It isn't necessarily awesome that the US has so many trees. Forests can get overcrowded which is bad for the forest overall even though there are a lot of trees. It isn't just quantity that is important it is the whole ecosystem, those trees that are overcrowded shade out helpful plants on the lower forest floor.
Forests in the US generally depend on regular forest fires for health. The US has mostly been putting out those fires and the result is we have a lot more trees than is ideal.
Here in Florida, those forest fires are required for some of the tree species in the endangered Florida scrub[1] and sandhill[2] ecosystems to germinate, in addition to clearing out space for smaller plants to thrive. Florida has a pretty regular controlled burn system though, developed over the years of trying to protect these habitats.
I've never lived on the west coast, but I wonder sometimes if the out-of-control wildfires that happen out there so often would be better if there were more controlled burns happening? Or is it just too dry out there for even that?
The situation in California is quite complex. John McFee's excellent "Control of Nature" has a long essay on the interactions between forest fires, geology, and landslides. I'll probably do a shitty job of paraphrasing, but I'll try.
As the population of California has increased, people have increasingly settled farther and farther up the neighboring mountains. The mountain ranges in the area like the San Gabriels are very young geologically. They haven't had the chance to erode down much and are composed of brittle rock just waiting for a chance to break off.
So you have a growing population in an area prone to devastating landslides and debris flow[1].
Meanwhile, the mountains are covered in chapparal. These small scrubby bushes have evolved to endure (and in fact in some species require) periodic wildfires every decade or so. When the chapparal burns, it leaves a coating of ashy dust on the ground. That prevents rain water from soaking into the earth. So when a summer storm comes around later, the water starts sheeting down the mountain, taking dirt, rocks, and boulders with it.
This is a devastating event. It's very hard to build defenses against it, and hard to predict precisely when it's going to occur. You're talking going from "everything is fine" to "thousands of tons of rock crashing through homes" in a matter of minutes.
Ironically, debris flow would be easier to predict with controlled burns, but it's pretty hard sell to say, "Yeah, you're house is going to get flattened next month and we're going to make it happen." So, because of the much greater threat to life (people die in big debris flows all the time) and property, California ends up very hesitant to do controlled burns of the chapparal.
Thank you. I've added that book to my wishlist, it sounds really interesting. Don't really ever have to worry about landslides in Florida (just hurricanes and sinkholes).
Wouldnt, also, in certain cases, the ash mix with the soil and make a more hardened clay-like mix which would harden and prevent a certain amount of erosion?
Not in California where the mountains are growing at a fast rate (for a geological process fast). The roots hold the mountain up while the trees grow, but when the trees burn those roots no longer have life and the next rainstorm lets the mountain side fall as the mountain has grown.
Read the book, it is described much better than I can summarize.
I've been told that yes - more frequent, smaller burns would be all around better; however, these areas are largely populated and there is zero political will to voluntarily threaten the properties - even if it reduces the risk of catastrophic fires.
That sucks. Around here at least most of the areas that need controlled burns are sparsely populated due to it mostly being federal parkland[1].
Anyway, I guess we have sufficient political will here in Florida, or at least we do after we saw what happens when we don't - the wildfires we had in 1998 [2]. Which were terrifying. The fires got within a few miles of our house at one point, and the sky looked like the scene from Fantasia where all the dinosaurs are dying, with an orange sun that was so dimmed by smoke you could look directly at it without even getting an afterimage on your retina. Ash fell from the sky like snow, and everything smelled like woodsmoke for months.
Which is where we come in the loop, logging for wood instead of burning. It's when we suppress fires and don't thin the forest that there's dangerous fuel accumulation.
Periodic forest fires definitely seem more healthy for forest ecologies than logging, since they reduce potential fuel and return nutrients to the area. Logging or large forest-fires means significant deforestation/defloration leading to erosion.
We should be managing our lands with more controlled burns to periodically reduce the fuel load so a huge unmanageable natural forest fire doesn't break out.
Plus some species require forest fires, like ponderosa pine whose pine cones will only open to release their seeds from the heat of a forest fire.
Sure, if the area is clear-cut and not replanted. It wouldn't be good for business if there weren't any more trees to log a few decades from now. Believe it or not, we do think long-term in the timber industry ;)
Controlled burns often accompany harvest operations to return nutrients to the soil.
> Plus some species require forest fires, like ponderosa pine whose pine cones will only open to release their seeds from the heat of a forest fire.
Not the Ponderosa Pine. You are probably thinking of the Lodgepole Pine and Knobcone Pine.
I asked a forester. Admittedly this is not the best response for a pseudonymous internet forum.
Further searching for links on serotinous (externally triggered) cones turn up sources that almost all refer to the Lodgepole Pine [0]. Also note that these trees have both serotinous and non-serotinous cones - they can still reproduce without the presence of fire, albeit at a lesser rate.
That being said, the Ponderosa is fire-resistant, and will survive typical non-crowning fires.
We can do both. You log the large valuable trees, and burn the underbrush. A healthy tree will survive a small forest file without problems and it makes it easier for the loggers to get in to cut the valuable trees they want. This assumes you are doing selective logging and not clear cutting.
Forests in the US generally depend on regular forest fires for health. The US has mostly been putting out those fires and the result is we have a lot more trees than is ideal.