Purpose of Review

Human-caused global change is fundamentally altering natural forest ecosystems. More trees are exhibiting a wide range of symptoms indicative of poor vigour, particularly stressed species at the edge of their native ranges and stands growing on marginal sites. This review will focus on complex tree diseases (declines) caused by native pathogens and the key environmental drivers that contribute to this phenomenon. These systems are frequently complex, with multiple drivers at work.

Recent Findings

Using four cases studies on different continents, we explored the direct and indirect environmental drivers underlying these decline syndromes. Although climate and weather events seem to be usually associated with forest decline, we found that environmental disturbance by either forest management or land-use changes is also a global predisposing factor of decline which deserves more attention. Changes in land use have directly benefited pathogens such as root rots in the Pyrenees (Spain) or indirectly by making the environment more conducive for canker and foliar diseases in Australia and the USA. Focus on land-use changes could improve understanding of current decline problems such as those affecting Araucaria in Chile.

Summary

The next century will almost certainly see an unprecedented rise in forest pathogen epidemics, requiring a proactive rather than reactive response. Diseases caused by native pathogens with complex aetiologies will become more common, and recognising, characterising and managing these epidemics are difficult because native pathogens are frequently already widespread, and eradication is not feasible. We need to start approaching these issues from a ‘whole ecosystem’ perspective, highlighting the many aspects and entanglements of forest declines and allowing us to respond with management options tailored to each scenario. The approach proposed here provides logical steps based on six questions to untangle the direct and indirect environmental drivers of tree declines.

中文翻译：

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人为干扰和本土疾病的出现：对森林健康的威胁

审查目的

人为造成的全球变化正在从根本上改变天然森林生态系统。越来越多的树木表现出各种症状，表明活力不足，特别是在其原生范围边缘的受压物种和生长在边缘地带的林分。本综述将重点关注由本地病原体引起的复杂树木病害（衰退）以及导致这一现象的关键环境驱动因素。这些系统通常很复杂，有多个驱动程序在工作。

最近的发现

Using four cases studies on different continents, we explored the direct and indirect environmental drivers underlying these decline syndromes. Although climate and weather events seem to be usually associated with forest decline, we found that environmental disturbance by either forest management or land-use changes is also a global predisposing factor of decline which deserves more attention. Changes in land use have directly benefited pathogens such as root rots in the Pyrenees (Spain) or indirectly by making the environment more conducive for canker and foliar diseases in Australia and the USA. Focus on land-use changes could improve understanding of current decline problems such as those affecting Araucaria in Chile.

Summary

下个世纪几乎可以肯定会看到森林病原体流行病史无前例的上升，需要主动而非被动的反应。由具有复杂病因的本地病原体引起的疾病将变得更加普遍，并且识别、表征和管理这些流行病是困难的，因为本地病原体通常已经很普遍，并且根除是不可行的。我们需要从“整个生态系统”的角度着手处理这些问题，突出森林衰退的许多方面和纠葛，让我们能够针对每种情况采用量身定制的管理方案来应对。这里提出的方法提供了基于六个问题的逻辑步骤，以解开树木衰退的直接和间接环境驱动因素。