Resprouting by seedlings of four North American deciduous broadleaved tree species following experimental burning
In eastern North American Quercus forests, the historic fire regime, characterized by periodic, low-intensity surface fire, facilitated the development and maintenance of mid-successional Quercus forests across multiple spatial and temporal scales. One physiological mechanism favoring Quercus over mesophytic and/or shade-tolerant deciduous broadleaved species is prolific and vigorous resprouting following topkill. Generalizations regarding interspecific differences in fire-induced resprouting are confounded by interactions between biotic and abiotic factors. The goal of this study was to quantify resprout dynamics by 2- and 3-year-old seedlings of four prominent deciduous broadleaved species (Acer rubrum, Liriodendron tulipifera, Quercus alba, and Q. rubra) following topkill via experimental burning, where seedling age, competition, fire intensity, and light were controlled. Resprouting was independent of fire intensity and seedling size. The resprout rate of Q. rubra (82%) was greater than that of A. rubrum (53%), L. tulipifera (56%), and Q. alba (52%). A second burn conducted a year later did little to inhibit resprouting by topkilled individuals. After both burns, L. tulipifera sprouts were significantly taller than the other species. Although absolute height of Q. rubra sprouts was greater than A. rubrum after the first burn, absolute height of Q. rubra sprouts was lower than A. rubrum following the second burn. Results suggest that broad, cross-genus generalizations may not accurately reflect interspecific differences in resprout potential, which may have implications related to the ability to regenerate and recruit Quercus under a re-introduced periodic fire regime.