Tinisha Spain: Hello and thanks for joining us for another episode of Mid American gardener.

I'm your host, Tinisha Spain, and we are not going to waste any time today, because, as you can see, we've got a lot to cover my palm.

Ryan Pankau is here from extension.

So introduce yourself and tell us a little bit about you before we are off and running Sure.

Unknown: My name is Ryan Pankau.

I'm a Horticulture Educator for Illinois Extension here in Champaign, Urbana.

And so I serve Champaign vermilion Ford in Iroquois County, so a little chunk of Central Illinois.

And so we're here today to talk about kind of tree and shrub pruning.

And my experience is as a forester and an arborist.

I've worked in kind of both roles all of my career.

And so my first job right out of college was as a commercial arborist doing residential tree care.

And so it's kind of the love of my life, and the thing that I really like to talk about, and Tinisha Spain: how timely is it that we are having this discussion, because it's about time for us to get outside and start tinkering around and seeing what needs to be done and shaping things up.

So I'm going to let you just jump in, and I'll ask some questions as we go, because and grab a pen and paper and take some notes and record this episode, because you're going to need it as you get out there and begin to shape up those trees and shrubs.

So all right, so March, take it away.

Unknown: We're in March.

Yeah, sure.

Well, so one of the first questions I get from folks is, why do I need to prune my trees?

Because a tree in the forest doesn't need to be pruned.

And that's that question really hit home for me, or has kind of resonated being also a forester and an arborist.

But the simple explanation is, the trees in a forest, if we look at a natural stand of trees, have developed under competition, and we have really tall, straight trunks, not a lot of side limbs, till you get way up in that canopy.

So everybody can kind of picture that where, if you look at an urban tree, or a lot of trees that grow in cities, or with open light or no competition and just full sun, they tend to branch out and spread out.

And what we really see a lot is just a big clump of limbs around the stem at about head height.

Because as humans, we'll prune those limbs up out of our way, and then we stop.

Tinisha Spain: And then once they get up there, they're not our problem.

Yeah.

Unknown: And so what that does is create some instability, or some structural, you know, weakness in the stem right there, where you have this big cluster of all these limbs coming out.

So that's why we need to prune, is to kind of get that that proper form that trees developing under competition in a forest, as they evolve to do for millions of years, typically have, and that that competition and that that just competition for light and resources eliminates the weaker trees, the ones with that, that straighter trunk and better canopy form, win overall and become that the mature canopy.

So in a nutshell, that's why we need to prune.

That's why we prune.

And so let's talk about timing and pruning.

You alluded to that this is the time of year that is the best for pruning our trees, and that's because they're in dormancy.

And we take, when you think about a tree's annual energy budget, you know, its energy is produced in its leaves in the fall time it takes that energy back into the plant.

In the springtime, it reinvests that energy in new growth.

So right now, all that energy is saved up.

And if we do pruning right now, we don't take away as much as if we pruned it at more of the worst times of the year, you know, not as good at times of the year.

So that will be during flowering and leaf out, because energy has been invested into those twigs, and then we're cutting them off before they can produce a leaf that would return some of that energy.

So the single best time is during dormancy.

If you can't prune during dormancy, the next best time would be after those leaves have fully emerged.

And the thinking behind that is that then those leaves have emerged, they've produced some energy, and the tree has no net loss.

Then when you cut off that that twig, another bad time to prune is as you start to creep into fall, all these little twigs start to harden off and get ready for winter.

And if we prune, you know, I usually say after about mid September or so, you can promote some new growth that doesn't have time to harden off and get ready.

So that can be timing is really important for this.

The timing is really important.

But I do get questions from homeowners a lot.

It's not the right time of year to prune, but I have this limb that's hitting me in the head, and I just really have to take it off car, yeah, and so, so that's not a big deal out of the regular season, especially for a healthy tree.

If you're just taking off a limb or two.

What I'm talking about is pruning that entire canopy.

So anyway, that's kind of that's how timing works.

But I'd like to have quite a bit of discussion today about the strength of branch unions and the structure of the canopy, and those things that we can really influence early on in a tree's life to set them up for that, you know, really stable canopy structure as an adult.

So the first concept I want to talk about is aspect ratio, and that's just the concept of the diameter of this side limb, whichever one of these, these are really even in size correct.

So we're really looking at, you know, the size of the diameter of the main stem versus.

Is the side limb, or, you know, the comparison of these two, where, when we get to a one to one ratio like this, this is not as strong of a branch union as another one that has a smaller side limb.

