Episode 514 Forests in Cities

Sandy Smith, Heather Schibli, and Michael Rosen are foresters and arborists who often work with trees in urban areas, including farmland. They agree that we an expect only negligible early effects on global carbon sequestration from planting forests in cities, and that the urban environment makes such forestry difficult. Nevertheless the many services provided by trees make such a project highly desirable, even as a climate control measure, for among other factors, the temperature of cities with forest canopy is about ten degrees less during hot periods than without trees. For the video, audio podcast, transcript and comments: https://tosavetheworld.ca/episode-514-forests-in-cities. After watching or listening, post your thoughts on the comment column.


Sandy Smith

Heather Schibli

Michael Rosen


trees, forest, carbon, plant, people, cities, sequester, land, tree, cut, big, canada, growing,      foresters, carbon sequestration, forested, backyard, agriculture


Heather Schibli, Robin Collins, Michael Rosen, Sandy Smith, Peter Meineke, Metta Spencer


        Metta Spencer opens the forum by mentioning the research a Crowther and his researchers who estimated the number of threes in the world at three trillion. They argued that the world needs about one more trillion to reduce global warming. The idea caught on, and Canada promised to plant an additional two billion trees, which sounds impressive until you realize that a trillion is 1000 billion, so two is very little.

        Moreover, Crowther’s study proposed that there is room for a trillion more trees, but they were counting on the Arctic for that, though trees in the Arctic have a net warming effect rather than cooling the planet because of the albedo effect. They are darker than the snow around them, so absorb light and heat rather than reflecting it. Also, Crowther’s study supposed that trees would not be planted in farmland or where people live, though in Spencer’s opinion, cities are the best place to add trees, for people live close enough to care for the trees for a couple of years. Besides, people enjoy trees.

       The experts on this panel are foresters who will discuss whether whether promoting urban forestry is a reasonable proposal or not. All Canadian Pugwashites are welcome to join the discussions with the experts.

        The goal is to encourage millions of Canadians to plant trees in urban regions and along highways and country roads, where people can help them survive. In cities, lawns and parking lots can be replaced with mini-forests. There are three or four parking spots for every car, but soon we will be taking driverless electric taxis instead of owning cars. The taxis do not park but move on, so there will be millions of parking spots to fill with trees. They do have to be looked after in cities, but many Canadians will gladly adopt a local tree — planting it and then watering and weeding it.

       Sixty percent of urban trees are on private land, such as backyards, where they thrive for long lives if allowed plenty of root volume. However, institutional and highways lands also offer opportunities to plant trees in urban regions.

        Landscaper Heather Schibli specializes in “mini” forests in cities, inspired by the Miyawaki system of planting native species densely together in small spaces such as strip malls, beside churches, and behind school yards. Recognizing the social nature of trees and their capacity to nurture the soil and the social life of people, she has planted nearly 300 species in her own backyard and her forest is flourishing.

        Robin Collins agrees that urban tree planting is worthy, but it will not be a major sequestration solution soon because of scale and the lengthy period required for a tree to mature.

        Peter Meineke asks about using other types of trees, like bamboo and hemp, that absorb carbon faster than traditional trees, and expresses concern about the damage to houses caused by trees during storms.

        Sandy Smith, a forestry professor, observes that the age of an urban tree affects its ability to sequester carbon. She emphasizes the multiple values that trees provide, not just carbon sequestration, but also other services that society needs. Urban trees often reduce the average temperature of a city by ten degrees or more, providing comfort to people. 

      Metta Spencer asks about the logging industry and whether there is a better way to remove individual dead trees from the forest with less damage to the whole ecosystem than clear-cutting swaths of trees.

        Michael Rosen replies that clear cutting is actually a recognized silvicultural system that can regenerate forests in perpetuity, when applied in the right way. However, this depends on the type of forest and the shade tolerance of the trees. Some species of trees, including pines and oaks, are intermediate in shade tolerance, and for them a silvicultural system called the shelterwood system is widely used. It is in between selection and clear cutting.

       Dead trees, according to Rosen, also play an important role in forest management, as they support much more biomass and biota than live trees and should be left for insects and bird production. Clearcutting is not the same thing as deforestation, which actually changes the land from a forest to farmland, say, or road construction, or mining. When it comes to global warming, cutting down big trees at their optimal growth for carbon sequestration is important, as elderly trees can actually release more carbon. However, the utilization of harvested wood is crucial, as burning it will prevent carbon sequestration and increase global warming.

       Metta Spencer replies with dismay to Rosen, noting that the amount of canopy cover in the world is decreasing,  Whenever you clear-cut, you reduce the amount of CO2 being sequestered by trees. To maintain the number of trees in the world, we need to find more other places to put them, such as urban areas or along country roads and expressways. Spencer worries that the method of silviculture that Rosen is promoting will exacerbate the global warming problem.

       Michael Rosen suggests that there is marginal agricultural land that can be converted into forests, and that agriculture has become more efficient, requiring less land to grow more food. Metta Spencer replies that we need to focus on improving the quality of soil to make it more productive and reduce the impact of industrial farming. Robin Collins believes that while planting trees in urban areas is a good idea, it will not significantly contribute to the sequestration of carbon causing global warming.

