Some considerations concerning micro-topography and forest soil

Abstract

Writers report a result of study, done by micro-topographical observations, soil survey, chemical analysis of some soil elements and measurements of heights of trees in a mountainous slope of forest. Experimental slope is compoundly classified into three stages, on the one hand, according to division of geomorphic cycle and into two types of slope, on the other, according to division of erosion type such as vally-type slope (by mass-wasting) and ridge-type slope (by surface erosion). In other words, experimental slope is divided into unit slope which is characterized by geomorphic cycle, and erosion type and in which the topographic elements are arranged monocyclic. Writers have made observations of properties of soil such as thickness of solum and of soil horizons, identified forest soil types, and estimated content of organic carbon and exchangeable acidity. Generally, micro-topographical factors regulating modes of denudation, scouring, eluviation, deposition, accumulation and illuviation of soil materials, vertically and laterally, seemed to be important to the soil formation on the mountainous slope. On the multi-cyclic slope, the continuous variation of soil properties, caused by lateral movements of soil materials, was longitudinaly broken at the slope-transformation zone, and it was usually recognized that there was local variation in the unit slope. On the relations between soil properties and heights of trees, clear tendency was not always recognized.