Vigor of old Pinus tabuliformis using the AHP-fuzzy comprehensive evaluation model

Abstract

In response to concern for negative effects of air pollution and destroyed environment, a serious worry is now increasing in China. Monitoring forest health is important for the protection of plants. Old and famous trees are a natural human heritage. So, to scientifically and accurately assess the health status of old trees for better protection is necessary for managing the forest, fifteen old Pinus tabuliformis trees in Taishan were chosen, and an analytic hierarchy process AHP-fuzzy comprehensive evaluation model was used. Fourteen indexes were studied in total including morphological index, growth index, physiological index, and deadwood states. Field investigations were took in the research along with laboratory experiments. Three of the fourteen indexes were studied in the laboratory including the content of chlorophyll, photosynthetic rate and cell membrane permeability. The rest were investigated in the outside. Results showed that all fifteen old P. tabuliformis trees had aging characteristics. Compared to healthy trees, two had low grade senescence with only slight decreases in indexes, higher chlorophyll content，photosynthetic rate and cell membrane permeability, luxuriant foliage, intact bark and several dead shoots. Six showed moderate senescence with an incomplete canopy, dead branches, and decreased photosynthetic capability. Four were unhealthy with sparse needles, a large number of dead main branches and limbs, and damaged cell membrane permeability. According to the vigor of old P. tabuliformis trees, a series of protection measures were put forward including pest control, setting the fences, spreading fertilizer, pruning. ［Ch，1 fig. 13 tab. 30 ref.］