Investments in forestry are long-term and thus subject to numerous sources of risk. In addition to the volatility from markets, forestry investments are directly exposed to future impacts from climate change. We examined how diversification of forest management regimes can mitigate the expected risks associated with forestry activities in New Zealand based on an application of Modern Portfolio Theory. Uncertainties in the responses of Pinus radiata (D. Don) productivity to climate change, from 2050 to 2090, were simulated with 3-PG, a process-based forest growth model, based on future climate scenarios and Representative Concentration Pathways (RCPs). Future timber market scenarios were based on RCP-specific projections from the Global Timber Model and historical log grade prices. Outputs from 3-PG and the market scenarios were combined to compute annualized forestry returns for four P. radiata regimes for 2050–2090. This information was then used to construct optimal forestry portfolios that minimize investment risk for a given target return under different RCPs, forest productivity and market scenarios. While current P. radiata regimes in New Zealand are largely homogenous, our results suggest that regime diversification can mitigate future risks imposed by climate change and market uncertainty. Nevertheless, optimal portfolio compositions varied substantially across our range of scenarios and portfolio objectives. The application of this framework can help forest managers to better account for future risks in their management decisions.

林业投资是长期的，因此会受到多种风险的影响。除了市场波动之外，林业投资还直接暴露于气候变化的未来影响。我们基于现代投资组合理论的应用，研究了森林管理制度的多样化如何减轻与新西兰林业活动相关的预期风险。辐射松反应的不确定性（D. Don）使用3-PG（基于过程的森林生长模型）基于未来的气候情景和代表性集中路径（RCP），模拟了2050至2090年的生产力对气候变化的影响。未来的木材市场情景基于全球木材模型对RCP的特定预测以及历史原木等级价格。将3-PG的输出和市场情景相结合，以计算2050-2090年四种辐射放射制度的年度林业收益。然后，该信息用于构建最佳的林业投资组合，从而在不同的RCP，森林生产力和市场情景下，将给定目标回报的投资风险降至最低。而当前辐射松新西兰的体制在很大程度上是同质的，我们的结果表明，体制的多元化可以减轻气候变化和市场不确定性带来的未来风险。然而，最佳的投资组合构成在我们的各种方案和投资组合目标之间大相径庭。该框架的应用可以帮助森林管理者更好地考虑其管理决策中的未来风险。