S.6 Ep.10: Uneven by Design

The legacy of the “cutover” has left much of the Lake States—and many other regions—with a dominance of even-aged forest stands. Today, both landowners and foresters increasingly consider converting these stands to uneven-aged management to achieve a range of ecological, economic, and aesthetic goals. However, the outcomes of these efforts—even after multiple stand entries—have sometimes fallen short of expectations. Significant silvicultural challenges remain in determining the most effective approaches for even- to uneven-aged conversion. To explore these challenges, we’re joined by Dr. Ralph Nyland, Distinguished Service Professor Emeritus of Silviculture at the SUNY College of Environmental Science and Forestry. 

To earn CEU/CFE credits, learn more, or interact with SilviCast, visit the uwsp.edu/SilviCast.

Transcript

S6 E10 Uneven by Design

[Greg Edge]

Welcome to Silvicast, the podcast about all things silviculture. My name is Greg Edge.

[Brad Hutnik]

And I'm Brad Hutnik.

[Greg Edge]

And we are both silviculturists with the Wisconsin DNR Division of Forestry and your hosts for today's show. 

[Ralph Nyland Doll]

Skill, patience, deliberateness.

[Greg Edge]

Brad, are you still using that Dr. Ralph Nyland action figure?

[Brad Hutnik]

Giddy up. And I made some improvements.

[Greg Edge]

Oh, no.

[Brad Hutnik]

You might recall you just clip Dr. Nyland onto your cruising vest. And anytime you find yourself in a stand where you need just some good silvicultural advice, you just pull the string.

[Greg Edge]

I recall. Yep. Okay.

Pull the string.

[Ralph Nyland Doll]

Well, once a runt, always runt.

[Greg Edge]

Man, I was hoping that thing would not make another appearance, but I guess I'll bite. Brad, what improvements have you made?

[Brad Hutnik]

All right. Well, first, and you may recall, I, I did make this thing a little more heavy duty. So we put a carabiner on here, so that should hold it in place.

The, the shower curtain hook, you know, that, that was just coming off in the hazel and that. I almost lost him twice.

[Greg Edge]

Oh, I can imagine some hunter in the woods finding this freaky doll and he pulls the string and just spooks him out. 

[Brad Hutnik]

Yeah, Well, we don't have to worry about that now. And so second improvement, I even added some more sage advice. So check this out.

[Ralph Nyland Doll with Brad’s voice]

Hutnik, stop your whining and move it.

[Greg Edge]

Wait a minute. That does not sound like Ralph at all. He's way too nice for that.

[Brad Hutnik]

Well, remember that day we were taking regen plots at sand hill wildlife area and it was like, what surface of the sun hot? And I just wanted to add some, I don't know, like, you know, kick yourself in the butt quotes, you know?

Cause some days it's a little unpleasant. You just got to keep things moving.

[Greg Edge]

Okay. Well, yeah, that was a, that wasn't very unpleasant day. Yeah.

What else do you got?

[Brad Hutnik]

All right. You'll like this one.

[Ralph Nyland Doll with Brad’s voice]

A brilliant application of relative density. Brad, tell me more.

[Greg Edge]

Oh, geez. Now I know you're living in a fantasy world.

[Brad Hutnik]

Oh, okay. Okay. I used a little creative license, but the important thing is how the action figure makes you feel, Greg.

And Dr. Nyland has inspired me and foresters to become better silviculturists for decades. And you know what? I think he would even approve of it.

Well, we'll see about that.

[Greg Edge]

I can agree with you that Dr. Nyland has taught and inspired foresters for years. So guess what? You can actually show him the action figure yourself because today on silvicast we'll be having another conversation with Dr. Ralph Nyland, distinguished service professor emeritus of silviculture at SUNY college of environmental science and forestry today, we're going to talk with Ralph about the challenging and sometimes perplexing silviculture around converting even age stands to uneven age management. 

[Brad Hutnik]

Perfect. Now I can get more quotes. This season of silvicast is brought to you by the Nelson paint company, McCoy construction and forestry, and the family forest carbon program. You make the silvicast world go round.

So thank you. Dr. Ralph Nyland, welcome to silvicast.

[Ralph Nyland]

Thank you.

[Brad Hutnik]

For those out there who are still working through your silvicast episodes, Ralph, you've been on before and we had a great conversation at that point. Today, we're going to talk about something different, but I got to tell everyone in the audience, this is for the rest of the silviculture nerds out there. Ralph, when you were in Wisconsin back in 2018, you spoke at our Wisconsin SAF meeting.

[Ralph Nyland]

Yes.

