Effect Of Forest Structure And Health About Locust Plantation On Thinning

In this research,we selected locust plantation in the loess plateau for the study. Plots located in Shaanxi province Yongshou of Huaiping forestry. This study hopes to find out what kind of thinning intensity could more effectively improve forest structure and forest health about locust plantation in the loess plateau. Provide a theoretical basis for soil and water conservation and forest management in the loess plateau, at the same time help locust plantation change to near natural forest. According to tree height and DBH of reference, compared three calculation methods of the amount of thinning. Combined with the purpose of the forest management and the specific situation of forests, chose which calculation method is more suitable for the study area and calculate out the value of theory. Based on the value of theory set up four kinds of thinning intensity(25%、15%、5%、0%)to compared with each other. Researched the distribution of trees about locust plantation by DBH neighborhood comparison and uniform angle index. Used Jinliang Liu put forward the “Locust Plantation Health Assessment System” to evaluate the health of locust plantation. Analyze the effect of forest structure and forest health about locust plantation under different thinning intensity. The results were as follows:(1)Because of the locust plantation in Huaiping forestry are belong to Water Conservation Forest, It’s not suitable for high-intensity thinning. Under the comparison of three calculation methods, based on the correlation of DBH and crown width to determine the calculation method is more suitable for locust plantation in Huaiping forestry, the value of theory of thinning intensity is 28%.(2)Compared with the other three thinning intensities,25% thinning intensity can optimize forest structure、release stand space、reduce the space extrusion between plants more better than others in different age locust plantation. It can make the trees in cluster distribution translate into random distribution and evenly distributed effectively. This change can help reserved trees fast-growing.(3)Overall, the locust plantation in Huaiping forestry are most in sub-health, those stands which belong to healthy account for 25 per cent,sub-health stands account for 55.6 per cent,unhealthy stands account for 19.4 per cent. After 25% thinning intensity, health degree of locust plantation are better than others thinning intensity, all plots are belong to healthy. plots without thinning intensity have poorest and least forest healthy, The young forest(age 7) more healthy than middle age forest(age 18) and near mature forest(age 25).Above synthesis conclusion, 25% thinning intensity locust plantation can improve the forest structure and forest health more significant than other three kinds of thinning intensity.