Orchard People

[00:00:00] Introduction and Community Orchard Update
Susan: Hi everyone. This year my community orchard in Ben Nobleman Park in Toronto is looking absolutely beautiful and that's due to the hard work of the volunteers. And they include three young, fantastic students from local schools who have joined us on stewardship days until now.
The team has been really busy weeding around the fruit trees in the park. And last week we were finally ready to feed our trees. We spread out two inches of quality compost and we also added some biochar from the American Biochar company and bio fertilizer from Earth Alive. Hey, we all need good quality nutrition and, in our park, we make sure our trees get it.
[00:00:46] Challenges of Poor Quality Soil
Susan: But we do have a serious problem in our Orchard Park, and that is something that our hardworking volunteers can't really fix, and that's poor quality soil. Our community orchard was planted on a site where there was once an apartment building, and in many areas, the soil is compressed and that makes it really hard for tree roots to expand and for essential microorganisms in the soil to thrive.
So what do you do if your fruit trees have been planted in poor quality compressed soil? That's what we're going to discuss in the show today.
[00:01:23] Guest Introduction: Glynn Percival
Susan: My guest is Glynn Percival. He manages the Bartlett Tree Experts Research Lab laboratory in the United Kingdom, and Glynn has been studying the impact of combining vertical mulching with worm technology as a way of improving tree health in compressed soil.
So now with me on the show today is Glynn Percival.
Glynn, thank you so much for coming on the show today.
Glynn: It's a pleasure and, thank you very much for inviting me back.
Susan: So glad to have you back.
[00:01:54] Understanding Soil Compaction
Susan: And we're talking about soil and poor quality soil. So there may be a lot of people listening, Glynn, who don't even know what that means.
How do you know right away that your soil is compressed or really bad quality? Is there a way you can find out without doing a soil test?
Glynn: There is, and I believe in keeping things really simple. And, as I always say, when people ask me the same question, it comes down to one real issue.
If you don't like digging it, trees don't like growing in it. So just go out there with your spade and fork, and if you are having issues turning the soil over, then that's a really good indication that the soil's compact.
Susan: Yeah, now I can see that. And actually in our park, there's certain parts of the park where you start digging where we were hoping to plant a tree, and it's like rock solid.
It's so hard. Also, what about worms? if you're growing vegetables, you do expect to see worms in your soil. What about, in a general site where you're thinking of planting a tree, should you have worms there?
Glynn: Worms are a great measure of soil fertility. We know that, and you touched on it, soils have a lot of biological activity because we have to remember one important thing. Soil is a living, breathing organism and as you say, it is in essence alive. So a real quick way of determining how fertile the soil is, the general rule is for every spade full of soil, you should have between four to six worms. If you are turning the soil over and there's no worms in it, it is a really good indicator that there is something wrong with the soil.
It could be possibly contaminated, very low fertility. It could be compact.
Susan: So let's talk now about the tree's perspective here. You've planted your tree in the soil that may be less than perfect. How will it actually affect the tree? Is it simply a problem with the roots not being able to push through?
Let's get a little closeup view of how the tree feels about being in crummy soil.
Glynn: Yeah. That is pretty much in essence, there's two major problems with a soil that is compacted. One is what we would term physical impedance to root growth. The roots simply cannot push through the soil that you can't get that nice, big spread of root system we want.
The other issue is, because the soil is so compact, you've squeezed all the oxygen out of it, or most of the oxygen, and obviously roots are alive and they need oxygen to breathe. And without that oxygen or with low levels of oxygen, it's gonna influence how they grow just as it would us, oxygen levels go down and we struggle quite badly.
So does any living organism. So that is the two main issues that we face.
Susan: So with us, if you put us in a room with low oxygen, I don't know, I guess we turn blue, we don't look too good.
[00:04:59] Symptoms of Tree Stress
Susan: What will a tree look like if it's struggling and it doesn't have enough oxygen, it doesn't have enough nutrients? The soil, will you actually see some side effects or something?
