My brothers MA thesis was about comparing the multiple model forests that have been planted throughout the EUs different climate zones (I didn't even know such a thing existed, bur it makes sense).
His focus was looking at resilience against weather, insects etc. and mixed forests fared significantly better throughout all climate zones.
As someone from the alps, a thing that should not be forgotten is how important a diverse tree structure can be for stabilizing soil, especially in mountain areas. And those areas can expect more extreme wheater conditions due to climate change, especially in the form of rain. Mudslides can become a real economic factor in such regions.
Mixed forests are also better at stabilizing the soil because the root structures are less uniform.
So the best moment to plant mixed forests is 20 years ago, the next best is now.
Edit: For non-wood people, the reason why there aren't more mixed woods is that harvesting is easier in non-mixed environments (although that also has changed with newer methods and tech).
You just have to look at how utterly the Harz pine forests have been completely destroyed by the bark beetle to see what monocultures get you. It's just huge swaths of lands filled with nothing but dead trees
There's the additional complication that when the beetle or the windstorm come there's suddenly an overabundance of wood on the market, which depresses prices. You'd need to do forest maintenance but cannot afford it, market forces are against it. It's like the Schweinezyklus but worse.
I have heard estimates of 100 million trees dead in the Harz. The common refrain is that this was caused by climate change, but also choice of monoculture was a major contributing factor as the area was historically covered by mixed deciduous. Furthermore, choice of forest type will affect soil moisture retention, so reduced rainfall would have been buffered by better choice of forest type.
Loss of those trees was an economic disaster. I’m not sure it’s an environmental disaster yet - especially as replanting seems to be with better reference to the agro-climatic zone.
I‘ve heard from a local that in the onset of the bork beetle infestation, it was decided not to intervene (leaving dead trees there). This contributed to the catastrophe. Not sure if this is true.
Is that the case? I didn’t realise. Although as a tourist draw, dead trees are not exactly that appealing. A couple of years ago, I took my three year old daughter up a mountain, and she earnestly said to me: “the once’ler”. We haven’t been back.
We had in Slovakia in 2004 a small catastrophe in our tiny higher mountains (High Tatras) - wind up to 110 kmh IIRC, and literally large swathes of pine/spruce forests that were on higher grounds were cut like with lawnmower. They often broke in half with bare trunk still standing, not even ripped out of the ground. Then parasitic beetles had a feast and their population exploded.
Main reason was stated as monoculture planted decades ago, since these forests are pretty and they were used also for treating respiratory illnesses (clean mountain air with strong pine sap smell really helps, sort of natural aromatherapy).
Almost 20 years passed, its still a sad sight. More logging, some ad hoc growth but forest definitely didn't regrow in any meaningful form, rather fast growing bushes took over. There was a lot of fight between forest / natural park management and ecologists on how to proceed, and everybody (including forest) lost.
In some tree monocultures, you can just see the soil is covered with layers of organic matter that just isn't decomposing fast enough. This is because there isn't the diversity in the soil food web required to process it, reflecting the lack of biodiversity above the ground. Such soils often have a very low ph and poor nutrient cycling.
> His focus was looking at resilience against weather, insects etc. and mixed forests fared significantly better throughout all climate zones.
It makes sense. The diversity means that while one genera is suffering from some Hostility X or Y (e.g., insects) the others might not be, or at least as much so.
Hedging your bet is one part, another big one is creating habitat for predators. Pests often arise in monocultures because there just isn't any suitable habitat for the organisms that eat them.
A part of that habitat is food, so ironically and perhaps counter intuitively, a good agro-ecological practice is to farm your pests. This provides a source of food (but not in your main crop) to attract the predators that you want to help control the pest.
This is the reversal of a negative spiral where you control pests by killing them, thus preventing predators to settle in your land and making it a very nice place for the pests to multiple. And they will, because you can never kill them all - unless you keep using massive amounts of pesticides. This is why monocultures often need a lot of pesticides to work, its very hard to do without.
No offense meant at all to your brother, it sounds like an interesting investigation. That said, the answer to these sorts of eco-questions always seems to be that the way nature has worked for millions of years is actually the best way (for loads of reasons we didn't know) - and if we mess with it too much, there will be some problems. This just seems kind of inevitable though. If nature's way didn't work, it wouldn't be happening. I suppose finding the reasons behind it being optimal are where the "meat" of such an investigation is. Interesting stuff.
Your comment bothers me because it is based on very shaky premises.
Nature doesn’t work in the most optimal way, so it’s not always best to replicate it. Tons of things happen in nature that may wipe out important ecosystems. I suppose one could argue that at a long enough time scale it will even out but that time scale can be millennia. In the meantime, nature can wreak tons of havoc.
Nature (and by that I mean ecosystems because nature is a vague) also doesn’t behave in necessarily intuitive or easily observable ways either. What might seem “obvious” at first can be very wrong.
Nature (and again I mean ecosystems) also doesn’t exist in vacuums. What may have worked for centuries can be upset by even the most subtle of temperature shifts, and those might be caused by effects hundreds of miles away.
Unchecked nature is also not always going to be conducive to human needs either.
The entire field requires constant observation and inference. Even the ways of indigenous people that are fetishized as natures way by many, are scientific in nature. They’re the result of many years of observation, experimentation, learning and modifying how nature works to fit our needs.
"but that time scale can be millennia. In the meantime, nature can wreak tons of havoc."
For sure - I suppose I'm questioning humans' ability to mitigate such havoc without causing a load of unintended consequences.
"Nature (and by that I mean ecosystems because nature is a vague) also doesn’t behave in necessarily intuitive or easily observable ways either. What might seem “obvious” at first can be very wrong."
