Elfin Woodland of the Caribbean
High up, from 6,500-13,000 feet,
rain forest vegetation becomes downright fanciful .
The cloud forest is the highest level of the Caribbean. As the name implies, this region almost always is covered in clouds, mist and haze.
It's nickname of elfin woodland shows that early European naturalists who explored the high altitudes of the Caribbean had a sense of imagination and wonder. To them, the combination of twisted and stunted vegetation, moss, dense foggy atmosphere, clouds and the eternal eastern tradewinds must have seemed a sinister, mysterious place...just the kind that the elves of German literature were said to inhabit.
In the high cloud forest, trees grow thicker and farther apart than at lower levels. Due to the harsh conditions of cold and wind, they also grow much more slowly than in the lower rain forest (figure a 3-degree F drop for every 1,000 feet). At altitude, epiphytes still appear in great numbers, but many of the lowland creeping plants disappear.
Where the canopy of the lower rain forests may reach well over 100 feet, elfin forest trees rarely stretch above 15 to 20 feet. Only about 40 species of trees and shrubs have adapted to the harsh weather and high humidity at the Caribbean 's highest points, a far lower diversity compared to the hundreds of species found in the lowland rain forest.
Puerto Rican botanist Vicente Quevedo reported that a combination of elements accounted for the stunted nature of the cloud forest in the Caribbean National Forest. These factors include: shallow oxygen; poor clay soils that are saturated by heavy rainfall; the resulting poor transport of nutrients from the roots to the branches; and a low transpiration rate (casting off of waste products) due to the constant, high relative humidity.
In addition, damage from high winds, the low amount of direct sunlight and its corresponding reduced rate of photosynthesis, lower temperatures and other decreased biochemical processes also appear to play a part in dwarfing the trees.
Animals don't fare well in such extreme conditions. In the cloud/elfin forest, you normally find only birds and lizards.