And if we think back to the forest, you know, the model of a forest tree, this is more like what we would have on a side limb, rather than equal sizes.

Or on an urban tree, a lot of limbs in one spot.

So to demonstrate this concept of aspect ratio and strength, I'm going to test your muscles today.

I have a few, a few different branch unions we're going to try and break.

So this would be kind of similar to that one to one ratio, a weaker branch union, then this little guy that is smaller.

So why don't you try see if you can just bust that apart.

Just give it everything you got.

Okay, wait, can't quite so that was fairly easily broken, too, and we can see it split just right down the middle, right down the middle.

So that's we'll talk about this in a minute when we start to assess some of these branchings A little more.

So give that one a try.

See how that works.

If that breaks as easily, I didn't give you as long, well, pull a little further out on the edge there, right out of the tip, so see that much smaller limb, tough, but much harder to actually break.

I don't want to look Tinisha Spain: this.

Okay, so it's hot.

Unknown: So, so, yeah, so that kind of, that kind of shows us that this, that's strong this, this is a stronger branch unit.

And some of the reason is that relates to how trees and we plants grow.

And so the the main way they grow, what we call primary growth, is from the buds from the very tips of the limb, way out on the edge, as opposed to a grass that grows from the base.

And that's why we can kind of mow off a grass.

If we mow off a tree, we know that's really going to hurt the plant.

So primary growth starts in the tips, and that would spur this kind of side limb to start to grow first, and then secondary growth in a tree.

Think of tree rings.

So think of this trunk getting larger each year, secondary growth happens after that primary growth, which creates this kind of nice overlapping structure within this branch union versus this more like a one to one ratio where, remember, your split went just right down the center of this thing.

We don't have that overlapping growth.

We just, we really just have secondary growth interacting here.

And in this case, you can see a little bit of bark is being trapped in the middle part of this branch union, which creates a weakness, which is probably why you could just easily snap that apart.

Tinisha Spain: So these are the ones that we lose during the storms and the wind and the ice and when it's heavy, these are the first ones to Unknown: go exactly right down the middle, and that's why we're trying so when we're making pruning decisions, we want to look for more U shaped branch unions like I would call this, you know, that's maybe an L shape even.

But really, really tight shaped branch unions like this are not as strong as more open ones, and it has to do with just some of this bark getting trapped in here and having some issues with that.

So as we're making pruning choices around the canopy of our tree, if we can favor more open branch unions versus tighter ones, that's just a basic choice that's good to make with a pruning cut.

All right, so far.

So So anyway, that we've kind of talked about branch strength, so you're going to be thinking about that as you're pruning, but really a step ahead of even making a cut is to assess that tree's health.

So there's a couple things we can look at with that now.

Tinisha Spain: Is that difficult to do when the tree is dormant?

Is that a tough job this time of year?

Unknown: It's more challenging.

Yeah, I'd say like step one in all this is probably trying to identify your tree species.

So you really kind of need to know that, and know a little bit about the tree, to know how much we're going to prune and how it's what its natural growth habit would be, some of those things, but, but you're right that we don't have this canopy of leaves to assess where, if we could look at this tree in the growing season, or if it's in your yard, and you could think back to the summertime, think about how full that canopy is.

Is Is it full of leaves?

Are there dead spots?

You know, we can really just easily think about, was that a healthy tree canopy or not?

If we did have leaves on, we'd look at maybe leaf color and leaf size.

If you know how big that leaf should be for the species that you're looking at, that's a real good indicator of health.

Because as soon as trees start to get stressed, their leaves shrink.

Although we can't see it, they get thinner instead of thicker.

A lot of times they'll be off colored.

So I mean, those are some things during the growing season, but we don't have all that right now, right?

So we need to look at other indicators.

And the best thing that I and this is what I look at during the winter or summer, any time of year, is annual twig growth.

And how long of a twig was this plant able to grow?

Tinisha Spain: How close what species This is sugar maple.

I know Unknown: because I took it up a tree where?

But no actually, if we wanted to identify this sugar maple, we could tell that it was opposite branching the twigs come out across from each other on the stem.

We could also see that it has.

Little clusters of really pointy buds on the tips.

It looks like that one was actually busted off.

I don't know if that happened, but right here you can see it really.

See that really pointy bud.

That's one thing that's really common with sugar maple, but little bit on the ID there, if you're interested.

So but with with sugar maple, I brought it in because you can really see that twig from last year, right?