      Sandy Smith suggests that there is an optimal time for cutting down a tree – when it is at its prime or just beyond it, while it is still sequestering carbon and before it has gone into decline. For example, a jack pine can live over 100 years but you should cut it at 80 because it is mature and storing a lot of carbon. You take the carbon and make it into furniture or buildings so it doesn’t rot in the field. Then you plant some more — preferably fast-growing trees like poplar in plantations to sequester carbon.

        Spencer replies that if you replace a tree, it will be with a tiny sapling and you’ll reduce the amount of carbon being sequestered in the world. Robin Collins believes that elderly trees actually release more carbon, so you want to get rid of them before they become problematic. Here the group remains in disagreement, needing more factual information about tree metabolism in relation to the age of the tree.

       They discuss the logistics of planting trees, such as choosing the right trees, where to plant them, and how to care for them. While they recognize that urban forestry is not a big contributor to sequestration, it is a good idea for other reasons.


This transcript has been machine generated using “otter.ai.” Prior to using information from the transcript, please watch the video to catch any obvious errors.

Metta Spencer  00:00

Hi, I’m Metta Spencer. Today we’re going to do trees, and especially trees that grow in cities because I think that’s the most important project on my agenda today. And because on Saturday, there’s a meeting of the Pugwash group which I belong to, and I’m making a pitch for Canada’s public organization to take on the idea of promoting urban forestry is one of our big objectives. So I’ve invited some real foresters in who are going to help me sort out what people need to know in order to judge whether this is a reasonable proposal or not. So in a way, I’ve also invited all the Canadian public servants who want to, to join us and ask questions or argue with people if they if they have points of view. So I have some good good foresters here today, in Toronto here, my dear friend, Sandy Smith, who’s a professor of forestry. At least, we’re dear friends in the sense that I use you all the time, whenever an issue came at us. I appreciate that. And in Quebec is Michael Rosen, who is retired as an arborist. But he spent many years as the president of Tree Canada, a very worthy organization. And in Guelph is have Heather Schibli, who is a landscape architect and an ecologist, and she is an expert on me and lucky for us. And since the wonderful thing that the Miyawaki people do best is by teaching people how to make wonderful forests in small pieces of land in the city, the size of your bathroom, you can have a little forest. So I’m going to be drawing all these people to give some reflections on the potential value to Canada of investing in a big project to try to encourage millions of us to go plant some trees, especially in the cities. So let me let me say where I’m coming from, because a few years ago, I read an article – everybody in the world read that article – by an outfit the Crowder group in Switzerland, that went out and counted trees by various methods. They estimated that there are about 3 trillion trees on the planet today, and that we need about one more trillion in order to reduce global warming. Well, everybody got on the bandwagon, and indeed Canada promised to to plant an additional two billion trees. Well, that sounds really impressive. But if you realize a trillion is 1000 billion, and Canada is going to produce plant 2 billion, I’m sorry, two out of 1000 is not all that impressive, but we’re going to have to work hard to even make that commitment, because it’s not happening. Now, the question is, where do you put all those trees is the room for an additional trillion trees? Well, the Crowder people said yes, but they were counting the idea of having them growing in the Arctic, which is a very bad idea, because we know that the growth of trees in the Arctic has a net warming effect rather than cooling effect on the planet because of the albedo effect. That is,  the trees are darker than the snow around them, and therefore, they warm things. Also, Crowther said, Well, we’re not counting the space in cities or the farms because we got to leave agricultural land for farmers and city people to live. Well, that’s a bad idea. In my opinion, that’s just where we need to put trees — in the city because trees need to be cared for a couple of years in order to have a good prospect of survival. And that means that people have to look after them if you really want to improve the survival rate of your trees. And want to have trees where the people are, and besides, people need trees. And so we can do various things that use the agricultural land to plant them around. There are all kinds of great ways of using farmland without depleting your agriculture. And but the main thing that I think is: Let’s plant trees along the roads or anywhere where people go, and so that’s that was my starting point. I started calculating could we put 2 billion trees along in city areas where the Crowder people hadn’t even counted? Well, I think we need them. Cities are heat traps, and we need to have trees that will actually help cool the cities. In fact, the reality is that the amount of co2 that a brand new tree will capture isn’t I’m very much within 20 years. It takes a while for these trees to be grown up. So the most important thing we do to improve the quality or the amount of co2 in the atmosphere would be to save the trees that we already have. And big trees. We want to do that for sure. But we also need find ways in cities. Cities can be something like 10 degrees hotter than the countryside around them. So the trees can begin to cool the cities, even before they actually do much for us in terms of sequestering carbon. So there’s a lot of room in cities where we could plant trees, I think, especially lawns.  I would say, Let’s plant trees, really along both sides of every street and every road in the in Canada if we can. And we have to calculate how closely we can plant them together, and so on. But you’re not going to want to have a car within five or 10 years because there’ll be electric driverless taxis that will come and pick you up and drop you off, but they don’t park. So you don’t need all those parking spots. There are something like three or four parking spots for every car in Canada, which is going to free up an awful lot of space, if we put our minds to making sure that the law says we have to plant trees in them. So we can take these parking spots and turn them into forests. And for that, I think we want to ask somebody who knows how to make Miyawaki forest because they’re a wonderful use of small space in cities. We could get high school kids to go out and church groups and the yoga classes and all kinds of people to turn out. The government could say, okay, meet me at the corner of so and so at 10 o’clock. And we’ll have spades and trees and water and all the things you need to plant trees. So expect to spend an afternoon planting trees. And I calculated  – just my own crazy estimates as a completely uninformed person – I figured out that we could probably plant about a billion and a half trees this way, in addition to the ones that the government in Canada has promised to be planting in remote areas.They have a service that collects seeds, so we could get them to collect seeds and give trees to us and figure out where where we need to plant the right kind of trees and so on. This is not a radical idea, because I know that China did something like that with the Loess Plateau, which is home to 50 million people. And it’s been done in many other places. Stockholm planted 40,000 trees a few years ago, and they’re doing fine, thank you very much. So this is my my proposal that I want to get the Canadian Pugwash group to to support – at least to support a study of the idea and then we could do a real life cycle calculation of how many trees we can plant and how much co2 we can sequester that way and so on. Sandy, why don’t you start off.