[Brad Hutnik]

And of course, as a proper silviculture nerd, I brought my copy of silviculture concepts and applications, third edition for you to sign. And I love the inscription you put in there because I think it applies to some of the stuff we're going to be talking today.

[Ralph Nyland]

Oh, it's censored now but yep.

[Brad Hutnik]

You said with best wishes for the future and for many interesting challenges. And to me, that's what like good forestry is really looking forward to the challenges that we find. So today, and Greg, it made me think of what we're going to be talking about today, which is this whole concept of converting even age stands to uneven age stands, and you've had a long history of working with this.

[Ralph Nyland]

I have. I started with that paper some years ago, and then I've been following a couple of stands where accidentally people had been doing a conversion, but we need to make it more deliberate.

[Greg Edge]

Yeah. And actually this week, Brad and I were up at the Argonne Experimental Forest, which was kind of formed, uh, to look at those second growth, even age, Northern hardwood stands we have here in the Lake States and study, uh, that, and so we had quite a few conversations about conversion of that even age condition to an uneven age condition.

So we thought, oh, having a conversation with, with Ralph would be a great, um, topic in this area. And I was, I was just kind of holding my breath. When Brad was reading the inscription in the book, I thought maybe you had put something about their best of luck, Brad.

[Brad Hutnik]

No, no, that was my, that was my college professors, Greg, at the end of my, at the end of college, they're like, I hope you get a job. Yeah.

[Greg Edge]

Yeah. Yeah. I hope, I hope you stay employed.

Yeah. Yeah.

[Brad Hutnik]

So, so Ralph, so it seems like we're talking about this and we, Greg, I know you and I, we've been having conversations about conversion for a while. Um, and it, and it, I don't know if it's maybe the thing, but it seems like we're, we're talking more about the concept, um, based on your perspective, cause you've been working with this for quite some time, Ralph, uh, what do you think is driving this?

[Ralph Nyland]

Well, I think back to my time and working with non-industrial private owners who had limited acreage and they just didn't want to use a even age regeneration method, thinking it might be ecologically destructive, at least based on everything that's said about it. They don't want to see that abrupt change in conditions that would follow either clear cutting or shelterwood method. And I think consistent with that, many non-industrial owners and many others to just want to have a continuing forest cover to realize somewhat consistent values and yields from their forest and look for greater stability in, in what happens within a stand, then you get with even age development.

[Greg Edge]

So landowner objectives really many times drive that desire to move that stand to an uneven age condition. So they don't experience some of those things you described.

[Ralph Nyland]

Yeah, I think that's true. The, they may want to add some greater structural complexity. That's been hyped a lot of late in the theme for many people.

On even age stands with their greater structural complexity provide for a different kind of habitat for plants and animals, and they provide a greater stability or consistency in, in the hydrologic conditions and the visual qualities and whatever values are associated not only with complexity, but also with tall tree cover. So conversion, a long patient process gives one way for people to try to address those concerns. I think in all of this though, it's looking for some kind of consistency through time that they might get from multi-aged stand rather than a single cohort one.

[Brad Hutnik]

I know from talking to a lot of landowners, it does feel like, you know, sometimes we consider a lot of that, but, but I think it is sometimes just really the aesthetics of it too, right? Like people don't want to look at, at what that even age management looks like. And so we, maybe sometimes we couch it in the ecological, but it's really just them thinking, you know, I don't want to see that.

And so even if it is a two aged or like you mentioned, multi-aged, no matter what it does, at least it gives them some respite for their eyes.

[Ralph Nyland]

I agree. I agree that to me, that's a, that's a driving factor in many of the things that have been controversial over the last several decades. It's a change in visual quality.

That's what sparked the clear-cutting controversy in the Appalachians. You remember when the Senator went squirrel hunting and didn't find his stand there anymore?

[Greg Edge]

Yeah. There in kind of lies the challenge I see for foresters to meet those objectives and move those stands from that even age to the uneven age condition. So we've had, as Brad said, a lot of conversation about this and we've tried it in different ways.

But what are some of the conditions, Ralph, that you think should be present for the conversion process to be successful? I know here in the Lake States, for example, we talk a lot about even just the assessment of that stand initially is a challenge for us to determine. Is this an even age stand?

Is it an uneven age stand? And so making that determination sometimes, for example, in Northern hardwoods is, is a challenge. So I guess, yeah, what are some of those conditions that we need to be thinking about?

[Ralph Nyland]

That question is the most important in all of silviculture to know what you're working with. In uneven and even age stands and uneven age stands with a important component of shade tolerance species like sugar maple and beech in Northern hardwoods, small trees of short heights and even age stands, they are there because they grew poorly, not because they're young. And you see this structure, apparent structural characteristics where the the shortest trees, the overtopped ones are in the understory.

