秦岭华山松红桦混交林与纯林生长调查

通过研究,17a生华山松混交林,树高、胸径和材积的总生长量均比同期纯林要大,树高、胸径的连年生长量下降趋势比纯林慢,材积连年生长量上升比纯林快.8a生华山松仅树高定期生长量比纯林大,胸径与材积定期生长量不及纯林.混交林的叶量、叶面积及单位重量的叶绿素含量均比纯林高.华山松营养根呈簇状疏散分布,无明显主根,根系分布浅而细根密集,根系总长度比纯林大20％以上,种间根系无互相排斥现象.

Investigation on the Growth Increment of Pinus armandi and Betula albo-sinensis Mixed Forest and Pure Forests

Total of height and DBH with 17a Pinus armandi in mixed forest with Betula albo--sinensis is higher and current annual increment of them decline much slower than those in pure forest, whereas timber volume annual increment is faster than that of pure forest. Periodic increment of Pinus arman- di forest at 8a mixed forest with Betula albo--sinensis is bigger than that of pure forest of it, whereas periodic increment of DBH and timber volume are less than those of pure forest. Amount of leaves, leaf area and chlorophyll content in unit weight of leaves are much higher than those in pure forest. Rooting system of mixed forest are distributed in branches in shallow layer of soil, without main root. The total length of roots is 20 ~ longer than that in pure forest.