Pumpwood (Cecropia schreberiana) is the main species of Cecropia tree found in the Pacific lowlands of Costa Rica. It was formerly classified as Cecropia peltata.
Like those of all Cecropia trees, Pumpwood leaves are palmately compound and peltate (circular in shape and flat with the stem attached in the center of the leaf). Pumpwood leaves usually have 9 to 11 lobes that merge together near the middle of the leaf. These umbrella-like leaves are very large and can be up to 20 inches (51 cm) in diameter.
The new leaves are a reddish color. Pumpwoods are evergreen, but the old leaves are regularly shed. After an old leaf falls, it will leave a triangular leaf scar on the branch, and these scars can be used to estimate the age of a Pumpwood in areas with pronounced annual wet and dry seasons. During the yearly dry season when growth is slow, the leaf scars will be close together, while during the rainy season when growth is fast, the leaf scars will be far apart on the branches.
Pumpwoods are dioecious, and the female trees will produce clusters of green, finger-like fruits that become covered with numerous, small, gummy-coated seeds when ripe.
These fruits attract birds and fruit-eating bats, and the seeds will pass through these creatures unharmed and be widely dispersed throughout the jungle.
Cecropia trees are very common in disturbed areas and at the forest edges. These fast-growing, sun-loving trees are usually one of the first pioneer species to colonize an area after a natural disaster like a hurricane or after human-caused destruction like logging. Cecropia seeds require direct sunlight for germination, so they wait dormant in the shaded soil of the jungle until a giant jungle tree meets its unfortunate end and falls, exposing the ground below to the sun for the first time in many years. The resulting shade and soil stability provided by these pioneer Cecropia trees allows more delicate forest species to sprout and re-colonize a disturbed area.
Although Pumpwood and other Cecropia trees can grow quite tall, quickly reaching heights of 50 feet (15 m) or more, they are relatively short-lived, usually only living around 20 years or so. Cecropia trees have hollow stems and trunks and lightweight wood, so they are not as sturdy as other trees. Sun-loving Cecropia trees are also very intolerant of shading from competing tall trees or smothering vines.
Cecropia trees have a remarkable association with Azteca ants. These biting ants live in the hollow internodes in the stems and help guard the Cecropia trees from any threats. A Cecropia tree not only shelters its protective Azteca ants, it also feeds them as well by producing glycogen-containing beads at the base of the leaf petioles (leaf stalks). Because of the presence of vigilant Azteca ants, you should definitely think twice about climbing a Cecropia tree!