[Effects of human disturbance on coarse woody debris of Larix gmelinii forest on northern slope of Greater Hinggan Mountains].

An investigation was conducted on the living tree volume, coarse woody debris (CWD) loading, and composition of Larix gmelinii forest along a human disturbance gradient, i.e., no disturbance (natural larch forest), one-time disturbance (natural forest was disturbed once only), and two-time disturbance (natural forest was disturbed two times consecutively), on the northern slope of Greater Hinggan Mountains.

[Effects of heavy machinery operation on the structural characters of cultivated soils in black soil region of Northeast China].

With the cultivated soils in black soil region of Northeast China as test objects, this paper measured their structural characters such as soil strength, bulk density, and non-capillary porosity/capillary porosity (NCP/CP) ratio before and after heavy and medium-sized machinery operation, aimed to study the effects of machinery operation on the physical properties of test soils. The results showed that after machinery operation, there existed three distinct layers from top to bottom in the soil profiles, i.e.