have been described as "summer every day and winter 

 every night." At these higher elevations, tall montane 

 forests give way to elfin forests. And finally, above 

 about 4,000 meters (13,000 feet), trees can no longer 

 survive and alpine/paramo vegetation predominates. 



Just as in the contrast between thorn scrub and 

 deciduous broad-leaf forest or evergreen rain forest, the 

 types of forest found at the different altitudinal levels 



forest at 3,000 feet elevation and in a forest at 8,000 

 feet. There are other factors as well; steepness of slope, 

 the exposure to wind, and the length of the dry season 

 can produce very different kinds of forests on these 

 higher mountains. 



What all these diverse ecological factors add up to 

 is the simple observation that there is no such thing as a 

 "generic tropical forest. " Soil conditions, flooding, and 



Tree terns often grow on steep open slopes in lowland rain forest formations. Golfito. Costa Rica, 



are composed of different species. It is unusual for a 



plant species to have an elevational range of more than 



5,000 feet (1,500 meters). The trees as well as under- 



12 story shrubs and high epiphytes are very different in a 



many other factors also affect forest structure and com- 

 position. Every local region differs in subtle ways from 

 other nearby regions, and the stature and composition 

 of the local forest biota will reflect these differences. 