And then you get an elevated canopy with intermediates, co-dominants and dominants above that. But as you start looking at those trees and even age stand, you'll find that the overtopped trees may have only about a 10 percent live crown ratio. The intermediates may be 15 percent, the co-dominants 20, maybe 25 percent.

And the dominants really only 25 to 30 percent. So there's a limited length of crown on all those trees. And there's a tight upper canopy, a lot of crowding within that canopy and slow growth.

But if you do a thinning, the truth is that the intermediate size never get big. It's like in agriculture with pigs. Once a runt, always a runt.

And that's that's what's going to happen with small trees in even age stand. Now, contrast that to uneven age stands where you find an irregular canopy layer to have short trees that are young and intermediate trees that are midsize and old trees that are big. And they'll all probably have something like a 40 to 60 percent live crown ratio in managed stands.

So if you do a cutting and thin out the canopy layers, the small trees really grow. In fact, the data we have shows that the small trees in uneven age stands grow faster than the large trees. So you can depend on those small trees in even age stands.

So you cannot go into an even age stand and do a selection like cutting, something that mimics the selection system marking guide for even age stand and expect anything but long term disaster. It just does not work. So getting back to the most important question, take time to examine the stand and make a determination.

Now, there are some things you can look at besides the live crown ratios. The bark patterns in small trees of even age stands look old. In uneven age stands, they look young.

The canopy is elevated and tight with a gap between the ground and the canopy and even age stand. There's a continuous what I call a green wall of foliage in uneven age stands, and those help you to understand or make a decision about even or uneven age. So don't do these selection like cuttings to mimic selection system, but you need an entirely different strategy if you want to start converting an even age stand to a multi-age arrangement.

[Brad Hutnik]

You know, Greg, it's probably an indictment of a lot of our management where we've been doing stuff like this. But when you think about that inversion of growth, right, so where your bigger trees aren't growing faster, your smaller trees are growing faster. I'm just trying to think of there aren't many places where we actually see that where we're doing this work.

I mean, like, and we don't oftentimes look at the growth rates, but I know a lot of times I've looked at, we've seen smaller trees and they might, they're still growing slower, even though we've kind of, we've worked with them in an uneven age condition or work toward that uneven age condition.

[Greg Edge]

I was thinking about just in that assessment process of oftentimes we don't look really closely at those growth rates, but just could we look at those growth rates of the different sizes in a truly uneven age stand and see what you're saying, Ralph, is that we do still have good growth rates in the small trees to help us make some of those determinations.

[Ralph Nyland]

You can look at the crown and really make a pretty good judgment. If the tree has a large, full, vigorous crown, it probably is growing well, has good vigor. If it has a small, short, narrow crown, it's probably not growing well.

And the small ones never do rebuild a crown adequately. They'll get better, but never really good.

[Brad Hutnik]

You know, Ralph, so you've been thinking about this. I know you wrote a 2003 paper that talked about the even age to uneven age conversion process. And, and it was kind of interesting.

I'd like that where you talked about uniform cutting and then kind of a patch cutting as strategies that we might employ if we were going to work through this. So maybe for our audience that, you know, we haven't all read that, but what's the difference between uniform cutting and patch cutting and maybe some of the other things that you've been thinking about?

[Ralph Nyland]

Let's think about the uniform cutting strategy. And we're, we're talking even age stands now.

[Brad Hutnik]

Yep.

[Ralph Nyland]

So, so essentially you need to thin the upper canopy a bit, but really take out the small trees. And I vision that as kind of a C grade thinning for below. You cut the overtop, you cut the intermediates and some of the co-dominants enough to give some light around the crowns of the better co-dominants and the dominant trees.

[Brad Hutnik]

And so Ralph, with that C grade, you're, you're taking that down on the stocking chart. You're going to the C line. So going below the B line going, no.

[Ralph Nyland]

You take out intermediates and some of the lower co-dominants.

[Brad Hutnik]

Okay.

[Ralph Nyland]

But back to 60% relative density.

[Brad Hutnik]

Oh, okay. Got it.

[Ralph Nyland]

Yeah. You want to maintain that full net production per acre.

[Brad Hutnik]

Okay. Okay. 

[Ralph Nyland]

Then when you do that, it'll brighten the understory sufficiently that if you have a stand in reproductive mature age, you should get an understory response. It'll be not just trees, but you should see some herbaceous growth as well, forming down there. The key is you have to wait until you get a reproductively mature tree.

