Data from: Burn or rot: leaf traits explain why flammability and decomposability are decoupled across species

In fire-prone ecosystems, two important alternative fates for leaves are burning in a wildfire (when alive or as litter) or they get consumed (as litter) by decomposers. The influence of leaf traits on litter decomposition rate is reasonably well understood. In contrast, less is known about the influence of leaf traits on leaf and litter flammability. The aim of this study was twofold: (a) to determine which morphological and chemical leaf traits drive flammability; and (b) to determine if different (combinations of) morphological and chemical leaf traits drive interspecific variation in decomposition and litter flammability and, in turn, help us understand the relationship between decomposability and flammability. To explore the relationships between leaf traits and flammability of individual leaves, we used 32 evergreen perennial plant species from eastern Australia in standardised experimental burns on three types of leaf material (i.e. fresh, dried and senesced). Next, we compared these trait-flammability relationships to trait-decomposability relationships as obtained from a previous decomposition experiment (focusing on senesced leaves only). Among the three parameters of leaf flammability that we measured, interspecific variation in time to ignition was mainly explained by specific leaf area and moisture content. Flame duration and smoulder duration were mostly explained by leaf dry mass and to a lesser degree by leaf chemistry, i.e. nitrogen, phosphorus and tannin concentrations. The variation in the decomposition constant across species was unrelated to our measures of flammability. Moreover, different combinations of morphological and chemical leaf properties underpinned the interspecific variation in decomposability and flammability. In contrast to litter flammability, decomposability was driven by lignin and phosphorus concentrations. The decoupling of flammability and decomposability leads to three possible scenarios for species’ influence on litter fates: (I) fast-decomposing species for which flammability is irrelevant because there will not be enough litter to support a fire; (II) species with slow-decomposing leaves and a high flammability; and (III) species with slow-decomposing leaves and a low flammability. We see potential for making use of the decoupled trait – decomposition – flammability relationships when modelling carbon and nutrient fluxes. Including information on leaf traits in models can improve the prediction of fire behaviour. Herbivory is another key fate for leaves, but this study was focused on fire and decomposition.

Usage Notes
Leaf and flammability traits (individual leaves)This data set contains the leaf traits and flammability parameters as measured on individual leaves. The first sheet displays the MEAN values per species, which were mainly used for the publication. The second sheet holds the RAW data and the third sheet holds the species list. Abbreviations are explained in the overview.Grootemaat 2015_FE_Dryad.xlsx

在易燃生态系统中，叶片的两种重要替代命运是：在野火中燃烧（无论是活着还是作为落叶）或被分解者消耗（作为落叶）。叶片特性对落叶分解速率的影响已得到较为充分的了解。相比之下，关于叶片特性对叶片和落叶可燃性的影响了解甚少。本研究的目标有两个：(a) 确定哪些形态和化学叶片特性驱动可燃性；(b) 确定不同的（形态和化学叶片特性的组合）是否驱动物种间在分解和落叶可燃性方面的差异，进而有助于我们理解可分解性与可燃性之间的关系。为了探究叶片特性与单个叶片可燃性之间的关系，我们使用了来自澳大利亚东部的32种常绿多年生植物物种，在三种类型的叶片材料（即新鲜、干燥和衰老）的标准化实验燃烧中进行研究。随后，我们将这些特性-可燃性关系与先前分解实验（仅关注衰老叶片）中获得的特性-可分解性关系进行比较。在测量的三个叶片可燃性参数中，物种间点火时间的差异主要由特定叶面积和含水量解释。火焰持续时间和阴燃持续时间主要受叶片干重的影响，在一定程度上也受叶片化学成分的影响，即氮、磷和单宁含量。物种间分解常数的变化与我们测量的可燃性无关。此外，不同的形态和化学叶片特性的组合构成了物种间在可分解性和可燃性方面的差异。与落叶可燃性不同，可分解性是由木质素和磷浓度驱动的。可燃性与可分解性的分离导致了物种对落叶命运影响的三个可能场景：(I) 对于分解速度快的物种，由于其落叶不足以支持火灾，因此可燃性无关紧要；(II) 对于分解速度慢且可燃性高的物种；(III) 对于分解速度慢且可燃性低的物种。我们看到了利用分离的特性-分解-可燃性关系在建模碳和养分通量方面的潜力。在模型中包含叶片特性信息可以提高对火灾行为的预测。食草动物是叶片的另一种关键命运，但本研究专注于火灾和分解。