Trees

The Amazon basin leads the world in tree density: dark green represents 1 million or more trees per square kilometer. There are fewer trees in the lighter shades of green. The buff color has very few trees, and darkest brown represents areas with no trees. Crowther, et al./Nature

I'm reading Dandelion Wine by Ray Bradbury out loud while Osmany cooks breakfast.  Tom and Doug are discussing the rites of summer and Tom mentions that there are five billion trees in the world. That sounds a little low to me, after all there are seven billion people in the wold, and they are mostly concentrated in urban areas. Trees cover vast swatches of most of the continents and they are probably as dense on the ground as people are in cities, so the number of trees has got to be much higher, right?

Google turns up a story on NPR that gives some different, larger numbers.

There was one estimate based on satellite images: about 400 billion trees worldwide, or 61 trees for every person.
But there were doubts about that number because another recent estimate, based on ground-truthed measurements, found 390 billion trees in the Amazon basin alone.

Thomas Crowther and crew spent a couple of years digging up information. When they had added it all up it came to around three trillion trees. Okay, that's good. It's good to have trees. But how does this compare with the good old days? No so good:

Crowther says their work suggests that, compared with the days before human civilization, the world has lost roughly half its trees. And the gross number of trees lost each year because of humans is now about 15 billion.

If that 15 billion trees per year was a constant, then it would have taken us just over 200 years to cut down three trillion trees and a like amount of time to cut down the the remaining trees. It's not a constant of course. People have been cutting down trees every since some dude came up with the stone ax. We've been cutting down more and more trees every year ever since. We might be approaching peak tree cutting time. If we keep it up trees might become kind of scarce, which means it's going to be harder to find enough trees to cut down so we might not be able to fill our god given quota.

Silent Running Trailer

Reminds me of Silent Running, the goofy Science Fiction movie with Bruce Dern as the custodian of the last remaining forest, which is in a spaceship in orbit around earth because there is no room on earth for any trees because of all the people.

Update April 30 (the next day). Corrected a mathematical error.