Sandy Smith  08:19

I’m very supportive of planting trees. I work in forestry –always. For as long as I can remember, I’ve worked in forests. I started in the north and the boreal spent 15 or 20 years and now, I spent the last decades down here and based in Toronto, but urban forests, Southern Ontario. And I’m the type of person who defines an urban forest as anything south of the French River for those who are in Ontario.  I always have been supportive of planting trees. The problem is that we tend to get focused on the numbers. And I think trees are so much more than the number and you know, then we get into the semantics: Is an acorn actually a tree if it hasn’t sprouted yet? And is a seedling a tree or is it just the big old ones? I’m going to say we need as people to develop this a better relationship with trees because I think despite being Canadians, and thinking of ourselves as a forested nation, I think we tend to think of those trees as being somewhere else — someplace we go, to the cottage or hiking and camping or Banff National Park. It’s our vision, but I think we have a hard time actually relating to the everyday challenges of trees. There’s huge benefits that you know, in the last 10- 20 years it’s been getting more clearly quantified: the ecosystem, services but people still, when I speak with them that aren’t foresters, focus on the disservices — about how they have to rake up the leaves. And they have problems with the walnuts that drop and all these issues, which is about the relationship with nature, which we know is really important. So, my big point too, is yes, plant trees, but you do have to look after them. And it’s not just the first couple of years if you’re in an urban environment. And I include agriculture in that urban environment, because I think there are lots of opportunities there. But you do have to look after them.There’s lots of opportunity on private land. And I’ve been working with some corporations in the city in institutional lands; 60% of the urban forest is owned privately, whether it’s by individuals in their backyards, or institutions. And so I’ve been working with corporations to try and think about better ways to plant trees. So yeah, I’m on board.

Metta Spencer  11:13

Terrific. Okay. Michael Rosen. We haven’t really had much of a conversation about this yet. Is my proposal crazy?

Michael Rosen  11:22

Mmm hmm. That’s a kind of a planted question. Anyways. Metta. First of all, I want to congratulate you. I read most of the document you sent. I didn’t read the whole thing. But first, I looked at it and thought 36 pages Wow, that’s a lot of pages for me to read. But it’s really well done. And it’s really interesting. And, and yeah, the research is really good. And I liked the approach, it would appear that we need a lot of trees in our cities. Like Sandy mentioned, we’re blessed — or not blessed, depending how you look at it — with lots of trees, outside of our city, and we were the were the forest nation, but we’re not really a forest people. I spent a lot of my career as a forest. I’m a trained as a forester as well as an arborist. So, a lot of the emphasis was, well, if you want forest, you know, if you’re in Toronto, go a couple hours out of town, you’ll get all the forests you need. And then it became a trend recently, although it was reversed a bit with a pandemic, that people actually don’t seek their forest experience from going to a big provincial or National Park. Most of their forest experiences are the ravine, or it’s the backyard, or it’s the line of trees on the street. So it’s a nice thing that Canadians can think that they have all this forested area, but honestly,  the number of people who actually venture out there is kind of limited, although, the pandemic kind of changed that.  I’m not really sure.Algonquin Park is putting all these limits on who can visit the park. And some other parks are like that. Now,  I didn’t think the usership of those parks was serious. Well, the restrictions are more on the camping areas, I think, than anything else. But all this to say I guess you have a point in that the cities matter with regards to trees, unfortunately. Our cities were not created with trees in mind at all. They were created to facilitate the automobile. That’s, that’s the bottom line. So everything we do with trees in a city now, it’s a total retrofit. And it’s really expensive. And logistically, it can be really, really difficult. Take Toronto, say you’d land at Pearson, and  look around at Pearson and it’s like 80 –90% hard surface. I look at all this horrible, hard surface infrastructure that was created, not just for airplanes, but for automobiles. And my mind goes to when this can be nice with trees. Trying to put the trees in that area is is incredibly difficult, but but we’re not here to talk about what’s difficult. We’re here to talk about what’s possible, so I’m not I’m not going to dwell on that. Maybe this is where Heather comes in. It is possible to plant trees in hard surfaces. It just takes the right type of tree and lots of work to prepare the land and that sort of thing. But the argument around carbon sequestration in urban areas was always a tough sell for me, actually, because if you’re sequestering carbon with trees, there’s better places in the city to do that. Actually, your paper talks about it, you know, all this abandoned highway land. Although reforesting extra highway is problematic, we use a lot of salt and stuff that trees really, really don’t like. So that’s a  whole other book. But that can be easier than trying to rip up Dixon road to put in trees, that kind of thing. And then the other thing I’m just thinking of is that if we’re gonna talk about carbon sequestration,  the city is not the best way to do it. I think a better argument to use in the cities is not one of purely obviously carbon sequestration, but all the other benefits that trees can give. Yes, trees will sequester carbon in a city. Sometimes they don’t do it a lot because the tree has a hard timeestablishing itself and growing. And we all know these studies of what the average life of a city tree is. And it’s really low. I don’t know, it used to be seven to 10 years sort of thing was the average life of a of an urban tree. So how much carbon can you really sequester within seven or 10 years, you know, in a city? But if the argument is around the other benefits that are provided by urban trees, in addition to carbon sequestration, I think that’s a better sell, if you will. Does any of this help you at all, Metta?

