that So this, this in Jasper for these, these, these, these, these are where the these new sprouts were browse, browsed off by cattle or or elk and what that does the key, the key to get successful aspen back? Is to get them taller than this, that what you have aspen sprouts grow very quickly because they’re sucking they’re there they’re using the resources of that existing root system. So they don’t have to, they don’t have to make their own root system and so forth they have all of that carbohydrate. They got all those those add, They got they got all that energy drink available to them in the existing root system. And they use that to grow so they grow very very rapidly right from the get-go But the key because they’re so desirable for elk and deer to eat that, that you have to get them tall enough, quick enough, So that so that browsers don’, don’t destroy and And so what happened with with repeated browsing in places that it keeps getting browse back And it never escapes that browsing pressure, so the key is to get it to be 15-20 feet tall and get a little diameter on it. So that ungulates can’t can’t destroy it and So it’s it’s keeping that pressure off it for those first three or four and it ought to happen often times in three or four years, that’s all it takes. But if it’s if it’s continually browsed then you run the risk of losing it because it never escapes. [We were told once that where you really find them, there has to be a lot of moisture on the ground.Is that true?] Well, you, tend to see them in places like that because that’s where they’ve regenerated at some point and formed the root system. But you also find them on uplands like this. This is this is all of this is almost a ridgetop situation. So they are where they are aspen is one of those things where ever it got established it’s going to persist by this suckering, so It’s not really you often find them you know at the basis of valleys in wetter areas because those would be good conditions for it to have germinated sometime in the past. But also you just find it wherever it happened to have got a foothold. [Then what you said about the browsing. I know it was spot where their high schools close to 15 – 20 feet, and you look at them and they are all trimmed up at the same height.] Yep, so, And as you get more and more elk in the Black Hills you’re going to less and less Aspen That’s then the trade off across the West. [Do you need to kill all the older trees to get regrowth started.] No, no [What would be a number, like 80 percent, or 70 percent?] Yeah a bunch, more more is better. But but you know you roll the dice, if you do it, if you take them all you better, you better grow them up to escape browsing pressure. Because that root system will eventually die off, if you don’t. So it’s a roll of the dice if you do it and you take them all you got to be successful if you leave some living you can keep the root system alive, so it’s one of those one of those trade-offs in life. Pardon? [Why would you want to cut off the old ones to get new ones?] Oh, because That’s the only way you can, and, and because the old ones ah get the Aspen is what, they’re there are a couple of different life strategies of trees. There, there are trees that, that, that are like the tortoise and the tortoise and the hare and they just keep plodding they live to an old age but they just move slow their whole life and and then they’re there the hares among trees, the James Dean and and they they live fast and die young and Aspen is a James Dean of trees. It lives fast and it dies young and so they kind of get decrepit. Pine will live to be three you know to 300 years old and Aspen no 50 – 60 years old and and it’s it’s in Senescence. So you have to turn aspen clones over to keep them. It’s kind of a contradiction, but you got to kill them to keep them. So you have to kill them to make new ones because they’re there they’re senescent. [So are sheep and goats the same problem as browsing Aspen?] Yes [Our aspen just finally blossomed and there’s a lot of them that are tall and dead. They’re not good. They’re not sprouting anything at all.] [Is this an appropriate time of year to clear those out will that help the health of the stand?] Yeah, you don’t want to go too much later because this is the time where stuffs happening. Because of the day, it’s a carbohydrate storage and utilization thing so they during, during the growing season while they have leaves on them. They’re making carbohydrates and storing it in the root system and, and then in the spring that those carbohydrates are translocated back up either You know to make new leaves or to create new suckers. [Is that true when the tree has no signs of life?] No, no then it then it’s it’s gone, and you got stored carbohydrate in the root system. And you better turn that stored carbohydrate into new suckers that get above the browsing before it’s gone. [My experience with aspens been a little different, I’ve tried to thin a little aspen and left maybe a 8 inch diameter aspen, seems like whenever I’ve cut the things, they look great on the outside but black on the inside.] [Does that reflect that the overstories are pine or?] No, no, no aspen in you know live fast and die young a big part of that is that it’s susceptible to ah just about every disease there is, amongst trees. That you, you, you look crowd You know you walk through you walk to the forest. and you kind of look at an aspen like that and and it gets a disease and dies. Hey, you know just its ah and, and so that that’s an example of a you know a stem rot disease. That would be an aspen. It. Just is really really sensitive. [A mature dead aspen, should you cut it or cut it at any time?] Who cares and it falls and rots really quickly, so if you don’t get to it nature will. [So when’s the best, you wanna if you wanna cut down the old to promote growth and have spring hopefully then the best time to cut is March or April?] Yeah, Fall – Winter, fall winter, fall winter when it leaves are off. [music]

One thought on “Today’s Forest: Ecology & Management

  1. A SPECIES FOREST is of, by and for all the other native species of plants, animals, fungi and soil microbes that already occupy that place. A species forest is not a resource. Sorry, Skip, but you are out of touch with the Rights of Nature. A conservationist conserves and serves the natural landscape. You are conserving resources.

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