Restoration goals in fire-prone conifer forests include mitigating fire hazard while restoring forest structural components linked to disturbance resilience and ecological function. Restoration of overstory spatial pattern in forests often falls short of management objectives due to complexities in implementation, regulation, and available data. When historical data is available, it is often collected at plots too small to inform coarse-scale metrics like gap size and structure of tree patches (e.g., 1 ha). Principles of ecological forestry typically emphasize overstory removal patterns that emulate those of natural disturbances. So, low- and moderate-severity portions of contemporary wildfires may serve as a guide to restoration treatments where mixed-severity fires occur. Here, we compare forest spatial pattern and configuration in 15 mechanical restoration treatments and low- and moderate-severity portions of three wildfires in ponderosa pine-dominated forests to determine how they differ in spatial pattern. We obtained satellite imagery of restoration treatments and wildfires and used supervised classification to differentiate canopy and openings. We assessed elements of landscape structure including canopy and gap cover, gap attributes, and landscape heterogeneity for each disturbance type. We found that both mechanical restoration treatments and low- and moderate-severity portions of wildfires reduced forest cover, increased gap cover, and altered pattern and arrangement of gaps relative to undisturbed areas, though the magnitude of changes were greatest in the burned sites. Low- and moderate-severity wildfire consistently increased landscape heterogeneity, but mechanical treatments did not. This suggests that a greater emphasis on increasing gap and patch spatial structure may make mechanical treatments more congruent with natural disturbances. Outcomes of low- and moderate-severity portions of wildfires may provide important information upon which to base management prescriptions where reference data on landscape patterns is unavailable.

中文翻译：

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中低强度火灾为黄松林景观恢复提供了关键见解

易火灾针叶林的恢复目标包括减轻火灾危害，同时恢复与抗扰性和生态功能相关的森林结构成分。由于实施、监管和可用数据的复杂性，森林覆盖层空间格局的恢复往往达不到管理目标。当历史数据可用时，它通常是在太小的地块收集的，无法告知粗略的指标，如间隙大小和树斑的结构（例如，1 公顷）。生态林业的原则通常强调模仿自然干扰的覆盖层清除模式。因此，当代野火的中低严重性部分可以作为发生混合严重性火灾的恢复治疗的指南。这里，我们比较了 15 种机械恢复处理中的森林空间格局和配置，以及在黄松为主的森林中的三场野火的中低严重性部分，以确定它们在空间格局上的差异。我们获得了恢复处理和野火的卫星图像，并使用监督分类来区分树冠和开口。我们评估了景观结构的要素，包括树冠和间隙覆盖、间隙属性和每种干扰类型的景观异质性。我们发现，机械修复处理和中低严重程度的野火都减少了森林覆盖率，增加了间隙覆盖率，并改变了相对于未受干扰区域的间隙模式和排列，尽管烧毁地点的变化幅度最大。低度和中度野火持续增加景观异质性，但机械处理没有。这表明，更加强调增加间隙和斑块空间结构可能会使机械处理与自然干扰更加一致。在无法获得景观模式参考数据的情况下，野火的低度和中度严重程度部分的结果可能会提供重要的信息，作为管理处方的基础。