因應減碳之疏伐規劃研究—以整合羅東及新竹林區柳杉人工林為例

A Study on Forest Thinning Scheduling for Carbon Reduction : The Case of Integrated Japanese Cedar Plantations in Luodong and Hsinchu Forest Districts

劉峻嘉(Chun-Chia Liu)

指導教授 ： 鄭欽龍

國立臺灣大學/生物資源暨農學院/森林環境暨資源學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201701744

摘要

隨著氣候變遷日益嚴峻，有效地管理森林碳吸存的議題漸漸受到重視。然森林經營者針對不同區域進行碳吸存規劃時，常面臨可用資源不足、資訊不夠充分、甚至是利益衝突等不同的限制。由於過去文獻中，有關疏伐減碳多著重於單一森林區域為主，因此，本研究發展新的一套森林疏伐規劃作業，即整合規劃兩區域以達成碳吸存量之最大化，即以轄區相鄰之羅東及新竹林區為例，藉由疏伐作業使柳杉人工林在二十年之經營期程內，發揮最大之碳吸存功能，將土壤流失增量、就業機會、各期材積和面積控制、各齡級面積限制及材積收穫總量限制做為經營條件，並運用線性規劃配合多段目標規劃法求出碳吸存量最大化之最適解。
本研究結果顯示，整合規劃和個別規劃於相同經營條件下，整合規劃之碳吸存量略優於個別規劃。同時，羅東林區的林分傾向增加弱度疏伐，而新竹林區則無明顯的差異。再者，兩林區之疏伐面積及材積收穫不僅增加，而且除了齡級11-20的林分在35年生疏伐，其餘齡級都在45年生之後才進行收穫。再者，透過整合規劃，在空間上可以更有效地減少疏伐作業和勞動力的成本。最後，就長期而言，由於收穫更多的疏伐木，使得森林疏伐作業可增加就業機會。
綜合上述，本研究認為整合規劃可增加不同林區的疏伐面積選擇性，雖然其碳吸存量之最大化僅略高於個別規劃，但可提供較佳的疏伐面積配置及材積收穫等效益，為經營者可考量之規劃方式。

關鍵字

區域整合 ； 森林經營 ； 森林疏伐 ； 碳吸存 ； 柳杉

並列摘要

As climate change becoming more severe, the issue of efficient carbon sequestration by integrated managing regional forests is more and more important. However, forest managers often encounter dilemmas when they aim at the goal of carbon sequestration with various restrictions, such as limited resources and information, lack of financial supports and conflicts of interests among stakeholders in different regionals. Since most of previous studies mainly focused on carbon sequestration by forest thinning in a single region, this study develops a new approach to plan forest thinning by the integration of two forest districts for achieving the maximization of carbon sequestration. The study try to maximize the amount of carbon sequestration of Japanese cedar plantations by thinning in neighboring area of Luodong and Hsinchu forest districts with the considerations of soil erosion, employment opportunities, the flows of volume removed and area thinned over a 20-year planning horizon. The linear programming technique combined with a multi-segment goal programming algorithm is applied to search the optimal solution of carbon sequestration by thinning.
The result first indicated that, compared with planning of two forest districts separately, the amount of carbon sequestration was slightly higher in an integrated planning of two districts under the same restrictions. Second, an integrated planning conducted more weak thinning in stands of Luodong forest district, but it had no difference in stands of Hsinchu forest district. Thirdly, not only area thinned and timber volume increased through integrated planning, but the age to be thinned mainly around age 35 which is a typical rotation age of Japanese cedar in Taiwan. Fourth, integrated planning can save the operation costs and labors of thinning by a more efficient thinning scheduling spatially. Finally, thanks to a more amount of timber removed, forest thinning can increase the employment in the long run. In conclusion, the study suggests that integrated planning can increase the flexibility of areas to be thinned over different forest districts. Although the maximum amount of carbon sequestration by integrated planning is only slightly higher than that of separated planning, the study results shows that integrated planning can provide a better allocation of area thinned and timber removed for decision-making of forest managers.

並列關鍵字

regional integrated ； forest management ； forest thinning ； carbon sequestration ； Japanese cedar

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