太白山太白红杉种群空间分布格局研究

针对研究区太白红杉种群分布特点，设置了15个20 m×20 m样地，采用离散分布理论拟合和聚集强度测定方法，对太白红杉种群空间分布格局进行了比较分析.太白红杉种群空间分布格局属于聚集型，在25 m2和100 m2面积上聚集强度较大.随海拔上升，聚集强度降低；在分布下限地区，聚集最强的尺度较小，中下部地区较大；阴坡的种群分布聚集强度大于阳坡.随着年龄增加，种群分布由聚集型向随机型过渡，强度减弱；聚集性最强的格局尺度在幼、老龄期为150 m2，中龄期则为100 m2.分布格局受生物学特性、年龄阶段、群落组成、环境因素等影响.在未来保护与利用中，低海拔和阴坡应该适度间伐乔木层非目的树种；在高海拔和阳坡地区，适度间伐灌木,促进群落内团块状更新；育林作业面积应该与聚集性最强的面积相适应.

Spatial distribution pattern of Larix chinensis population in Taibai Mt.

Larix chinensis is an endangered species only distributed in Qinling Mountains of China. It has a concentrated distribution in Taibai Mt., and plays an important role in environmental protection in the high altitude. After an investigation on fifteen 400 m2 plots, a comparative study on the spatial distribution pattern of L. chinensis population and its dynamics was made by the tests of discrete distribution pattern and aggregation intensity. The results showed that at different sampling areas, L. chinensis populations all performed the pattern of clustering distribution. As the sampling area increased, the congregating intensity of L. chinensis population appeared the pattern of high-->low-->high, but the highest congregation occurred in the areas of 100 m2 and 25 m2. The clustering intensity went down from low to high altitude, and the area with the highest clustering intensity occurred on that of 25 m2 in low altitude, 150 m2 in middle altitude, and 100 m2 in higher altitude. The clustering intensity in shade slope was higher than that in sunny slope, and the area with the highest clustering intensity was 100 m2 on shade slope, and 150 m2 on sunny slope. With the population age increased, the distribution pattern had a trend from clustering to random, the clustering intensity decreased somewhat, and the area with the highest clustering intensity was 150 m2 in young or old stages, and 100 m2 in middle stage. The distribution pattern of L. chinensis population was related to its ecological characteristics, community composition, and environmental factors. In situ conservation should be strengthened in the future. In lower altitude or on shade slope, the measurements of thinning no-aim in tree and shrub species should be taken; while in higher altitude area or sunny slope, thinning shrub species in patch form would be better for L. chinensis populations block renovating. The fostering area for L. chinensis populations should be suit to the area with the highest clustering intensity of populations.