Glynn: Yes. The initial symptoms tend to be, obviously, they all manifest above ground. First of all, you will have a sparse canopy you'll see influenced by premature leaf drop. The leaves will be paler, maybe slightly necrotic, as in they start to go brown around the peripheral edges.
And one of the techniques I always like to use is, most healthy trees, irrespective of species, should grow at least 10 centimeters or four inches a year. So I always measure the new growth the tree has put on at the end of the growing season. And I say I know it will differ between species, but really, if you are having less than four inches, then it really is indicating the tree's not very happy.
Susan: So most of the people who are listening to the show today, they grow fruit trees. And fruit trees are expected to grow way more than four inches a year. Yeah. There is a big expectation that it'd be minimum 12 inches, maybe 24 inches, depending if it's a cherry tree or a plum tree. I know you work both with fruit trees and with native and ornamental trees.
How are fruit trees different in terms of what they need in terms of soil?
Glynn: Fruit trees, because in essence like you say, we're growing them for the yield, the amount of fruit. So they tend to really need potentially more TLC, they need, as you touched on in the beginning, with the woodchip layer of mulch and the biochar.
These are excellent soil amendments we can use to really improve fertility. They maybe need higher inputs of types of fertilizers, whether they're organic or natural compared more to like trees going in urban landscapes. So it is a case that they are designed, as I say, to produce fruit.
So sometimes you tend to find maybe their stress tolerance, their disease resilience isn't quite as great as maybe some of our more hardier trees that would see growing in like urban landscapes such as streets and car parks.
Susan: Yeah, that and disease. Talking about disease, for anybody who grows fruit trees, knows that disease can be such a problem.
Pests can be such a problem. We have an email here and let's see who it's from. Hello Susan. Thanks for your radio show today. We love it. Just saying hello from Red Deer, Alberta. Interesting topic. Thank you. And that's from Wallace in Red Deer, Alberta. Thank you, Wallace.
Okay. We know that compressed soil not a good thing.
Tell me, how did you start your study? Like how did this all come about that you started to study compressed soil?
Glynn: Compressed soil in urban landscapes is, has always been a major issue. We have pedestrians. We have traffic. We have lots and lots of infrastructure, and it's probably one of the major, I would say, potentially killers of trees in urban landscape.
I've seen people planting trees and they're using like pickaxes and crowbars to try and get a hole in the ground. And I would say if you are planting trees into that level of compaction, they're really not going to survive, irrespective of species. And it was really just constantly seeing and going to these new building developments, going to construction sites and even a lot of supermarket car parks have lots of trees and they all look awful.
They're all struggling. And it's just this issue of compaction. So that's what really brought me into that area. And then we started to look at potential technologies that we could use to really overcome compaction. What works, what doesn't work. Because sometimes you can get some systems that really do work, but they're incredibly expensive.
And of course, time and money then become factors. So it's a case of we'd love to use this technology but it's too expensive. So maybe we can start looking at other ones. Which is really where the vertical mulching came into play, because that is actually a relatively cheap and inexpensive way of decompacting soils.
[00:09:50] Vertical Mulching Explained
Susan: So tell me about vertical mulching. That's so interesting 'cause we talk about mulching our fruit trees. We do circles around the fruit trees, expand the circles out to the edge of the canopy to make sure that we can feed the roots so there's no grass around our fruit trees up until the edge of the canopy. We put down beautiful compost.
We might put woodchips on top, and that's mulching from the top. Yeah. So maybe that's horizontal mulching. We'll call that horizontal mulching. But what is vertical mulching and how is it different?
Glynn: Vertical mulching is pretty much what you've said. In this case, all we do is we take a core of soil outta the ground before any large scale planting. I teach a lot of arborists. The first thing they do is look up. They always look into the canopy. And I'm like, no, you don't. 90% of all tree related problems are caused by problems below ground, i.e. the soil. You get the soil right and the trees will do wonderfully well.
