1. As used by W. Köppen in his 1931 climatic classification, the part of the earth's surface that is able to support plant life. It is bounded on the one hand by the cryochore, or region of perpetual snow, and on the other by the xerochore, or waterless desert. Transition zones on either side are the bryochore, or tundra region, and the poëchore, or steppe region. The bulk of the biochore consists of the dendrochore, or treed region. Compare biosphere. 2. In ecology, a group or region of similar plant and/or animal life.