So, a while back I saw the announcement that scientist have tried to arrival at some kind of comprehensive estimate of just how many trees there are in the world. The result: three trillion trees.*
That's the good news.
The bad news is that this represents about half the trees we had 12,000 years ago, at the start of the Holocene. So since the end of the last Ice Age we've lost some 46% of the planet's tree cover. This is almost certainly the result of human activity, just as was probably also the case with the mass extinctions of that era -- the mammoth and mastodon and saber toothed tiger and the rest. But even if it weren't, it would be sobering, esp. since by all accounts it's currently accelerating.
Here's the link:
Reading this piece takes me back to Marquette days, when one of the essays I had to teach as part of freshman comp. was a piece by Otto Friedrich called "There are 00 Trees in Russia". Friedrich's point was that journalists often write pieces calling for specific knowledge they don't actually know, which is filled in by editors and fact-checkers. He gave the specific example of how many trees there were in Russia as an example of an unknowable fact. I guess extrapolation has come of age in the interim, thanks to better statistical sampling (e.g., satellites) and vastly increased computational skills
*with a current world population of about seven billion, that's about 500 trees per person. Which is a lot, but possibly not enough.