So really, given the fact that in many cases, the vertical mulching is where we would do a soil analysis. We would work out whether we do have a compacted soil, we would send it away for analysis for its nutrient composition. We'd maybe look at its drainage, and if the soil really is very poor, we simply take out soil and just take it away.
And then we backfill. We buy a soil in the UK called John Innes. It's a very high quality topsoil. We would mix it with a really good kind of tree compost. We would put some organic matter. Really something that the roots are going to flourish. We know they're going to thrive.
And that's really about it. There's many types of formulation you can use, once you've taken the bad soil away. But we just find a good quality topsoil mixed in with compost and some organic matter. If, for example, the soil is very alkaline, if the pH is too high, that will be a good time to add some of these pH amendments such as like iron sulfate, something like that, just to lower the pH.
So really that's it in a nutshell, just taking cores out at fixed distances under the canopy and either replacing it with a really good quality soil. Or, if the soil you have is reasonable, you could then amend that soil and a great additive you could use is biochar that you mentioned earlier.
And I'm a huge fan of biochar. I think it's great soil amendment, and we've had some really excellent results using it. So I always look at addition of biochar into soils through vertical mulching to either the existing soil or to a fresh soil we've made up.
Susan: So I want to get a little more specific.
You talk about taking these core samples. So describe what that process looks like. Do you need a fancy machine? Obviously with a shovel you couldn't really make a long, skinny, hole without damaging the roots of your tree. So describe what are these core samples.
Glynn: There's two pieces of equipment you can use.
One, if you do have the money, you can buy what we call a mechanical auger. It's, in essence, like a very large drill. It makes holes, you only need to go three inch wide and we normally make them down to something like maybe 12 to 15 inch below ground. You can either use a mechanical auger, or there is another implement you can buy. It's called a Dutch auger.
I dunno if you've ever heard of it. In essence, it really is like a giant cork screw and you can just put it on and you can just twist it round and it is slower, but at the same time, it's far more inexpensive. So if you have a small area, it makes it economically feasible. And again, the Dutch auger will last for years.
So in some instance, we will just come in with the Dutch auger and start taking cores out doing it that way. At the same time, there has been a lot of criticism of the vertical mulching because people will say, it damages the root system.
Susan: I was gonna ask. Yeah.
Glynn: Valid point. It does damage the root system, which is why what I will say. It's like that little bit of short term damage is more than compensated by the long term gains.
Because if you don't alleviate the compaction, the tree will not magically get better. It will just go into a slow and steady decline, and it will eventually die and you'll end up removing it. So that short term damage, as I say, in my opinion, I'm sure there'll be people out there who will disagree, but I would always say, to me, it's worth it.
Alleviate the compaction and that little bit of damage to the root system is more than justified.
Susan: Okay.
[00:15:11] Listener Questions and Expert Advice
Susan: We have a question here from Julie, from Scarborough, Ontario. She says, my dogs love to chase each other around the trees in the backyard. Our lawn is mostly clover with a bit of yarrow, but the dogs trample down the dirt around the fruit trees and nothing seems to grow where they run.
When we planted the trees, the soil was beautiful, but the trees seemed to be very inviting to the dogs as an obstacle course. She says, we have a quince, an Asian pear and a plum tree, and they love to weave around them. We tried putting down mulch in the bare patches. What do you recommend? Thank you, Julie.
Glynn: Again, the first thing I would do is just test the soil. The simple one is pH 'cause pH can have a huge influence. Maybe just look at the nutrient composition, if there's any deficiencies or potential toxicities. And then, I think this is where a Dutch auger would be absolutely ideal.
Just take out some small cores just around the tree, actually get some really good quality soils, some good quality organic fertilizer, just below ground level. And then just try and put the mulch layer back. And, I'm sure in similar situations where we've done that, we really have had some great results.
Susan: It's interesting because I've seen pictures, and I will put up your PowerPoint on this page, where the radio show will be posted afterwards. And when I see the pictures of where you are making your holes for vertical mulching, it is actually underneath the canopy of the tree.
