Centre for Environmental and Maritime Studies (CESAM), Department of Environment and Planning, University of Aveiro, 3810-193 Aveiro, Portugal.
School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Dr., Houghton,, MI 49931, USA.
Sci Total Environ. 2016 Dec 15;573:1242-1254. doi: 10.1016/j.scitotenv.2016.04.064. Epub 2016 May 5.
Mulching is an effective post-fire soil erosion mitigation treatment. Experiments with forest residue mulch have demonstrated that it increased ground cover to 70% and reduced runoff and soil loss at small spatial scales and for short post-fire periods. However, no studies have systematically assessed the joint effects of scale, time since burning, and mulching on runoff, soil loss, and organic matter loss. The objective of this study was to evaluate the effects of scale and forest residue mulch using 0.25m micro-plots and 100m slope-scale plots in a burnt eucalypt plantation in central Portugal. We assessed the underlying processes involved in the post-fire hydrologic and erosive responses, particularly the effects of soil moisture and soil water repellency. Runoff amount in the micro-plots was more than ten-fold the runoff in the larger slope-scale plots in the first year and decreased to eight-fold in the third post-fire year. Soil losses in the micro-plots were initially about twice the values in the slope-scale plots and this ratio increased over time. The mulch greatly reduced the cumulative soil loss measured in the untreated slope-scale plots (616gm) by 91% during the five post-fire years. The implications are that applying forest residue mulch immediately after a wildfire can reduce soil losses at spatial scales of interest to land managers throughout the expected post-fire window of disturbance, and that mulching resulted in a substantial relative gain in soil organic matter.
覆盖是一种有效的火灾后土壤侵蚀缓解措施。森林残茬覆盖物的实验表明，它将地面覆盖率提高到 70%，并减少了小空间尺度和短火灾后时期的径流量和土壤流失。然而，没有研究系统地评估了尺度、燃烧后时间和覆盖物对径流量、土壤流失和有机质流失的联合影响。本研究的目的是评估尺度和森林残茬覆盖物的影响，使用 0.25m 微区和 100m 坡度尺度的葡萄牙中部烧毁桉树种植园。我们评估了火灾后水文和侵蚀响应中涉及的潜在过程，特别是土壤湿度和土壤抗水性的影响。微区的径流量是较大坡度尺度的十倍多，第一年减少到第三年火灾后的八倍。微区的土壤流失最初是坡度尺度的两倍左右，而且随着时间的推移，这种比例还在增加。在 5 年的火灾后，覆盖物大大减少了未处理的坡度尺度上测量的累积土壤流失（616gm）的 91%。这意味着，在野火后立即应用森林残茬覆盖物可以减少土地管理者在预期的火灾后干扰窗口内关注的空间尺度上的土壤流失，并且覆盖物导致土壤有机质的相对显著增加。