Metta Spencer  17:26

Yeah, yeah. Well, the whole point of my proposal to Pugwash is that they study the issues and find out all the downsides and all the problems and what makes sense. And maybe some things don’t make sense so we’ll just change the proposal accordingly. So for that, I need a lot of good advice. And I’ll probably come back to both of you. But let’s get to Heather.

Heather Schibli  17:49

I agree fully with what Sandy and Michael are saying. There are issues in terms of where to place trees in urban settings because of utilities and problems with road salt, not enough soil volume for different areas and air pollution and all of that.  I’m a landscape architect, terrestrial ecologist and consulting arborist. I think, as an ecologist, why I find Miyawaki forest methods so exciting is that it’s looking at more of the community approach, as opposed to individual trees. So it’s a real shift away from kind of this legacy of colonial European landscape management practices, which is grass and an individual tree plunked kind of in between it, kind of harking back to the upper crust of of Europe when when North America was first colonized.  I think that’s totally antiquated. It’s outdated. And it’s not in keeping with where we need to be right now, especially given climate change. And also the general disconnect that our culture is experiencing between people, but also, especially between people and the land that we live on. So looking at a method of recognizing that trees, just like humans, are social creatures and evolved to live with other animals and plants. This kind of method of bringing, you know, the ones that we’ve done in Ontario, we loosely follow the methods so we don’t call it a Miyawaki forest, we call the “mini forest”  just because there’s some recommendations that come out of India that don’t necessarily fit the Canadian context, from our experience. But we do try to aim at putting an assemblage of species together that historically have evolved together. So it’s recognizing those communities that we see when we’re out inventorying forests in southern Ontario, central Ontario, Quebec. And it’s about nurturing that soil. Bringing that kind back to life and recognizing that we’re only seeing half of the reaction — mostly above ground, whereas most of what’s happening is below ground. So if you can bolster that and add health and diversity into that, there’s a better chance for this community to survive. So there’s a lot of opportunity to include these kinds of plantings in traditionally forested landscapes. I’m not proposing that we put these forests in Saskatchewan or other areas where it’s really tall grass, prairie and other types of ecosystems, but to fill up the landscape that’s been kind of devoted to grass. At these places where the only time anybody ever walks over the grass is to mow it, but it’s not used for anything else. So what you were saying, using these empty kind of forgotten spaces in between highways or along these shopping centers, strip malls or beside churches, in the back end of school yard — wherever there is an active place that’s not being utilized for something else, we should really be filling it back with trees, because that’s what this landscape wants to revert to anyway. And then we really need to get past this perception that our own personal properties are not part of the larger context. Because your backyard and your front yard are part of this landscape. And so, as stewards of the landscape, we should be really treating that in respect to other species. By planting native species, they are species that can can handle the kind of conditions that that site offers. I planted a mini forest in my backyard, and there’s close to 300 trees and shrubs and I’m downtown in Guelph, Ontariom so it’s a pretty small plot. In my front yard I have  Norway maple from the city.  I have a shade garden and a lot of woodland species that can kind of handle the shade of Norway maple. And I will use those seeds,  and populate my backyard once the seedlings in the back are big enough to support a shaded backyard. So I’m encouraging people to plant these in their back yards, because you’re not dealing with utilities and those kinds of issues in your back yard. And in your corner, go for it. This landscape needs to be forested again. Thank you. Okay, we have a couple of my friends here with us from the Pugwash group and I want to make sure that they both have an opportunity to ask questions or introduce their own concerns. Robin Collins? 

Robin Collins  22:57

 I would agree entirely that urban tree planting is a good thing in and of itself. But I would also agree that it will not be a major sequestration solution, just because of the scale. That doesn’t mean that the project isn’t worthy. But if the focus is on carbon sequestration, then other tree opportunities may be the ones to focus on. Michael’s comment about the average life of the urban tree — seven to 10 years or whatever he said, that’s news to me. But that’s really interesting. That also leads to where’s the best dollar for afforestation and reforestation.

Metta Spencer  23:59

Thank you. Let me ask if Peter Meineke has an issue.

