Study On The Main Types Of Forest Structure And Optimization Of Management Measures Of MengLuan Forest Farm In HeiBei Province

Forest structure is an important part of stand characteristics, is the theoretical basis of forest management. Yanshan Mountains in the larger with the gradually increase of operating level, in production practice needs more overall stand size and space distribution information, diameter structure of stand, species composition, spatial location between trees have great contacts with the structure and function of the stand, and the reasonable stand structure is the basis of forests playing multi-function, on the stand structure of forest management and the optimal decision to have important theoretical and practical significance.In this article, as the research object to several different types of stand in Meng Luan forest farms in Hebei Province, including Populus davidiana-Betula platyphylla Secondary Forests, Oak Secondary Forests, Larix principis-rupprechtii plantations and conifer and broadleaved mixed forests. Analysis the species composition of various forest types, diameter structure of the basic structure of forest stands, based on the minimum structural unit from the diameter, species composition and spatial structure three parameters that is mingling, angle Index and neighborhood comparison. And starting from the update of different forest types and diversity study, doing on the qualitative and quantitative analysis of the different types of stand structure characteristics. The results showed that:(1) In the four forest types, diameter class distribution of forest plants for the path-order trees line the majority, up to 68%. Application of Weibull distribution and the negative exponential distribution describe the relationship between the number of various types of diameter class and the diameter, and found the diameter distribution of all types of diversity. Natural secondary forest generally shows inverted J-type characteristics, however, the unreasonable stand structure there are still some unimodal, bimodal and multimodal-shaped curves. Found to fit them for the path-order more stands application the negative exponential distribution fit a good effect.(2) In the spatial structure of stand the horizontal distribution basically showed the characteristics of random distribution, the average angle Index of Populus davidiana-Betula platyphylla Secondary Forests is 0.3925, the average angle Index of Oak Secondary Forests is 0.5425, the average angle Index of Larix principis-rupprechtii plantations is 0.4475, the average angle Index of conifer and broadleaved mixed forests is 0.4925. The segregation between species in addition to Larix principis-rupprechtii plantations basic mixed in moderate condition, in which the maximum mingling of Populus davidiana-Betula platyphylla Secondary Forests is 0.4700, Oak Secondary Forests is 0.4125, conifer and broadleaved mixed forests is 0.425. In diameter ratio of the number of species of various forest types the largest is conifer and broadleaved mixed forests to 0.5275. Smallest is Populus davidiana-Betula platyphylla Secondary Forests to 0.3325, Oak Secondary Forests to 0.4275, Larix principis-rupprechtii plantations to 0.3400.(3) The stand update of four different types are poor, compared to the overall number of updates Larix principis-rupprechtii plantations＞conifer and broadleaved mixed forests＞Oak Secondary Forests＞Populus davidiana-Betula platyphylla Secondary Forests. And the height are small, growth is not good. Under the other four types of stand diversity compared, Whether from the perspective of the shrub coverage height or richness and evenness. The diversity of conifer and broadleaved mixed forests are higher. Because Populus davidiana-Betula platyphylla and Oak Secondary Forests have poor operating conditions, the diversity is not very high. In Larix principis-rupprechtii plantations the diversity of herbal is higher, shrubs represent more inferior.Research on the Mengluan forest farms stand structure of main types, regeneration and diversity. According to their development objectives situation of the forest management, restructuring of its stand and practice management propose measures and theoretical basis to adjust the structural characteristics, for the optimization of operating conditions of its stand have theoretical and practical significance.