Increases in forest disturbances have altered global forest demography rates, with many regions now characterized by extensive areas of early‐successional forest. Heterogeneity in the structure, diversity, and composition of early‐successional forests influence their inherent ecological values from immediately following disturbance to later successional stages, including values for biodiversity and carbon storage. Here, using 14 years of longitudinal data, we describe patterns in the structure, richness, and composition of early‐successional forests subject to one of three different disturbance types: (1) clearcut logging followed by slash burn, (2) severe wildfire followed by salvage logging, and (3) severe wildfire only, in the Mountain Ash (Eucalyptus regnans) and Alpine Ash (Eucalyptus delegatensis) forests of southeastern Australia. We also documented the influence of disturbance intervals (short, medium, and long) on early‐successional forests. Our analyses revealed several key differences between forests that regenerated from wildfire versus two different anthropogenic perturbations. Most ash‐type plant communities were resilient to wildfire within historical fire‐regimes (75–150 years), exhibiting temporal trends of recovery in plant structure, richness, and composition within the first decade. In contrast, the richness, occurrence, and abundance of some plant lifeforms and life history traits were negatively associated with clearcut logging and salvage logging, relative to forests disturbed by wildfire alone. These included resprouting species, such as tree ferns and ground ferns. However, Acacia spp. and shrubs were more abundant after clearcut logging. Our findings also provide evidence of the pronounced negative impact of salvage logging on early‐successional plant communities, relative to that of both clearcut logging and wildfire. Notably, plant richness declined for over a decade after salvage logging, rather than increased as occurred following other disturbance types. Early‐successional forests provide the template for the stand structure and composition of mature forests. Therefore, altered patterns of recovery with different disturbance types will likely shape the structure and function of later‐successional stages. Predicted increases in wildfire will increase the generation of early‐successional forests and subsequent salvage logging. Therefore, it is pertinent that management consider how different disturbance types can produce alternate states of forest composition and structure early in succession, and the implications for mature stands.

中文翻译：

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伐木和野火后早期演替林更新的不同轨迹


森林干扰的增加改变了全球森林人口统计率，许多地区现在以大面积的早期演替森林为特征。早期演替森林的结构、多样性和组成的异质性影响着其从干扰后立即到后期演替阶段的固有生态价值，包括生物多样性和碳储存的价值。在这里，使用 14 年的纵向数据，我们描述了早期演替森林的结构、丰富度和组成模式，这些森林受到三种不同干扰类型之一的影响：（1） 皆伐后砍伐，（2） 严重野火后抢救性采伐，以及 （3） 仅严重的野火，在澳大利亚东南部的山灰 （Eucalyptus regnans） 和高山灰 （Eucalyptus delegatensis） 森林中。我们还记录了干扰间隔（短、中、长）对早期演替森林的影响。我们的分析揭示了从野火中再生的森林与两种不同的人为扰动之间的几个关键差异。在历史上的火灾状态（75-150 年）内，大多数白蜡树型植物群落对野火具有恢复能力，在第一个十年内表现出植物结构、丰富度和成分恢复的时间趋势。相比之下，相对于仅受野火干扰的森林，一些植物生命形式和生活史特征的丰富度、出现和丰度与皆伐和抢救性采伐呈负相关。这些包括重新发芽的物种，例如树蕨和地蕨。然而，金合欢属和灌木在皆伐后更加丰富。 我们的研究结果还提供了证据，证明相对于皆伐和野火，抢救性伐木对早期演替植物群落的显着负面影响。值得注意的是，植物丰富度在抢救性采伐后的十多年里有所下降，而不是像其他干扰类型后那样增加。早期演替林为成熟林的林分结构和组成提供了模板。因此，不同干扰类型的恢复模式改变可能会塑造后期演替阶段的结构和功能。预计野火的增加将增加早期演替林的产生和随后的抢救性采伐。因此，管理层应考虑不同的干扰类型如何在演替早期产生森林组成和结构的交替状态，以及对成熟林分的影响。