Forest Health Assessment And Research In Southwest Of Guangxi Karst Area

Forest is the main body of land ecosystem and it is one of the most complex ecosystems on the land, it plays an important and indispensable role in the global ecological system. Along with the rapid development of urbanization, resources are rapidly wasted by humans and leading to the environment that human relies to survive become worse and worse, making human survival pressure becomes greater and greater, so, the ecosystem health evaluation as an emerging science field has become more attentional. As everyone knows, karst forest ecosystems itself is very uniqueness, therefore, it’s meaningful to research the health evaluation of it. This research took the present situation of southwest karst ecosystem as the starting point, use analysis hierarchy process method and combined with data analysis software such as SPSS, YAAHP and so on to explore the southwest karst forest ecosystem, at the same time, by choosing SBE rule and Stepwise regression analysis method to assess landscape quality practice, to reveal landscape quality and main factors affecting it. The main content and results are listed as followed:(1) The research puts forward a set of feasible and practical forest ecosystem health evaluation index system for Guangxi karst plantation, we selected14indexes from functional integrity, sustainability and stability these3aspects and through the analysis of soil properties and plant diversity to evaluate soil Guangxi karst ecosystem, we used analytic hierarchy process method to determine index weight. At the same time, in order to make the evaluation result more practical, we set up the evaluation model by comprehensive index method.(2) The result of the forest health evaluation of6areas shows that there are2area’s health index is0.71, they are Huashan of Ningming, Longguigou area; the health index of center of Pingxiangrelin and Daliancheng area is0.60; the health index of Daxinnaya country and Shijiugang is0.75; the comprehensive index of sixed regions is0.68, this indicated that forest ecosystem in southwest Karst area is generally in healthy level, and has many advantages such as forest ecological system stability is strong, species diversity is rich and community structure is complete.(3) The result of the correlation analysis on influence factors and health value shows that tree height,DBH,Shannon-Weiner index and Margalef index of tree layer and shrub layer was a significant positive correlation, canopy density, slope, rock exposed rate and organic matter was a significant negative correlation. (4)Through the research of forest landscape quality evaluation, the contribution degree that each elements to SBE is follow this law: forest layer> shrub diversity index H> shrub diversity index R> DBH> bareness degree of rock slope. Forest health value changes with the SBE value follow cubic function distribution, the general trend is:when the SBE value is less than0, the health value decreased with increasing SBE value, when SBE is greater than0, it increased with increasing SBE value first and then began to decreased when SBE value reaches a certain value.(5) According to different influence factors, we have put forward some management measures:starting at the view of stand characteristics, we’d better through thinning at those area that canopy density higher than0.8to increase the forest gap and promote the succession of ecological system; When considering the plant diversity, we should take afforestation measures at areas where species is not rich to promote forest regeneration; in those areas with poor habitat conditions we could combine the biological and engineering measures to adjust stand structure, to improve forest environment and improve the forest itself resistance ability, in some area where with the landscape value, we can set the tourism protection zone and take measures to strengthen the management and operation of landscapes here we can tourism and rest.