Bonus Episode: Are Trees Really the Answer?

Erin: 0:08

Hey there. It's Erin Kawazu, one of the co-hosts of About Sustainability..., a podcast where we discuss and draw attention to contemporary issues and events relevant to sustainability. This podcast is an initiative by staff at the Institute for Global Environmental Strategies (IGES). Today, we want to share with you a short side conversation between André Mader, Bob McDonald, Simon Olsen and me when we were talking about the Convention on Biological Diversity or CBD. By the way, check out that episode too, if you haven't already. Okay, so we need to keep planting more trees if we want to save the planet, right? Or not. It's often really hard to see the forest for the trees, but maybe we need to take a step back, actually, and see beyond the forest first. Let's get into it.

Simon: 1:01

I've just heard that- I think there's a lack of definition or common understanding of what nature really means. And there are some countries that are trying to introduce it in order to replace the environment. For what reason? I don't know. But they aren't successful yet because I think because there is no common definition of it- Political Political definition.

André: 1:22

Right. Okay. So I don't know too much about that, but certainly the word "nature", just like "biodiversity", is open to interpretation to some extent. Right. So I mean, having grown up in South Africa, which is a country- a very biodiverse country, first of all, and also a country where there's still relatively large amount of land that's considered 'pristine' - and I have to add the inverted commas there, because no one really knows what pristine is. There's been there have been papers written on how even the deepest recesses of the Amazon have shown signs of human habitation. So it may be that the forest there, which is regarded as, you know, ancient forest, might not be so ancient after all. So is a very just an incredibly interesting but incredibly complex topics. An old professor of mine, I watched a YouTube video of his the other day where he's talking about or arguing against the world's obsession with forests. And he's a grassland and savannah expert and he's done empirical research and also reviews showing that some of the world's grasslands are older than many of the world's forests, and grassland is often- grassland and shrubland are often considered to be kind of a degraded state of nature. But in some cases, they're- they precede the forests. And the forests are also, in some cases, the result of human habitation. There's actually an amazing- in that presentation, he shows a map of the place where he worked - I think it's probably East Africa considering the landscape - but it's an aerial view of a fairly sort of grey- brown landscape, which is shrubland or grassland, and then it's got these green blotches all over the place. It's taken at quite a height, so it's maybe an area about fifty by fifty kilometres or maybe a hundred by a hundred. And then you zoom in, those dark patches are forests, and if you zoom in even more, you'll see a village in the middle of each of those. And the research that was done basically going back, you know, using aerial photos and and other evidence, and then also speaking to the oldest people in the villages, they determined that basically those forests are manmade forests - human-made forests that was savannah or grassland before. And it's difficult to kind of - to always know whether it would be better if it was completely protected and people would just pulled out of there. But some of these- some of these SEPLS (socio-ecological production landscape or seascape) have been SEPLS for hundreds or thousands of years, especially in Asia. There are lots of examples of that, where we don't even know what the place looked like before they were doing that. And what we do know is that when people pull out of some of these places, like in Japan, where, you know, people are moving to cities more and more, the rural areas- maybe that's reversing a bit now with COVID- but typically also in in parts of Europe, especially Eastern Europe, rural areas are emptying out and that's leading to these agricultural areas being overtaken by natural vegetation. And in many cases, that's actually a reduction in biodiversity. This kind of goes back to the forest argument a little bit. The dominance of trees is not necessarily good for biodiversity, and there are plenty of examples of that. Another example is in eastern and southern Africa, where the fire regime or the grazing regime is being changed because of human- usually because of human interference, especially with fire. If the fire frequency and intensity has changed, that's going to change the entire dynamics of the system. And very often that leads to an increase in tree cover. So these landscapes that are naturally or traditionally savannah or grassland changed to tree landscapes covered entirely by trees, and they have their own suite of species, but very often, it's far less biodiverse than the grassland that preceded it.

