362 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1953 



ferent character from those tropical forests that experience no dry 

 season; hence it has been classified as a tropical seasonal evergreen 

 forest. In these beautiful primeval woods as many as 60 to 80 species 

 of trees and shrubs may grow on an acre. 



All these forest elements are bound and laced together by hundreds 

 of large woody lianas and smaller herbaceous vines, making a canopy 

 so tight that only scattered small spots of sunlight reach the ground 

 at any one time. Under this protective canopy one may stand for sev- 

 eral minutes after the start of a heavy shower before he feels a single 

 drop that finally gets through the mass of leaves above him. In the 

 deepest parts of these woods there is twilight at noonday and light- 

 ning bugs or fireflies may be seen emitting their tiny lights. Here a 

 photoelectric light meter will measure less than 0.2 foot-candle at 

 noon even on a cloudless day. It is a forest where the biologist sees 

 organic pressures for survival at their highest. It is a forest where 

 nearly every plant form, where nearly all animal behavior traits are 

 used by some other species with its own special adaptations to attain 

 its own survival. Thus the interrelationships and dependencies of this 

 biotic community are infinitely more intricate and more complex than 

 those of temperate regions. One has to walk only a few yards over 

 any trail to see these interrelationships. Here, for example, is a 

 strangler fig (pi. 1, fig. 1) over 50 feet above the ground with its root 

 system rumiing down into the earth by going along and around the 

 trunks of three other trees. One of these supporting trees is entirely 

 gone, leaving a hollow tube formed by the anastomosing roots of the 

 fig. Another of the fig's victims is dead and rotting away as it is held 

 upright by the entwining roots of its murderer. The third tree is still 

 living but is doomed to die by strangulation just like its neighbors. 

 On the place once occupied by these three trees, one over 3 feet in 

 diameter, there will eventually stand one giant fig tree on its three 

 sets of strong tubes of roots which give the trunk of the fig a big advan- 

 tage over other trees by holding it up 50 feet or more above the forest 

 floor. From its elevated position it grows on up into the bright sun- 

 light above the upper canopy of the woods. The strong fig will also 

 be used by other lesser kinds of plants to get their food-making fronds 

 and leaves into more and more sunlight. Already there are long lianas 

 swinging down from its leafy crown and on its larger branches grow 

 ferns, orchids, and bromeliads. Some of these epiphytes have leafy 

 cups that catch and hold i-ain water in which a peculiar fauna lives. 

 Certain species of mosquitoes and amphibians, for example, live and 

 reproduce only in these tree gardens high above the gi'ound. 



The fig itself started from a tiny seed that perhaps was left on a limb 

 of one of these trees by a bird or a monkey many years ago. After 

 germinating it grew as an epiphyte until its long roots followed down 

 the three trunks to the ground. Once in the moist earth the tree grew 



