SPECIES COMPOSITION AND FIRE IN A DRY DECIDUOUS FOREST

Abstract

A century of annual burning of the understory of otherwise fire-free deciduous tropical forest in central India has favored seven tree species that produce sprouts or suckers from root buds (root-sprouters) over 37 species that produce sprouts basally from root crowns (root-crown resprouters). Experiments over two years demonstrated that low-intensity ground fires killed seedlings (<1 year old), resulting in a 30% decrease in seedling diversity in burned relative to unburned plots. Overall fire-related mortality of seedlings was 74% for 17 root-crown resprouters, compared to 63% for six root-sprouters. Repeated-measures ANOVA showed that the number of juvenile (>1 year old) stems of root-sprouters increased in burned study plots but decreased in plots protected from fire. Annual burning by people favors species that repair damage by root sprouts. Root-sprouting offers a means of occupying new ground with clonal ramets away from the original parental base. Over time, forests may become dominated by clonal root-sprouters, in contrast to historical accounts of forest dominated by root-crown resprouters that do not spread by clonal growth. If this process continues in the Mendha Forest in India, >80% of its tree diversity could be lost within 100–200 years.