And that'll be anywhere from 50 to 70 years of age before you start this. It also means that you can't have serious herbivory, you know, the deer problem, the moose problem, snowshoe hare, but also understory interference. If you've got interfering shrubs or herbaceous plants or understory beets, for example, you need to do something about that as the first step.

Then let the stand develop. We found that we would even get a component of shade intermediate trees in this stand after the first cut. But so 10 to 15 years later, you thin again.

This time we're going to use a crown thinning or a modification of that to free the crowns of the best dominance and the best of the co-dominance at uniform spacing that will help to maintain tree vigor in the stand. It'll brighten the understory again. And with reproductively mature trees in the overstory, we should get another cohort forming the second cohort in that stand.

And then as time goes on, we'll repeat this process at recurring intervals, possibly needing to lengthen the return time as the stand gets older, or even put a pause and just wait long periods of time, maybe after the fourth or fifth entry. So we get enough upgrowth from the younger age classes to allow for an operable cutting in. That would be the overall strategy for the single tree process.

[Greg Edge]

It almost sounds like a uniform shelter wood in a way, but you're just extending that overstory longer.

[Ralph Nyland]

Yeah. Yes. The reserve shelter would keep only a low density of seed trees and maintain them for a few decades and then remove them, but we're doing something here that's, I guess, mimicking that process, but gradually building from the bottom up a series of age, and this is going to take time, several decades.

[Brad Hutnik]

So that's the, like what you described as the uniform system, which kind of leads you then to kind of, we could take a look at selection, but what about, you mentioned a patch approach as well, or patch cutting.

[Ralph Nyland]

Right. This would move you towards eventual application of group selection system, but it's also like the uniform cutting, you could potentially balance the age classes this way. So what I would do is I would thin from below again to 60% relative density for most of the stand, and that will brighten conditions inside the patch and facilitate potential for regeneration of mid-tolerant species if you have a seed source.

And it also will, because of the brighter conditions, at least in the center of those patches, the new cohort will grow more rapidly than they would under the partial shade of the other strategy. Then perhaps 10 to 15 years later, you make a second entry. And this time do a crown thinning and add some new patches at the same rate, no more than two for three acres, that helps to maintain tree vigor, promote understory development.

So you do this through repeated time and you collectively begin building up cohorts from the bottom up to eventually get a multi-aged stand. I think though that as with single tree cutting, after maybe four, possibly five entries, we may need to put a pause in here to wait for sufficient growth to support another treatment, either for the thinning or for the patch cutting.

[Greg Edge]

Brad, that method sounds a lot like what came out of the argon in what we call here for our Northern hardwoods are even to uneven age conversion process. And that's essentially just what you described, Ralph. It's creating, well, we call them gaps, but openings of about that size frame and then essentially thinning the rest of the matrix of the stand, and then kind of starting to try to build those new age classes in there.

That's interesting though, like thinking about what you said too, is we may need a pause in that system to allow just those new age classes to develop more and become more operable, and that's something that we don't often talk about. I don't know if we're there yet, you know, in terms of...

[Ralph Nyland]

Well, no one has been there yet. So we're trying to use what we have in our brains to anticipate. We have to be adaptive and ready to adjust.

[Brad Hutnik]

With the patch system thinking more, that may have a greater application across a wider range of cover types as well. And maybe just that selection, kind of one that leads to selection too.

[Ralph Nyland]

I think that where you're depending on species of lower shade tolerance, that might, that would be the truth. Yeah. Perhaps in some of the oak types, but I think in Northern hardwoods it would work and in Bruce fir it would work, and in many of the mixed wood stands it would work.

[Greg Edge]

If you're dealing with ones that have a little lower shade tolerance, could you change up the size of those patches a little bit just to get a little more brightness in them?

[Ralph Nyland]

Well, you could, yeah. You'll have to use your judgment here, but remember the bigger you make that opening, the fewer you have in the stand. So the bigger patches might very well work better where people have larger properties and just accept the fact that on limited acreage owners, you're going to, and in many cases, you're just going to make a conversion to mostly shade tolerant species and any mid-tolerant tree you get is kind of a bonus.

So you take it, but don't plan on it.

[Greg Edge]

So Ralph, those two methods, and then are there any variations or other systems people could consider to look at that conversion or variations on those?

[Ralph Nyland]

Yes, certainly. And some of these things have emerged as people talk about this, what they're often calling ecological silviculture, trying to mimic what people have proposed or the dynamics of the pre-settlement forest, the forest before Europeans immigrated to North America, which seemed to call for large patch cuttings, so there's a couple of different ways we could do that. One would be what I'll call dispersed patch cutting without thinning.