So I'm not sure if Julie's dogs are actually running very close to the tree or in the walkway between, but what you are saying is, again, you need to put, I don't know how many holes if it's like a big Asian pear tree, let's say she only does five holes or something. And I think what I'm understanding is you're making sure the tree gets access to nutrition.
It's a way to fight back because of the compressed soil around it a little further away. Is that correct?
Glynn: Yes. Yeah.
Susan: Yeah. So yeah, go ahead. Sorry.
Glynn: You are right. In terms of distance, we normally find something like, sorry, I'm trying to convert because I use metric, we normally go 30 to 50 centimeters to make the holes.
And the other issue, if the dogs are running around the tree and the area under the canopy, then you could do it like a giant grid and really just have the holes every 50 centimeters apart and just go down to, like we say, maybe just something like 10, 12 inch and I'm sure that would have a huge positive impact on the tree.
Susan: Sounds good. Okay. We've got an email here. who is this from? Let's see. Aldo from Toronto writes organic soil bought at nurseries. Is this soil good to mulch around the base of fruit trees in the spring? Should you do mulching during the growing season? Thanks, Aldo. So he's talking about soil that you buy, soil that you buy in bags from the garden center, not necessarily compost or manure.
He's talking about organic soil.
Glynn: Right. My only concern if you use soil as mulch, what you could run the risk of doing, is maybe bringing up the soil levels too high and actually bury in the root collar. And that's not really a good thing. Now, the beauty of using a mulch, which is normally derived from woodchips, something like that, is it degrades.
And so it really doesn't influence the soil level because if you are just putting soil on top of soil, you are bulking up the level. And that can actually be quite detrimental. So if I had an organic soil, I personally wouldn't use it as a mulch layer, I would literally apply it as a vertical mulch and get it below ground.
You really don't wanna start putting soil on top of the soil.
Susan: That makes total sense. Okay, we got, Roger wrote an email. So Roger says, hello, Susan and Glynn writing to you from Howe Island, one of the Thousand Islands in the St. Lawrence River, Canada. Nice place. You have a very interesting topic today.
Part of my property is clay and very hard to dig while another part is sandy. The sandy soil is very easy to dig. However, I think it could benefit from vertical mulching and worm technology. Will you be covering this type of soil as well? That's Roger.
Glynn: Yes. when we start talking more about the experimental setup, we will talk a little bit more about the amendments, but it is a good question because if I was treating a very heavy clay soil, then obviously I would be replacing the soil with a more sandy one to try and get that mix of clay and sand, where if I had a very sandy soil, then obviously I would be looking at a different amendment because sandy soils, again, very prone to nutrient leaching because the water runs through them very quickly, whereas the clay soil is literally the opposite.
And potentially through vertical mulching, you could actually start to move the soil, take some of the sandy soil and put it into the clay, and take some of the clay and put it into the sandy soil, and then add some of these biochar amendments and nice woodchip mulch. The right types of organic fertilizers just to get the root system stimulated and start to stimulate some of that biological activity in the soil, such as worms, et cetera. Yeah.
Susan: That's amazing. Roger's property would be fantastic to play around with. He has everything he needs. He's got the sand. He doesn't have to bring anything in.
Okay. We've got an email from Brett from Arlington, Texas. Is peat moss good for mixing in a new fruit tree? I think what he's saying is he wants to plant a new fruit tree.
Should he be mixing in some peat moss into the soil in Texas?
Glynn: Again, it's really gonna come down to actually his soil as it is at the moment. As we always say, if you have a good quality soil to begin with, you honestly don't really need any amendments. You don't need anything. But if it has a poor quality soil, then any of these types of amendments, like the pea moss, particularly if the pH of the soil is high, if it's an alkaline soil, then obviously that would help lower it.
So to me, it always comes down to what I mentioned earlier. you really have to know your soil. And this is where I always find a soil nutrient analysis of great value. And again, that little simple compaction test, if you are struggling to dig the soil, then you have an issue with compaction.
