Department of Forest- and Soil Sciences, Institute of Forest Growth, BOKU, University of Natural Resources and Life Sciences Vienna, Peter-Jordan-Str. 82, A-1190 Vienna, Austria.
Department of Forest Resource Management, Swedish University of Agricultural Sciences, Skogsmarksgränd 17, 907 36 Umeå, Sweden.
Sci Total Environ. 2024 Sep 10;942:173342. doi: 10.1016/j.scitotenv.2024.173342. Epub 2024 Jun 5.
The climate change scenarios RCP 4.5 and RCP 8.5, with a representative concentration pathway for stabilization of radiative forcing of 4.5 W m and 8.5 W m by 2100, respectively, predict an increase in temperature of 1-4.5° Celsius for Europe and a simultaneous shift in precipitation patterns leading to increased drought frequency and severity. The negative consequences of such changes on tree growth on dry sites or at the dry end of a tree species distribution are well-known, but rarely quantified across large gradients. In this study, the growth of Quercus robur and Quercus petraea (Q. spp.) and Pinus sylvestris in pure and mixed stands was predicted for a historical scenario and the two climate change scenarios RCP 4.5 and RCP 8.5 using the individual tree growth model PrognAus. Predictions were made along an ecological gradient ranging from current mean annual temperatures of 5.5-11.4 °C and with mean annual precipitation sums of 586-929 mm. Initial data for the simulation consisted of 23 triplets established in pure and mixed stands of Q. spp. and P. sylvestris. After doing the simulations until 2100, we fitted a linear mixed model using the predicted volume in the year 2100 as response variable to describe the general trends in the simulation results. Productivity decreased for both Q. spp. and P. sylvestris with increasing temperature, and more so, for the warmer sites of the gradient. P. sylvestris is the more productive tree species in the current climate scenario, but the competitive advantage shifts to Q. spp., which is capable to endure very high negative water potentials, for the more severe climate change scenario. The Q. spp.-P. sylvestris mixture presents an intermediate resilience to increased scenario severity. Enrichment of P. sylvestris stands by creating mixtures with Q. spp., but not the opposite, might be a right silvicultural adaptive strategy, especially at lower latitudes. Tree species mixing can only partly compensate productivity losses due to climate change. This may, however, be possible in combination with other silvicultural adaptation strategies, such as thinning and uneven-aged management.
气候变化情景 RCP4.5 和 RCP8.5，分别代表稳定辐射强迫的代表性浓度路径为 4.5 W/m 和 8.5 W/m，预计欧洲的温度将升高 1-4.5°C，同时降水模式也会发生变化，导致干旱频率和严重程度增加。这种变化对干旱地区或树种分布干燥端的树木生长的负面影响是众所周知的，但在大梯度上很少被量化。在这项研究中，使用个体树木生长模型 PrognAus 预测了 Quercus robur 和 Quercus petraea（Q. spp.）和 Pinus sylvestris 在纯林和混交林中的生长情况，包括历史情景以及 RCP4.5 和 RCP8.5 两种气候变化情景。预测是沿着一个生态梯度进行的，范围从当前的年平均温度 5.5-11.4°C 和年平均降水总量 586-929mm。模拟的初始数据包括在 Q. spp.和 P. sylvestris 的纯林和混交林中建立的 23 个三胞胎。在模拟到 2100 年之后，我们使用 2100 年的预测体积作为响应变量拟合了一个线性混合模型，以描述模拟结果的总体趋势。随着温度的升高，Q. spp.和 P. sylvestris 的生产力都降低了，而且在梯度中较温暖的地区降低得更多。在当前气候情景下，P. sylvestris 是生产力更高的树种，但在更严重的气候变化情景下，竞争优势转向能够耐受非常高负水势的 Q. spp.。Q. spp.-P. sylvestris 混合林对增加的情景严重程度具有中等的恢复力。通过与 Q. spp.混合来增加 P. sylvestris 林分的丰富度，而不是相反，可能是一种正确的造林适应性策略，特别是在较低的纬度地区。树种混合只能部分补偿由于气候变化导致的生产力损失。然而，这可能与其他造林适应策略相结合，如疏伐和异龄林管理。
