造林獎勵與碳吸存補貼對台灣農林部門社會福利之影響

Welfare Evaluation of Subsidy for Afforestation and Carbon Sequestration on Agricultural and Forestry Sectors in Taiwan

本研究是考量台灣林地特殊的所有權屬，考慮森林具有的公私效益，及其與農作物互競之關係，建構一個平衡農林部門土地利用之概念架構，並納入造林面積與競租作物價格，同時考量時間和折現的動態林木長期生長及造林獎勵政策之決策模型。比較有無造林獎勵政策，再加上不同碳吸存補貼水準之政策組合，對農林部門社會福利的影響。結果顯示，從無造林獎勵政策到有造林獎勵政策，農林部門社會福利增加8 億多元，若再加上每公噸100 至1,200 元不等之碳吸存補貼，則相對於完全無任何獎勵及補貼政策時，社會福利又更增加約8～10 億元不等。而在已有造林獎勵金之前提下，碳吸存補貼使得農林部門之社會福利由每公噸100 元的1 千萬逐步遞增至每公噸1,200 元的1 億4 千萬，此乃表示在目前所選擇的碳吸存補貼範圍內，碳吸存補貼對農林部門之社會福利的增加仍在遞增的階段。此外，加入碳吸存做為補貼之手段，且在每公噸碳稅大於100 元時，林農將延長其砍伐年限，延長的年限同樣隨著補貼金額的上升而延後更長。

The purpose of this study is to construct a model in which accountsfor the special forestry land property right regime and the competitionbetween agricultural and forestry land utilization in Taiwan. The modelconsiders also the dynamic long-term tree growth and afforestationsubsidy policy. The welfare on agricultural and forestry sectorscomparison is made between that without policy and with afforestationsubsidy and further with different levels of carbon sequestration subsidies.The results indicate that the welfare will increase 0.8 billion whilechange from no policy to current afforestation subsidy policy. Thewelfare will further increase 0.8～1 billion when there is different levels ofcarbon sequestration subsidies, with 100 NT $ per ton to 1,200 NT $ perton, along with afforestation subsidy policy. The marginal welfare ofcarbon sequestration with 100 NT $ per ton is about 10 millions NT $ andwill increase to 140 millions NT $ with 1,200 NT $ per ton of carbon price. This shows that the impact of carbon sequestration subsidy on socialwelfare is still falling in the monotonic increasing domain. Moreover,with additional carbon sequestration subsidy, farmers will postponeharvest.