Abstract
Aims: Tree species can affect litter flammability through leaf size and shape. Larger, simpler-shaped leaf litters form better-ventilated, more flammable litter-beds. However, leaves are generally mixed with twigs in the forest litter layer and together they likely contribute most to surface fire behavior. Here we ask: “Do leaf-twig mixtures have non-additive effects on litter-bed flammability?”
Methods: Using laboratory fires, we tested the direction and magnitude of non-additivity of inter- and intra-specific leaf-twig mixtures on litter-bed flammability for four tree species contrasted in leaf size and shape and widespread in fire-prone temperate-boreal forests.
Results: Across species, small needles reduced mixture fuel-bed ignitibility through filling the space between twigs and inhibiting ventilation. Within the small broad-leaved species, the thin, frequently branched and open spaced twigs were too loosely packed to be flammable, while in mixtures the small broad leaves connected these twigs to produce flammable fuel-beds. Once ignited, across species flame spread rate in mixtures was driven by leaves, while fire sustainability was predicted by fuel mass. Fuel-bed flammability was driven more by leaves at larger leaf-to-twig ratio.
Conclusions: For the first time, we demonstrated the existence and mechanisms of non-additive effects of leaf-twig mixtures on experimental litter-bed flammability.
Original language | English |
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Pages (from-to) | 311–324 |
Number of pages | 14 |
Journal | Plant and Soil |
Volume | 436 |
Issue number | 1-2 |
Early online date | 10 Jan 2019 |
DOIs | |
Publication status | Published - 1 Mar 2019 |
Funding
We are grateful to the Chinese Scholarship Council for funding WWZ through a 4-year fellowship to study at VU University Amsterdam. The setup of the FLARE laboratory greatly benefitted from grant 047.018.003 by the Netherlands Organization for Scientific Research (NWO) to JHCC. This work was supported by National Key R&D Program of China (grant: 2016YFC0503100) and National Natural Science Foundation of China (grants: 31670429). JHCC and WWZ benefitted from Grant CEP-12CDP007 by the Royal Netherlands Academy of Arts and Sciences (KNAW). Acknowledgements We are grateful to the Chinese Scholarship Council for funding WWZ through a 4-year fellowship to study at VU University Amsterdam. The setup of the FLARE laboratory greatly benefitted from grant 047.018.003 by the Netherlands Organization for Scientific Research (NWO) to JHCC. This work was supported by National Key R&D Program of China (grant: 2016YFC0503100) and National Natural Science Foundation of China (grants: 31670429). JHCC and WWZ benefitted from Grant CEP-12CDP007 by the Royal Netherlands Academy of Arts and Sciences (KNAW).
Funders | Funder number |
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Netherlands Organization for Scientific Research | |
National Key R&D Program of China | |
WWZ | |
Chinese Scholarship Council | |
Vrije Universiteit Amsterdam | |
China Scholarship Council | |
Koninklijke Nederlandse Akademie van Wetenschappen | |
Not added | 047.018.003 |
National Key Research and Development Program of China | 2016YFC0503100 |
National Natural Science Foundation of China | 31670429, CEP-12CDP007 |
Keywords
- Flammability
- Leaf
- Litter mixing
- Non-additivity
- Plant traits
- Surface fire behavior
- Twig