瓦屋山常绿阔叶次生林建群种扁刺栲的细根分布及其碳氮特征.

The Wawushan Mountain National Forest Park in Sichuan Province, where there is relatively intact Castanopsis platyacantha-Schima sinensis formations, is a typical representative of the mid-subtropical moist evergreen broad-leaved forest in West China. Using the soil core method, this study investigated the fine root distribution and characteristics of carbon and nitrogen of sample C. platyacantha which is the main constructive species in this formation. The results were as follows: (1) The total fine root biomass of C. platyacantha was 173.62 g·m−2 and the total biomass of live fine roots was 135.29 g·m−2. (2) The fine root biomass, root length density, root surface area and specific root length decreased with the increase of soil depth, and their proportions in 0－30 cm layers were 67.23%, 69.53%, 69.48% and 57.20%, respectively; root length density, root surface area and specific root length decreased significantly with increasing root diameter, and 58.84%, 52.59% and 51.36% of them were in the roots that diameter was less than 1 mm, respectively. (3) Root extinction coefficient in biomass, length and surface area of C. platyacantha fine root increased with the rise of the root diameter. (4) In the first soil layer, the roots C content increased significantly with the rising root diameter, but there was no significant difference in other soil layers; the C content of the roots whose diameter was less than 2 mm in the first soil layer was significantly lower than other soil layers, while the differences of roots C content of greater than 2 mm among soil layers was insignificant. (5) The roots N content decreased with the increase of soil depth and root diameter while the C/N ratio value was opposite. These results reflected the vertical distribution of the secondary forest underground fine root system and nutrient characteristics, which would provided some basic data for revealing the subsurface ecological processes and the effects of environmental change on ecological processes in the underground in the ecosystem. [ABSTRACT FROM AUTHOR]