Study On The Forest Ecosystem Health Assessment And Control Mechanism Of Pinus Tabulaeformis Forest In Badaling

The forest coverage and the forest area, especially the planted forest area, haveincreased continually in China. However, some new problems have appeared, for example,the planted tree species are less; the proportions of young and middle-aged forests, pureforests are too high; the forest biodiversity and forest productivity are low, and so on.Therefore, how to improve the level of the forest ecosystem health, the forest biodiversityand forest productivity are becoming the new issues. However, as a new research field ofthe forestry and the ecology protection, the forest ecosystem health has got much lots ofdisputes at present, study on the forest ecosystem health can provide scientific basis andguidelines for forest protection and sustainable forest management theoretically andpractically. This paper analysed the planted Pinus tabulaeformis forest ecosystem inBadaling forestry centre and the natural Pinus tabulaeformis forest ecosystem in Linhuamountain in Hebei Yu County, assessed their health level, tried to find the influencingfactors of the forest health ecosystem and proposed the control methods. It would providethe theory and techniques for the planted Pinus tabulaeformis forest ecosystem healthmanagement and the planted Pinus tabulaeformis forest ecosystem's service function'sexertion in North China. The research mainly contained the following contents:(1) Basing on the forest's ecosystem service, we started the research with the vigor,the organization and the resilience, and selected 23 indicators to assess Pinus tabulaeformisforest ecosystem health in Badaling forestry centre. The 23 indicators are the relativeproductivity, the vertical structure of community, the tree composition, the successionyoung tree quantity, the regeneration young tree quantity, the arbor canopy cover, the shrubcoverage, the herb coverage, the litter coverage, the complexity of the arbor verticalstructure, the complexity of diameter distribution, the arbor Gleason index, the shrubGleason index, the herb Gleason index, the arbor Pielou index, the shrub Pielou index, theherb Pielou index, the arbor Simpson index, the shrub Simpson index, the herb Simpsonindex, the biomass of shrub and herb, the mean height of first branch, the litter thickness.(2) To assess the Pinus tabulaeformis forest ecosystem health, the research took therelative productivity as the indicator, and showed its operational method: first, got and examinated the site index models and site index of the 49 sampling plots with data ofdominant trees of the 49 sampling plots and 7 stem-analysis; second, taking the samplingplots' site index as the independent variables, and the net primary productivity (NPP) as thedependent variables to fit the site index-NPP model; third, using the measured net primaryproductivity to divide the theoretical value (from the site index—net primary productivitymodel) to got the relative productivity.(3) Because there are too many indicators and there are some certain relationshipsbetween indicators sometimes, so the research used Principal Component Analysis toreduce dimensions from the sdected 23 indicators. To guarantee that the cumulativeproportion was not less than 85％, it confirmed 7 irrespective principal components, andelaborated their significances. Based on the 7 principal components data, using ClusterAnalysis to class the 51 groups of data with Euclidian distance, and confirmed that the 51sampling plots should be clustered into 5 sorts with RSQ, SPRSQ, PSF, PST~2 Statistic.Using the Discriminant Analysis to make sure the results of Cluster Analysis, it knew that 4sampling plots were misclassed, about 7.84％of all the sampling plots. Analysis on all theindicaters' mean value of all healthy rank Pinus tabulaeformis forests, the result is: theⅠlevel of the high quality healthy status Pinus tabulaeformis sampling plots was least, 1piece accounting for 2.04％; theⅡlevel of the good healthy status ones were 14 pieces,accounting for 28.57％; theⅢlevel of the general healthy status ones were 13 pieces,accounting for 26.53％; theⅣlevel of sub-healthy status ones were most, 17piecesaccounting for 34.69％; theⅤlevel of the ill-healthy status ones were 4 pieces, accountingfor 8.16％.(4) Through the analysis, the paper pointed out that the structure of the natural Pinustabulaeformis forest should be the goal structure of planted Pinus tabulaeformis forests inBadaling. The direct factors which affected Pinus tabulaeformis forest ecosystems' healthydegree were the forest canopy structure and the low species diversity of arbor. Based on theabove, the paper pointed out the following 4 control methods:①Thinning the forestswhich are in sub-healthy and the ill-healthy status;②Promoting the forest naturalregeneration, and plant the broad-leaved seedlings or young trees in the forest canopy gapafter thinning;③Pruning trees to reduce the fire danger rating toward the ill-healthy statusforests which had the low mean height of first branch;④Implementing both biologicaland the engineering measures to the sub-healthy and the ill-healthy status Pinustabulaeformis forest ecosystems which are in ecology amusement and rest areas along theroad and have high fire danger rating.