Peter Meineke  24:03

Oh, hi. Sorry, my camera isn’t working. So you’ll have to put up with this talking black space. There’s always concern that people have had about using trees for removing carbon from the atmosphere. But I have a couple of other concerns. I have a lot of trees in my backyard, but I just lost a few of them during the last big storm we had. And when you look at the hurricanes and the effect of this strange law here in Ottawa that we can’t even book put a windmill in our backyard because of the problem with falling over or something like that. But we certainly have a lot of trees that have done a lot of damage to houses. And I guess that’s one of my concerns if we keep adding them. Maybe we’ve got better trees to do this with. I’m fascinated by bamboo. And are there other types of trees that actually absorb carbon faster than maples or whatever we normally have?

Metta Spencer  25:33

I’ve heard hemp.

Peter Meineke  25:36

Yeah, hemp. The idea of using people to look after the trees, I think is a great idea. I wonder if anybody would like to comment on this recent report concerning the the federal government’s analysis of the effect of trees. They claim that really, that the forests are not doing the job that the federal government says it’s doing.

Sandy Smith  26:08

I haven’t read this report specifically. So I can’t comment on it.

Peter Meineke  26:17

And I’ve only read the news that came out this morning on it.

Sandy Smith  26:21

Mike, you might know, runner. In forestry is it’s really hard to make a complex topic simple. And to come back to carbon sequestration, I do think they’re important. And it’ll vary. Ask any scientist, and they’ll say, it depends on where they’re growing, and the species and age. And Mike, I might say, just to respond to a little bit that Robin picked up on the age of an urban tree. I think that’s older data that came from trees that we’re putting into planters on the streets,  so it’s not your average urban tree. As I said, 60% of the trees are on private land. It really is about root volume. If you look after your trees, you can have them reach a full size and live for a long time I’m thinking of Europe where you look after trees in very urbanized areas through pollarding, or other arboricultural systems so you can get them to sequester carbon. But for me as a forestry person, a professor and someone who works in the area? It is about multiple values — it’s the complexity of a tree that provides its great value. Yes, it does sequester carbon, of course, but it also does all these other services that society in this time in this place really seems to need. And to speak to Robin’s point, even lecturing to students this morning, just the relationship of people with the land and nature. There are situations where our boreal forests are going to release more carbon than they sequester. That’s the nature of the forest dynamics. But I don’t see where that negates the need or the desire or the benefit of putting in more trees.

Metta Spencer  28:46

Well, at least we know that they do cool. When we’re dealing with global warming, we’re actually talking about how much comfort there is for people walking around in the cities. And these trees can reduce the average temperature of a city by several degrees.

Sandy Smith  29:08

Probably so, in the shade versus the sun. I’ve done this several times living downtown at Spadina and College, and it’s 10 degrees cooler in the shade.

Metta Spencer  29:19

Which is worth worth a lot right there. That’s true. And I have a question about the size of the trees, I’m arguing for urban trees, but at the same time, obviously, the important thing is to be able to sequester carbon too. And that means that we need to protect big trees. Now what I’m wondering is, we see all these pictures of forests that have been chopped down, clear cut, and and it breaks your heart. You see these gorgeous old stumps of trees that are 10 feet in diameter — trees that have been made into toilet paper or something. It’s an egregious offence against everything we should care about. But what I’m wondering is, can’t they do a better job of removing dead trees from the forest, because clearly, when a tree has lived its full life expectancy, then of course, you want to take the wood and use it for something, especially if you can use it to store carbon indefinitely by making a building or furniture or something from it, so that it has useful value and doesn’t just get burned up to send that co2 back to the atmosphere. Is there a better way of logging that doesn’t do as much damage to the whole forest than what I’ve seen in the horror stories that I’ve been watching?

Michael Rosen  30:56

The forests are being logged according to a “silvicultural system.”  There are many silvicultural systems in place. And it’s all dependent on the type of forest, the shade tolerance of the trees. In nature, many of these forests that are clear cut, are actually shade intolerant. They are trees that in nature would have grown back after catastrophic natural events such as wildfire, insect infestation, or wind events. The clear cutting, with standards and in small, small patches, is an attempt, if you will, to imitate what nature would have done anyway. That being said, if you have a forest, that’s more of what we’re used to, in the southern parts of, say, Ontario and Quebec and all aged forests, then obviously, that type of silvicultural system does not make any sense and you’re forced to implement something that’s more of an all age system, which we would normally call a selection type system. And then, for some species of trees, not maples, and not beech, for instance, but more like your pines and your oaks, they are actually intermediate in tolerance, and it’s all about shade tolerance. And in those cases, there’s another silvicultural system that’s widely used, and it’s called the shelterwood system, which resembles something in between selection and clear cutting. So the way I look at it, Metta, is that it’s better than it ever has been, and that the standards are being applied now that are all party to a lot of third-party certification. There’s a number of systems that are set up — FSC and SFI and CSA and a bunch of others — which actually apply standards to the way forests are managed and give these forests a certification. Now, a huge percentage of Canada’s forests are subject to that third-party certification. So things that look bad to the human eye can actually just be –and I’m not excusing it, I’m just being real. I’m just stating that what’s reality can be a temporal disruption, and that in the long term,  forests are dynamic and replace themselves accordingly. Clear cutting is often equated to deforestation, but the two have actually nothing to do with each other. Because clear cutting is actually a recognized silvicultural system that when applied in the right way will regenerate force in perpetuity. In other words, clear cut forests will actually develop back into forests. Deforestation is something we see when we actually change the land use. So urban areas that people live in, farming, farmland, road construction, mining, that sort of thing, is a conversion from what was previously a forested use to something else. And that is really true deforestation. So in fact, in Canada, the amount of land that’s actually “deforested” is relatively small, and it’s limited to urbanization and agriculture and road construction — that sort of thing. Okay, but that being said, you mentioned one other thing about dead trees. And that’s a that’s an interesting one as well, because I consult with the residents and landowners on managing their woodlots and their forests and one of the biggest mistakes  a lot of people assume when they manage their forest is that they’re going to cut the dead trees. That’s a big piece of forest management and I’m forced to point out that it is not actually the best management strategy, because actually more biological activity in a dead tree than a live one. As far as biota goes, as far as insect mass and bird production, and all those sorts of measures, dead trees support much more biomass, much more biota than a live one. So, in fact, it’s a bit of a mistake to walk into a woodlot and cut all the dead trees. Many of them should be left for wildlife. And it’s really the live trees that warrant the cutting to manage properly, to let more light into the forest floor, to allow more age classes of trees to develop. Because, that’s part of a sustainably managed woodlot. Now, I’m not advocating that we do forest management on 100% of every forest everywhere. Besides, that’ll never happen, that’s not realistic. But for those people who want to manage for many purposes, you know, one of these silvicultural systems should be implemented.

