云南金沙江流域云南松天然林林隙特征

通过对云南省金沙江流域永仁县响水河和白马河林场云南松Pinus yunanensis天然林中45个林隙的调查,研究了云南松天然林林隙的基本特征和自然干扰规律.结果表明:永仁县云南松林林隙的形状近似于椭圆形.扩展林隙和树冠空隙的平均面积分别为469.42 m2和181.90 m2,扩展林隙和树冠空隙在云南松林景观中的面积比例分别为28.23%和10.49%,年干扰频率分别为0.672 1%和0.249 7%,林隙干扰的返回间隔期约有400.48 a.大多数林隙在40 a以前形成.大多数林隙是由1～3株形成木创造的,而由1株形成木创造的林隙最多.林隙形成木的径级结构以30～50 cm这一范围居多,高度以20～30 m居多,林隙形成木通过掘根、干基折断、干中折断、枯立、折枝或枯枝这几种形式形成,其比例分别是33.7%, 27.9%,18.6%,17.4%和2.4%,在不同的林隙中可见到形成木这几种形式的不同组合.以林隙动态理论为基础,对永仁县云南松天然林的经营提出了几点建议.表5参10

Gap characteristics in the natural forests of Pinus yunnanensis alone the Jinshajiang Basin in Yunnan Province

The gap characteristics and natural disturbance regimes of 45 gaps in the natural forests of Pinus yunnanensis were studied,in Baimahe Forest Farm and Xiangshuihe Forest Farm of Yongren County, in Yunnan Province. The results showed that these gaps were elliptic in horizontal form. The average area of expand gap (EG) and canopy gap (CG) were 469.42 m~2 and 181.90 m~2 respectively, the area percentage of both in the forest landscape were 28.23% and 10.49% respectively, and annual natural disturbance frequency of both were (0.672 1%) and 0.247 9% respectively. So the return interval of the gap was gotten, about 400.48 a. These gaps mostly formed 40 a ago, and made by 1 to 3 gap makers(mainly by one).The diameter of gap makers was mainly from 30 to 50 cm, and the height of which was mainly from 20 to 30 m. The manners of gap formation in the percentage order from high to low were: uprooting(33.7%), breakage at trunk base(27.9%), breakage on trunk(18.6%), standing die(17.4%), and breakage on branch(2.4%). The combination of the different manners can be found often. Finally, based on the theory of gap dynamics, some suggestions on the natural forest of Pinus yunnanensis management were provided.