Ecological Pyramids

bacteria into humus. The process involved in the early stages of this transformation depends throughout on oxidation : afterwards it takes place in the absence of air. The process is entirely sanitary. There is no nuisance of any kind - no smell, no flies, no dustbins, no incinerators, no artificial sewage system, no water - borne diseases, no town councils, and no rats. On the contrary, the forest affords a place for the ideal summer holiday with sufficient shade and an abundance of pure fresh air. All over the surface of the woods the conversion of vegetable and animal wastes into humus is never so rapid as during the holiday months - July to September. The mineral matter needed by the trees and the undergrowth is obtained from the subsoil. This is collected in dilute solution in water by the deeper roots, which also help in anchoring the trees. Even in soils markedly deficient in phosphorus, trees have no difficulty in obtaining ample supplies of this element. Potash, phosphate, and other minerals are always collected in situ and carried by the transpiration current for use in the green leaves. Afterwards they are either used in growth or deposited on the floor of the forest in the form of vegetable waste being one of the constituents needed in the synthesis of humus. This humus is again utilized by the roots of the trees. Nature’s farming, as seen in the forest, is characterized by two things, a constant circulation of the mineral matter absorbed by the trees and a constant addition of new mineral matter from the vast reserves held in the subsoil.