Forested peatlands and changing fire regimes: implications for peat resources and fire management

泥炭地覆盖了加拿大约1.7亿公顷的土地，这些广泛的泥炭储量使加拿大成为世界上工业泥炭资源开采、利用和出口的领导者之一。然而，由于气候变化降低了地下水位，并使更深的泥炭暴露在燃烧中，北部泥炭地可能变得越来越容易受到野火的影响。最近在加拿大西部的研究表明，火灾活动已经在泥炭地碳循环和区域火灾排放中发挥了重要作用。然而，对于加拿大北部地区的泥炭地是否容易受到燃烧的影响，以及气候变化对该地区地表土壤湿度的预测是否会增加泥炭火灾的频率和/或严重程度，仍然存在不确定性。如果火灾活动增加，灭火成本可能会急剧上升（加拿大每年平均花费5亿美元用于直接灭火成本）。此外，消防管理机构的成功与失败之间的差距很小，在气候变暖的情况下，不成比例的火灾可能会逃脱最初的袭击，导致燃烧面积的增加远远大于火灾天气严重程度的相应增加。目前泥炭火灾是火灾管理的一个问题，因为人们对泥炭资源燃烧中主要的闷烧消耗的发生和持续时间知之甚少。关于泥炭地对野火的脆弱性和生态后果的更多信息对泥炭资源和火灾管理界都至关重要。我们将为泥炭地火灾开发新的定量火灾危险和阴燃潜力模型，以指导环境政策。我们还将研究在这些重要的生态系统中作为生态系统健康敏感指标的几个生态过程（泥炭积累、水平衡、生物多样性）。鉴于深层泥炭层的闷烧会减少消防资源，并可能涉及负面的生态系统和人类健康后果，这些预测工具的开发将有助于作为火灾和泥炭资源管理的决策工具，并在未来可能导致在与火灾排放有关的危险空气质量之前发出公共卫生警报。

Peatlands cover c. 170 million hectares of Canada's land surface and these extensive peat reserves make Canada one of the world's leaders in industrial peat resource extraction, use and export. However, northern peatlands are likely to become increasingly vulnerable to wildfire as climate change lowers water tables and exposes deeper peat to burning. Recent research in western Canada has shown that fire activity already plays an important role in peatland carbon cycling and regional fire emissions. Yet there continues to be uncertainty as to whether peatlands across Canada's boreal zone are vulnerable to burning, and whether the greater surface soil moisture deficits predicted for this region with climate change will increase the frequency and/or severity of peat fires. If fire activity increases, fire suppression costs likely will rise dramatically (Canada spends an average of $500 million a year on direct suppression costs). Additionally, fire management agencies operate with a narrow margin between success and failure, a disproportionate number of fires may escape initial attack under a warmer climate, resulting in an increase in area burned much greater than the corresponding increase in fire weather severity. Peat fires currently are problematic for fire management, as the occurrence and duration of smouldering consumption that dominates the burning of the peat resource is poorly understood. Additional information on peatland vulnerability and ecological consequences to wildfire is critical to both the peat resource and fire management communities. We will develop new quantitative fire danger and smoldering potential models for peatland fires that will guide environmental policy. We also will examine several ecological processes (peat accumulation, water balance, biodiversity) that are sensitive indicators of ecosystem health in these important ecosystems. Given that the smouldering of deep peat layers serves as a draw-down on firefighting resources and is likely to involve negative ecosystem and human health consequences, the development of these predictive tools will aid as a decision tool for fire and peat resource management and in the future could lead to public health warnings in advance of dangerous air quality linked to fire emissions.