So you'd simply locate patches across the stand randomly or in some systematic way, and then not thin between the patches. As a first entry, you would cut those large patches perhaps as wide as two times the height of adjacent dominant trees, and even covering areas of one to two acres in some cases. Now remember, when you have a width of at least two times the heights of adjacent trees, conditions at the center of those large openings will resemble clear cuttings, so there may be some advantages to that, but there are, you need to be cautious about any downsides of that clear cutting.

You will get brighter conditions at the center of the patch, and that improves the chances for the less shade tolerance, and it will also facilitate rapid height growth of whatever regenerates within the opening. But don't thin between the patches. Allow the natural dynamics to change there.

Through time, the trees will decline in vigor, and that's a downside of this, and some trees will likely deteriorate and die to the point that they become useless, or in the new interest in things like cavities and snags, they will become the future cavities and snags. In a regular interval, you need to return from another series of patches located adjacent to the original ones perhaps, and do this periodically until you eventually cover the entire stand. We might call that way to get to a multi-age range for the progressive patch silviculture.

[Brad Hutnik]

Ralph, I'm curious if one were thinking about that, would there be prioritization of where you would put patches within the stand? Like I'm thinking about advanced regeneration, or maybe adjacent to seed sources for things you would want. Would you work to set a criteria for that, or just make them kind of maybe regular at some distance within the stand?

[Ralph Nyland]

No, you could do that, and I think that's where the on-the-ground inspection in advance, doing some inventory to figure out what's out there. The problem with normal inventories is you don't know where these things occur. So with the new GPS, you could mark the locations of trees you want to use as an adjacent seed source, for example, or where you find a scattered patch of advanced regeneration.

So yes, take advantage of what you find there. That's where a thinking mind becomes the essence of silviculture.

[Brad Hutnik]

Looking for continuing education credits? Check out the Silvicast webpage for more information. And now, back to our show.

[Greg Edge]

We've had a lot of conversation with foresters who like to establish those openings as a separate operation ahead of time, because then they can go through and assess where this stuff is spatially, and put those openings in, and get it to the right level that they want.

[Ralph Nyland]

Now, I think we could also think about a particular European strategy, femelschlag. You've had Bob Seymour discuss this in a previous cast. Some people call this a regular shelterwood method.

I'm not going to argue about the terminology, but you would start that process by cutting several large patches or openings dispersed at random or systematically, even covering as much as an acre or perhaps a little bit more per patch, and not thinning between those patches. And at some preset interval, perhaps you would turn for cutting a second set of patches around and adjacent to the original ones. So if you started by cutting maybe five or six patches out there dispersed around the stand, you'd come back and cut new patches adjacent to each of those five or six openings.

And then as that would create a second age class in the second cut patch, and you repeat this through time, each time expanding this cluster of patches, each time getting a new age class in the newly cut areas until eventually you will have covered the whole stand and have a multi-age arrangement in clusters with several age classes per cluster, but each cluster being similar in their age arrangement. That's called a femelschlag.

And again, I would refer people to the Silvicast by Bob Seymour. He also has a YouTube video that people can access to see an example on the ground.

[Greg Edge]

Yeah, right, Brad, we won't get into terminology debates around irregular shelterwood because we've had plenty. 

[Brad Hutnik]

Oh, yeah. 

[Greg Edge]

But both Bob's episode talks about that, and we also talked with Tony D'Amato about that as well.

[Brad Hutnik]

So what I found really interesting and just kind of preparing for talking about things like that, and actually, Ralph, I found it in your book, is that sometimes I think we kind of skip past some of the terminology we already have. But when I was looking at group shelterwood, a group shelterwood, and you can correct me if I'm wrong here, but group shelterwood essentially look like expanding gaps, but maybe with regularity.

[Ralph Nyland]

That's right. And in fact, that's another variation. It's an unusual variation that you could, and I think it's one that people could consider.

The difference here is that instead of coming back in a relatively short period of time to expand each gap, you extend the cutting interval. So you have a longer wait between doing one cutting and the next. So you start by cutting a series of circular patches, if you want to call them that, to the stand in some sort of a pattern.

Perhaps a grid works best here to facilitate the future development, and likely you'd have widths of about one times the height of adjacent dominant trees. Then at pre-planned intervals, you come back and cut a concentric ring around each of the original groups. And usually this would happen after you see that regeneration is formed inside the original patch and along peripheries underneath the edges of the uncut areas.

So you would then cut this ring of trees around the original patches. And as time goes on, repeat that process so that each of the original patches gets larger and larger and larger, each surrounded by concentric rings of different age classes, until eventually everything coalesces into one big regenerated stand of these clusters of concentric rings of different age classes. It's a takeoff then on the group shelterwood method.

