The 2019–20 wildfires in eastern Australia presented a globally important opportunity to evaluate the respective roles of climatic drivers and natural and anthropogenic disturbances in causing high-severity fires. Here, we show the overwhelming dominance of fire weather in causing complete scorch or consumption of forest canopies in natural and plantation forests in three regions across the geographic range of these fires. Sampling 32% (2.35 Mha) of the area burnt we found that >44% of the native forests suffered severe canopy damage. Past logging and wildfire disturbance in natural forests had a very low effect on severe canopy damage, reflecting the limited extent logged in the last 25 years (4.5% in eastern Victoria, 5.3% in southern New South Wales (NSW) and 7.8% in northern NSW). The most important variables determining severe canopy damage were broad spatial factors (mostly topographic) followed by fire weather. Timber plantations affected by fire were concentrated in NSW and 26% were burnt by the fires and >70% of the NSW plantations suffered severe canopy damage showing that this intensive means of wood production is extremely vulnerable to wildfire. The massive geographic scale and severity of these Australian fires is best explained by extrinsic factors: an historically anomalous drought coupled with strong, hot dry westerly winds that caused uninterrupted, and often dangerous, fire weather over the entire fire season.

2019-20 年澳大利亚东部的野火为评估气候驱动因素以及自然和人为干扰在引发高强度火灾中的各自作用提供了一个全球重要的机会。在这里，我们展示了火灾天气在导致火灾地理范围内三个地区的天然林和人工林中的森林冠层完全烧焦或消耗方面的压倒性优势。对 32% (2.35 Mha) 的烧毁区域进行采样，我们发现超过 44% 的原生森林遭受了严重的冠层破坏。过去天然林的伐木和野火干扰对严重树冠破坏的影响非常小，这反映了过去 25 年的伐木程度有限（维多利亚州东部为 4.5%，新南威尔士州南部为 5.3%，北部为 7.8%）新南威尔士州）。决定严重冠层损害的最重要变量是广泛的空间因素（主要是地形），其次是火灾天气。受火灾影响的木材种植园集中在新南威尔士州，26% 的种植园被大火烧毁，超过 70% 的新南威尔士种植园遭受严重的树冠损坏，这表明这种集约化的木材生产方式极易受到野火的影响。这些澳大利亚火灾的大规模地理规模和严重程度最好用外部因素来解释：历史上的异常干旱加上强烈、炎热干燥的西风，在整个火灾季节造成不间断且通常很危险的火灾天气。新南威尔士州 70% 的种植园遭受了严重的树冠损坏，这表明这种集约化的木材生产方式极易受到野火的影响。这些澳大利亚火灾的大规模地理规模和严重程度最好用外部因素来解释：历史上的异常干旱加上强烈、炎热干燥的西风，在整个火灾季节造成不间断且通常很危险的火灾天气。新南威尔士州 70% 的种植园遭受了严重的树冠损坏，这表明这种集约化的木材生产方式极易受到野火的影响。这些澳大利亚火灾的大规模地理规模和严重程度最好用外部因素来解释：历史上的异常干旱加上强烈、炎热干燥的西风，在整个火灾季节造成不间断且通常很危险的火灾天气。