Effects and outcomes of Caribbean hurricanes in a climate change scenario.

Hurricanes are complex disturbance systems with significant effects on vegetation and built-up land. This paper summarizes research on the effects and outcomes of hurricanes on Caribbean forests. Twelve effects and outcome topics are presented: sudden and massive tree mortality; delayed patterns of tree mortality; alternative methods of forest regeneration; opportunities for a change in successional direction; high species turnover and opportunities for species change in forests; diversity of age classes; faster biomass and nutrient turnover; species substitutions and changes in turnover time of biomass and nutrients; lower aboveground biomass in mature vegetation; carbon sinks; selective pressure on organisms; and convergence of community structure and organization. Effects of hurricanes on urban systems are also discussed. While there is scientific uncertainty as to whether hurricane frequencies and intensity will change as a result of global climate change, available understanding on the effects and outcomes of hurricanes can be used to anticipate possible effects of either increasing or decreasing hurricane frequency and intensity. Proposed mitigation actions and research priorities can be effective and desirable even if the frequency and intensity of hurricanes remains unchanged.

Biomass of tropical forests: a new estimate based on forest volumes.

Recent assessments of areas of different tropical forest types and their corresponding stand volumes were used to calculate the biomass densities and total biomass of tropical forests. Total biomass was estimated at 205 x 10(9) tons, and weighted biomass densities for undisturbed closed and open broadleaf forests were 176 and 61 tons per hectare, respectively. These values are considerably lower than those previously reported and raise questions about the role of the terrestrial biota in the global carbon budget.