Dissertation
Dissertation > Agricultural Sciences > Forestry > Forest tree species > Coniferous > Loose > P. tabulaeformis

Effects of Thinning Intensity on Aerial Seeding Pinus Tabulaeformis Stands

Author GuoZuo
Tutor LiuYong
School Beijing Forestry University
Course Forest cultivation
Keywords Chinese pine Aerial seeding forest Thinning intensity Comprehensive Evaluation
CLC S791.254
Type Master's thesis
Year 2007
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Chinese pine is our warm temperate humid and semi- humid climate of the important tree species in northern China aerial seeding species . Explore the woodland quality control measures Pine aerial seeding Sustainable Management of Forest has important practical significance . 2000 in Beijing the Yanqing County wangjiapu aerial seeding afforestation base status level IV of the beginning of 1990 to create the Pine aerial seeding forest thinning intensity set 4 ( 30.00% , 48.75% , 53.75% , 77.13% ) processing and set a thinning ( CK ) stand as a control. In 2005, the situation by comparing the growth of trees , understory vegetation cover , diversity and biomass , soil physical and chemical properties , soil enzymes change , the use of PCA to explore the pros and cons of the thinning effect of understory vegetation, soil Comprehensive Evaluation . The results showed that , after thinning the stand , increase its growth indicators than thinning stands where thinning intensity of stand growth of 53.75% . The thinning intensity also affect the Pine aerial seeding forest community life form one of the factors . Thinning intensity , different dominant species of understory vegetation , shrub layer dominant species by China drought biological species to students replacement . With the thinning intensity increases, the understory vegetation species replacement rate is accelerated , the biomass increases . Pine aerial seeding understory vegetation diversity peaks between canopy density of 80 to 87% . Soil physical and chemical properties , in addition to the obvious response of the pH value to thinning intensity and other properties with the deepening of the soil layers decreases , the A layer thinning suffered the greatest impact . The five soils enzyme sensitivity to thinning different alkaline phosphatase by thinning the greatest impact , catalase , followed by the middle of urease , invertase , polyphenol oxidase impact minimum ; different levels of soil enzyme response to thinning A layer of soil enzyme activity changes the most obvious, with the increase of soil depth , enzyme activity convergence and reduced sensitivity to thinning . Different seasons, soil physical and chemical properties and enzyme activity in response to thinning . Combination of stand growth conditions , understory vegetation development status , the three indicators of soil fertility status , we arrive at the position level IV initial density 8000 · hm -2 , 9 years old aerial seeding young Chinese pine trees select 48.75% thinning intensity .

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