The general structure of forests of the canal area is quite similar, except for small areas of mangrove, freshwater swamps, and mountain peaks. Large disturbances such as hurricanes and fires are absent; thus, individual treefalls and small windstorms are the sole natural source of canopy turnover. A closed canopy 20–40 m tall with emergent trees reaching 50 m in height and a dense understory of saplings, treelets, palms, and lianas can be found in well-drained sites (Condit et al., 2001). The majority of the watershed (90%) is classified as tropical moist forest in the Holdridge (1967) system. Small areas of wet ridges near the Atlantic are classified aswet and submontane forest, but these are not much different structurally from the moist forest (Condit, 1998).