Tree height is more important than bark thickness, leaf habit or habitat preference to survive fire in the cerrado of south-east Brazil

Abstract

Although cerrado trees have evolved with fire for millions of years, it is not well-understood which tree attributes are more important to survive fire in the Brazilian savanna. To address this issue, we used pre- and post-fire data on 367 cerrado trees (113 native species) planted in an arboretum in south-east Brazil and then left unburnt until 2019, when a prescribed burn was applied. Tree size (height and diameter) had been measured in 2017. Four months after the fire, we assessed tree size, relative bark thickness (bark-to-diameter ratio), leaf habit (evergreen or deciduous) and habitat preference (savanna specialist or generalist). These were the predictor variables used in generalised linear models exploring tree survival and resprouting type. Most trees survived fire: 59% resprouted epicormically, 25% resprouted basally, 6% had root suckers, and only four trees died. Basal and epicormic resprouting were related to tree size: small trees (diameter ≤ 5 cm) resprouted basally more frequently, whereas tall trees (height ≥ 3.7 m) resprouted epicormically more frequently. Our results suggest that rapid growth is more important than bark thickness, leaf habit or habitat preference to escape the fire trap, because it allows cerrado trees to reach a fire-resistant height more quickly.