Disturbance and Canopy Structure
In Two Tropical Forests
Brokaw, N., S.
Fraver, J.S. Grear, J. Thompson, J.K. Zimmerman, E.M. Everham III, R. Waide,
S.P. Hubbell, and R.B. Foster.
Disturbance and canopy structure in two Tropical forests. In E. Losos
and E. Leigh Jr. (eds.) Forest Diversity and Dynamism. The University of Chicago Press. In
Press.
Abstract: Variation in tropical forest
architecture reflects many site and historical factors. Similar studies at El Verde, Puerto Rico,
and Barro Colorado Island, Panama, provide an opportunity to compare forest
canopy surfaces and treefall gap variables between two tropical locations. Before Hurricane Hugo struck the forest at
El Verde in 1988, its upper canopy surface was relatively smooth, and its gaps
were few and small, compared to Barry Colorado. After Hugh, El Verde’s canopy appeared to be recovering its
previous structure. We suggest that
chronic hurricanes limit the size of trees, prevent individual trees from
emerging above the main canopy, and cause pulses of treefalls at El Verde, all
of which leads to a relatively smooth canopy and reduces the size and number of
gaps between major storms. We discuss
additional factors, including human disturbances at El Verde, that also
influence the canopy structure of these and other forests. A projected increase in the number and
intensity of tropical cyclonic storms could significantly alter canopy structure
of some forests.