木林子大样地多脉青冈种群动态及点格局

采用生存分析函数和成对相关函数g(r),对木林子常绿落叶阔叶混交林15 hm2大样地内多脉青冈的种群动态及不同生长阶段个体的点格局进行分析。结果表明:样地内多脉青冈种群第Ⅰ、Ⅱ龄级出现死亡高峰期,低龄级个体数量波动较大;年龄结构完整,呈金字塔型,属增长型种群;存活曲线在Ⅰ~Ⅳ龄级为Deevey-Ⅲ型,Ⅴ~Ⅷ龄级为Deevey-Ⅰ型;小树(1 cm≤DBH≤5 cm)、中树(5 cm20 cm)个体点格局分布聚集强度的变化趋势较为一致,即在小尺度上强烈聚集,聚集频率随空间尺度的增大而减弱,在大尺度上趋于随机分布。在113~150 m尺度上,年龄越大的个体其聚集强度越弱,小树显著聚集分布,中树保持聚集分布但聚集强度减弱,成树由随机分布过渡为均匀分布。小树、中树的聚集强度分别在0~4 m和144~150 m尺度上与成树无关联,分别在5~150 m和0~143 m尺度上与成树正关联。

Population dynamics and point pattern analysis of Cyclobalanopsis multinervis in large plot,Mulinzi Nature Reserve

The Cyclobalanopsis multinervis population in the 15 hm2 large plot where located in the evergreen and deciduous broad-leaved mixed forest of Hubei Mulinzi Nature Reserve were selected as the study object, then the population dynamics and point pattern analysis among different growth stages were analyzed by using survival functions and the function g ( r ) ( the pair-correlation function) . The results showed that the peak of death rate of C. multinervis population were appeared in theⅠandⅡage classes, and the number of young age class were volatile. The age structure was integrated as the pyramid shape suggesting the population was growing. The survival curve of C. multinervis population trended to the typical type of Deevey-ⅢinⅠ-Ⅳage classes, and was close to Deevey-Ⅰin theⅤ-Ⅷage classes. The point pattern of C. multinervis at small tree (1 cm≤DBH≤5 cm), middle tree ( 5 cm20 cm) period were presented as the aggregation distribution, and aggregation intensity change were comparatively consistent. The aggregation distribution intensity decreased with the increase of scale. The aggregation intensity performed heavy aggregation in small scale, and all individuals tended to show random distribution in large scale. At 113-150 m scale, older individuals′ aggregation intensity were weaker. Small tree performed conspicuous aggregation distribution. Middle tree also presented as aggregation distribution, but it′s aggregation intensity were decreased. And the random distribution changed into regular distribution in the big tree class. The small tree exhibited no association with the big tree at r<4 m scale, and middle tree exhibited no association with big tree at r>144 m scale, but small tree and middle tree all exhibited positive association with big tree in the other scales.