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The Evaluation Indicator System And Appraisement Methods Of Forest Vegetation Restoration In Forest-type Scale

Posted on:2008-11-29Degree:MasterType:Thesis
Country:ChinaCandidate:W ZhangFull Text:PDF
GTID:2143360215468181Subject:Forest management
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According to the principles of restoration ecology in view of the total objective and basic requirements of forest ecological restoration projects such as the Natural Forest Protection Project in China, an evaluation index system for detecting the restoration results of forest vegetation in forest-type scale was established, including seven indices relative to forest community factors and biodiversity factors respectively, such as the stand volume, prominence, coverage, canopy density, height of the community, species richness, species diversity indexes,etc. Meanwhile, a set of assessment methods was developed by using the analytic hierarchy process and grey correlation analysis methods. In addition, as an assessment example, the restoration conditions of forest vegetation in forest-type scale of two forest regions in Gansu Province, the Lianhua Mountains and Taizi Mountains, were appraised on the basis of the actual data relative to evaluation indexes above from eighteen typical stands. The results and conclusions were drawn as follows:1. The index system for measuring restoration of forest vegetation was established , the weight of each index that measured by the analytic hierarchy process were as follows: stand volume (0.2806), prominence(0.1161), coverage (0.0633), canopy density (0.0506), height of the community(0.0314), species richness (0.2923), species diversity indices(0.1656).2. The communities changed a little after artificially restored for 10 to 20 years, their structure were not differentiated much, and the average height and diameter breast-high of trees increased slowly. However, after restored for 25 years, the community structure changed tremendously, rapid increases of the average height and D.B.H of trees were observed. By the contrast, due to the existence of big amount of young trees, the average height and D.B.H of trees in naturally restored communities were lower than those of artificially restored communities. Moreover, the average height and D.B.H of trees were slowly increased with the time in naturally restored communities in most cases.3. Current plantation resources were mainly constructed from 1970 to 1980, and they are still young forest. Few problems were spotted: single species planting and dense planting result in excessive closeness degree of forest. Overdue renewal of young trees, unreasonable forest construction and lacking of optimized adjustment caused the extinction of undergrowth, failing of forming reasonable multi-layer stand structures, decreasing of species diversity and unreasonable ecosystem structure.4. Both species richness and species diversity were found higher in naturally restored forest comparing with the counterparts from even-aged plantation. The result suggested that the artificial restoration was slower than natural restoration, although trees of artificially restored forest grew more faster.5. Correlation analysis based on the Grey System Theory showed that the correlation degrees of 18 sample plots were in follow order: natural forest of Picea crassifolia, Picea wilsonii(Q8)ï¹¥natural forest of Abies faxoniana, Betula utilis(Q7)ï¹¥man-made forest of Picea asperata, Pinus armandii(Q12)ï¹¥man-made forest of Picea wilsonii, Picea asperata(Q18)ï¹¥natural forest of Betula albo-sinensis, Betula platyphylla(Q4)ï¹¥natural forest of Picea asperata, Betula utilis(Q5)ï¹¥natural forest of Betula platyphylla(Q6)ï¹¥natural forest of Abies faxoniana(Q9)ï¹¥forest of Larix principis-rupprechtii, Picea crassifolia, Betula utilis(Q14)ï¹¥man-made forest of Pinus tabulaeformis(Q16)ï¹¥man-made forest of Pinus armandii(Q11)ï¹¥man-made forest of Populus cathayana(Q15)ï¹¥man-made forest of Larix principis-rupprechtii(Q17)ï¹¥man-made forest of Picea wilsonii, Larix principis-rupprechtii(Q13)ï¹¥natural forest of Populus davidiana, Quercus wutaishanica(Q2)ï¹¥natural forest of Populus davidiana(Q1)ï¹¥man-made forest of Picea asperata(Q10)ï¹¥natural forest of Picea asperata, Quercus wutaishanica, Populus davidiana(Q3).6. The restoration of degrees vegetation in the Lianhua Mountains and Taizi Mountains forest rigion were divided into five Class A (the best) to F (the worst) , Class A (N/A) Class B (Q8), Class C (Q7, Q12), Class D (Q18, Q4, Q5, Q6, Q9, Q14, Q16, Q11), Class E (Q17, Q15, Q13, Q2, Q1, Q10, Q3) and Class F (N/A). As the results showed, most sample plots were graded as Class D and E.7. Forest conservation, plantation and artificial promotion of natural regeneration were put forward as three main approaches for reconstruction and restoration of vegetation in the Lianhua Mountains and the Taizi Mountains forest rigion.
Keywords/Search Tags:forest vegetation restoration, forest-type scale, evaluation indicator system, analytic hierarchy process(AHP), grey correlation analysis, Lianhua Mountains, Taizi Mountains
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