Simon: 5:20

You painted a picture of this aerial photo that showed the grey brown grassland area with some green dots. And then you said as you zoom in, the green dots are where people live. But then in the European example, you say when people leave, it's reforested. So what? The forest comes no matter what, with or without people?

André: 5:40

It depends on the ecosystem entirely. So in the African context, you're looking at- I'm just thinking about some of the drivers. I mean, this would require studies and probably studies have been done. But in the African - East African, Southern African - context, one thing that will increase the cover of trees is reduction of fire. So fire, typically speaking, favours grasses. It also depends- it gets quite complex because frequent- frequent cool fires will favour trees because they don't kill the trees, so they keep on burning the grass down. But the trees can keep growing because they don't get killed by the fire and less frequent, more intense fires or simply less intense fires- oh sorry, more intense fires - may kill the trees and then perpetuate the grass cycle, which is more the natural way of doing things. And then another thing in the African context might be that people would be managing the way that the area is grazed around them. So they might have cattle that graze on grass but don't eat trees so much. In the meantime, they're keeping out or they're hunting the wildlife that would normally be there, that would normally keep the trees suppressed- ah yeah, that would normally keep the trees suppressed. So those are just two possible drivers behind the forest increasing around human settlements. They may even be planting trees. That's another possibility. Whereas in the European context and Japanese context... I don't really know, but I think that probably forest is more the natural state of things. And so- that's kind of why it comes back. But the species that come back are not necessarily the ones that were there thousands of years before, you know, before people were there. So yeah, in those landscapes, it might be a case of people, for the sake of production, completely clearing large areas of trees and planting crops and other things there. But even though they're crops, they can be- they can be beneficial to a lot of those animals. So those are just some possibilities. There's not some sort of a definitive answer, but just to give you an idea of how different things can be in different places.

Simon: 7:54

But I guess the... Thank you for the explanation, André. I remember that, being from Europe, I remember in primary school we used to learn that [400] or 500 years ago a squirrel could jump from tree to tree from the south of Spain to the north of Scandinavia without hitting the ground. And that certainly wasn't possible when I was a kid. And I don't think it's possible now either. But of course, a lot of what... I mean, there's a lot of agriculture in Europe and has been a strong agricultural tradition that, of course, has influenced [this]. But you're saying that even- even a clear-cut land can be more biodiverse than forested land. But I guess it depends on how you actually use the land and what you do to the land.

André: 8:36

Yeah, yeah, yeah. Absolutely.

Simon: 8:38

Intense agricultural systems - I mean, the way that we have used them tend to take away from the biodiversity and the species that can live healthily on the land, right?

André: 8:46

Yeah, yeah, that's right. It depends a lot. So these SEPLS (these socio- ecological production landscapes and seascapes) are typically kind of low-intensity and they're using sort of surrounded by by forest, you know - they'll be forest nearby and then there'll be a variety of crops. They're not just doing one- in a monoculture (one thing). They don't use much in the way of pesticides and herbicides and that kind of thing. So there are various factors that contribute to that.

Erin: 9:12

I want to know more about how this might relate to the"30 by 30" target, which is, you know, to protect 30% of global lands and seas by 2030, and how this might relate to local communities. Right? Because as we said, like, local communities have been managing ecosystems sometimes for hundreds of years. So can you tell us a bit more about the potential controversy?

André: 9:42

The controversy behind that was the concern that some countries - you know, the more autocratic regimes who might want to fulfill the obligations or the commitments to the CBD by getting to 30 by 30 - are may be doing that at the expense of communities. Long story short.

Simon: 9:59

Yeah, in fact, some civil society people from Pakistan and Philippines representing indigenous people- that's exactly what they mentioned. We're supposed to report on SDG 15 ([Life on Land]) and they say, you know, there's so much going on. The government is... First of all, the government is redefining plantation as "forest". That's one thing. And then the other thing is that they are kicking out- they are basically using Indigenous Peoples and Local Communities' land, kicking those people out and saying this is now protected land and this will count as our reforest- as our net positive forest gain. But basically, those people are left at the sidelines.