And that's when these amendments do start to work. So I'm not saying don't use a peat moss. I think whether or not it will have any benefit will depend on this soil as is. Because in many cases, I've been on sites and clients or builders or contractors have said we spent all this money and we added all this, and the tree showed no improvement. And I was like, you didn't really need to want it in the first place because if you've got a good quality soil. That it's all you need.
Susan: Exactly. Exactly. Okay.
But here's an interesting one from Bob, from Regalsville, Pennsylvania. Bob says, hi, great show. Question. I have a 120 year-old sugar maple 80 foot tree. Also a 20 tree fruit orchard, but the soil is great there.
But this is talking about the sugar maple. One quarter of the drip line area of the sugar maple is a dog yard / patio. Very shady, hard to establish grass or other ground cover. So the ground or soil is slowly eroding since there's constant activity there. Are there any strategies on reversing compaction erosion in this heavily used area?
Thanks, Bob. Sounds like Julie's question a little bit.
Glynn: Yes. Yeah, I think first of all here we're dealing with something very different because this is a very old tree. And the older trees get, a bit like us, a bit like humans, the more resilient to change they are. And so when it comes to these really old, like in the UK, we get these very old veteran trees. As we always say, you've gotta be very careful, as in very cautious.
If you wanted to amend the soil, I would suggest the vertical mulching, the quarter that the dogs are using, because the product is being put below ground. But just do a little bit, I wouldn't really go in there and treat the entire area because it's 120 year old sugar maple. And they would react, I would say, differently from a tree that is 40, 50, 60 years old. This is an old tree. So by all means do that. Do what we recommended for Julie, but just do maybe just something like, take the whole area, that whole quarter area and maybe only do something like 20% of it. And then just slowly look at how the tree responds, and the trees tell you everything you need to know.
If the leaves start to green up a little bit more and if that dieback starts to slow down. We all know our trees. Sometimes it's hard to define, if 'cause you can look at a tree and say, doesn't look right and you know it doesn't look right, but you know when it does.
But look for those signs that the tree is slowly improving. The leaves get a little bit bigger, they get a little bit greener. You get that little bit of extra extension growth.
[00:25:37] Gentle Care for Old Trees
Glynn: You see a slight better resilience to pests and diseases. With a very 120 year old sugar maple, just do a little bit rather than the whole area.
Susan: So the answer is be gentle. Gentle with your nice little old tree.
Okay, we've got one more question, and that is from David. Hi from Miami, Florida. Thanks for the great advice today. Stay healthy, David. Thank you, David. You stay healthy too. That's awesome. Okay. We have so much more to talk about.
[00:26:11] Vertical Mulching Techniques
Susan: I wanna talk about the experiment in Stockley Park that you did 'cause you had such interesting results.
So Glynn, before we dive in a little bit more, to Stockley Park, there was another email here. We were talking about, in general, vertical mulching, and you were saying you would do a three inch hole, a number of them under the canopy of your fruit tree or your native tree in periodical little spots. And you would put good soil and compost, a mix of good quality ingredients in there, and that hole would be 12 inches deep. Yes. So here we have a question from Robin, from Chelsea, Michigan, and Robin says, your recommendation is to put the hole 12 inches down, but is it okay for us to do a more shallow hole?
Thanks for the presentation, Robin.
Glynn: Yes, I mean, there's really no hard and fast rules here. It's just that we know the bulk of tree root systems are in the top 60 centimeters of soil. So by going down 12 to 15 inch, you are going to get a good portion of the root systems. But any, even if you were only going down like 2-3 inches would be beneficial.
We just went with, as I say, into the top 25-30 centimeters of soil. So the answer is yes. Yeah. Even if you can just make 1-2 inch deep. It's gonna be beneficial.
Susan: It'll be beneficial. Okay.
