Efficiency of forest carbon policies at intensive and extensive margins
研究比较了不同森林碳政策（如碳税、补贴）在改变森林面积和采伐年龄方面的效果与效率，发现不补偿碳汇的碳税效率最低，而每公顷土地补贴成本远高于每吨碳税加补贴政策。
Abstract The economic potential of forest carbon sequestration is widely acknowledged. However, no consensus has been reached regarding the appropriate policy instrument for promoting carbon sequestration. In this study, we develop a dynamic framework to measure the effects and efficiencies of alternative carbon policies. A stylized optimal control model of the timber market is first employed to illustrate the mechanisms through which different policies affect the decision making of the forest sector at the extensive margin (i.e., changing forest areas) and the intensive margin (i.e., changing harvest ages). We then introduce carbon price projections and species‐specific production information into a multi‐age dynamic timber market model. Different carbon policies are simulated numerically. Our results reveal that a carbon tax on forest emissions without compensating for sequestration leads to net carbon emissions and, thus, is the least efficient policy choice. Further, policies that do not increases carbon uptake at the intensive margin result in very high efficiency losses. A per‐hectare land subsidy may be more than 10 times more expensive than a per‐ton carbon tax and subsidy policy or a carbon subsidy policy.