Population structure and spatial distribution pattern of dominant tree species of forest communities in the Xiaowutai Mountain, China

摘要

The point pattern analysis was applied for analyzing plant spatial distributions, predicting species associations, and providing an efficient representation of ecological process. Pinus tabulaeformis forest, Betula platyphylla forest, Betula albo-sinensis forest, Larix principis-rupprechtii forest in the Xiaowutai Mountain were selected as research objects, and four 50m×50m quadrats were set up. We measured diameter at breast height (DBH) and location of trees, and analyzed population structure, spatial distribution pattern, intraspecific and interspecific associations of dominant tree species in four forest communities by point pattern analysis and Monte-Carlo simulation test, in order to provide a theoretical basis and development strategies for natural resource protection in the areas. The results showed that a total of 166 vascular plant species in 49 families were recorded in quadrats. Betula platyphylla had the largest average and maximum of DBH among all plant species. Betula albo-sinensis had the largest average tree height, while Betula platyphylla had the maximum tree height among all plant species. Pinus tabulaeformis presented random distribution within 13.5m and cluster distribution outside 13.5m. Betula platyphylla presented random distribution on all the scales. Betula albo-sinensis and Larix principis-rupprechtii presented cluster distribution on the small scales and random distribution on the larger scales. The study also revealed that Betula platyphylla and Acer mono on the scale of 2.4m-22.5m, and Betula albo-sinensis and Sorbus alnifolia on the scale of 3.5m-7.5m had a significant negative correlation. Furthermore, Pinus tabulaeformis and Larix principis-rupprechtii were expanding populations mainly affected by intraspecific competition. Betula platyphylla and Betula albo-sinensis were stable populations respectively affected by interspecific competition, intraspecific and interspecific competition. Spatial distribution and species associations of four forest types were regulated by dispersal limitation and environmental heterogeneity in the Xiaowutai Mountain. We should effectively adhere to sustainable principles for protecting natural forest resources.