The objective of this study was to explore methods to measure the effect of the choice of discount rates on the expected value and risk (measured with standard deviation) of the net present value (NPV) of financial returns, and on the expected value and risk of undiscounted ecological criteria resulting from optimum financial policies. An application to mixed-species uneven-aged forests of the US South showed that high discount rates, known to lower the NPV, also lowered its standard deviation, making investments appear less risky. However, the discount rate had practically no effect on the expected value and standard deviation of the undiscounted annual financial returns obtained by maximizing the NPV. Furthermore, when maximizing the NPV, the discount rate had little effect on the expected value of the undiscounted basal area, stock of CO2, and tree diversity. However, the standard deviation of these ecological criteria was markedly lower at high discount rates, making the forest ecosystem appear more stable.

本研究的目的是探索衡量折现率选择对财务收益净现值 (NPV) 的预期值和风险（用标准差衡量）以及对预期值和风险的影响的方法最佳金融政策产生的未折现生态标准。对美国南部混种不等龄森林的应用表明，已知会降低 NPV 的高贴现率也降低了其标准差，从而使投资的风险似乎更小。然而，贴现率对通过最大化 NPV 获得的未贴现年度财务回报的预期值和标准差几乎没有影响。此外，当最大化 NPV 时，贴现率对未贴现基底面积的期望值、CO2 存量、和树的多样性。然而，这些生态标准的标准差在高贴现率下明显较低，使森林生态系统显得更加稳定。