title: Flammability across the gymnosperm phylogeny: the importance of litter particle size.
abstract: Fire is important to climate, element cycles and plant communities, with many fires spreading via surface litter. The influence of species on the spread of surface fire is mediated by their traits which, after senescence and abscission, have 'afterlife' effects on litter flammability. We hypothesized that differences in litter flammability among gymnosperms are determined by litter particle size effects on litterbed packing. We performed a mesocosm fire experiment comparing 39 phylogenetically wide-ranging gymnosperms, followed by litter size and shape manipulations on two chemically contrasting species, to isolate the underlying mechanism. The first-order control on litter flammability was, indeed, litter particle size in both experiments. Most gymnosperms were highly flammable, but a prominent exception was the non-Pinus Pinaceae, in which small leaves abscised singly produced dense, non-flammable litterbeds. There are two important implications: first, ecosystems dominated by gymnosperms that drop small leaves separately will develop dense litter layers, which will be less prone to and inhibit the spread of surface litter fire. Second, some of the needle-leaved species previously considered to be flammable in single-leaf experiments were among the least flammable in litter fuel beds, highlighting the role of the litter traits of species in affecting surface fire regimes.
authors: Systems Ecology, Department of Ecological Science, Faculty of Earth and Life Sciences, VU University, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands; Ecology and Evolution Research Centre, School of Biological, Earth and Environmental Science, University of New South Wales, Sydney, NSW, 2052, Australia.
authors: William K
authors: WK
authors: Cornwell
authors: Alba
authors: A
authors: Elvira
authors: Lute
authors: L
authors: van Kempen
authors: Richard S P
authors: RS
authors: van Logtestijn
authors: André
authors: A
authors: Aptroot
authors: J Hans C
authors: JH
authors: Cornelissen
mesh_terms: D002980:Climate; D032462:Cycadopsida / Q000235:genetics*; D017753:Ecosystem; D005390:Fires; D010316:Particle Size; D010641:Phenotype; D010802:Phylogeny; D018515:Plant Leaves / Q000235:genetics*; D013045:Species Specificity; D013696:Temperature
keywords: fire; gymnosperms; litter; phylogeny; traits