Date of this Version
One of the pronounced trends in American forestry during the past decade has been the development of a widespread interest in soils. As a consequence to the soil as a part of the environmental complex has been attributed much greater importance than formerly in forest production. In fact, the individual horizons of the soil profile are receiving attention each as a more or less distinct habitat of that highly organized body designated as soil. Just as soil scientists, until recent years, have given inadequate attention to the factor of vegetation in the constitution and development of soils, so too little attention has been paid to the effect of soil profile on root development. This investigation is, in fact, among the few that give adequate consideration to the diverse factors of soil profile and their effects upon root growth. The modern concept of the dominant role of climate and vegetation in soil formation and that of the effects of soil horizons on root activities furnishes a broad foundation for further ecological research. For example, when it is determined that the vertical distribution of the roots of forest trees in the substratum is closely related to certain soil horizons, a better understanding of methods of soil sampling and a clearer interpretation of soil data in terms of tree behavior are to be had.