Each and every one has been due to human carelessness.
A campfire ill-extinguished;--a smolder of tobacco not stamped out;--the flaming cinders of a railroad train,--a match dropped among dry leaves before spark and blaze have both been destroyed,--these be the first and only causes of the average forest fire.

All are avoidable.

None is avoided.

And the loss to property and to life and to natural resources is unbelievably great.
Any fool can start a forest fire.

Indeed, a fool generally does.