It's a different color, if we could see enough detail right here, there's actually a structure called the terminal bud scale scar.

And if you want to think about this as this was last year's twig, there's a little bud right here.

It started to grow and produce this twig.

Tinisha Spain: You can definitely see the difference in coloration.

Yeah, there's Unknown: really a contrast.

And you can see some little wrinkly bark right there.

Tinisha Spain: That's growth from summer or spring summer 25 Wow.

So that's Unknown: pretty good growth.

This was a healthy tree.

So if I saw this, I would say this tree is pretty healthy.

I can prune away on it.

You know, where what I see in really stressed trees is just a few inches.

Or we can actually look further back down this twig and find that terminal bud scale scar for a few years back, if the bark is smooth enough on really thick bark, trees, like a Burr Oak, has quirky twigs that'd be harder to see.

But you can also assess the trend.

You know, are the twigs getting shorter?

Are they getting longer over the years, which would indicate its stress condition.

And so that kind of leads into talking about pruning dose, or the amount that we might prune on a healthy plant.

And that's really kind of changed over my career.

I started pruning trees in the late 90s, early 2000s and back then, we kind of said you could, for a healthy tree, you can prune a third of the canopy out in one pruning, it's a good chunk.

That's a good chunk.

And you know, to sit there and discuss, have you pruned a third?

What are with all these limbs on the ground?

That's really kind of a hard thing to see, too.

But you know, as science has come along, we started to dial that back and say, really, it's probably closer to a quarter that we should prune.

And in 2023 the industry pruning standards were updated to say you really need to assess each tree and prune no more live material than necessary.

Tinisha Spain: Now is that for the trees recovery?

Is that for?

Why are they being more conservative there?

Unknown: Yeah, it's for the kind of that energy flow in the tree and trying to preserve that.

It's also taking into account the amount of energy put in, put into closing over wound, pruning wounds, and that, you know, what's invested there, and how quickly those wounds can close over.

Because each time we make a pruning cut, we, you know, give an opportunity for a pathogen or something that can produce rot to start to enter the tree, right there.

So a tree is trying to grow over that wound and seal it shut.

Tinisha Spain: And if it's got a whole bunch of cuts all, okay, yeah, that makes sense.

That's kind of like our immune system, yeah, very, very similar.

So you have to always, like, I need the comparison.

So that makes sense.

I like to kind of humanize trees, too.

Unknown: So, so anyway, that that helps us kind of assign a pruning dose where I still think one quarter of the canopy, if you have a really healthy tree, if you've seen good twig growth, and you can kind of check the boxes on that, I think that's probably still a pretty good and, like, kind of ballpark figure for what you should prune.

So another thing to think about is transplant history.

And you know, I really think we could do a lot better job pruning trees when they're younger.

We could probably do a better job of pruning them in that first five to 10 years to set them up with this canopy structure that would set them up for life.

So think about that transplant history.

We say trees are usually in transplant shock for two to three years.

This twig growth is going to tell you as they're kind of coming out of that.

But for a newly transplanted tree, I might make a cut or two to kind of correct a big problem, but I'm probably letting it sit in the ground for a year or two and kind of recover Tinisha Spain: that get established.

Okay, Unknown: so let's see.

So for our steps, pre pruning, we're also going to look at dead, diseased and dying twigs and limbs and stems.

That's what we're going to try to assess.

Are there any problems?

There any problems?

And I brought in a really common problem that we're seeing across central Illinois nowadays.

This is off a service Berry, and I've got the twig upside down, but we can see a lot of damage along the bottom side of the twig.

And I think you probably know what I'm getting.

Tinisha Spain: To my nightmare summer of the cicada.

Cicadas, I'll never forget it.

Unknown: Yeah, so we had a big cicada emergence.

I guess it wasn't last summer, summer before, but you can still, still see the damage on this twig from that and what this and so it's not always a bad thing that there's some damage, but you can see this surface barrier hasn't quite grown over and closed up these wounds.

So it's, it's not doing wonderfully at closing those over where I've seen other plants that in a season, they just, you know, close that up.

So this Tinisha Spain: is an indication that Unknown: something's maybe not as healthy on this plant, or this plant had just extensive damage.

I mean, every twig had it.

On it.

So it's going to take a little while to seal, you know, grow over that.

This is kind of a special case, but when I see like a whole surface barrier canopy that has this, I'm probably pruning it pretty lightly to not create more wounds.

If you had one limb with some damage like this, it's not a bad idea to cut it off, let that that wound close right here, and not have this big, ragged twig that has to have a lot of lot of closure happening.

