[ClassicConservative]

OK, who thinned the forests for the millions of years before we were there?

[DuncanWaring]

who thinned the forests for the millions of years before we were there?

Regular lightning-sparked fires, I would presume.

[Retired Chemist]

OK, who thinned the forests for the millions of years before we were there?

Natural occurring forest fires

[VOA]

OK, who thinned the forests for the millions of years before we were there?

As much as it pains me to say this...PBS's NOVA had a decent episode titled "Fire Wars"
that aired a few months ago.
It seemed to stick pretty much to facts and clearly identified differing points of views
on forest management.

The general historical view is that fires of natural origin would go through forested
areas on a random basis...but this occurred often enought that what you ended up with
was a forest with mostly big trees with open spaces between each other...and very little
flammable litter on the forest floor.

The show was good to talk fairly about the battle between those who oppose/promote
controlled burning as a way to imitate this natural method of forest "management"...and the
show was honest about how controlled burns sadly don't always stay controlled.

But while the current Arizona and Colorado fires are not fun, the show talked about the
big fire of 1910 (think that was the year). It was started by lighting strikes in
the West, burned millions of acres and killed something like 90 people (in what was sparsely
populated area). The story about people trying to escape and seeing belly-up fish
from the over-heated water in rivers and streams was pretty intense. And the smoke clouds that made
it all the way to NYC/East Coast.

Website for the episode at:
http://www.pbs.org/wgbh/nova/fire/