Effects Of Artificial Disturbance On Spatial Structure And Species Diversity In Myrica Rubra Forest And Phyllostachys Pubescens Forest

This research studied on the mingling, neighborhood pattern, neighborhood comparison, species diversity, and the relationship between spatial structure and species diversity of the main Eco-economic type plantations, Myrica rubra and Phyllostachys pubesscens under three different artificial disturbance intensity.Systemically, and confirm the suitable environment of the main plantations, in order to offer theory bases to construction of High-efficient ecological forest.The result is showed as follows.The mingling degree of the M.rubra under severe disturbance, intermediate disturbance and light disturbance were 0, 0.336 and 0.208 respectively. The average neighborhood comparison of each plot range from 0.564 to 0.667 all were belong to normal distribution.Therefore intermediate disturbance M.rubra forest is closer to uniform distribution than other two types. The neighborhood comparison measured by diameter at breast height(DBH), biomass, canopy breadth, and tree height under intermediate disturbance type had a slight fluctuation range than the other two.The mingling degree of the P.pubescens under severe disturbance, intermediate disturbance and light disturbance were 0, 0.378 and 0.270 respectively. The average neighborhood comparison of each plot range from 0.533 to 0.553 all were belong to normal distribution.Therefore intermediate disturbance P.pubescens forest is closer to uniform distribution than other two types. The neighborhood comparison measured by diameter at breast height(DBH), biomass, canopy breadth, and tree height under intermediate disturbance type had a slight fluctuation range than the other two. Compared the richness index, diversity index and eveness of the three different artificial disturbance intensity, it was clear that intermediate disturbance M.rubra and P.pubescens was higher than that of others.The change of mingling and richness show the consistent trend;the change of neighborhood pattern and eveness show the consistent trend;but the change of neighborhood comparison has no correlation with Simpson index. The interactive mechanism betwwen spatial structure and species diversity needs a further investigation.At last, the results confirm the conclusion of moderate artificial disturbance can improve tree species diversity. Intermediate disturbance type is the most beneficial way of the three classes of artificial disturbance intensity to maximize the ecological benefits.