[00:27:38] Stockley Park Experiment
Susan: So let's talk about Stockley Park. That's where you did your experiment and vertical mulching has been around for a while, I understand, but what you did was something different. So tell us the story.
Glynn: Vertical mulching is actually frowned upon by the industry because, really, you are drilling holes under trees and it damages the root system. But Stockley Park is a business park and it's located on the peripheral edges of Aether Airport.
So it's a very important, as I say, lots of organizations like Sony and Canon and Bayer all have offices there. It's this huge, beautifully, heavily manicured landscape with thousands of trees and hundreds of thousands of shrubs and fountains. Lots of pedestrians and traffic. The dilemma is they have huge issues with compaction.
So all these thousands of trees are, what we say, they are surviving, not thriving. And I mentioned growth rate. So, on average, they will grow in like maybe two centimeters a year. So in 10 years they will grow 20 centimeters, which is about four five inch. It's really not much. So the problem was that there was such a vast expanse of area that decompacting everything was, it was just impossible.
We couldn't do it. So we sat down and we thought, can we have an alternate approach? And what happens if we have something like, say a 500 square meter area, with trees and landscape? And it's where people come out and they sit under the trees for the shade. We can't decompact it all, but we can't afford to replace our trees.
So I said, why don't we take pockets like islands within that area of say, 20 square meters? And why don't we decompact it in such a way that, in theory, once we've decompacted it, we can add things to the soil that will slowly move out and decompact the surrounding area.
[00:29:48] Implementing Worm Technology
Glynn: And, of course in nature, what decompacts soil in nature? It's worms.
So we started to think about why don't we start looking at adding worms, put them into these 20 square meter pockets, these little islands. Make sure the soil is really well decompacted. We've got lots of organic matter in there. And then, in theory, once the worms established, they're gonna start to push out.
They're gonna move from that decompacted area. And the hope was that, with time, these little islands, the worms would push out and actually meet up. So that's exactly what we did. And it was a great trial site because it allowed us to look at a whole range of soil amendments such as biochar, such as slow release fertilizers, such as organic fertilizers.
And another thing we did, which I think you mentioned earlier, was it also allowed us to do what we call a green cover crop, where we literally decompacted the soil and then sowed clover. And then, later on, in winter, when the clover dies, it's fixed all the nitrogen. So again, even then we were trying to look at ways and means of really letting nature do the work. Decompact the soil, and let nature do the work.
And the reason why we went with the vertical mulching is because it's actually very quick. There are other technologies to decompact and one of them is called air spading where you use compressed air. But that is, it does a better job when it's far more time consuming. And what we found with vertical mulching is, we could do eight to 10 square meters of vertical mulching in the time it took to do one using an air spade.
So I'm not saying don't use an air spade 'cause it really is a great tool. This was just a niche situation where you literally had thousands of square meters to decompact. So that was the premise behind it. And what we found, over time, is those worms are doing exactly what we wanted them to do. They are pushing out, and that heavily compacted soil is slowly over time.
This experiment's been running for three years. We want it to go for at least another two. But they are definitely pushing out and we're just seeing such the trees are just looking so much better. As you mentioned, you referred to my PowerPoint where we have some really great photographs of trees that are in that decompacted, worm amended soil versus trees that are still in the compacted soil.
Susan: That's an amazing, an exciting experiment. And the pictures will be available for people to download when they go back to get the podcast of this show. I wanna clarify, so you are putting in, if you say, however many square meters in that space, let's say 5% of the square meters will be, of the holes that you're making?
Glynn: Yes.
Susan: 5%. Let's say now you're making the holes and you will fill the holes with a mix of soil and compost and whatever appropriate amendments. Are you actually putting the worms into those holes?
Glynn: In some cases we do. We actually add the worms. And in other cases, and I know it sounds absolutely incredible, but the worms we actually use, they were native British worms, which, and I couldn't believe it existed, but we actually bought them off the internet. And I didn't realize you could buy worms, as in live boxes of worms, off the internet. But you can, 'cause they use worms for composting food waste.
