A Rainforest Chronicle: A 30-Year Record of Change in Structure and Composition at El Verde, Puerto Rico

Measurements over approximately a 30-year period in a Dacryodes-Sloanea forest indicate two distinctive phases in stand development. Secondary species were common in the early stand (1940's), and rapid accumulations of biomass and basal area were measured. Many new species entered the stand, and the number of stems increased. In contrast, the stand of the 1970's approached steady-state for biomass and basal area accumulations, and, relative to earlier measurements, fewer stems and fewer species were recorded in the plot. This apparent dichotomy can be correlated to the periodic disturbance caused by tropical storms. The last severe hurricane to strike Puerto Rico occurred in 1932, 11 years prior to the establishment of the El Verde plot. It is postulated that the early measurements reflect the rapid recovery of the stand following this hurricane, with both invading secondary species and residual primary species present in the stand. Subsequent perturbations (i.e.,, cutting and another storm) were insufficient to disrupt the unmistakable trend toward a mature forest and the stand quickly approached steady-state conditions.