Metta Spencer  36:21

Ouch, ouch. You’re really bothering me. What I know, is being reported as fact is that there’s still more reduction in forestry in the number in the coverage of the canopy of forests in the world now, than there is additional growth to this forest cover. So if we’re focusing on co2 removal, and we see trees as a mechanism of capturing and retaining carbon as long as they’re alive, then clearly, if you go and do a clear cut, you’re going to reduce the amount of co2  being sequestered by those trees, especially the big trees. You want to keep the big trees. If you replace them,  if you cut them all down and replace them with baby trees, it’s going to be many years before they’re able to sequester the amount of carbon that’s there. The other thing is, when a tree dies, that’s exactly when it stops sequestering carbon, but starts rotting and restoring the co2 back to the atmosphere. So I would have thought that that’s when you want to cut the thing and use it for some permanent durable product like furniture or houses if you’re just thinking about the co2 sequestration. The rest of your argument I can live with, but boy, it sure bothers me when I’m thinking about global warming. Because this this method of harvesting silviculture that you’re promoting doesn’t sound like it’s going to do much for our warming issue.

Sandy Smith  38:11

Could I could I jump in just very quickly?  I think what Mike’s talking about is what we do right now is and that’s forest management. Even in clear cutting, trees are cut at the peak growth. The growth is optimized. To come back to your argument, Metta, when growth is optimized, the amount of carbon being sequestered is proportional. So you’re at your optimal carbon sequestration when the tree is at its optimal growth. That is the window and you can correct me if I’m wrong on the specifics here, Mike. But that’s when you actually do cut them. You don’t want it to go into decline, and you don’t want it to slow down in its growth, because that’s when it’s not growing and it’s not sequestering carbon. So actually, the forest management strategies, even for clear cutting, you cut the trees when they’re sort ofjust at their prime or just going beyond it.

Metta Spencer  39:15

So that has to do with metabolism. Clearly, a baby is metabolizing at different rate than an old person. But the amount of carbon or material that’s contained in a big thing is obviously going to be a lot more than is contained in a little thing.

Sandy Smith  39:33

That’s why you want to cut it. That’s why you want to cut a, let’s say Jack pine at 80 years. Jack pine could live over 100. But you cut it at 80 because it’s sort of like a mature adult. It stopped growing, it stopped, you know, bringing carbon in. It’s got lots of carbon stored and that’s exactly what you would do is say “Okay, this is when we take the carbon. It’s been sequestered. Now we will put it into furniture.” Toilet paper wouldn’t be the best use, probably.  We put it into buildings, we lock that carbon into place, so it doesn’t rot in the field.  Like when you’re

Robin  40:15

And you plant some more, that’s the point.

Sandy Smith  40:19

And you plant some more, which will take some time, another 80 years to get to where it needs to be. That’s exactly what we do.

Metta Spencer  40:28

But the minute you cut it down and replant, you replace that tree with a baby tree that’s two feet tall. Yeah, you have reduced the amount of carbon being sequestered in the world by a huge amount.

Robin Collins  40:43

Well, no, because, if I’m not mistaken, the elderly trees are potential carbon emitter.  They actually release more carbon, so you want to get rid of the old ones. But you want to get them at their peak before they become problematic. So you cut them down can use that carbon that’s been collected and locked in for useful purposes. And begin again, with new trees that can now

Metta Spencer  41:14

Do you mean to say that the big, big tree like a huge Redwood or something, is emitting more carbon than it is containing?

Sandy Smith  41:25

It could be could be. It depends on what condition it’s in. If it has a lot of decay and rot, if it slowed down in growth of its broken branches, and all sorts. There’s some studies now going on in Haliburton forest; we’re looking at wood decay. And there’s quite a bit being emitted by trees that are attacked by diseases and in squirrels living in them. Every time there’s a wound or something that, the tree starts to emit. And the older it is, the more likely that’s to be the case. It will start releasing carbon. At what point is the balance of storing and releasing? This is what you’re asking about, Metta, is when does the balance happen? And that’s usually back to what foresters would say “optimal growth.” Like, you’re still young and healthy, and you’re storing carbon. I mean, you might let it go a little longer. But there’s some trade off. I don’t think we’ve ever looked at it that way. We usually look at the volume of wood. Wood is carbon. That’s what you’re trying to get. Carbon. Wood.

