A review of Soviet research on the productivity of forest biogeocenoses finds confusion in terminology and urges general agreement on specific concepts and terms. Research has thus far been limited to the plant aspect of the forest communities, ignoring the animal and microbial communities. Changes in the amount of litter fall and phytomass from one natural zone to another are analyzed for spruce and oak communities and for forest biogeocenoses of various ages. A program for future research is outlined.