They use tiger worms. But these are specifically designed to decompact soil. So really we just bought these boxes of worms and some we added directly to the hole. And in other cases we made a bigger hole, amended the soil, and just simply opened the box, gently put the box in the hole, and then just covered up.
There's honestly, there's no real rocket science here. I sometimes feel a bit fraudulent, as a scientist, saying it's really that easy. We are just drilling holes and taking away the bad soil. And replenishing with a good soil and adding worms. Now obviously the worms in Canada, I don't know what the native worms are in Canada, but they will be different from the UK.
But in my situation, we just simply, as I say, literally got them off the internet and did exactly what you've just said.
Susan: Okay. So you've got a site. A large site. You've got your box of worms. Are you expecting each worm to move for miles and miles, or is your big hole quite close to the small holes?
The vertical mulching holes? So that somehow, because they've got terrible soil to be working through. How are they gonna do it? Even if you've got a hundred of them in a hole, like they might just end up squirming around and hanging around each other, not going anywhere?
Glynn: That's a great point.
That's why I was really keen to emphasize the holes really have to be maximum 50 centimeters apart, which is half a meter, one and a half feet. If you make the holes too far apart, then potentially, the worms will exhaust all those resources and you've got too many worms in too small of a hole or too great of a distance, and they're not going to make it.
So spacing is critical. So 30 to 50 centimeters apart, three inches deep. Go down 12 to 15 inches, and then add a few worms, and that's what gave us really good results. Obviously, over time, we may play around with the spacings. But we know the system we have works really well, so we're staying with that. And as I say, we'll tweak it over time.
Susan: That's amazi
[00:36:02] Measuring Success at Stockley Park
Susan: ng.
So Glynn, I wonder how exactly you were able to measure the results at Stockley Park.
How did you know? Was it just by looking at the trees and you saw, okay, one tree looks a little happier than the other, or was there something a little more, in terms of record keeping, that you were able to record?
Glynn: Yeah, I mean, it's, for example, I touched on earlier that soil is a living, breathing organism.
So one of the things you can do, is literally measure how much oxygen and or carbon dioxide the soil gives off. So we literally looked at the decompacted soil and the amount of carbon dioxide it was producing. And then we looked at the compacted soil and then over time we could start to take these values.
So we really looked at below ground and then we knew things were happening 'cause we were starting to see worm casts coming above ground. So we knew that was good. And then the soil that we hadn't treated, we would send it away to look for a nutrient analysis. So this is all the sciency stuff we did, below ground.
And then also the tree itself. We could measure leaf color. We can measure how green. There are various instruments like a leaf chlorophyll content meter, which sounds very geeky and sciency, but you really just clip a leaf and press a button and it tells you how green, how much chlorophyll there is.
So we could measure how much chlorophyll it was putting on. We did more things like look at how much photosynthesis, et cetera. And then what we also did, because there's a lot of interesting trees for their functional value, as in how much pollution are they absorbing? How much shade are they producing to protect from ultraviolet light?
So we did a lot more of these measurements as well. So 'cause importantly, we have to remember that, sadly, there's obviously money needs to be behind this and the people at Stockley Park wanted to see a benefit. So we were looking at all these other hidden benefits and saying, oh, by the way, your canopy has increased by 20%, 30%.
And they're like, so? And I'm saying, that now means you are now basically absorbing, you are like neutralizing three or four cars, or you are neutralizing a bus with all the pollution it's given off. So we did lots of these types of measurements. We really wanted to show how much carbon the tree was sequestering.
So again, that's important at the moment in terms with climate change and trees are being looked at for carbon sequestration. So we could say, look, our treatment is giving you all these extra functional values. So that's really what we did. Lots of the basics, the size increase, the canopy increase, the girth increase, and then how much more pollution carbon dioxide, how much more dust it was filtering, how much ultraviolet light protection the tree was giving.
