The Research On Growing Proeess Of Plantation Cunninghamia Lanceolata Of Guangxi Daguishan State Forest Farm

The afforested area and forest stand volume of Cunninghamia lanceolata were in important position of plantations in China. It was special timber and widely cultivated tree in Southern forest region of China.At present the study of Cunninghamia lanceolata mainly in afforestation density effected on growth, growth model, mixed forests, biomass, etc. The Guangxi Daguishan state forest farm was located in east Guangxi. The region was a transition zone of center region and general production areas of Cunninghamia lanceolata. Climatic conditions had many characteristics, such as higher annual average temperature, rainfall was larger. At home and abroad to regular growth of its plantation in Guangxi east region study was less. So it was necessary to further study the growth of plantation Cunninghamia lanceolata now.This study aimed at the growth of plantation Ccunninghamia lanceolata to carried out the research. It accorded to the grades of site conditions, the different stand density level set to set standards. It threw the investigation and standard wood parsing of the data, and carried on the analysis of the data processing. It was concluded that the growth during the law of division growth stage, studied the characteristics of each stage, at the same time put forward corresponding tending management measures. While fitted the growth model of the diameter at breast height, tree height, volume. They provided theoretical basis for predicting the tree height,DBH, volume of plantation Ccunninghamia lanceolata in east Guangxi. The results were as follows:1. The average value of experimental form factor and DBH, tree height was not correlation, and the fractal number did not with increase by DBH, tree height. The level range of experimental form factor class was larger, the stem number of experiment form factor was similar to normal distribution.2.According to the exponential growth rate of volume changes along with the growth of the age was on the decline, and the growth rate curve was roughly same, there was no big difference.3.Used the logarithmic equation, binary equation, power equation, Richard equation and logistic equation of diameter at breast height, tree height, volume of Cunninghamia lanceolata growth curve fitting, selected the optimal model equation, and model test, growth curve model.4.Analyzed the correlation between the three of the tree height, DBH and volume, the correlation coefficient is greater than 0.7, showed that when the significance level alpha 0.01. We thought that there was a significant correlation between them.5. The current annual increment of DBH of plantation Cunninghamia lanceolata with age was a negative correlation. The mean increment of DBH had maximum between 11 and 15 years. The current annual increment of DBH intersected with mean increment in 12-16 years. The current annual increment of tree height intersected with mean increment in 15 years. After 15 years, the current annual increment of tree height was smaller than mean increment. The current annual increment of tree height had maximum between 8 and 9 years. And the mean increment of tree height had maximum in 14 years. The current annual increment of volume had maximum between 16 and 21 years. And intersected with mean increment in 26-33 years.6. On the average tree height, DBH and volume growth process of orderly classification and consider the analytic resulted of Cunninghamia lanceolata, the average growth process was divided into four stages:4-5 years as sapling stage, 5-11 years as a fast-growing stage,11-25 years as woody stage,25 years later as slow-growing stage.