Simioni Guillaume, Ritson Peter, Kirschbaum Miko U F, McGrath John, Dumbrell Ian, Copeland Beth
Forest Products Commission, Perth Business Centre, Western Australia 6849, Australia.
Tree Physiol. 2009 Sep;29(9):1081-93. doi: 10.1093/treephys/tpp049. Epub 2009 Jul 17.
We conducted a comprehensive modelling study to estimate future stem wood production and net ecosystem production (NEP) of Pinus radiata D. Don plantations in south-western Australia, a region that is predicted to undergo severe rainfall reduction in future decades. The process-based model CenW was applied to four locations where it had previously been tested. Climate change scenarios under four emission scenarios for the period from 2005 to 2066 were considered, in addition to simulations under the current climate. Results showed that stem wood production and NEP were little affected by moderate climate change. However, under the most pessimistic climate change scenario (Special Report on Emission Scenarios A2), stem wood production and NEP decreased strongly. These results could be explained by the trade-off between the positive effect of rising atmospheric CO(2) on plant water use efficiency and the negative effects of decreasing rainfall and increasing temperatures. Because changes in heterotrophic respiration (R(H)) lagged behind changes in plant growth, and because R(H) rates were increased by higher temperatures, NEP was more negatively affected than stem wood production. Stem wood production and NEP also strongly interacted with location, with the site currently having the wettest climate being least affected by climatic change. These results suggest that realistic predictions of forest production and carbon sequestration potential in the context of climate change require (1) the use of modelling tools that describe the important feedbacks between environmental variables, plant physiology and soil organic matter decomposition, (2) consideration of a range of climate change scenarios and (3) simulations that account for a gradual climate change to capture transient effects.
我们开展了一项全面的建模研究，以估算澳大利亚西南部辐射松人工林未来的干材产量和净生态系统生产（NEP）。预计在未来几十年里，该地区降雨量将大幅减少。基于过程的模型CenW被应用于此前已进行过测试的四个地点。除了当前气候条件下的模拟之外，还考虑了2005年至2066年期间四种排放情景下的气候变化情景。结果表明，适度的气候变化对干材产量和NEP影响较小。然而，在最悲观的气候变化情景（排放情景特别报告A2）下，干材产量和NEP大幅下降。这些结果可以通过大气CO₂浓度升高对植物水分利用效率的积极影响与降雨量减少和气温升高的负面影响之间的权衡来解释。由于异养呼吸（R(H)）的变化滞后于植物生长的变化，并且由于较高的温度会提高R(H)速率，因此NEP比干材产量受到的负面影响更大。干材产量和NEP也与地点密切相关，目前气候最湿润的地点受气候变化的影响最小。这些结果表明，在气候变化背景下，对森林生产和碳固存潜力进行现实预测需要：（1）使用能够描述环境变量、植物生理学和土壤有机质分解之间重要反馈的建模工具；（2）考虑一系列气候变化情景；（3）进行能够考虑到气候变化逐渐演变以捕捉瞬态效应的模拟。
