Forests can play a significant role both in halting biodiversity loss and in mitigating climate change. A variety of payments for ecosystem services (PES) schemes exists to promote biodiversity conservation in forests. These schemes could be used to strengthen the role of forests as carbon sinks as well. This paper analyzes the implications of supplementing a PES scheme that targets boreal forest biodiversity with a carbon index. We use a site selection framework to examine how the proposed scheme impacts the promotion of both targets. We compare a case where the selection is done solely based on biodiversity values to a case where the selection is done based on both biodiversity and carbon benefits. The carbon index is formulated as current carbon storage or as future carbon sink. Correspondingly, biodiversity is maximized based on either current ecological values or potential ones. We compare equal or differing weights for biodiversity and carbon indexes, and examine trade-offs between biodiversity and CO₂ in current and future values. Combined index values increase with the carbon index, but there is a trade-off between biodiversity and CO₂ values if the conservation budget is not increased when the carbon index is introduced. There is a temporal trade-off in biodiversity and carbon values between selecting sites based on current or future values. Younger stands are preferred at the expense of old-growth stands with the carbon index. Weights can be used to balance the trade-off between biodiversity and carbon benefits. Overall, risks to losing significant ecological value from the conservation network are negligible, but the limited number of sites decreases the generalizability of the results.

森林可以在阻止生物多样性丧失和减缓气候变化方面发挥重要作用。存在多种生态系统服务付费 (PES) 计划，以促进森林生物多样性保护。这些计划也可用于加强森林作为碳汇的作用。本文分析了用碳指数补充针对北方森林生物多样性的 PES 计划的影响。我们使用选址框架来检查提议的方案如何影响这两个目标的推广。我们将仅根据生物多样性价值进行选择的情况与根据生物多样性和碳效益进行选择的情况进行比较。碳指数被表述为当前的碳储存或未来的碳汇。相应地，基于当前生态价值或潜在生态价值，生物多样性最大化。我们比较生物多样性和碳指数的相同或不同权重，并检查生物多样性和二氧化碳之间的权衡₂当前和未来的价值。综合指数值随着碳指数的增加而增加，但如果在引入碳指数时不增加保护预算，则在生物多样性和 CO ₂值之间存在权衡。根据当前或未来价值选择地点之间存在生物多样性和碳价值的时间权衡。较年轻的林分更受青睐，但以牺牲碳指数的老林分为代价。权重可用于平衡生物多样性和碳效益之间的权衡。总体而言，保护网络失去重要生态价值的风险可以忽略不计，但站点数量有限会降低结果的普遍性。