Researches In The Naturalness Evaluation Based On Forest Stand And Technology Of Close-To-Nature Management Of Wuhan Urban Forest

Forest naturalness is the degree of the native state of forest ecosystems keeping or human disturbance, evaluation and gradation of forest naturalness is important to the forest close-to-nature management.This study use AHP to construct evaluation system of wuhan urban forest naturalness which based on the forest stand and evaluate the wuhan urban forest naturalness.Make contrastive analysis of the construction between pure forest and mixed forest communities,and to sump up the influential factors of forest naturalness, made the preliminary technical specification of the close-to-nature management in wuhan urban forest, management pattern of different naturalness forest,close-to-nature reformation program of pure forest. The main findings are as follows:(1) This study selecte the evaluation indexes which can reflect the uneven aged, mixed, complex forest community to construct evaluation system of forest naturalness. The forest naturalness of wuhan urban city is the destination Layer.Criteria level include community composition,community structure,community succession,the degree of Interference. Criteria level include ten indexes are number of tree species,number of groundcover plants, total coverdegree, number of diameter class,the toplevel fitness value, number of natural regeneration seedlings,stand origin,degree of supervision,natural disturbance.Use AHP to determine the index weight and estab.lish naturalness evaluation model and evaluation criterion.(2) Make comparison analysis from community composition,community structure community succession and the degree of Interference for each community.①Mixed forest community is more lager than pure forest community in the total proportion of arbor,shrub,herb②Mixed forest community have rich trees,shrubs, herb and interlayer plants and is more complex than pure forest community in the vertical structure③The small and medium-sized DBH trees dominant the pure forest community④Mixed forest community have rich natural regeneration species and quantity, pure forest community almost have no natural regeneration⑤The heterogeneity degree of pure forest community is poor result in that whose ability to withstand natural disasters is weaker than mixed community.⑥Mixed community have simple tree structure like Pinus massoniana+Chinese sweet gum and Pinus massoniana+Fagaceae plants⑦The factors impact of forest naturalness are as follows:little update seedlings and mixed trees,young trees dominant the community and so on.(3) This study evaluate the forest naturalness of 32 pure and mixed communities in wuhan urban forest,The highest forest naturalness is a secondary forest community which reached 0.78,the lowest forest naturalness is a artificial pure forest community which reached 0.18. The naturalness of contrasting community is 0.27and the naturalness of transformed community is 0.44, raised 63%, The number of tree species,the top-level fitness value,the number of natural regeneration seedlings, number of diameter class are the most impact factors to the transformed community naturalness.(4) Combined with naturalness evaluation results research the technology of close-to-nature management in wuhan urban forest, estab.lish the preliminary technical specification of the construction for close-to-nature plant communities and the cultivation and maintenance method of close-to-nature forest. Analysis the management pattern of different naturalness forest, put forward the close-to-nature reformation program of pure forest base on sample investigation.