Effect of fire on survival and growth of Acer rubrum and Quercus seedlings

Controlled ground fires had a significant effect on survival and growth of 1- to 2-year-old seedlings of Acer rubrum, Quercus rubra and Quercus alba. In addition, although not statistically significant, seedling survival of fire was higher at lower than at higher fuel loading levels. Seedlings of Q. rubra survived fire better than those of A. rubrum. This superior survival was associated with a greater rate of resprouting in Quercus after fire in the spring, but not after an autumn fire. Starch concentrations in roots fluctuated seasonally in all species, reaching minimum levels in May. Seedlings of both Quercus species maintained higher root starch levels and greater seasonal stability in starch levels than A. rubrum seedlings: results that may have contributed to the superior resprouting capacity of Quercus seedlings after spring fire. However, starch reserves could not account for differences in autumn fire survival, as starch concentrations in this season were high and roughly equivalent in all species, and there was little subsequent resprouting observed in surviving seedlings of any species. The lower rate of resprouting in A. rubrum seedlings may be attributable to some combination of morphological constraints and lack of starch reserves. Carbon allocation patterns of Quercus seedlings apparently favored maintenance of high root starch levels while carbon allocation of A. rubrum seedlings apparently favored rapid growth. (C) 1999 Elsevier Science B.V. All rights reserved.