The most obvious property of the cloudforest is its dense, dripping wetness. Cloudforests are formed by a constant, near-one-hundred-percent humidity created by mists, produced here when northeasterly trade winds from the Caribbean drift across the high ridge of the Continental Divide to cool and become dense clouds settling over this high-altitude forest.
The cloudforest environment can be rather eerie, due to the sheer layering of vegetation, and the preponderance of epiphytes – plants that grow on other living plants for physical rather than nutritional support. Everything seems to be stacked on top of each other, and when walking the Monteverde and Santa Elena trails you’ll notice that green mosses wholly carpet many trees, while others seem to be choked by multiple layers of strangler vines, small plants, ferns and drooping lianas.
The leaves of cloudforest plants are often dotted with scores of tiny holes, as though they were gnawed by insects that soon gave up – which is, in effect, exactly the case. Many cloudforest plants produce toxins to deter insects from eating an entire leaf or plant. The plants are able to produce these poisons because they harbour excess energy that would otherwise be used to protect themselves against adverse weather conditions, such as a prolonged dry season or heavy winds and rain. The insects, in turn, guard themselves by eating only a little of a leaf, and by sampling a wide variety, so that they are not overwhelmed by one powerful toxin.
For an in-depth look into cloudforests, check out An Introduction to Cloudforest Trees, by William Haber, Willow Zuchowski and Erick Bello, available at the reserve visitor centre and in bookshops in San José.