But anyway, so we're going to look for kind of some of those disease and damage limbs.

Those are going to be some of the first things we take out.

We're going to look at all sides of the plant.

And I have a picture of a Japanese tree, lilac from our Extension Office that you've got pulled up there.

And this is just a good example.

I took this picture with the corner of the building lined up with the trunk.

And notice on the left side of that canopy there's not a lot of limb structure.

On the right side there is, and that just has to do with like its light exposure over the course of a day.

But if you walked up to that left side of the tree and just started pruning away and thinned it out even more, you sure would have an imbalanced canopy by the time you looked walked around the other side.

So that's just another step.

Is to walk around your plant, look at all sides, even while you're pruning.

Go ahead and, you know, take, take a step back a few times and look at it to make sure you're keeping it balanced.

And so the last, the last step, kind of in, in this basic pruning process, is to establish pruning objectives.

Oh, gosh.

And, you know, this sounds like a huge thing.

Sounds like a serious step, but how pruning objectives kind of help us is that when you're trying to figure out, how much can I prune to get down to get to that one quarter, or whatever my target goal is, how can I prioritize my cuts to meet those objectives and stay within my dose?

And so that's why I suggest you kind of, and I wrote out kind of a set of pruning objectives we'll pull up and show here that just are a good example of with with a shade tree, it's really important to have a central leader.

So that's the second, you know, objective on that list.

The first thing was what we just talked about a second ago.

Let's prune out all the dead, dying and diseased limbs.

There's objective one, anytime you're really pruning a tree.

Number two, for a shade tree, is establishing a central leader, and that's just that, you know, Tip Top growing point of the plant that's free of competition from others.

And what happens with an open grown tree is a lot of these side limbs are spurred to grow and kind of compete with that central leader.

Tinisha Spain: They're chasing the sun, and there's competition and every Okay, and they're going to Unknown: create some of these really even sized branch unions up here that are competing.

So we're trying to kind of eliminate those couple problems there this permanent scaffolding limbs on the tree.

Are those just permanent side limbs that are there for all the life of the tree.

And remember, the tree grows from the tip, so if a limb is this high now, it's never getting higher or lower.

It's only getting longer.

So so there's kind of some basic numbers for that spacing.

I try to tell give people some a few numbers as guidelines, but don't get obsessed with that, because nature is never perfect.

You'll never get six inch spacing perfectly up and down your trunk or anything like that.

So that's kind of a kind of an idea of where it might fall.

Ground clearance is really important.

We've talked about that's usually the only pruning we do, is ground clearance.

So and then finally, duplicating and crossing branches.

If they're crossing, they're rubbing, creating a wound.

If they're duplicating, they're kind of growing to the same area and competing for light.

So at the end, we'd kind of look for some of that, some people refer to that more as thinning, as a concept.

But at the end, we kind of look at thinning, but that's my order.

And so at whatever point I feel like I've pruned a quarter of the limbs, I'm stopping then, you know, and hopefully I can get to, if I'm really good at balancing all this, I can get to the bottom, and I've accomplished all those objectives.

So let's talk again about how to determine when to when a tree's in dormancy and when it's not, because that's that's something we're about to approach right now.

And I brought in some Norway maple twigs here, and you can see, don't they have some big, just beautiful buds, just big, round, plump buds.

And this is one of the first trees in my yard to flower, and this is one of the first trees to start to open its its buds up.

And that's that's how you can tell when this tree has exited dormancy.

It's starting to infuse energy into these buds.

You can see a little bit of maybe green at the tip of this bud, but what you'll see a bud is usually a lot of scales pressed together, and as those start to open up, you'll see a little crack of green start to come through.

And that's what I'm looking for on these, normally maple buds.

Tinisha Spain: Of the bud, the indication that dormancy is breaking, or is it that little bit of green, that little bit of movement in there, Unknown: it's that, it's that bud starting to open up and get energy shot into that so once that green, once that bud starts to open up a little bit, all the energy is being sent there, and when you cut it off, you're just robbing your tree of that energy.

So that's that's when we're going to kind of stop.

Okay, so now we've kind of talked about branch unions, pruning objectives.

Why don't we talk about just the nitty gritty of how to make a single pruning cut the actual.

Cut, actual cut itself.

So a lot of this key is on.

Can you pull out a couple bigger samples we have here, identification of the branch collar.

And so the branch collar is just a really important part piece of tissue on this tree.

