| Summary: | 碩士 === 國立屏東科技大學 === 森林系所 === 102 === Thinning is an important construction process for artificial forest tending operations. Properly thinning will help the stand density management, the tree growth and enhance the stumpage values. Previous studies for red cypress artificial forest mostly focus on the establishment of different growth harvesting model, the thinning effects of individual tree and stands growth, and diameter distributions by thinning in different site. And less comprehensive discussed the trees health conditions in different thinning levels. In this study, the central thinning demonstration area - Snowy red cypress (Chamaecyparis formosensis Matsum) plantation as a study area, use the tree health assessment to assess the health condition for different forest thinning treatment in Snowy Mountains. We use the non-destructive probe of Increment Borer and Digital Micro Probe (DMP) to explore the tree growth for red cypress plantation in different thinning treatment. The tree-ring width, tree-ring density and species diversity would be used to assess the effects of thinning treatment. Finally, we would like to establish the monitoring process for thinning effects. Results showed that the moderate and severe thinning appear a good health condition, the ring width is also higher than the control area and showed a significant difference. Meanwhile, we found that the benefits trends have gradually weakened after 11-22 years thinning, ring density is increased with the passage of trend time but it is not affected by thinning operations. The species diversity of severe and moderate thinning is higher than control area. The thinning operation would increase light and growing spaces which are conducive to regeneration for ground cover plants. Finally a comprehensive tree health monitoring had been assessed that the moderate and severe thinning had excellent benefits, whereas control area was bad benefits which had been affected by the factors of tree competition. The thinning operation actually will improve tree growth, species biodiversity and tree health.
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