(Urgency Proposal) The catastrophic Victoria wildfires: impact of extreme burn severity on the soil system

2009年2月7日，墨尔本附近发生了前所未有的极端火灾天气，造成了许多生命的悲惨损失。风速高达每小时100公里的干燥北风恰逢该地区有记录以来的最高气温。这些条件，再加上成熟桉树森林非常高的生物量，非常低的燃料湿度条件和陡峭的斜坡，产生了迄今为止前所未有的严重燃烧条件。几乎没有关于这种极端燃烧条件对土壤系统影响的数据存在。这项紧急提案的目的是收集一组参考土壤样本，供科学界未来分析使用，并获得探索性土壤性质数据，从而确定这种极端烧伤严重程度对土壤系统的影响。这样就可以更准确地预测非常严重的野火的影响，预计随着全球变暖，这种野火将变得更加普遍，并影响到植被恢复、水文反应、土壤可蚀性、沉积物转移以及从山坡上侵蚀的灰烬和土壤的下游影响。当火灾发生在主要人口中心附近时（如墨尔本火灾），它们往往与水库低水位同时发生，并在强降雨后对水体构成重大污染风险。尽管维多利亚州的一些火灾仍然活跃，但样本收集工作迫在眉睫，因为一旦南半球发生重大冬季降雨事件，土壤表面物质将被侵蚀、混合和重新分布，从而关闭了这一短暂的机会之窗。

The catastrophic wildfires near Melbourne on Feb. 7 2009, which caused the tragic loss of many lives, occurred during an unprecedented extreme of fire weather. Dry northerly winds gusting up to 100 km/h coincided with the highest temperatures ever recorded in this region. These conditions, combined with the very high biomass of mature eucalypt forests, very low fuel moisture conditions and steep slopes, generated burning conditions of hitherto unprecedented severity. Virtually no data exist on the impact of such extreme burning conditions on the soil system. The aim of this urgency proposal is to collect a reference soil sample set, made available to the scientific community for future analyses, and obtain exploratory soil property data enabling the effects of this very extreme burn severity on the soil system to be determined. This allows a much more accurate prediction of the impacts of very severe wildfires, which are expected to become more common with global warming and affect, for example, vegetation recovery, hydrological response, soil erodibility, sediment transfer and downstream impacts of ash and soil eroded from hillslopes. Where fires occur near major population centres (as is the case for the Melbourne fires), they often coincide with low reservoir water levels and pose a major pollution risk for water bodies following heavy rainfall. Although some fires are still active in Victoria, sample collection is urgent because once major southern-hemisphere winter rainfall events occur, soil surface material will be eroded, mixed and redistributed, closing this brief window of opportunity.