The Evaluation Analysis To The Reconstruction Mode Of White Birch Low-quality Forest Based On The Grey System Theory

The Greater Khingan Mountains forest has a long history. It has became the Low-quality forest now with the interference and fell in different historical periods, which has affected the ecological function and economic value critically. The transformation pattern and method should be appropriate to the local conditions. In this paper, different transformation methods (forest gap transformation, ribbon transformation) and induce methods (plantation of Mongolica, Larix gmelini, and Siberian Korean pine) were used for the investigation of the White Birch Low-quality forest in Greater khingan mountains. Based on the Gray System Theory, experimental samples with different transformation effects were analysed to get the best methods for the White Birch Low-quality forest transformation in the Greater Khingan Mountains.By means of setting sample plots (different area sample plots G1-G6and different width sample plots S1-S4), properties of the White Birch Low-quality forest were investigated, which including the soil physical properties (density, porosity (capillary porosity and noncapillary poropsity), moisture content, organic carbon content, and the content of organic matter), the soil chemical properties(contents ofN、P、K, the available N, available P, available, the pH value, heavy metal(Cu, Pb, Cd), and so on). Comparative analysis of litter volume, water-holding capacity and biodiversity (richness index, diversity index, evenness index) of the low-quality forest was conducted. With the consideration of both the survival rate and growth rate of seedling, the best transformation method compared with the control group CK was achieved. The main conclusions are as followed:The experimental sample plots induced by Siberian Korean pine had the best soil physical properties, which including G2(10m×10m), S2(the width of sample is10m), S3(the width of sample is14m). The experimental sample plots induced by Larix gmelini had the best soil chemical properties and have the appropriate pH value, which including G2(10m×10m), S2(the width of sample is10m). G4(20m×20m), G5(25m×25m), S2(the width of sample is10m), and S3(the width of sample is14m) had the best biodiversity, at the same time, litter in S2sample plot had the lowest content of heavy metal Cd and a high capacity of water-holding. Seedlings induced by Siberian Korean pine had a low growth rate when the survival rate was high, while seedlings with high growth rate usually had a low survival rate. The final conclusion was that the best transformation modes of White Birch Low-quality forest in Greater khingan Mountains were G2(10m×10m) induced by Siberian Korean pine and S2(the width of sample is10m) induced by Larix gmelini.The results above provide a scientific reference and theoretical basis for the selection of transformation modes of the White Birch Low-quality forest in Greater Khingan Mountains.