Research On Tree Determination Of Forest Harvesting Based On Stand Spatial Paterns

As a landform related to life, forest supplies basic existing conditions for all lives on the earth.With the global ecological and environmental problem deteriorating, forest sustainable management becomes a important problem faced by the forestry. The approaching natural forest management thought is advanced, which stands for the German thought of near natural forest management and the American thoughts of the ecological forest management. The thought get some achievement about forest sustainable management. Just based on this thought, this thesis elaborates types of the forest spatial structure distribution and its mathematical model, and describes several indexes of the forest spatial structure. By the stand located data from the Zhan River bureau, the basic structures of the stands are analyzed. Moreover, by means of the aggregative index method, stands spatial distribution status is first judged. After the stands spatial structure indexes, it is proved again that this stands spatial distribution pattern is aggregative distribution. Because the optimized spatial distribution pattern of the natural forest is random distribution, based on the thought of approaching natural forest management, stands distribution should advance from aggregative distribution to random distribution. After the distribution pattern of stands is analyzed combining the basic principle of ecological harvest, reasonable selective felling is carried out on stands. After stands spatial structure is analyzed again, the result shows that all the structure indexes are improved, and the expected aim come out.Stand distribution is prone to random distribution after felled. Therefore stand can make most use of the varied environmental factors to grow, which is like to grow in nature.Moreover, by the program designed with the Microsoft Visual Basic, the index of the forestry spatial structure is calculated, which is convenient and efficient to compute the index.