The influence of leaf morphology on litter flammability and its utility for interpreting palaeofire

Abstract

One contribution of 24 to a discussion meeting issue 'The interaction of fire and mankind'. Studies of palaeofire rely on quantifying the abundance of fossil charcoals in sediments to estimate changes in fire activity. However, gaining an understanding of the behaviour of palaeofires is also essential if we are to determine the palaeoecological impact of wildfires. Here, I use experimental approaches to explore relationships between litter fire behaviour and leaf traits that are observable in the fossil record. Fire calorimetry was used to assess the flammability of 15 species of conifer litter and indicated that leaf morphology related to litter bulk density and fuel load that determined the duration of burning and the total energy released. These data were applied to a fossil case study that couples estimates of palaeolitter fire behaviour to charcoal-based estimates of fire activity and observations of palaeoecological changes. The case study reveals that significant changes in fire activity and behaviour likely fed back to determine ecosystem composition. This work highlights that we can recognize and measure plant traits in the fossil record that relate to fire behaviour and therefore that further research is warranted towards estimating palaeofire behaviour as it can enhance our ability to interpret the palaeoecological impact of palaeofires throughout Earth's long evolutionary history.This article is part of the themed issue 'The interaction of fire and mankind'.

Living on a flammable planet: interdisciplinary, cross-scalar and varied cultural lessons, prospects and challenges

“…These challenges cut across particular geographical, social and temporal scales that require equivalent scientific and policy emphasis. From transnational Earth system impacts [1], to domestic impacts on sovereign nations [2], to impacts on local communities [3] and the individuals who make up communities, the perceptions, decisionmaking and prioritization of policy goals are built upon cultural and historical experiences [4][5][6] that have legacy effects, lags and feedbacks across temporal scales [7][8][9][10][11][12]. Although there is a growing literature on building fire-adapted communities [13,14], it is important to recognize that there is both heterogeneity and variability in the historical, technological, cultural and environmental contexts in which humans perceive and respond to fire challenges [15], and that in turn these have cross-scalar feedbacks through sociopolitical structures [2,16], intergenerational cultural transmission [5], historical ecology of landscapes and biomes [12,17,18], and even fire-atmosphere-climate feedbacks [19][20][21].…”

Does fuel type influence the amount of charcoal produced in wildfires? Implications for the fossil record

“…A 3 cm depth fuel bed was created for each species by filling a 15 cm wide, 368 cm 3 porous metal mesh basket with a mix of foliar and vegetative material according to the natural packing density of the plant material (Belcher ) to ensure that an equal volume was analysed for each species. Leaf morphology affected packing density in the baskets, and wood, cones, Equisetum stems etc.…”

“…In modern ecosystems, plant litter and surface fuels are a major carrier of fires (Varner et al . ; Belcher ). Similarly, there is abundant evidence for charred surface fuels in the fossil record such as charred ferns, conifer needles, as well as charred flowers from early understory angiosperms (e.g.…”

The interaction of fire and mankind: Introduction

“…B 371: 20150162 changes in ecosystems. Belcher [24] takes an innovative experimental approach by examining the flammability of 15 species of conifer litter in order to explore the relationships between litter fire behaviour and leaf traits that can be more broadly applied to ancient fire records.…”