Effect of Forest fire on the regeneration of a bamboo species ( Cephalostachyum pergracile Munro) at a mixed deciduous forest in Mae Klong Watershed Research Station, Thailand

Abstract

To understand the effect of forest fire on the regeneration of Cephalostachyum pergracile Munro bamboo, we compared the culm dynamics in the early regeneration stage for 3 years between a site protected from natural fires since 1995 and a site that had been burnt almost annually in a mixed deciduous forest in Thailand. Although the repeated fires distinctly decreased the number and basal area of culms per clump and the proportion of surviving culms throughout the study period, this bamboo species basically represents an adaptation to fire disturbance. A greater number of thin culms and many small branches produced by the fire-disturbed bamboos may have maximized photosynthesis with minimum allocation of photosynthate after they lose their aboveground parts. Further, the ratio of surviving clumps was higher at the unprotected site than at the protected site where self-thinning among clumps occurred. In contrast to these dynamic responses of bamboos against the fire disturbances, the number of individual clumps and their sizes remained smaller at the unprotected site than at the protected site. These results indicate that the intensity and frequency of fires primarily determine the dynamics of the bamboo population, having potential to alter the forest succession to either less or more bamboo dominating forest community. Further studies are required to elucidate the role of fire on the interaction between bamboo and tree species, specifically at the middle and matured stages of bamboo life history and along a gradient of fire regimes for better understanding assembly of the MDF community.