André: 10:37

So yeah, I mean, there's plenty of history to recall. And this is in South Africa, in my my home country: some of the national parks famously became national parks by kicking people off the land, you know, in days when there was no accountability for doing that kind of thing. So yeah, it's a... It is a bit of a tricky one. Maybe the OECM ([other effective area-based conservation measures]) concept has a lot of potential here because, you know, if countries- and I need to understand it a little bit better perhaps- but if countries know that they can contribute to their target simply by saying that this land is being well managed, you know, in some way or another, even if they've got nothing to do with the management themselves as government, that could have a really beneficial effect. It might encourage them to support people who are using the land in a sustainable way, you know, so maybe there's... Yeah, I'm curious about the concept, and I have been quite skeptical about it, to be honest, so far, but I think that it could be used in a good way. Um... But can I just kind of comment on that plantation example that you mentioned? That... goes back to this whole obsession with trees thing. And the professor of mine that I mentioned has spoken out about this quite vociferously in the past as well - you know, the whole, there's been kind of a global trend towards tree planting in recent years, and without really going beyond that. You know, I think most people don't know enough about ecology to know that it's not enough to just plant a tree. It has to be the right tree in the right place in order for the tree a) to survive and b) to not harm the landscape. And that might not sound so important until you multiply it by a million or a billion or a trillion trees, which are the figures that people are talking about now. So there are some... Several examples around the world. The big one is in Pakistan, actually. Another one [is] in China. But there are plenty worldwide, where a lot of greenwashing has been done in the name of tree planting without any consideration for what the impacts on the landscape are. And there was an infamous paper recently - I forget which.. It was in a big journal, I forget which one - But looking at the potential of earth for tree planting and they did sort of a very rough level / rough scale map of the world - I don't know if they actually showed it graphically, but they spoke about which parts of the world could be planted with trees in order to help reach climate targets. And then it turned out that many of those areas, apart from being communal lands, were also places that had never been forest in the past, and were not supposed to be forests. So, on the one hand- as I said, on the one hand, this forest might not survive, which is a big factor in tree planting. A lot of it is just a waste of time because they didn't survive. And then probably the more damaging possibility is that those trees just take over and they can reduce biodiversity drastically. You know, you can go- you can decrease the number of species in orders of magnitude- by orders of magnitude by doing that kind of thing.

Simon: 13:48

But-

André: 13:49

And plantation is- sorry just to add - plantation is the most extreme example of that. That's kind of the form that tree planting initiatives often take, rather than trying to reforest and create [an] ecosystem.

Simon: 14:01

So thank you, Andre, for explaining this. I understand it a little bit better, but it seems to me that... I'm thinking [of] climate change objectives like, we need to find the best, most natural way perhaps to capture and store carbon - which I guess are trees. But then that goes against some of the the needs we have on the biodiversity side. So where do you- where do you find a balance between those objectives?

André: 14:26

Yeah, well, so one thing to mention is that the amount of carbon stored in soil is four or five times more than the amount that you could possibly- even if you planted every inch of the earth with trees, you would not be able to reach the level that is already stored in the soil. So preventing the permafrost from thawing is far more important than storing carbon in trees. And another thing is that trees are, you know, as soon as carbon is tied up in a tree, the tree can't be used for anything else. So that's one thing. It's sort of a minor issue, but in some cases, it is an issue. But the other thing is that, just as the permafrost- just as the thawing of the permafrost will release huge amounts of carbon and methane, you know, from the especially the northern regions of the world, in the same way, a single fire, you know, will release all the carbon that's stored in trees and to some extent underground as well, because fires go underground to burn roots and rootstock. So, yeah. So trees are part of the solution, but not the main solution. And then, of course, also the oceans sequester, more carbon than than the forests do. So, yeah. So it's tricky.

