Scion-New Zealand Forest Research Institute, Rotorua, New Zealand; Environmental Geography Group, Institute for Environmental Studies (IVM), VU University Amsterdam, Amsterdam, The Netherlands; Centre for Environment, Energy and Natural Resource Governance, University of Cambridge, Cambridge, United Kingdom.
Scion-New Zealand Forest Research Institute, Rotorua, New Zealand.
J Environ Manage. 2021 Jul 1;289:112482. doi: 10.1016/j.jenvman.2021.112482. Epub 2021 Apr 1.
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，因此会受到许多风险源的影响。除了市场波动之外，林业投资还直接受到未来气候变化影响的风险。我们根据现代投资组合理论的应用，研究了基于新西兰森林管理体制多样化如何减轻与林业活动相关的预期风险。我们利用基于过程的森林生长模型 3-PG，根据未来气候情景和代表性浓度途径（RCP），模拟了辐射松生产力对气候变化的响应的不确定性，从 2050 年到 2090 年。未来木材市场情景基于全球木材模型的 RCP 特定预测和历史原木等级价格。从 3-PG 和市场情景中得出的产出被用于计算 2050-2090 年四个辐射松体制的年化林业回报。然后，利用这些信息根据不同的 RCP、森林生产力和市场情景，为给定的目标回报构建能将投资风险最小化的最优林业投资组合。虽然新西兰目前的辐射松体制在很大程度上是同质的，但我们的研究结果表明，体制多样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，最优投资组合构成在我们的各种情景和投资目标中存在很大差异。该框架的应用可以帮助森林管理者在其管理决策中更好地考虑未来的风险。
