Physical and acoustic response of Pinus palustris to fire

Abstract

Crackling sounds from burning vegetation provide information to fire-experienced land managers regarding the combustion process. These acoustic impulse events can inform practitioners of a variety of situations, from the type of vegetation involved and relative “dryness,” to alerting wildland fire fighters to increased burning along tree boles and in canopies. More recently, acoustic sampling has supported these observations by quantifying species and drought-stress specific differences in the acoustics impulse events in both the laboratory and field. Our team builds on this work by quantifying the response of long leaf pine (Pinus palustris) in grass-stage to low-intensity fire. We planted live fuel beds in Northern Florida with long leaf pine seedlings. We then used prepared dead long leaf pine needles to carry low-intensity fire past the live plants. Crackling sounds from both the live and dead needles were recorded. These acoustic impulse events were then analyzed to identify any unique characters associated with the live and dead needles. We pair these results with single leaf-cluster scale laboratory experiments in which we documented the mechanical and acoustic response along the axial extent of the leaves. We present the results of long leaf pine’s acoustic and mechanical response to low-intensity fire.