Trees catch on fire by rubbing together?

With friction fire methods, pressure is critical, but so is speed. Regardless of the method (fire drill, fire plow, fire saw, fire plane, fire thong etc.), once baseline pressure is applied and things start to happen, it is increasing speed alone that makes the ember. This can be easily demonstrated with the hand drill method: slow, intense drilling gets you nowhere.

Also, even with the most energy-dispersing friction fire methods around, the fire plow and the fire plane, the total contact area between the two sticks is all of ~1.5 sq.in, which would translate to very small, precise wind movement between live trees. Any larger than that, and the energy just spreads too thinly for ignition to take place.

As others have said, I too think there is not nearly enough speed between trees in a wind, even if they were bone-dry. Charred wood powder needs to fall off the trees, to give one an idea of the speed involved. Further, that hot wood powder needs to accumulate into a small ball for ignition, so just below that intense friction spot between the trunks there’d need to be some kind of a natural nest for the ember.