| The study of forest biomass and productivity is a hot topic issue in ecological field at present since forest is the most important terrestrial ecosystem. It concerns the status that forest as a C sink has in the global C recycle; the capacity that forest reduces greenhouse effect; the soil fixation capacity that root system has would increase with stand biomass increasing, as well as the ability for intercepting rainfall and reducing erosion will increase too; in additions forest store a huge amount of energy so it is significant to make research on harvest, its energy consume mode and its energy transformation as well. In this paper, the Xiaokeng small river basin, located in subtropical zone of Anhui, was selected as the research area, author made a primary assessment on restoration situation of forest vegetation since mountain closed, and its productivity level as well. The object for this paper was to provide comprehensive theory and practice basic materials for study on forest functions in the course of vegetation restoration. The result showed that some forest types in the area had already been similar to zonal vegetation types in both community composition and physiognomy, thus indicated that forest vegetation in the area had recovered obviously since mountain closed for regeneration in 1970's, which had improved ecological environment and reduced erosion as well. Hence mountain closed for forest restoration was an effective method for integrated management of small river basin. Based on the survey date from 31 samples, the forest vegetation was divided into 3 vegetation types, 8 formations and 10 associations, meanwhile all of community characteristics such as species composition, species diversity and community evenness were described in the paper, the sequence of species diversity from high to low as the follows: Quercus phillyraeoides community>Cyclobalanopsis glauca>Castanopsis eyrei > Castanopsis sclerophlla > Sassafras tsumu > Lithocarpus harlandii >Liquidambar formosana; In additions evergreen species of Fagaceae were the major dominant species of community conmposition. The above ground biomass ( not including leaf liter) was measured only in the paper, Base on the data collected from 21 sample trees, the mathematical models of for biomass with dbh and tree height for major 4 evergreen species, Castanopsis eyrei, Castanopsis sclerophylla, Cyclobalanopsis glauca, Lithocarpus harlandii, were established; the average biomass of single tree for these 4 species was 80.557 kg,56.48 kg,45.645 kg,56.908 kg respectively, and the average productivity was 3.84 kg·a-1,2.17 kg·a-1 ,1.76 kg·a-1, 3.35 kg·a-1 respectively; as well as the average community biomass for above 4 species was 120.165 t·hm-2 , 96.168 t·hm-2, 72.73 t·hm-2,80.416 t·hm-2 respectively; However, the biomass of a typical shrub community reached to 104.48t·hm-2; these results indicated that all community biomass was little higher than the average level of forest vegetation in Anhui. In the above communities, the biomass distribution in dbh class was a normal distribution, and most were distributed in the trees with 12cm～24cm in dbh. In the paper, quadratic regulations for the 4 major evergreen species were built to simulate the vertical allocation pattern of biomass in communities, it was obviously that trunk biomass decrease with tree height increase, the biomass of community accumulated in the vertical zone between 2 and 8 m high was more than that of in both above the height and below. The biomass and average productivity of 48-year Castanopsis eyrei community were almost equal to that of some type community in Zhejiang province, both locations more close at latitude, but much less than that of 51-year Castanopsis eyrei community in Wuyi mountains. In additions based on Liu Shirong's model, the current productivity of Xiaokeng forest vegetation was much lower than the climate and vegetation potential productivity this region should has. Growth analysis of 4 major evergreen species showed: growth rate of Lithocarpus harlan... |
PDF Full Text Request