A few years I ago I read the book titled World Fire, where the author argues that human controlled & induced burning has had an enormous impact on the world’s ecology and that modern fire suppression is profoundly ‘unnatural’ (the book is pretty “on message” the whole way, so it is probably best to sample instead of reading front to back since it is more of the same). To say the author is polemical is understating, nevertheless, I think it is noncontroversial that the use of fire in concert with forethought in marginal forestlands probably had an enormous impact on biomes in all regions that man spread to over the last 50,000 years. The author of the above book makes a strong case that fire changed the Australlian & New World ecology to the point where we really don’t know what is ‘pristine’ and what is not. Quite clearly, Homo sapiens is part of nature, often our biomes become part of our ‘extended phenotype’, just like earthworms ‘recycle’ decaying matter in their gut to produce soil (or termites or ants if you have a tropical orientation) humans have been slashing and burning for thousands of years and recreating open meadows and quasi-savannas the are remiscient of our ancient hunting grounds in Eastern Africa.
Now, metal tools are great facilitators for clearing out dense forests, and this is the reason that indigenous peopels will often trade their most precious materials for these implements (ergo, the whole Napoleon Chagnon incident in Venezuela). I have read that the spread of ‘civilization’ into the central Gangetic plain in South Asia was only possible because of the spread of cheap iron tools which could clear the forest. If this is true clearly fire can only go so far, especially in lush & moist conditions. But, when I was in college an anthropology professor who specialized in the ancient cultures of the Pacific Northwest told me the following: when the white man showed up in the Willamette Valley he found a few straggling Native American tribes and enormous forests that seemed to be underutilized. During the course of his research he found that the pollen from the past did not show this situation to be the norm, rather, there was a much higher count of grass pollen. He hyopthesized that the pandemics that swept the New World in the first few centuries after the arrival of Europeans decimated Native American populations to the point where their fire facilitated clearing of the Willamette Valley ceased, so that it went ‘back to nature’.
In any case, humans obviously leave a big footprint, though not always in the ways we might think. Perhaps in the future a student of the spread of grain based agriculture will study pattern of the genetic relationship of various rodent populations across the six non-glaciated continents with phylogenetic methods.
Posted by razib at 01:29 AM