I think I was saying a very similar thing, actually. I certainly agree with you on that.
Nothing is "optimal", it's only ever "optimal for". So asking if nature is optimal is nonsense unless we have a firm agreement on what nature is for (which we certainly don't).
But the linked article doesn't have this problem. The "for" there is quite clearly the recovery of forests after logging, so they can be used again for whatever you may be expected to use a forest for (including more logging)
I think you’re arguing against a point that I am not making. In fact I think you’re making the same argument that I am, which is “nature isn’t seeking an optimal outcome because that is too abstract”.
The person I was replying to was saying “just do what nature does”. But that doesn’t mean much. My point was you can’t just blindly follow “nature” without observation and study because it can just as easily go and do something catastrophic as it can do something good.
Optimal as in preserving life if we’re going based off of the person I was replying to, but in general that is hard to define which is part of my point . Nature can just as quickly extinguish entire ecosystems, just as much as it can make them thrive.
Just trusting nature to do the optimal thing and trust that it’ll turn out okay isn’t sensible unless you also don’t care about the constituent parts of that ecosystem.
Insects can ravage entire populations of trees, rendering them dead and inhospitable to wildlife. Blight can do the same. Those are just as much nature at work as happy trees in a forest.
Well, yes and no. Yes, in the sense that 'nature' is what organisms learned in millions of years and the emergent processes of the ecosystems in which they 'learned' things. And because this is so vastly complex, we often don't understand it and our interventions will have unintended consequences.
No, in the sense that humans are actually part of these ecosystems and it is possible for us to understand these processes and work with them. And this is the point of the research posted here: planting native seedlings is superior for restoration than 'just leaving things to nature'.
There's a technical side to this and a 'worldview' side, where there are two competing concepts of 'nature': one defines it as 'everything except humans' and the other includes humans as being part of nature, a useful part even.
"No, in the sense that humans are actually part of these ecosystems and it is possible for us to understand these processes and work with them. And this is the point of the research posted here: planting native seedlings is superior for restoration than 'just leaving things to nature'."
I agree with what you're saying - but I think this point is slightly misleading. Planting native seedlings is exactly what nature would do - we are just accelerating nature's own process - not changing it for another process.
That is well put and also exactly my point. However, you are accelerating something, so there is an intervention. For some people this doesn't count as natural! The word 'just' in your sentence does a lot of work.
The line is, in fact, not always obvious. Would those seedlings have come there naturally? Or would it have been a different mix? If so, is the end result actually the same as would have happened without human intervention, or would it have been different? Maybe there are actually 50 or more species that could and would find a place in this biome.
You can say the same about exotic species, eventually most (or at least some) of them would have come here anyway - via birds for example, but its the pace at which they are introduced which makes all the difference. Well, is it a good thing then to introduce exotic species, after all its just accelerating nature's processes, or is it not? Evidently this one is not always only beneficial, so it depends.
Again, I agree entirely with you (yet still feel the need to respond) :-)
To some extent, who can say what exact mix of seedlings would arise if nature were left entirely to it's own devices. But one can imagine the basin of attraction for arriving at such a stable state is somewhat large (perhaps this is the crux of your point - such a basin cannot be mapped, and therefore one never knows if one is in it or not). Nevertheless - I feel able to draw a distinction between something that plausibly may have happened naturally, and, say, a vast grid of identically aged, undifferentiated pine trees. Though who knows, perhaps there is no distinction to be made - other than that of intention.
I agree too. That distinction is clear and useful.
I'm interested in creating a plausible-natural agricultural ecosystem, aka a food forest. Such a system draws more criticism from ecologists, probably because where I live almost all of the desirable species aren't native.
On the one hand, this clearly isn't a normal agricultural system and often looks more like nature, on the other hand 'nature people' often do not really understand its ecological value. So thats where I'm coming from, maybe that clears it up a bit.
There's a weird aside to this story though, because what we (Netherlands) generally consider to be desirable nature is often a landscape created by old agricultural practices.
I just know what he told me about it verbatim, but the "meat" of his investigation was that he did statistical analysis on vast amounts of (LIDAR-based) tree-height data and comparison of storm damages. On top there were many other GIS-data layers included, so in addition to that simple finding the "meat" is that he found multiple concrete combinations of circumstances that are especially benefitial to resilience.
Not that a skilled and experienced ranger might not have known some of these combinations as well, but the data-based approach can help planing better where to plant what specifically, as opposed to just mix it based on chance.
I was just listened to a podcast on this and they said planting a bunch of trees don't make a forest especially tropical ones. There's just too much going on there.
The best way to deal with fires is not to. The problems the west is facing are due to so much fire suppression for tire last century and a half left too much fuel near the ground, we are now learning to let them burn.
This is somewhat simplistic. There are many methods to wild fire control, including prescribed burns.
Yes, many forestry practices are antiquated and incorrect, but it’s not as simple as just letting fires burn.
There’s a significant science to forestry and wildfire management. Fire suppression is as important as fire management and fire encouragement. They go hand in hand, and require a measured balance
His focus was looking at resilience against weather, insects etc. and mixed forests fared significantly better throughout all climate zones.
As someone from the alps, a thing that should not be forgotten is how important a diverse tree structure can be for stabilizing soil, especially in mountain areas. And those areas can expect more extreme wheater conditions due to climate change, especially in the form of rain. Mudslides can become a real economic factor in such regions.
Mixed forests are also better at stabilizing the soil because the root structures are less uniform.
So the best moment to plant mixed forests is 20 years ago, the next best is now.
Edit: For non-wood people, the reason why there aren't more mixed woods is that harvesting is easier in non-mixed environments (although that also has changed with newer methods and tech).