...we conlude that fires due to natural causes--chiefly lightning--which have occurred since remote geologic time, have been a significant force in determining the characteristics and adaptations of our California chaparral. Some of these fires may have been of low-intensity; some were unquestionably severe and of catastrophic proportions. In more recent times the effect of fires has been principally on the composition and distribution of the various plant communities. Burning by man, prior to the European contact, had no significant effect in developing the so-called fire-type vegetation, because man arrived too late upon the scene. Burning by Indians had no significant effect on the general distribution or composition of vegetation, because there were too few Indians, and their methods were technologically inadequate. Their activities tended to maintain the distribution of ceratin plant communities on a local scale, where populations were most dense, but not to control the distribution of vegetation on a regional of larger scale.