Crawford Alastair J, Belcher Claire M, New Stacey, Gallego-Sala Angela, Swindles Graeme T, Page Susan, Blyakharchuk Tatiana A, Cadillo-Quiroz Hinsby, Charman Dan J, Gałka Mariusz, Hughes Paul D M, Lähteenoja Outi, Mauquoy Dmitri, Roland Thomas P, Väliranta Minna
wildFIRE Lab, Hatherly Laboratories, University of Exeter, Exeter, UK.
School of Environment, Earth and Ecosystem Sciences, The Open University, Milton Keynes, UK.
Nat Commun. 2024 Aug 27;15(1):7363. doi: 10.1038/s41467-024-50916-7.
Loss of peat through increased burning will have major impacts on the global carbon cycle. In a normal hydrological state, the risk of fire propagation is largely controlled by peat bulk density and moisture content. However, where humans have interfered with the moisture status of peat either via drainage, or indirectly via climate change, we hypothesise that its botanical composition will become important to flammability, such that peats from different latitudes might have different compositionally-driven susceptibility to ignition. We use pyrolysis combustion flow calorimetry to determine the temperature of maximum thermal decomposition (T) of peats from different latitudes, and couple this to a botanical composition analysis. We find that tropical peat has higher T than other regions, likely on account of its higher wood content which appears to convey a greater resistance to ignition. This resistance also increases with depth, which means that loss of surface peat in tropical regions may lead to a reduction in the subsequent ignitability of deeper peat layers as they are exposed, potentially resulting in a negative feedback on increased fire occurrence and severity.
因燃烧增加导致的泥炭流失将对全球碳循环产生重大影响。在正常水文状态下，火灾蔓延风险在很大程度上受泥炭堆积密度和含水量控制。然而，在人类通过排水或间接通过气候变化干预泥炭水分状况的地方，我们推测其植物组成对可燃性将变得至关重要，以至于来自不同纬度的泥炭可能因组成不同而具有不同的着火敏感性。我们使用热解燃烧流动量热法来确定不同纬度泥炭的最大热分解温度（T），并将其与植物组成分析相结合。我们发现热带泥炭的T值高于其他地区，这可能是由于其较高的木质含量，而木质似乎对着火具有更大的抗性。这种抗性也随深度增加，这意味着热带地区表层泥炭的流失可能会导致更深层泥炭暴露时随后的可燃性降低，这可能会对火灾发生频率和严重程度增加产生负反馈。
