Study On Quality Evaluation Of Timber Forest In Jiangle State-owned Forest Farm

Timber forests play an important role in the national economy of our country.It is necessary to resolve the country's supply-demand relationship for timber shortages,and also to play it's multi-functional benefits including the functions of carbon fixation and oxygen release,soil and water conservation,and air purification under the background of ecological civilization construction.The immediate,dynamic and accurate monitoring and evaluation of the quality of timber forest resources can provide a theoretical basis for the restoration,utilization and management of forest resources.In this paper,the timber forests of the Jiangle state-owned forest farm was assessed.Based on the forest resource planning and design survey data in 2012 and the field data of the fixed sample sites established in the study area,a comprehensive evaluation index system of forest resources quality including forest farm scale and forest stand scale was constructed.The subjective analytical hierarchy process(AHP)and objective entropy weight method(EWM)were combined to determine the weight of each index.Matter element analysis method that can solve the compatibility problem was used to timely and accurately analyze and evaluate the quality of timber forest resources.The results of the analysis of the timber forest in Jiangle State-owned Forest show:(1)Based on the principle of constructing evaluation index system,and combining frequency analysis method,theoretical analysis method and expert consultation method,a comprehensive evaluation index system of the timber forest resource quality that consist of 1 target layer,3 criteria layers,and 11 indicators was constructed.Among them,the average diameter at breast height,the average tree height,and the accumulation of per unit area were the common indicators of forest farm scale and stand scale.In addition,the forest farm scale evaluation indicators also include the ratio of grass coverability of 40%-60%,the ratio of canopy closure of 0.4-0.69,the ratio of mixed forest,the ratio of young and middle-aged forests,the ratio of humus layers greater than 5cm,the ratio of soil thickness greater than 40cm,the ratio of site quality ? and ?,and the ratio of slope less than 26°;the stand scale indicators also include the outturn percentage of stand,the growth of stand,the density of stand,the species diversity and structure of community.(2)The weight ratios of the corresponding indicators at different scales are different.Among them,the accumulation of per unit area,the average diameter at breast height,and site quality ? and ? have larger weight values on the forest farm scale;on the stand scale,the accumulation of per unit area,the species diversity,and the growth of stand accounted for most of the proportion,totaling 85%(3)At the forest farm scale,the general status of timber forest in Jiangle State-owned Forest in the grade ?,and there is a tendency to transform to grade ?;At the stand scale,The quality of the four different types of stands was:Chinese fir-masson pine mixed forest>chinese fir and broad-leaved mixed forest>pure chinese fir forest>pure masson pine forest.Among them,the Chinese fir-masson pine mixed forest,pure chinese fir forest and chinese fir and broad-leaved mixed forest were grade ?,while the pure masson pine forest was the worst,with grade ?(4)Although the quality of chinese fir-masson pine mixed forest and pure chinese fir forest were both in the grade ?,their comprehensive correlation is closest to the grade ? and extremely unstable;the quality of the xhinese fir and broad-leaved mixed forest is relatively stable,However,there was also a tendency to transform to the grade ?.The tendency of quality of the pure masson pine forests transform to the grade ? and IV.was similar.