Simulated Tending And Predicting The Pinus Tabuliformis Plantation In Huanglong Mountain

Long growth cycle and slow self-pruning are the characters of forests, observing the forests dynamic change with traditional method will take a long time. Moreover, Once the forest manager implement the forest management decisions, the result often take years or even decades later to evaluate. With the development and fusion of various disciplines, using the result of the forests dynamics simulation,that rely on the computer model, to provide the basis for forest management has became an important direction of forest research. In this study, based on 27 sample plots of Pinus tabuliformis plantations in Huanglong Mountain., on the basis of crown density, simulated tending the trees in the sample plotes with conputers. Then, used two kinds of the crown growth model to forecast the crowns after tending, and compared the result of two kinds of forecasts to determine the time of tending again. The main conclusions of the study are summarized as fowllows:(1)Circle is more appropriate to simulate the crown width projiection shape, when it is used to calculate the forest canopy density by projection method. The differences of calculate the forest canopy density with circular and elliptical respectively is not significant, so circle is more appropriate to simulating the crown width projiection shape.(2) Population density >4000 ind./hm2 and 2000-4000 ind/hm2 of sample plot can be classified as one class in the forecast analysis. On the basis of population density, Pinus tabuliformis plantations are divided into three types, >4000 ind./hm2, 2000- 4000 ind/hm2 and <2000 ind./hm2. After thending, the average DBH, basal area and stands of the>4 000 ind./hm2 and 2000- 4 000 ind./hm2 sample plots were similar.(3) The predicted results of the two crown growth models were similar.With one of the modelsto predict, after tending, sample plot D1’s canopy density will get 0.8 in 3a and 0.9 in 6a, while sample plot E6’s canopy density will get 0.8 in 2a and 0.9 in 4a. Using another model to predict, after tending, sample plot D1’s canopy density will get 0.8 in 3a and 0.9 in 7a, while sample plot E6’s canopy density will get 0.8 in 2a and 0.9 in 5a.(4) Pinus tabuliformis plantations of different density should take different measures to tending. Pinus tabuliformis plantations in Huanglong Mountain, which canopy density is 0.7, forest stand of population density under 2 000 ind./hm2, after first tending, 3- 6 a are suggested to be tended again, and forest stand of population density more than 2 000 ind./hm2 can be tended again within 2- 5 a. Forest stand of population density more than 2 000 ind./hm2, the canopy density will get 0.8 in 3a and 0.9 in 6a. Forest stand of population density under 2 000 ind./hm2, the canopy density will get 0.8 in 2a and 0.9 in 5a.