Primary Production of the Major Vegetation Units of the World

The primary productivity of the world is of paramount importance for man. Primary productivity captures that portion of solar energy that supports the life of all components of the biosphere. The largest portion of human food is provided by the productivity of plant life on land. From land production also comes our greatest single substance for construction and fabrication—wood—and a host of other products. The productivity of vegetation is one major aspect (the accumulation of toxic materials in the environment and potential psychologic effects are others) of the carrying capacity of the earth for man—its ability to support human populations on a long-term basis. Fossil fuels are accumulated profits from past primary production. The mantle of vegetation protects the Earth’s surface against destructive erosion; and it provides an important part of the environmental context in which man and his societies have developed and in which man himself feels most at home. It is by primary productivity and the growth of plants by the creation of organic matter through photosynthesis that the life of the vegetational mantle and thereby of man is maintained.