Allometry of the pyrophytic Aristida in fire-maintained longleaf pine-wiregrass ecosystems

Area of Science:

• Ecology
• Fire Science
• Plant Ecology

Background:

• Aboveground biomass (AGB) in herbaceous vegetation is a key fuel source for frequent fires shaping ecosystems like grasslands and savannas.
• Understanding AGB dynamics is vital for predicting fire behavior and the impacts of fire intervals.
• Nondestructive estimation methods for AGB are needed for ecological studies and restoration efforts.

Purpose of the Study:

• To develop allometric equations for estimating AGB in wiregrass (Aristida beyrichiana/A. stricta).
• To identify environmental factors influencing wiregrass AGB and its live-to-dead ratio (LDR).
• To provide data for parameterizing fire behavior models and improving ecological restoration strategies.

Main Methods:

• Collected wiregrass samples across a latitudinal gradient (North Carolina to Florida) and diverse site types.
• Utilized 32 mixed-effect models to determine predictors of live, dead, and total AGB.
• Applied regression analysis to investigate the relationship between time since burn (TSB) and the LDR.

Main Results:

• Wiregrass AGB increased with latitude, potentially due to precipitation, and was higher on clay soils compared to sandy soils.
• The live-to-dead ratio (LDR) showed a power-law decrease with increasing time since burn (TSB).
• Dead, flammable biomass accumulated rapidly during fire-free periods.

Conclusions:

• Increased AGB supports higher fire intensity, impacting fire behavior and adjacent vegetation.
• Developed allometric models enhance AGB estimation precision for wiregrass.
• Understanding environmental influences on wiregrass allometry is key for accurate fire behavior prediction and effective restoration.