In Gary Snyder's new book, Back on the Fire: Essays, he writes:
"A central teaching of the Buddhist tradition is nonviolence toward all of nature, ahimsa. This seemed absolutely right to me. In the Abrahamic religions, "Thou shalt not kill" applies only to human beings. In Socialist thought as well, human beings are all-important, and with the "labor theory of value" it is as though organic nature contributes nothing of worth. Later it came to me, green plants doing photosynthesis are the ultimate working class ... Almost all of the later "high civilizations" have been the sort of social organizations that alienate humans from their own biological and spiritual heritage.