Heather Schibli  42:39

Yeah, the question is, how is that wood that’s been harvested utilized,? Because if it’s used for burning, which is I think the number one use right now. So it really is like the afterlife, if you’re concerned about carbon sequestration. The other thing I just want to throw in is that trees are a lot more than just carbon sinks. And so that we don’t want to forget that like, even though they might, that curve might switch at a certain point in their lives from from collecting carbon to starting to release it, they’re doing a lot of other things, too. And we’re not only in a climate crisis, we’re in a biodiversity crisis. So it’s, it’s important to keep that in note, too, that those those heritage trees are very important.

Robin Collins  43:22

Yeah, it’s not an argument to cut down all the Redwoods.  You want to keep this stuff for aesthetic reasons. I mean, they’re the ones that everybody looks at. But we’re actually talking about the boreal forest or the Amazon or the taiga. These are the major sequesterers.

Sandy Smith  44:01

They have great potential because of the  land base that they occupy, especially in North America, and I presume the same in Russia. Back to the point Mike made about why we cut trees primarily. It’s not about forestry. It’s about agriculture. It’s about clearing land. And it’s exactly what we did here when we came to Canada or North America. First thing we did was start to clear the land. In fact, that’s how you got your property. As a pioneer here, you had to clear your land, or you didn’t own your your property. So the first thing you had to do was get rid of the trees so you could put your log cabin and start growing food and farming, to support communities. That’s what back to the colonial establishment. That’s what we’re still trying to do — take over the land.

Metta Spencer  45:05

We do need still a lot of land for agriculture. So the general net direction is:  there may still be clearing land in order to feed the growing human population, which means that if we want to keep the amount of trees even standing, much less growing in the world, if we really want to get an extra trillion trees, we’ve got to find someplace else to put them. And that needs to be, I think, in urban areas or along roads, in the countryside. I don’t know where else you can do it because the Crowder people were expecting these growths, these increases in number of trees, largely to take place in the Arctic, which is a terrible idea. They did not say they encouraged people to plant them there, but they didn’t caution people about the dangers of having trees in the Arctic. And there’s this wonderful book called Tree line where a guy went around all around the countries in the Arctic and looked at where the trees are growing. And it’s really a very serious problem. Anyway, the thing is, if we want to keep steady the number of trees that we have in the world while we have to continue clearing land in order to make agricultural off the fields, then we have to put them into an urban areas — or at least what you call urban, which most people would not call urban, that is, along country roads and expressways and that sort of thing. Am I wrong?

Michael Rosen  46:59

No, you’ve brought you brought it around really well, Metta, to the urban. You’ve done a really good job at that. And you’re absolutely correct. I think that’s the way to go. There’s also what I would call abandoned agricultural land or marginal. It’s abandoned for a reason. And actually, I think I’m not an agrologist, but I think we’re getting much better at our efficiencies in agriculture. So I don’t know, I think we need less land because we’re able to grow so much more food per hectare of land. I’m seeing this around where I live. I’m involved now in a very small project owned by a land trust, were near the Gatineau Park in western Quebec. And it’s a classic marginal agricultural land. It’s not really that productive. One field very sandy, one field clay, and the owners decided to put it back into trees, and it’s going to be an amazing project. It’s going to be so much more beneficial for the environment. And there’s space for 10,000 trees, not according to maybe how Heather would plant it but anyway, it’s it’s a lot. So there’s a lot of marginal farmland as well. With the 2 billion tree program of the federal government, it actually is difficult to find sites to plant trees. It’s kind of ironic. We’re sitting here thinking we need more trees. The government is actually giving people money to do that, and people are still having trouble coming up with sites to plant trees.

Metta Spencer  48:47

Well, I would have to take issue with whether we’re getting better and better at farming. Certainly we’re doing more and more industrial farming, but the overall effect is that we’re depleting the soil worse than we ever were before. So that is one of the other projects I’m promoting in this Pugwash thing.  The idea is using soil amendments such as biochar and rock dust and seaweed extract both as a way of improving the productivity of the soil as well as sequestering carbon. But unless we do that, I think the overall net effect globally is that, as somebody wrote (and I wouldn’t say this is absolute gospel truth) that we have something like 60 more crops in the soil now because it’s all being washed away or depleted or otherwise ruined. The soil is being ruined unless we do something to restore its quality. And that’s why I’m promoting the other thing. So I do think that, by all means, we want to use a marginal land and improve it and there are certainly ways of improving the soil with regenerative agriculture, which I think is absolutely important thing as well. But I still think that the that this needs to be complemented (and I don’t think you’ve disagreed with me really) with urban forestry in terms of sequestering co2. But we can make life much more habitable in cities by having cooler cities and better maintenance of the of the water in the soil the health of the of the atmosphere, the air that we breathe. There are a lot of other other benefits that come from having a lot of trees in cities. And I think any of you oppose the general idea of trying to find ways of improving the  urban forestry in Canada? If you’re against it, I want to hear it. 

