Theory And Practice Of Target Trees Management In Pinus Massoniana And Cunninshamia Lanceolata Plantation

China is the world's fastest rate of plantation forest area ranks first in the world,occupying an important role in the global forest ecosystems. According to the fact that forestquality is relatively low and there is a greater potential to enhance, I explore an improved forestmanagement method that has important significance to achieve sustainable forest management.This thesis was designed to carry out theoretical research and experiment study of target treesmanagement in major forest types Pinus massoniana and Cunninghamia lanceolata at theExperimental Centre of Tropical forestry, Chinese Academy of forestry in China in order topreliminarily construction in theoretical framework of plantation target trees management.1) Target tress value in26yr Cunninghamia lanceolata plantation were assessed.Cumulative basal area stocking, merchantable volume, and value for the most10%valuabletrees/ha account for26.8%,31.3%and50.1%of the stand. It only cost10%of the time andenergy to get50%of the stand value if only target trees are managed. The target trees, meantrees and suppressed trees were sampled and stem analyzed. Growth process of the3population were tested to find whether there are significant differences among them using theoverall average vector difference test and pairwise T-test for paired samples methods. Theresults showed there are significant differences of growth process among target trees, meantrees and suppressed trees and they should be classified into different population. The peaktime of diameter at breast height, tree height and volume annual increment of the target trees(9a,9a,34a) is inconsistent with the mean trees (9a,8a,25a). With the specific demonstrationof the different process from the target treed growth, our results emphasized the forestmanagement parameters of target trees management should be according to target trees notmean trees that adopted by traditional forest management.2) Standard deviation, coefficient of variation, skewness, the Kuznets ratio, Lorenz curve,Gini coefficient and Lorenz asymmetry coefficient of were referenced to measure the size difference on the individual trees in a stand, and the advantages, disadvantages andapplicability of the7methods were discussed. The different thinning methods (interferencetrees thinning, thinning from low, thinning from top, mechanical thinning) were designed toapply on the same Masson pine plantation and Chinese fie plantation to assess the influences ofsize inequality with no thinning as the control. This suggested Lorenz curve, Gini coefficientand Lorenz asymmetry coefficient can be used to measure size inequality dynamic responsebefore and after thinning and have the biological significance. The changes of the standaverage competition intensity before and after7thinning methods were compared, and therelationship between average competition intensity and individuals' volume inequality, andvolume annual increment inequality also were discussed. The results suggested averagecompetition intensity decreased, increased individuals' volume inequality, and volume annualincrement inequality through interference trees thinning at the same time.3) A target tree management individual operation method based on close-to-naturesivlculture were established by exploring the forest classification criteria, designing judgmentprocesses and methods of target trees and interference trees, improving crown simulationalgorithm, developing plug-in Target tree management supporting system (TMSS). Theresults showed that the operation method improved the feasibility and reduced the difficulty ofthe target tree management with GIS technology to help improve the operations on theindividual tree level. It was proved that TMSS was an effective tool for target treemanagement.4) The individual trees initial growth influences of interference trees thinning in themasson pine, Chinese fir plantation were both investigated. The results showed that the growthincrements of the target trees are significantly faster than the growth increments of non-targettrees before and after the interference trees thinning. There are significantly higher growth withdiameter and volume growth in thinning plots than in the control plots, while height growthdifferences little. With the increasing of FTG of the target tree, diameter at breast height, crowndiameter, volume growth increased. There is no significant relation between FTG and clear bole height. Target tree couldn't keep crown top level depends on the accuracy of target treeselection and adequacy of thinning measures.5) The influences of the target tree management on stand characteristics were investigated.The results showed that stand density decreased, diameter distribution skewed from left partialto the right, closer to normal distribution comparing with the control stand, there are two peaksof the mountain-shaped diameter distribution curve including the seedlings. The DBHincrement, volume increment and forest productivity is significantly greater than the controlstand. There also existed that species number of tree species, shrub layer and herb layer speciesincreased significantly, understory woody plants and herbaceous species richness, Marglaefindex, Simpson index, Shannon-Wiener index were significantly increased with a slight declinein evenness index. The soil nutrients have no significant loss and the soil pH values haveimproved in treatment plots. It suggested that soil fertility showed a trend towards animprovement generally. The Quercusgriffithii grew fastest of the6species in the broad-leavedcultivated under Pinus massoniana plantation. Our results suggested that the structure, growthand stability of the stand were improved through thinning and mixed hardwood species.