Establishment Of Site Index Table For Plantations Of Masson Pine In Enshi State

Enshi state locates southwest department in the province of Hubei, possess the good reputation of the" west wood's sea of Hubei" and " Chinese botanical garden", but till now, there is not any data processing table about forestry survey and calculation which can be used as the basis of forestry operation and management in Enshi state. Under in many ways of the support,â… chose the research lesson of making the site index table for plantations of Mason Pine in Enshi state to provide the basis and consults for the native forestry production and management.The Enshi state possess abundant natural vegetative covers, its topography is sophisticated, the elevation is entirely different, the land forms are diverse, the soil resources are rich, the climate is vary. Based on them, people still go on planting forest. In tree kinds choice of artificial forestation, mason pine had been wide-ranging used e.g. In tree kinds choice of ecological public-welfare forest, self-restraint headwaters forest, water and soil conservation forest, defending-wind and stabilizing-sand forest, breast wall forest, berm forest, environmental protection, forest national defense forest, seed forest, merchandise forest, scenery forest, famous spot historic monument forest, nature reserve forest, generally used material, forest fuel wood forest, short- term intermediate-cut timber forest.By understanding the relevant circumstances in Enshi state very much, applying the forest mensuration and statistics knowledge and these principles of choosing and establishing standard ground,â… had conducted field investigations in 6 representative country towns of Enshi state. According to the existing state of the plantation of mason pine,â… divided them into three classes, i.e. upper and middle and low level. The tree ages of sample plots were between 14 and 30 age gradations and every age gradation contained stands of three classes.At first, we randomly established 54 temporary sample lands which consisted of six plots by the way of choosing two plots from each stand among every different age gradation. The whole areas of temporary sample lands are about 500—600 m², their shapes contained both square and circle and firstly planted density is at 4500 stubs/hm².In addition to them, the standard ground were adopted the small piece form or the cave form, and could been taken out weed only once annually and couldn't been fertilized in the first three years of forestation, the forests of middle ages could been thinning cut once or twice.Then predominates were selected from three to fives stubs in each sample plot and surveyed and calculated the tree heights and the ages by regarding two years as an age gradation whose heights were handled by the method of a standard deviation.Regarding the average age of felling as standard age, which was supposed 30 years, and using 10% tree height of standard age as the grade distance, which was settled to 1.0m,â… made the site index tables by adopting standard deviation method.The curve regression equation of tree height-age relations is that H=10^{1.39-7. 32/A}, the regression standard mistake of estimate is that S_H/A=1.0 m, correlation coefficient: r =-0.996, r⁷_0.01=0.798, their relativity reached the striking level. As showed the curve regression equations of tree height-age relations matched the sample data nicely and reflected the trees' grown process nicely。So, by the curve regression equation of tree height-age relations and field investigated date,â… have made the site index tables for plantations of Mason Pine which contain the site indexes from 10 to 18 gradations between 14 and 30 age gradations. These tables reflected the relations between local mason pine plantations' growth and the site factors very much, and have good leadings and consults to forestry production and management in Enshi regions.