Robin Collins  51:06

But wouldn’t, I wouldn’t. The question to me is not whether growing trees in urban settings or in suburbia or along highways is a bad thing. It’s not.  It’s a good thing. For me, the question is: Will it substantially contribute to the sequestration problem? That’s the question. And I don’t think it will significantly — at least not urban.  I think there are some other projects — saving the Amazon forest.  Some have argued that in 20 to 50 years the the earth would recover its own forests through simple biological succession on its own if we didn’t get in the way of it. And there’s pretty good evidence that human planting is not necessarily the best way of doing it, for many reasons. But I think there are places where human planting is absolutely useful at this point in time, because we need to spur the the reestablishment of forests and sometimes you need human planting, even along Amazon forest destruction areas. You need human help to get that started back up again. But the urban forest project, as written, I believe, is not a bad project. It’s not a major or significant contributor to the sequestration issue in my vie. It’s a good idea on its own for other reasons.

Metta Spencer  52:54

I think in 50 years or so when these trees grow, they will actually sequester more carbon than in the first few. I was looking for things that we can do within five years that will make a difference. And you’re absolutely right. This plan will not increase the amount of carbon sequestration within five years, no matter what we do. It has other benefits that are really worthwhile. And eventually, it will be helpful, maybe not as helpful as we would like or as we need. So we have to use other methods. But

Sandy Smith  53:40

Yes. I don’t know if you are going to solve the crisis. We’re in a crisis we’re asking what grows slowly to solve it for us. I mean, back to Peter’s mention of bamboo etc. If you really want carbon sequestration, you can grow for that. It’s no different than any other product that gets produced. And we kind of do that the thing in Canada. We grow forests on the natural land base. But I came originally from agriculture. You go well, why aren’t we — like bamboo, grow it in plantations? Or poplar. Grow it  fast, cut it, store the wood or lock it into biochar, take the carbon. I think we’re not very creative or innovative and we’re kind of locked into what we do. I mean, all the other benefits of forests — the diversity and all these other great benefits. I don’t know as they’ll come out of our plantation forests. People don’t seem to like plantation forests, but hey, that’s what we’re doing to agriculture. I think it’s being more honest and if you want to grow trees for carbon, then you can do it. Can you solve the crisis? No, but it’s certainly not going to hurt. And if anything, it will help.

Metta Spencer  55:14

Suppose we try your thing with bamboo or hemp. I don’t know that bamboo grows well in Canada. But at any rate, where would we put bamboo forests?

Sandy Smith  55:26

I’m not advocating bamboo forests, actually. It’s a non-native plant. I don’t really want to

Heather Schibli  55:32

Poplars if you want to do that. I wanted to say that there is no one magic bullet. We seem to be very attracted to these like, “Oh, this is the solution that’s going to solve all our problems?” That’s not the case. There’s not one move that’s going to solve this. It’s all the little things, just like how we’re in this state, because of the 1000 cuts that we have thrown at the systems that were functioning on this planet for millennia. So I think it’s just recognizing that we all have a small contribution. And it’s okay, if your idea isn’t going to be the panacea for getting past this climate crisis.

Metta Spencer  56:22

Okay, we could have a whole conversation about whether we want to wait and see if everybody does things like, turn off the lights and ride bicycles. But I think we have to look for things that have a lot of mileage. And these have big enough effects on the quality of life —  including, by the way, production of food.If we plant a lot of fruit trees and nut trees in urban areas, that actually could help a lot, not because Canadians are going hungry, but in a lot of countries it would make a difference. Anyway, we do need to prioritize in terms of where we’re going to put our main energy. I have four things that I think are important enough to  focus on that will make an impact within five years. I agree with you that urban forestry is not going to have an impact on sequestering carbon within five years. But it will make some difference — a little bit — in several years. And in the meantime, there are a lot of other benefits. So I’m sticking by my original proposal.

Sandy Smith  57:36

Okay, and I said I support it. I do. I mean, it’s never wrong to plant trees!  Will there be issues? Probably.  And will it solve all your problem? No, it won’t be the whole solution to everything, but it’s never wrong. And we will need those trees for something in the future. We’ll need them. And right now, carbon is one of the pieces. I just think we lack creativity on how to do this.

Metta Spencer  58:07

Let’s think about what kinds of trees and where and how many we can do and all of that stuff. I’d like to get down eventually to some real specifics of what we can do and how much it’s going to cost and who’s going to do the work and how long they have to water the trees. And what about the bugs?

Sandy Smith  58:28

You have to water them forever.

Metta Spencer  58:32

Because getting from here to there is a big problem in terms of logistics and practical things. So I’m probably going to get back to you with other questions if you are willing to give it a little thought sometime. Thank you. Okay, blessings, thank you very much. And bye see you another time. Take care. Bye for now.  These conversations are produced by Project Save the World. This is episode number 514. You can watch or listen to them as audio podcasts on our website https://tosavetheworld.ca. People share information there about six global issues and to find a particular talk show, enter its title or episode number in the search bar, or the name of one of the guest speakers. Project Save the World also produces quarterly online publication, Peace <agazine. You can subscribe for $20 Canadian per year. Just go to PressReader.com on your browser. And in the search bar enter the word peace. You’ll see buttons to click to subscribe.


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