中文摘要：

以采自青海省互助北山国家森林公园的青海云杉新鲜枝叶为材料，研究在其自然腐朽过程中聚戊糖含量的变化。结果表明，经过1年的时间，树叶失重损失达70％，树枝失重损失约8％。新鲜树枝和树叶中的聚戊糖含量分别为14．44％和13．54％。经过6月到8月两个月的自然腐朽，其树枝和树叶中聚戊糖相对含量分别为17．59％和15．78％。自然腐朽1年后树枝和树叶中聚戊糖相对含量分别为11．27％和6．99％。研究结果表明，在自然腐朽过程中，青海云杉树枝和树叶聚戊糖相对含量都经历先升高再降低的过程。

英文摘要：

Variation of pentosans of Picea crassifolia in natural decay process have been studied by using fresh branches and leaves from Huzu Beishan National Forest National Park. The results showed that the mass loss for leaves was 70% and 8 % for branches after 1 year. Pentosan contents of fresh leaves and branches were 13.54% and 14. 44% respectively. Two months later （from June to August 2014）, pentosan contents reached to 17.59% （branches） and 15.78% （leaves）. While pentosan contents of braches and leaves were 11.27% and 6. 99% respectively after one year. This study indicate that in the natural decay process of Picea crassifolia, the relative pentosan contents of both branches and leaves have experienced increasing first and then decreasing.