This is the one I call expanding gap.

[Brad Hutnik]

And I have to admit, Greg, I don't think I've seen that very much here in the Lake States or here in Wisconsin. But I know we're talking about stuff like that.

[Greg Edge]

I think we're talking about it more. And I think in some senses, foresters have applied it, but not really necessarily named it as such. You know, they've gone in and reacted to openings where they have regeneration and then seen it around the perimeter, as you said, Ralph, of that and then expanded those in their marking.

But they just maybe didn't call it a particular name.

[Ralph Nyland]

The name is less important than the concept. Well, people have in mind what they want to do and have a deliberate plan for doing it. That's the important part.

[Greg Edge]

Yeah, I guess that's what I was thinking when you were talking, too, about, yeah, we discuss a lot about the terminology and the names, but it really goes back to the silvics of the species. And as you said, assessing the stand and being deliberate about what you're doing.

[Ralph Nyland]

Yeah, these are models, conceptual models. And we know that every place we go, something will be different. And that's where a forester, someone skilled in silviculture, will make the difference in interpreting what's there and figure out what to do next.

[Brad Hutnik]

I'm curious, Ralph. So we did mention, like, you know, with some of the, with the first conversion process, you can't really go in before you're getting seed production in that stand because you're basically not going to have anything to populate those openings. So are there general rules?

Is there, maybe you can't start it. So I think that's recognizing maybe we can't start it too early in some stands, but could you start it too late in a stand, too? Are there are kind of thoughts about, like, parts of the life of a stand where maybe it's most appropriate to try conversion?

[Ralph Nyland]

Well, I'm not sure there's, it's ever too late. But the most important part is that you must wait until the stand has reproductive and mature trees in the overstory. And then you can plan on getting some seed, but you want abundancy so that it blankets the understory of the ground.

There's another factor. You could probably start some of that as early as, say, 50 years of age in northern hardwoods, but you won't get an operable cut. So I would recommend waiting until you could get a first operable thinning in the stand.

And in northern hardwoods, that probably comes more like at 70 to 75 years of age. Here in New York, we could get one and a half to 2,000 board feet international per acre out of such a treatment, along with 12 or 13 cords of pulpwood or fuelwood. And that would make it operable if you had that fuelwood market.

Those are the constraints that I see. As long as you have reproductively mature trees, you could go ahead and do this. Remember that at some point, sometime after 100 years, you'll begin to see openings form naturally in the canopy.

It's the beginning of that gap phase dynamics that goes through what Mormon Likens called a transition period, that after maybe more than 250 and up to 200 years, you begin having something that we could call old growth. So I think certainly you could do this up to 100 or 120 years of age.

[Brad Hutnik]

I suppose the caveat would be with some, like say we weren't in northern hardwoods, if we were in oak, just as long as you're going to be able to hold that overstory through that long period of time. I guess that's one caveat for thinking about this and other things other than say northern hardwoods.

[Ralph Nyland]

Yes, and as long as the trees have sufficient vigor to produce good amounts of seed at regular interval.

[Greg Edge]

And I think what you're saying too is when you get to those older stands, some of this starts to happen, whether you try to or not, just because of that gap phase dynamics start to kick in.

[Ralph Nyland]

Yes, exactly. You may not get the species you want, but you will get tree regeneration at that time.

[Brad Hutnik]

Greg, that sounds like a familiar story that I've seen in a lot of places. That we'll get regeneration, we just may not get the target species that we were looking for when we use some of these systems. 

[Greg Edge]

Yeah, for sure.

[Brad Hutnik]

Thinking about this, Ralph, in a big picture, are there any downsides to thinking about this going from the converting even to uneven age? You know, I've talked to foresters who I think are a little leery because they're thinking about sacrificing volume and growth, or maybe they're just going to sacrifice some species or things like that.

[Ralph Nyland]

Yeah, that's true. With no single entry, may recover high amounts of volume. It'll be limited because you have to be patient and petition the cut of that original age class.

So it requires landowners who want to make the conversion to accept that fact. They're just not going to optimize or maximize volume production. We get less overall volume each time and less overall volume as a result of the conversion process.

So they have to perceive it's a decision that transforming a stand is the important objective, and they want to follow through with that. I think the slower growth, the rate of development of those younger age classes also feeds into in that it takes a long time for a tree to reach operable sizes. You know, it may be 75 or 80 years before you get anything that looks like saw timber, and your process may have to go 100 or 120 years to complete the transformation.

Thus, that's where the pause comes in. You may have to wait for stuff to grow up into operable sizes, and that results in a reduction in volume production. From the non-market value, the hydrologic conditions, the habitats for plants, that I don't see the downsizes in that as much, except that you're going from this structurally simplistic condition to a structurally complex one through a series of steps.

