I did a quick look to see if this only worked in tropical forests, or if this would be true in, say, Western North American forests.
I didn't really find an answer.
A study[1] in Virgina found that planting multiple varieties of trees was beneficial because it allowed the variety that was most suitable for that location to thrive, and survive problems that might affect other varieties.
A study[2] in Washington State tested a couple varities of common conifers planted in pairs, and found more conventional "trees are affected by competition" result.
This study[3] performed in the inter-mountain West found that some conifers _may_ benefit from being mixed with aspens, but didn't seem nearly as conclusive as the Borneo study.
If anyone can find a more conclusive study about temperate Western forests, I'd love to see it.
BC can have three our four species in play on the coast, interior and east typically has pine and spruce. You could argue for balsam but that is crap wood and it grows back on its own typically. I don't know about tropical reforestation, but in Canada the notion that we are replanting with only mono species isn't true. They leave seed trees standing and source cones directly from the logged blocks. It's very well done and highly regulated. Blocks that don't grow back are replanted again until they do.
Canada replants 600 million trees annually, USA about 1 billion.
Trees grow so much faster than they did a decade ago. CO2 is to 'blame'. I help maintain ski runs at my favorite ski hill and it's ridiculous how much more work it is now. Alpine areas that never in history had trees are beginning to get overrun.
Roughly where are you in BC? I am in Cranbrook and haven’t seen the seed trees left standing in logged blocks but maybe I’ve missed them somehow.
Isn’t part of the issue that historically there would’ve been more deciduous trees that acted as natural fire breaks and now loggers only are allowed to replant coniferous?
I've planted all over BC. Seed trees started being a thing early nineties and they don't do it everywhere. Quite often its because there aren't species needed as seed trees that won't already grow back are already slated for nursery production and replanting.
Smaller block sizes act this way too, the boundaries are seeded from the older growth on the perimeter.
Deciduous trees like poplar, Adler, and birch are like weeds and will grow very quickly and compete for a time with replanted trees. Eventually the evergreens tend to choke them out by taking over the canopy and changing the soil with their needles.
You may also hear this practice called selective cutting/lumbering. Essentially they leave trees in ones or twos scattered through to reseed the area around it.
Yeah maybe, selective cutting looks different though, like 1-2 hectare pieces and roads everywhere. This seed trees thing has blocks up to about 90 hectares that are rectangles with ten or twenty trees still standing in it.
There’s a more thoughtful way of designing this. In the permaculture world, these would be called “guilds”. Species are selected with an understanding of canopy layers (so that plants don’t compete for sunlight and can still fill in spaces at each canopy layer), and ecological function (such as, nitrogen fixer, dynamic accumulators, pollinator attractors, habitats, etc)
If you randomly mix up species in temperate forests that are all competing in the same canopy layer, I can see more competition. A study done where say, a mix of overstory, understory, and shrub (such as berries), would be more insightful.
I’d love to see a resource where someone could select their location and have example guilds like this provided. Every time I’ve looked it seemed like the only way to find out was to take a permaculture design course which is well beyond the limits of my interest.
These will inform you of how everything comes together, and it starts with an understand of your place on earth (particularly, the lat/lng and how that affects the sun cycle; then regional forces that is discussed in "Sectors". Then you designs zones on your site based on how much human contact you have.
Permaculture is very heavy on design, even if the end result doesn't look like it.
And yes, I had thought of creating a mod for an open source CAD that can pull in knowledge bases and databases as a permaculture design assistant. For example, there is a researcher whose lifetime work was to collect nutritional information for plants from all over the world so that people can select a nutritionally complete set of native plants. It's not more widely known because that knowledge base is locked into a desktop dbms from before web apps.
Forest is a complex ecosystem and based on some books [1][2] my understanding is that fungi plays a huge role in them. They provide a lot of things that trees need in exchange for what they need, they also create kind of a market which allows trees even from different species exchange their resources. Different trees have different strong sides and can make use of different conditions. Perhaps this, thanks to the huge forestweb underneath allows them to thrive.
Also, trees like to grow slow and solid. Older trees from the same specie will feed small tree hidden in their shadow and provide it necessary resources so that when some bigger tree falls and it can take it place, it can also grow faster. It's possible that when there's competition between species they grow faster because there's a fight for sunlight. The year's growth will be bigger and wood would be less dense (but it is sold by volume).
I strongly recommend "The Hidden Life of Trees". I listened to the audiobook multiple times while hiking/cycling through the woods and it changed the way I will see trees forever.
Forest study in China finds mix of trees can absorb twice as much carbon as areas with one species
More than 60 scientists from China, Switzerland and Germany were involved in the research, testing a hypothesis based on observations in the field.
“The study shows that forests are not all the same when it comes to climate protection – monocultures achieve not even half of the desired ecosystem service,” Schmid said. “The full level of mitigation of global warming can only be achieved with a mix of species. In addition, species-rich forests also contribute towards protecting the world’s threatened biodiversity.”
Such forests were also less vulnerable to disease and extreme weather events, which are becoming increasingly frequent as a result of climate change, Schmid said.
"Such forests were also less vulnerable to disease and extreme weather events, which are becoming increasingly frequent as a result of climate change, Schmid said."
That might well be an underestimated aspect. We don't know how climate will change locally, what pests will spread where, what species will turn out best adapted to future conditions, or what species turn out to be keystones in specific ecosystems. So we should strive for having as diverse a set of flora anywhere. Success factors are varied, complex & interconnected.
Climate changes so fast that past 'performance' of species in an area is of little value. Those trees are going to stand there 20, 50 or 100y from now. What will local climate be then? Take your guess / throw the dice.
Simard proved that deep rooted trees pull up water that ends up in shallow rooted plants, and that evergreens share sugars with deciduous trees in early spring, and then the direction reverses during the height of photosynthesis. Specifically in the case of water, the trees cannot transport enough water to keep up with peak transpiration, so they slowly dry out. But all night long they're still pulling up more water, more than they can use, more than they can store, and some of the excess ends up in their neighbors, through capillary action or the rhizosphere.
There’s an implication of intent here, regarding plant-to-plant transport and fairness, that I think is more likely explained by osmotic pressure. Entropy itself is 'fair' in this regard. Fungal hyphae aren’t designed to manage huge nutrient or water gradients. In fact they seem to be designed to communicate information at an alarming speed. Which we still do not entirely understand.
I can see benefits tied to wildfire R0 (in infectivity terms). A few fire resistant plants might play a role in decelerating the rate of wildfire spread and limit scope of damage.
I didn't really find an answer.
A study[1] in Virgina found that planting multiple varieties of trees was beneficial because it allowed the variety that was most suitable for that location to thrive, and survive problems that might affect other varieties.
A study[2] in Washington State tested a couple varities of common conifers planted in pairs, and found more conventional "trees are affected by competition" result.
This study[3] performed in the inter-mountain West found that some conifers _may_ benefit from being mixed with aspens, but didn't seem nearly as conclusive as the Borneo study.
If anyone can find a more conclusive study about temperate Western forests, I'd love to see it.
[1] https://www.si.edu/newsdesk/releases/tree-species-diversity-...
[2] https://cdnsciencepub.com/doi/10.1139/X09-040
[3] https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111...