Centro de Investigación Forestal de Lourizán, Xunta de Galicia, PO Box 127, 36080 Pontevedra, Spain.
University of Santiago de Compostela, Escuela Politécnica Superior, Soil Science and Agricultural Chemistry, Lugo, Spain.
Sci Total Environ. 2024 Jan 10;907:167669. doi: 10.1016/j.scitotenv.2023.167669. Epub 2023 Oct 15.
Prescribed fire (PB) is used to achieve ecological objectives and to reduce fuel hazard thus limiting detrimental impacts of wildfire and appropriate selection of prescription window is critical for these goals. Operational use of PB in the Mediterranean forest is scarce and information about its effects on soil remains incomplete. This study for the first time i) compared the immediate impact of spring and autumn PB and experimental summer fire on key properties of forest floor and mineral topsoil in Mediterranean black pine forest, and ii) assessed the capacity of PB to reduce fuel, with limited immediate impacts on soil. PB significantly reduced the 32.5 % of pre-fire forest floor depth, while summer fire consumed 88.5 % and exposed about 30 % of the mineral soil surface. Mean maximum temperature during fire at the mineral soil surface was 23 °C in PB, in contrast to 128 °C in summer fire, while soil heating at 2 cm depth was negligible in both cases. PB did not cause immediate changes in OM quality parameters, and chemical (C and N concentrations, C/N and pH) and microbiological properties (Cmic, Cmic/C, and β-glucosidase, acid phosphatase and alkaline phosphatase activities) in forest floor or mineral topsoil (0-2 cm). By contrast, summer fire greatly increased OM recalcitrance and reduced Cmic, Cmic/C and enzyme activities in forest floor immediately after fire. In the mineral topsoil, only microbial properties were significantly reduced. The maximum temperature reached during fire in forest floor and topsoil was associated with most of the overall changes in properties in both layers. The findings suggest that prescribed fire can significantly reduce fuel with limited initial impacts on soil. Although these findings are encouraging for operational use of prescribed burning in the ecosystem under study, long-term monitoring of repeated application of the technique on soil properties and other ecosystem components is necessary.
计划火烧（PB）用于实现生态目标并减少燃料危害，从而限制野火的不利影响，因此适当选择处方窗口对于实现这些目标至关重要。在 Mediterranean 森林中，PB 的运营使用很少，关于其对土壤影响的信息仍然不完整。本研究首次：i）比较了春季和秋季 PB 以及实验性夏季火烧对 Mediterranean 黑松林中林地表层和矿质表土关键特性的直接影响，ii）评估了 PB 减少燃料的能力，同时对土壤的直接影响有限。PB 显著降低了 32.5%的林地表层深度，而夏季火烧消耗了 88.5%并暴露了约 30%的矿质土壤表面。在矿质土壤表面，PB 中火烧期间的最高温度为 23°C，而夏季火烧中的最高温度为 128°C，而在两种情况下，土壤在 2cm 深度处的加热可以忽略不计。PB 没有立即改变林地表层和矿质表土层（0-2cm）中的 OM 质量参数以及化学（C 和 N 浓度、C/N 和 pH）和微生物特性（Cmic、Cmic/C 和β-葡萄糖苷酶、酸性磷酸酶和碱性磷酸酶活性）。相比之下，夏季火烧在火烧后立即大大增加了 OM 的抗分解性并降低了林地表层中的 Cmic、Cmic/C 和酶活性。在矿质表土层中，只有微生物特性显著降低。林地表层和表土层中火烧期间达到的最高温度与这两个层中大多数属性的整体变化有关。研究结果表明，计划火烧可以显著减少燃料，同时对土壤的初始影响有限。尽管这些发现对于在研究中的生态系统中运营使用计划燃烧是令人鼓舞的，但有必要对土壤特性和其他生态系统成分进行重复应用技术的长期监测。
