Macroscopic charcoal records from wetland sediment cores are used to reconstruct long-term records of fire frequency. A central premise for the use of this tool is that macroscopic charcoal (>125 μm) represents local fires involving local vegetation. Several records reveal that there may often be exceptions to these guidelines. Previous studies have shown that particles larger than 1 cm long can travel at least 20 km from the location of a fire. We present observations of unprecedented long-distance transport of large (⩽5 cm long) charcoal particles at least 50 km from a fire west of Sydney, Australia. Factors that contribute to long-distance transport of large charcoal particles are fire intensity, upper level wind speed and landscape topography. The fires west of Sydney were large and intense, upper level (~10 km) winds exceeded 90 km h-1, and the topography east of the fire was flat or undulating. Smoke plumes from intense fires like this can reach an altitude of at least 15 km. Charcoal morphology also contributed to long-distance transport in this case. Eucalyptus trees can produce large quantities of aerodynamically efficient particles; from paper thin, smooth, decorticating bark and large sclerophyllous leaves. The presence of large macroscopic charcoal particles in wetland sediments does not automatically indicate local fires and could result from distant, large, intense fires. Large, intense fires can occur in Australia, the grasslands of Kazakhstan, Namibia, the Sahel and Patagonia. High intensity fires also occur in the forested areas of the western United States and Boreal North America. Fires in these regions could result in long-distance transport of large macroscopic charcoal particles under the right circumstances. Local charcoal flux studies are therefore critical for the interpretation of macroscopic charcoal records. We cannot rely on information from areas with different fire regimes, fire intensities or vegetation types.

中文翻译：

---

澳大利亚东部一场大而强烈的森林火灾中宏观木炭史无前例的长距离运输：对火灾历史重建的影响

湿地沉积物核心的宏观木炭记录用于重建火灾频率的长期记录。使用该工具的一个核心前提是宏观木炭 (>125 μm) 代表涉及当地植被的局部火灾。几项记录显示，这些准则可能经常存在例外情况。先前的研究表明，大于 1 厘米长的颗粒可以从火灾地点传播至少 20 公里。我们对距离澳大利亚悉尼以西至少 50 公里的大型（⩽5 厘米长）木炭颗粒进行了前所未有的长距离传输的观察。导致大木炭颗粒长距离运输的因素是火灾强度、上层风速和景观地形。悉尼以西的大火又大又烈，上层（约 10 公里）风速超过 90 公里 h-1，火灾以东的地形平坦或起伏。像这样的强烈火灾产生的烟羽可以达到至少 15 公里的高度。在这种情况下，木炭形态也有助于长途运输。桉树可以产生大量的空气动力学高效粒子；来自纸薄、光滑、去皮的树皮和大的硬叶。湿地沉积物中大的宏观木炭颗粒的存在并不能自动表明局部火灾，而是可能由远处、大而强烈的火灾引起。澳大利亚、哈萨克斯坦、纳米比亚、萨赫勒和巴塔哥尼亚的草原可能发生大火。美国西部和北美北部的森林地区也发生了高强度火灾。在适当的情况下，这些地区的火灾可能导致大型宏观木炭颗粒的长距离传输。因此，当地木炭通量研究对于宏观木炭记录的解释至关重要。我们不能依赖来自具有不同火灾状况、火灾强度或植被类型的地区的信息。