[Greg Edge]

Yeah, I keep thinking about the amount of time it takes to do this in the multiple entries. That just also means you need to protect those new cohorts coming along each time you come in, right? And you have more opportunities to damage that in that process.

[Ralph Nyland]

Yes, that's a key factor, particularly if you just use conventional logging and drop those big crowns down on top of younger ones. It can prove devastating. I've been pleasantly surprised.

In the last selection system treatment I applied, we were able to get the contractor to bring in a good-sized feller buncher, and they could grab onto even those 20-inch trees and lay them on the ground so that we virtually found no logging damage at all. The contractor was diligent enough to develop appropriately wide straight skid trails, and that reduced skidding damage. So I think this is possible with the new approaches for mechanized harvesting, but probably not as such with conventional chainsaw felling.

I've seen where that was used, and it just devastates these younger age classes, smashes right down on them.

[Greg Edge]

And I think Bob Seymour mentioned, too, with the Acadian femelschlag system, the importance of those skid trails and thinking about how you're going to get wood out in those subsequent entries.

[Ralph Nyland]

But that's true with all silviculture. When you do thinning and even-aged stands, you plan your trails not just for now, but what will happen in the future. And it's absolutely critical in the selection system with uneven-aged stands.

[Greg Edge]

Bob, what about the effects on species composition? Is there a downside to doing this conversion process?

[Ralph Nyland]

Yes, particularly in stands that have mixed species to start with. In northern harvests, perhaps, a component of ash, cherry, yellow birch, you're likely to lose those species, even with patches of one times the height of adjacent trees. There will not be many of them.

So you just have to accept a transformation that results in shade-tolerant composition. And if you get that occasional birch or ash or whatever, that's a bonus in the process. But accept the fact that this will bring a transformation to primarily a stand of shade-tolerant species.

[Brad Hutnik]

You know, as foresters, we go out, we do inventory, and I think we do practices, and then we kind of sometimes just wait, right? Like we're not necessarily monitoring what's happening out there over a longer period of time. It feels to me like monitoring and inventory are really critical to, especially, conversion process.

[Ralph Nyland]

Well, all silviculture, and particularly here, you need to make a good inventory before you start to know what's out there, to see how you're going to make adjustments. Then, after you've done your first treatment, I always find it helpful to go right back in and see what happened, because you get surprises every time. In the second entry before that, you do a detailed inventory, make a new prescription, particularly important for the thinning part, but also deciding where to locate the next set of patches.

So you need to confirm the status of what you created and plan the strategy for the next entry to a stand. It's absolutely necessary in any silviculture, and that includes a conversion process.

[Greg Edge]

I keep thinking about the time frame of this, and I know, Ralph, you mentioned a little bit about we have to be patient. We're looking at four or five entries, and I think about the lake states here, and sometimes we have not been patient. We've not waited for these stands to get to that condition.

I don't know. It's not so much a question for you. It's just thinking about the long time frame of doing these types of processes.

[Ralph Nyland]

Well, that's true, but think about what forestry amounts to by its definition. It's this long-term process for sustaining values seven generations into the future, and we have the sustainable yield concept. It doesn't get much attention these days, and it may be because of the short ownership of many non-industrial owners who have a tenure for, what, 10 or 20 years at most.

And I think we just generally get impatient. We expect to push a button and the results come out in 50 or 60 seconds, so patience, long-term thinking, but that's the essence of forestry, isn't it? And it's the critical part of silviculture to remember that when we do something in silviculture, we're setting up a residual stand to grow and develop into the future, so silviculture is the process of creating residual stands, and then long-term will grow and develop to satisfy the interests of a landowner.

[Brad Hutnik]

It sounds like something I've heard other professors or foresters talk about, like when you're working with the stand. In a way, you're not as worried about what you're taking out as what you're leaving behind, because that's what you're going to be working with as you go forward.

[Ralph Nyland]

Exactly.

[Greg Edge]

Brad and I like to ask our guests a question, and I think you kind of already just answered it, Ralph. Which is what, Brad? What's that question?

[Brad Hutnik]

Well, if you were going to give a piece of advice to a forester starting this process or anything like this, any kind of topic we're working with, what would that be?

[Ralph Nyland]

I always told my classes on the last day of the semester, when all else seems to fail, think. We have brains. We have good brains.

We have brains we've filled with all kinds of understanding and knowledge, and there's nothing mechanical about silviculture. You don't do the same thing over and over again. You make a prescription each time to fit the situation at hand and the needs of the landowner into the future.

