| The community characteristics and spatial distribution were analyzed for the Forms Pinus tabulaeformis-Quercus wutaishanica in the Nature Reserve of Lingkong Mountain by following the CTFS protocols, in which all free-standing trees were mapped and identified.The results showed that a total of 25 tree species in 18 genera and 12 families were recorded among the 8,210 individuals. Most species are commonly found in the temperate Asia and East Asia including the endemics in China. The dominant species of P. tabulaeformis and Q. wutaishanica accounted for 86.81% in abundance. The mian companion species were also observed as the Pyrus betulaefolia, Fraxinus chinensis, Toxicodendron vernicifluum in the communities. The diameter-class structure of dominant species was found similar to that of the whole community, roughly in inversed "J" shape, in which most individuals were in small diameter-class, suggesting sound community renewal under wood. Meanwhile, the main species demonstrated the bottleneck phenomena to various degrees, most like due to the self-thinning effects of P. tabulaeformis and Q. wutaishanica, especially among the young trees of 4 cm and 15 cm in DBH respectively. In comparison, Pvrus betulaefolia showed a faultage phenomena among the trees of 2—5 cm in DBH, probably due to the thinning effect by other species. The age structure of Fraxinus chinensis suggested the transition from growth to stable phase. The diameter-class structure of Toxicodendron vernicifluum was approximately in inversed "J" shape, showing active natural renewal as being indicated by the seedlings in high abundance.In the tree Community of the Forms P. tabulaeformis-Q. wutaishanica in Lingkong Mountain,micro-phanerophytes and meso-phanerophytes occupied the dominant position, accounted for 48% and 40% respectively. P. tabulaeformis and Q. wutaishanica constitute meso-phanerophytes synusia which was the dominant one.The vertical structure of this community was complex, P. tabulaeformis and Q. wutaishanica were the upper dominant species of the community; middle layer composed of Carpinus turczaninowii and Crataegus kansuensis etal,which was the mian layer of the community; lower layer mainly were young trees.Using R2.11.1 and point pattern method analysed the spatial structure and patterns of main species.The results showed that:in small scale the clustered distribution was observed among the dominant species. In P. tabulaeformis the individuals of small diameter-class demonstrated cluster distribution in the scale of less than 20 m, but random distribution in scale of 60—100 m that is the same as that of the individuals of big diameter-class in all scales. In comparison, the Q. wutaishanica showed the trend from clustered to even and random distribution along the scale gradient from small to large.. The trees of Pyrus betulaefolia of small diameter-class showed clustered distribution in the scale of less than 10m but random distribution in scale of 10—100 m; and the trees of big diameter-class demonstrated random distribution in all scales. The small diameter-class individuals of Fraxinus chinensis showed clustered distribution in scale of 0—25 m and even distribution in scale of 25—70 m, demonstrating trend to random distribution with the increase of spatial scale. Toxicodendron vernicifiuum showed clustered distribution in scale of 0—20 m and even distribution over of 20 m. The main species showed high density in relatively flat habitats except for Toxicodendron vernicifiuum.The results show that:The data indicated P. tabulaeformis being dominant over Q. wutaishanica in the community and all tree populations being in relatively steady state in the Nature Reserve of Lingkong Mountain. |
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