台灣杉人工林不同疏伐策略碳吸存效應

EFFECTS OF THINNING STRATEGIES ON THE CARBON SEQUESTRATION OF TAIWANIA (TAIWANIA CRYPTOMERIOIDES) PLANTATIONS

邱志明(Chih-Ming Chiu)；唐盛林(Sheng-Lin Tang)；孫銘源(Ming-Yuan Suen)；彭炳勳(Ping-Hsun Peng)

碳吸存 ； 台灣杉人工林 ； 疏伐 ； Carbon sequestration ； Taiwania plantation ； Thinning

中華林學季刊

51卷1期（2018 / 03 / 01）

21 - 36

繁體中文

本研究探討台灣南部地區台灣杉人工林，經過二次不同程度疏伐之永久試驗地，探討不同觀測期間林木定期及總生長、枯死及碳吸存不同時間序列之效應。結果發現，林分第一次不同程度疏伐對碳吸存效益，差異不顯著，第二次疏伐處理後，材積、吸存碳量差異顯著，40年生時(疏伐後23年)總吸存之碳量，加上疏伐利用之固定碳量，若以50%之疏伐木利用率，不同疏伐度吸存碳量分別為強度疏伐129.4 ton/ha，中度疏伐116.1 ton/ha，弱度疏伐101.5 ton/ha，對照區91.3 ton/ha，強度疏伐和對照區大小差距達142%，但仍視林分疏伐之林齡，疏伐之強度、疏伐之間隔及次數而異。且隨著林分林齡之增長，適當疏伐撫育之林分較放任未疏伐經營之林分，碳吸存效益差距會愈大，以本研究台灣杉人工林為例，40年生時未疏伐之林分，林分總碳之吸存量已減緩，因枯死腐朽之碳之釋出量，40年生時株數累積枯死率已達24.6%。

This study explored the effects of the times series for different thinning treatments on periodic and total volume growth, and carbon sequestration of Taiwania (Taiwania cryptomerioides Hay.) plantations. The experimental sites were located in southern Taiwan. The Taiwania plantations had been treated 2 times with different thinning intensities and through different time regimes. The results showed the total volume growth and carbon sequestration grown under the first thinning treatments had no statistically significant differences. However, those parameters from the second thinning there were significant differences among different thinning intensities. Furthermore, the beneficial effects depended on thinning age, thinning intensity, thinning interval and thinning times. For the 40-yr-old Taiwania (after thinned 23 yr), the average carbon sequestration, including 50% thinned wood utilization grown under different thinning treatments of heavy, medium, light and no thinning were respectively 129.4, 116.1, 101.5 and 91.3 ton/ha. Comparisons of carbon sequestration of heavy thinning stands to control stands the difference reach 142%. The total carbon sequestration of no-thinning stands decreased since the tree mortality had increased; reaching 24.6%. Thus, the carbon sequestration of such stands was roughly offset by carbon releases of decay wood when the stands age were about 40-yr-old.