Simon: 15:41

It's tricky.

Bob: 15:44

There was recently a big YouTube project for planting a million trees, I think it was. Do you know anything about that?

André: 15:52

I don't know about the particular one, but they're really all over the place. And the million is tiny compared to what's being done in many parts of the world at the moment. They're usually in the billions these days - the really major ones. But there was a very, kind of, high-profile young professor in the UK, who was pushing the tree planting thing quite strongly. And a lot of the- he was raising the ire of a lot of other scientists who were saying what I've just said now- you know, all the considerations. And he's changed his tune quite drastically. He's like... He's sort of corrected what he said before, and he's now kind of trying to push in the opposite direction. And there are some governments, I think, that are doing the same thing. They're recognising that this is not as simple as planting a bunch of trees.

Simon: 16:38

Sorry. What? André, what is the opposite direction then, to planting lots of trees? Is that to not plant any trees at all or I mean, if we-

Erin: 16:46

I guess is just to be more careful, right?

André: 16:48

Yeah. Just to be- to, you know, to be more careful. So that would involve, I mean, planting trees where trees belong, first of all, and then planting trees, not just planting trees, but also maintaining trees, which is the difficult part. I remember a very famous South African botanist telling me that- these things differ hugely depending on the rainfall. This kind of thing is so much easier where there's a lot of rainfall than it is when... Even if you're planting dry- adapted trees, it's much more difficult to make them take in dry areas than it is in wet areas. But he was saying that in... At least in the sort of semi-arid parts of South Africa, if you plant a tree, even if it's a, you know, sort of a three-metre- tall tree you planted - which is a lot of effort, right? to plant trees of that size at any number - He said that the herbivores, the browsers, will go directly for those trees. And as far as he knew at the time, there was no kind of scientific reason for that. But he reckons that there's something about being raised in nursery conditions of maize that makes the leaves more succulent or whatever. But that's a bit of an aside. But I've also heard that typically about the success rate or the survival rate of trees beyond a couple of years is about 10% in these tree planting initiatives.

Simon: 18:10

That's low.

André: 18:11

Again, that depends a lot on the climate, and wet areas are going to be a lot higher than dry areas. Even in wet areas, the success rate is not so high. Unless, of course, you plant an invasive species, which is going to have its own consequences.

Bob: 18:26

One thing is- related to you are saying why herbivores go straight for these newly planted big trees. I've also heard that wood for use in building things -rees that come from natural forests like dense forests are a lot stronger, a lot better wood, more dense than wood that grew up planted in rows without as much competition for sunlight, because they grow more slowly when they grow in a forest like that. So that could be one reason for that. But that wasn't really a question. The question I had was on something you said earlier, which was that, once you plant the trees, you can't use them for anything.

André: 19:09

Mm hmm.

Bob: 19:10

I was- I thought that trees kind of captured carbon. And then if you- if you cut that wood down and replaced it with another tree, that new tree would start capturing carbon, maybe at not the same rate, but I didn't think that, like, using the tree to build a house would then release that carbon. Am I wrong about that?

André: 19:28

No, you're right, actually. So I should have said that more carefully. So as long as the- as long as the wood doesn't rot or burn, then it remains captured. So eventually, it could be- it could be a couple of hundred years - some houses, some wooden houses are as old as that. And there's some other ways that you could use wood usefully without it either rotting or burning, but eventually, it's going to happen and eventually that carbon is going to be released one way or another. And so everything is about kind of flux and change over time, I guess, including the permafrost. It's just a case of the time scales and managing those timescales. Yeah. So, so I guess the- you could technically be growing trees and then harvesting the wood and using it not for firewood, but for building, for example, and then replacing the tree. And that will continue sequestering carbon. So there's no net loss of carbon until that wood is, as I said, either burned or rots in some way.

Bob: 20:31

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