PARENT SESSION
Poster Session #16: Fire Ecology.
Tuesday, August 7, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall

Growth and leaf nitrogen responses of oak and red maple seedlings to canopy gap fraction following prescribed fires.

Chiang, Jyh-min¹, Arthur, Mary¹, ¹

ABSTRACT- Prescribed fire is assumed to benefit oak seedlings compared to fire sensitive species, but the mechanisms remain poorly documented. Using hemispherical photography, we examined mechanisms of competition between oak and red maple seedlings receiving different prescribed fire treatments on oak ridgetops in eastern Kentucky (10 seedlings of each of 3 species on 6 sites; 180 seedlings). Gap fraction (%) was significantly correlated with annual height growth (mm/year, R²=0.81, p=0.0001), leaf nitrogen per area (LNA, g/cm², R²=0.42, p=0.04) and specific leaf mass (SLM, g/m², R²=0.25, p=0.03). LNA was also significantly correlated with annual height growth (R²=0.39, p=0.0054). Gap fraction, annual height growth, LNA, and SLM were significantly greater in sites burned multiple times and fewer than 2 years ago than in sites not burned or burned 3 years ago (p=0.0001). Annual height growth of red maple was greater than that of oak at the multiple and recently burned sites (p=0.0095) where gap fractions were at least 12%, whereas it was similar to that of oak in sites not burned or burned 3 years ago (p=0.1109). Large annual height growth per LNA and the dominance of biomass accumulation aboveground were the likely causes of greater annual height growth of red maple seedlings compared to oak. Long term documentation of seedling survival, growth rate, and light environment are required to further demonstrate the effect of prescribed fire on oak versus red maple regeneration success.

KEY WORDS: oak regeneration, prescribed fire, red maple, hemispherical photography