Susan: It's interesting because in your slide, just a lot of detail. Oh my gosh. There's so much detail and there's one picture that's really striking and where you show four trees in a row and one says control, and it's a small tree. It looks small, and the treated one is huge. So it looks to me like the treated trees actually get bigger and grow more.
Glynn: Oh, yeah. Literally we were seeing like 30%, 40% increases in canopy size. We were expecting some benefits, but we were really like, wow. Because when we first set this project up, we just really had no idea it was going to work. So every so often, and you go along the lines with the experiments, and a lot of experiments I do tend to be what we call busts.
They don't really show that much, but this was great. We really source some excellent benefits from it. Yeah. Which, visually, are quite striking.
Susan: It's amazing. Guys, whoever is listening to this show, you really must, and I will put it up. You must download the PowerPoint. Very interesting.
Lots more information in detail.
[00:40:25] Additional Fruit Tree Care During Decompaction of Soil
Susan: I've got another email here. And it's from Julie again from Scarborough. Hi again. Thank you so much for answering my question. I was wondering if we would need to prune our trees to reduce stress on them while we work on decompacting the soil.
Glynn: I personally don't prune trees when I'm decompacting, mainly because the decompaction is so heavy.
The trees are struggling anyway, and if you start to prune away. You're pruning away leaf area and leaves are the main photosynthetic organ, and really the whole point of the decompacting, is to really try and get that extra canopy growth. 'Cause the more canopy growth, then obviously the more kind of what we call photosynthetic productivity, the more energy the tree has.
So I personally would not prune while decompacting. I would let the tree have as much green leaf area as possible.
Susan: Okay. And we've got another email. This one is from Hannah from Raleigh, North Carolina. Hello. Amazing advice today. Thank you, Susan. Thank you Glynn. This is great.
[00:41:41] Meeting Royalty
Susan: I don't know if you guys realize this, Glynn is actually a very special person and he has met royalty in his work.
So Glynn, can you tell me how it is that you hobnob with royalty and what kind of interactions you've had?
Glynn: I'm very lucky. I do look after the trees, or I help manage and advise on the trees at some of the royal households. And, it's quite an honor and a privilege. Do you want me to quickly tell the story?
Susan: Yes, please.
Glynn: Okay. the first time I met, it was when I first met the queen and I was in the palace and there are two rules when you're in the palace's.
No mobile phones and, no walking on the ornamental lawns. And my mobile phone went and it was a health and safety officer. So I walked right into the middle of the mobile to the middle of the lawn with a mobile phone, went outta nowhere. These two rather feral corgis came and were ripping away at my bottom of my chainsaw trousers.
And, we have a saying in the UK. I was on the verge of, sticking the boot in and I was just about to kick, which, I didn't because then I heard this voice and it said, Come here, come here, you. And there was the Queen of England walking straight towards me, and I'm in her ornamental lawn on the mobile phone, and she's getting closer and I could not turn the mobile phone off.
It wouldn't turn off and I'm trying to say to the health and safety officer, I've got to go. I've got the Queen of England walking towards me. You say, yes, of course you have. I said, no, I have. And she's six feet away from me when I managed to turn the phone off. And she just stopped. And she smiled and just smiled so sweetly and just said, there was no need to hang up on my account.
It might have been somebody important, which I thought was truly wonderful.
Susan: Oh, that's so adorable. That is very sweet. Aw. That is such a great story. Glynn, thank you so much for being with me on the show today. I love having you on the show. You're gonna have to do some more research on something else Amazing, because we gotta get you back.
Glynn: I would love to come back on the show. It's been an absolute pleasure and I will carry on doing lots more research.
Susan: Good. Do lots of interesting stuff because we're learning a lot from you and all the other amazing experts that come on the show. We may be home growers or small scale growers, but we really benefit from the research that you guys do, so thank you so much.
Glynn: Okay, thanks Susan.
[00:44:05] Conclusion and Farewell
Susan: Thank you so much for tuning in. It's been wonderful to have you as a listener, and I hope to see you again next time.