毛白杨根系分布的研究

对沙地上不同年龄毛白杨人工林的根系，从形态、数量和分布密度３个方面进行了调查研究。结果表明，其根系为水平斜生复合根型，１４ａ生林木根系的分布深度可达４．５ｍ，水平根幅达８ｍ左右。以重量划分７，９，１４ａ生林分的根系，分别集中在０￣６０ｃｍ、０￣１００ｃｍ和０￣１００ｃｍ土层内，占根系总重的８６％以上，树木周围２．０ｍ范围内根系的重量占总根量的８０％以上。以根系长度衡量，整个林地内根系分布较均匀，０

Study on the Root Distribution of Populus tomentosa

The root distribution of Populus tomentosa plantation were investigated andresearched in the aspects of form,quantity and density. The result showed: the model ofroots form was combined horizontal and plagiotropic type. the roots of 14 years old treescould extend to 4. 5m deep in soil and 8. 0m around the trees. Take root weight asmeasurement parameter, the roots distribution concentrates on 0 ~ 60cm, 0 ~ 100cm, 0 ~100cm deep of soil for 7, 9, 14 years old trees respectively, which takes more than 86%total roots,weight,and the main roots distributed in 2. 0m around the trees and the weightof it takes more than 80% of the total amount. And if take the length of roots as a ruler,the roots are fairly well-distributed all over the soil,and the roots which distributng in 0~80cm deep in soil take more than 80 % of the totalamount. The density and characteresticof its distribution were different with stand age, land position and deepth of soil layer.