Swiss Federal Research Institute WSL, Zürcherstrasse 111, Birmensdorf, Switzerland.
Plant Biol (Stuttg). 2013 Jan;15 Suppl 1:138-47. doi: 10.1111/j.1438-8677.2011.00552.x. Epub 2012 Jan 30.
Global climate change is expected to increase annual temperatures and decrease summer precipitation in Central Europe. Little is known of how forests respond to the interaction of these climate factors and if their responses depend on soil conditions. In a 3-year lysimeter experiment, we investigated the growth response of young mixed oak stands, on either acidic or calcareous soil, to soil water regime, air-warming and drought treatments corresponding to an intermediate climate change scenario. The air-warming and drought treatments were applied separately as well as in combination. The air-warming treatment had no effect on soil water availability, evapotranspiration or stand biomass. Decreased evapotranspiration from the drought-exposed stands led to significantly higher air and soil temperatures, which were attributed to impaired transpirational cooling. Water limitation significantly reduced the stand foliage, shoot and root biomass as droughts were severe, as shown in low leaf water potentials. Additional air warming did not enhance the drought effects on evapotranspiration and biomass, although more negative leaf water potentials were observed. After re-watering, evapotranspiration increased within a few days to pre-drought levels. Stands not subjected to the drought treatment produced significantly less biomass on the calcareous soil than on the acidic soil, probably due to P or Mn limitation. There was no difference in biomass and water regime between the two soils under drought conditions, indicating that nutrient availability was governed by water availability under these conditions. The results demonstrate that young oak stands can cope with severe drought and therefore can be considered for future forestry.
预计全球气候变化将导致中欧地区年气温上升和夏季降水量减少。目前尚不清楚森林如何应对这些气候因素的相互作用，以及它们的反应是否取决于土壤条件。在一项为期 3 年的淋溶土柱实验中，我们研究了在酸性或钙质土壤上生长的年轻混合栎树种群对土壤水分状况、空气增暖和干旱处理的生长反应，这些处理对应于中等程度的气候变化情景。空气增温和干旱处理分别以及联合进行。空气增温处理对土壤水分供应、蒸散或林分生物量没有影响。暴露于干旱下的林分的蒸散减少导致空气和土壤温度显著升高，这归因于蒸腾冷却受损。水分限制显著降低了林分叶、枝和根生物量，因为干旱严重，如低叶片水势所示。尽管观察到更负的叶片水势，但额外的空气增温并没有增强干旱对蒸散和生物量的影响。重新浇水后，蒸散在几天内迅速增加到干旱前的水平。未进行干旱处理的林分在钙质土壤上产生的生物量明显低于酸性土壤，这可能是由于 P 或 Mn 限制。在干旱条件下，两种土壤之间的生物量和水分状况没有差异，表明在这些条件下，养分供应受水分供应的控制。结果表明，年轻的栎树种群能够应对严重干旱，因此可以考虑用于未来的林业。