We can kind of see it where this branch starts to enlarge and this barks a little bit wrinkly.

You can see that collar tissue.

And really, if we look at, you know, kind of point with my marker, you can really see just about right there is where we would cut, right along this line to leave this, this area that's enlarged and cut off this, this limb.

And I'll pull up another kind of example here that really illustrates this.

This is a large chunk from firewood splitting that I saved, and you can really see that branch collar right here.

So this, this was actually probably a dead limb at the time it we don't there's not a great example of that overlapping, interweaving tissue right here.

And I know that's what makes tells me this is dead, for one thing, and also its color.

Some rots been started right here.

But you can really see this collar tissue wrapping around it.

Illustrates it well.

Why we want to leave this in place is that this is the area on the plant that is stimulated to then grow over the wound.

And we say pruning cuts don't heal.

They seal to humanize it again, like trees cannot regenerate tissue like us this, this area that behind the cut is never going to start to grow again.

The tree just grows around it and encapsulates Tinisha Spain: it so but if you cut that too close, then it has trouble healing itself exactly.

Unknown: Okay, yeah, so we, I've got an example of a red maple pruning cut I made, and I've just kind of watched, and this was at a family member's house.

And so you can see where that that pruning cut kind of start to form a little donut of what we would call callous tissue that starts to grow there, and then eventually it closes over and just blocks everything out.

So any, any type of rot inducing fungi that got into there, it's cut off water, it's cut off oxygen from that, and it's hopefully limited the spread of that.

Tinisha Spain: So nature is so fascinating.

Oh, Unknown: it's super cool, super cool.

So that that's great when we can see the branch collar like on this particular cut.

But if we go back to one of these, this isn't a great, you know, limp stem we've already talked about.

It's not an awesome stem to branching and have in the first place.

But if we go back to this, we don't really have a branch collar.

And this is what happens when you have, you know, equal size stems.

We can see the same thing on a lot of these twigs.

So the way that we usually make this cut then, and there's collar tissue in here.

We just can't see.

It's not as pronounced.

We center, we center off of what's called the branch bark ridge.

And there's a little bit of, like, maybe an old limb right here that made this little more pronounced.

But you can find this on almost every twig.

It comes out of the center of the branch union.

It's what kind of gets trapped in here, it comes down the branch.

If we take, if I take this marker and I draw what I'm estimating to be a 90 degree, it's not showing up super great, a 90 degree angle off of our branch bark ridge.

So right there and then.

If we bisect that angle by drawing more of a 40 degree, 45 degree angle.

That's about the angle of our cut on this.

And that's a really rough drawing, but this helps you kind of visualize when you can't see it, how to make a cut like that.

And so this would also work on like a smaller twig.

So we've got about three minutes left, so just enough time for you to try and make a few of these pruning cuts.

So on, on these twigs, you can still see kind of that branch, branch bark ridge.

And to make that cut, you're still, you're going to try and, you know, capture that 45 degree angle off the branch bark ridge.

So see if you can, see if you can prune one off, and we'll assess your grade.

Tinisha Spain: Me.

Oh, boy.

Okay, all right, whichever one you want, here we go.

Unknown: All right, so that's, that's a pretty good cut, capturing our angle, I would probably get just a little bit closer, okay, but, but no, that's got about the right angle there of our 45 degree.

But you know, if you can, you did pass the test, but if you can picture that kind of callous tissue starting to grow around this, we're going to leave that in place, let it grow around it.

The other thing I wanted to point out is, if we make a really tiny cut by a bud, we're always going to make a pruning cut at a branch union or a bud, not just in the middle of the stem, because in the middle of the stem we don't have that branch collar tissue, so near a bud, you're gonna leave just a little, just like you did here, you're gonna leave a little bit, because that bud could dry out.

So that was the main thing I wanted to mention about that.

Tinisha Spain: Whoa.

That was a whirlwind.

So get out there and prune those trees, folks, now you've got your marching orders.

Thank you so much for this.

This was a lot of really great information, and.

So timely, we've been trying to get you in the studio for a while, so I'm glad that you came.

Really appreciate it.

If you have any questions or any questions about pruning or gardening in general, send them in to us at yourgarden@gmail.com or search for us on socials, and you can find Ryan with extension.

You can find him just search Ryan Pankau... Unknown: Yeah, University of Illinois, Illinois Extension, you'll find me.

Yeah, im on the Champaign County page, and we've got to get you back here, so.

Definitely, thanks for having me.

Thank you and thank you for watching.

We'll see you next time.

Good night.