The Quality Control Technology Of Chinese Pine And Oriental Arborvitae Forests In Mountain Areas Of Beijing

Forestry is a public beneficial (welfare) forestry focused on ecological construction in Beijing. Improving the present non-commercial forest (NCF) quality especially in mountain areas in North-west of Beijing has become a major task in forestry development. Pinus tabulaeformis and Platycladus orientalis forests are two important types of conifers in mountain areas of Beijing. They occupy a large coverage and proportion and are distributed on the surroundings for people to living, producing and working, and improving quality is the keystone to managing them. Therefore, it is of great significance to study on the theory and technology to control quality.Based on the investigation and systemic analysis of the status of the NCFs in mountain areas in Beijing and aimed at the specific features of the NCFs, this dissertation advances that the long-term policy for improving the quality of forests should be to conserve and improve soil fertility and adjust the forest composition and structure. The main problem to solve in silviculture of the NCF has converted from the increasing quantitative problem to the improving qualitative one. Promoting the growth of individuals and improving the quality of stands come to be the main object of NCF development. Forest tending has become an important technique and approach to reach the aims.The low-hill Pinus tabulaeformis and Platycladus orientalis forests in Beijing have function of soil and water conservation, water regulation and recreation for people. The aim of management should be to restore the regional vegetation and the aim of quality control should be to set up a management system with the present forest as the object, quality as the goal and forest tending as the approach. Through study and analysis of Beijing NCF's forming features, rules of evolution and development and the existing achievements from three aspects, i.e., individual, population and forest, the dissertation puts forward that the Pinus tabulaeformis and Platycladus orientalis forests and block mosaic mixed forests of other conifer andbroadleaf trees should be cultivated in accordance with the evolution and development of regional vegetation and forest and with the requirements of the NCFs in Beijing. Oaks (Quercus spp) play an important role in the forming of NCFs and the relative fostering technology is proposed.Quality control over the Pinus tabulaeformis and Platycladus orientalis forest divisions lays emphasis on density control in order to form optimal stand density. Advanced in this dissertation include a density table for the optimal management of Pinus tabulaeformis and Platycladus orientalis forests in different sites and developing phases and three methods to control the density, at the same time, importance should be attached to the features and function of the distributing patter changes of the fostered Pinus tabulaeformis and Platycladus orientalis forests in different developing stages and site conditions in the fostering process of NCFs, in the forest tending some features such as clumped distribution pattern should be considered when fixing on reserve-trees. There are three methods in controlling the density of forest divisions, i.e., tree crown width control (TRWC), tree crown area control (TCAC), and management density control (MDC). By studying the relationship between the breast height diameter (BHD) and nourishing area of Pinus tabulaeformis and Platycladus orientalis individuals in different sites and developing phases, the optimal TCAC table, TCAC table and MDC table are worked out for the Pinus tabulaeformis and Platycladus orientalis NCFs with the canopy density of 0.6-0.8, which may ascertain the thinning intensity, time and cycle and also provides reference for fixing on optimal planting density. What is more applicable is in practice is the methods of TRWC and TCAC.Individual quality control of Pinus tabulaeformis and Platycladus orientalis forests mainly refers to defining a standard of superior grade and inferior grade for individual tree to keep the superior and get rid of the infe...