秦岭北坡栓皮栎种群动态的研究

对秦岭北坡栓皮栎种群动态进行了系统研究，分析了种群的年龄结构和分布格局。编制了静态生命表。绘制了存活曲线．结果表明，秦岭北坡栓皮栎种群年龄结构属于进展型，幼龄个体多。中老龄个体少；种群在I、Ⅱ龄级时死亡率最高．随着年龄增加，死亡率逐渐降低；到Ⅶ、Ⅷ龄级。由于生理衰老。死亡率回升；栓皮栎种群存活曲线属于DeeveyⅢ型；种群分布格局总体上的呈聚集型。随年龄增加，种群聚集强度降低。在高海拔地区，种群趋向随机分布．海拔800～1100m是栓皮栎种群较为适宜的生境．对于低海拔地区栓皮栎林要加强保护，减少人为干扰；中海拔地区应加强抚育管理和适时间伐，高海拔地区应加强目的树种的抚育．

Population dynamics of Quercus variabilis on northern slope of Qinling Mountains

Studies on the population dynamics, age structure, spatial distribution pattern, life table, and survival curve of Quercus variabilis showed that the Q. variabilis population on the northern slope of Qinling mountains was increasing. The number of young - aged individuals was larger, and that of middle-aged and old individuals was smaller. The life tables for different age classes showed that the mortality at age classes I and II was the highest, and the mortality rate was decreased with increasing age. However, at age classes VII and VIII, the mortality rose again for their decrepitude. The expected life span of age classes III, IV and V was higher, and decreased gradually with increasing age. The survival curves were the type of Deevey III, and the distribution pattern of population was aggregative as a whole. As the age increased, the intensity of aggregation decreased, and tended to a random distribution at higher elevations. A wise management should accelerate the recovery of Q. variabilis population and the enhancement of its productivity. The altitude 800-1 100 m was the favorable habitat for Q. variabilis population. As for the Q. variabilis at lower altitude, its protection should be reinforced, and the disturbance from human beings should be reduced. Forest thinning and other fostering management at middle altitude should be given in time. The target trees at higher altitude should be fostered.