Ecological Health Assessment Of Artificial Forests By Grain For Green In Minshan

The assessing indicators for forest ecosystem health especially for artificial ecological forests health is the critical component of biodiversity and an essential aspect of artificial forests restoration and management. However, compared to general ecological heath assessment, information about the assessing indicators for artificial ecological forests is scant, only for some concepts, theories and standards. Actually, in China, artificial ecological forests health has become one of most urgent and important focuses for ecologists and forest scientists.The Grain-to-Green Program, which aims to restore hillside agricultural lands into forest or grasslands over the next 5 to 8 years, is one of most important issues for China to expedite the development of forestry and strengthen forest protection. However, due to lack of the assessing indicators for artificial ecological forests, the characteristics and mechanisms of artificial ecological forests are not became important issues, but the breeding models of timber forests such as the composition and density of planting, and breeding of young forests are still referred.First, based on the summary of the vegetation restoration by Grain for Green and some previous results, the theories about primary ecology, restoration ecology, forest silviculture, and ecosystem security and health were discussed. And then, as a case study, the methods for developing forests by synusiums was put forward to ensure the health of ecological forests, which was the methods for breeding forests by creating a harmonic and healthy relations for trees, shrubs and grass. In other words, the shrubs and grasses are the important synusiums for the forest stand, especially for the muti-funtional ecological forests, whose healthy condition such as characteristics of species, height, coverage and evenness were controlled by the characteristics of tree synusiums such as species, canopy coverage and distribution pattern. The individual density and non-evenness pattern were the key factors for culturing forests, which could ensure the healthy development of tree, shrub and grass synusiums.Through the relationship analysis of the plants habitats and vegetation restoration in Minshan Area, Grain for Green program was considered as one of the vegetation restoration approaches under human disturbance. Zonal vegetation and vertical zonality of vegetation could be referred as suitable ecosystems during the restoration. Based on the analysis of the surface runoff, microclimate and the ground layer, it was considered that the restored land by Grain for Green program was in the process of forward succession. Then the effects of structure, vigor and function on the health of artificial forests were discussed.Tree canopy coverage, tree density and tree distribution pattern, gap density, gap pattern, gap sizes, tree composition and mixed ratio of needle-broadleaves were the most important determinants for the health of artificial ecological forests according to the system diagnosing. At the same time, by ordering the importance of vigor, tissue and function, it was concluded that the tree canopy cover, DBH, tree composition, grass cover and tree pattern were the key factors determining to the health of the forests by Grain for Green.According to the discussion of the above factors, the indicator systems for representing the health and vigor of ecological forests by Grain for Green program were built up. And then sixteen controlled factors and their measuring function and scale, and their assessing models for the restoration resolution were suggested.At last, the healthy density of ecological artificial forests was discussed. The concepts such as the projective indicator of canopy, canopy coverage, light-gap and healthy density of artificial forest were proposed. By analyzing the relationships of the projective indicator of canopy, light-gap, canopy coverage, stand density, canopy scale, canopy size and the, the models for the projective indicator of canopy and the light-gap were built. And the healthy density by projec...