title: Effects of fire frequency and season on resprouting of woody plants in southeastern US pine-grassland communities.
abstract: Past studies suggest that rates of woody plant resprouting following a "topkilling" disturbance relate to timing of disturbance because of temporal patterns of below-ground carbohydrate storage. Accordingly, we hypothesized that fire-return interval (1 or 2 years) and season of burn (late dormant or early growing season) would influence the change in resprout growth rate from one fire-free interval to the next (Δ growth rate) for broadleaf woody plants in a pine-grassland in Georgia, USA. Resprout growth rate during one fire-free interval strongly predicted growth rate during the following fire-free interval, presumably reflecting root biomass. Length of fire-free interval did not have a significant effect on mean Δ growth rate. Plants burned in the late dormant season (February-March) had a greater positive Δ growth rate than those burned in the early growing season (April-June), consistent with the presumption that root carbohydrates are depleted and thus limiting during spring growth. Plants with resprout growth rates above a certain level had zero or negative Δ growth rates, indicating an equilibrium of maximum resprout size under a given fire-return interval. This equilibrium, as well as relatively reduced resprout growth rate following growing season fires, provide insight into how historic lightning-initiated fires in the early growing season limited woody plant dominance and maintained the herb-dominated structure of pine-grassland communities. Results also indicate tradeoffs between applying prescribed fire at 1- versus 2-year intervals and in the dormant versus growing seasons with the goal of limiting woody vegetation.
authors.affiliation: Tall Timbers Research Station and Land Conservancy, 13093 Henry Beadel Drive, Tallahassee, FL, 32312, USA, krobertson@ttrs.org.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Robertson
authors.forename: Tracy L
authors.initials: TL
authors.lastname: Hmielowski
mesh_terms: D018533:Biomass; D050260:Carbohydrate Metabolism; D005390:Fires; D005845:Georgia; D019684:Magnoliopsida / Q000254:growth & development* / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism*; D012621:Seasons; D014934:Wood