Fire Tolerance and the Fire-related Sprouting Characteristics of Two Cool-temperate Broad-leaved Tree Species

This study was conducted in a secondary broad-leaved forest in northern Hokkaido, Japan, which burned on 20–21 April 1998. The study plot, set up on 13 July 1998, contained Quercus mongolica var. grosseserrata and Betula platyphylla var. japonica trees. The latter were more severely damaged by the fire. Size-dependent survivorship was observed in both species with larger trees being more likely to survive the fire. However, many largeBetula trees were completely destroyed. Both species developed abundant root collar sprouts immediately after the fire. The number of sprouts ranged from 0 to 296 in Betula and from 0 to 34 in Quercus. Trees with no sprouts were not necessarily dead. The frequency distribution of the sprouting pattern in Betula was bimodal. This was related to damage severity, with the most abundant sprouting manifest in the most severely damaged trees. This pattern was not observed inQuercus . Stem diameter also appeared to influence the extent of sprouting in Betula, while in Quercus there was no distinct correlation between basal area and the number of sprouts. In Betula, the relationship between the number of sprouts and the damage severity suggests a trade-off in resource allocation for sprouting vs. shoot flushing in the crown.