Fuel flammability and fire responses of juvenile canopy species in a temperate rainforest ecosystem

Abstract

Historically, rainforests have been considered vulnerable to fire. Recent research, however, has shown that many rainforest species can survive fire by resisting burning and by resprouting and seeding post-fire. We investigated the response of a warm temperate rainforest community to fire by burning juveniles of the dominant canopy tree species (Doryphora sassafras, Syzygium smithii and Wollemia nobilis) and examining litter flammability in a controlled environment. The three species resprouted after the experimental burn, predominantly from buds on the stem that were below the soil surface. Higher fire temperatures resulted in reduced overall plant height and resprouting from buds lower on the stem. Increasing proportions of W. nobilis litter generated fires with higher intensities and fuel consumption compared with rainforest angiosperm litter. Moreover, fuel moisture content decreased with increasing W. nobilis litter proportions. Higher litter flammability may result in increased likelihood of fire ignition and fire severity near W. nobilis trees, which would negatively impact the juveniles of all three rainforest species. Alternatively, after lower-temperature fires (e.g. in rainforest angiosperm litter), W. nobilis may have an advantage over the other species because of faster-growing resprouts occurring higher on the stem.