So when all else fails, think.

[Greg Edge]

You know, I've been telling Brad that for years.

[Brad Hutnik]

I think I'm going to get a tattoo that says that, so I can just look at it every so often.

[Greg Edge]

He just doesn't seem to listen to me, so maybe. 

[Brad Hutnik]

No, you say, listen to me, and there's a difference between think and listen to me, Greg, so yeah.

[Greg Edge]

Well, I think it kind of just emphasizes that there's so many variables in doing this process, and as you said, between stands, that's the fun part of it is, to me, is thinking, is trying to puzzle it out and to work out the best strategy.

[Ralph Nyland]

Agreed. That's what makes silviculture fun.

[Greg Edge]

Yep, exactly. 

[Brad Hutnik]

Or as you said, Ralph, looking forward to the interesting challenges.

[Ralph Nyland]

Yes.

[Brad Hutnik]

So maybe it's just in the end here too, so thinking about conversion, you know, we've been talking about this whole concept and then the different parts of that, so we talked about like maybe where this pressure is coming from, or maybe not pressure, but just the interest in what we're doing with it. Do you picture more of this happening over time, like this expanding and people doing more and more conversion in the future?

[Ralph Nyland]

It will take landowners with a commitment to the future, so that's the first step, to get more people who seem to be concerned about the future rather than the present, but I hope we will never focus on only one thing. To satisfy that wonderful diverse array of landowner objectives out there, we need a variety of silvicultural methods, and so we need to keep all of them alive, all of them in our toolkit, so as we meet a situation and a set of concerns, we can dig into our tool bag and pull out the one that's going to be appropriate at that time and that place. Of them, conversion, one tool among many.

Let's keep our tool bag as full as we can with as many different options as we can.

[Brad Hutnik]

Well said.

[Greg Edge]

Yep. Well, another really interesting conversation with you, Ralph, like Brad and I so much appreciate talking with you about these topics, and so I just say thank you.

[Ralph Nyland]

You're welcome.

[Greg Edge]

This was fantastic.

[Ralph Nyland]

It's fun to do. Thank you. Thanks for having me on Silvicast.

[Brad Hutnik]

Yeah, and we'll look forward to future conversations with other projects coming up or other topics. We're going to bring you back in, Ralph.

[Ralph Nyland]

Sounds good.

[Brad Hutnik]

For sure.

[Ralph Nyland]

I'm here. Take care. Bye.

[Greg Edge]

I just love our conversations with Ralph Nyland, Brad. It almost makes me wish, and I emphasize almost, that we could fit all his knowledge into that action figure of yours.

[Brad Hutnik]

Yeah, be careful what you ask for, Gregor. AI is on the way. We're going to improve this thing.

But hey, do you remember on our first episode with Ralph that we did on single tree selection?

[Greg Edge]

Yeah.

[Brad Hutnik]

I went back and listened to it, and I forgot we had a limerick on that show.

[Greg Edge]

I do recall that you wrote a limerick.

[Brad Hutnik]

Yep.

[Greg Edge]

And you actually put it out there as a quiz because it was a riddle.

[Brad Hutnik]

And it was good. And it inspired me to write another one.

[Greg Edge]

I don't know if it was good, but you wrote another one?

[Brad Hutnik]

I did. You're going to read it, aren't you? I'm going to read it.

You can't stop me, Greg. You might try, but you cannot stop me. There once was a forester from SUNY whose vest held his tools close and handy.

He measured each tree with great jubilee and waltzed to the tune of sound forestry. Yeah? I should just cut you off right there and say thank you, Greg.

You're welcome.

[Greg Edge]

Okay. But aren't those lines supposed to rhyme better? You had like SUNY and handy?

[Brad Hutnik]

Yeah, they end in Y, Greg. You're getting so picky. See, this is why creative people have a hard time in regular society because people like you ask for details.

That's just…

[Greg Edge]

Just go with the flow. 

[Brad Hutnik]

Whatever.

In any event, thanks for listening to today's episode of Silvicast. If you have ideas for future episodes or a question for the Dropbox or comments on Limericks or anything, just let us know. You can reach us at UW-Stevens Point's Wisconsin Forestry Center by emailing wfc at uwsp.edu. Now, feel free to include a sound file of a question so you can record your question and send it to us or just send us a comment or whatever you want. But always remember, we learn best when we wrestle with questions. So please keep them coming.

[Greg Edge]

And take care, everyone. And as always, thanks to our team. Susan Barrett, our editor-in-chief. Joe Rogers, our IT master. Theme music by Paul Frater. And of course, UW-Stevens Point's Wisconsin Forestry Center.