You know you’re in a cloud forest when most of the trees around you are covered with epiphytes. A single tree may have literally dozens of different species of plants growing on it, and it’s exactly this kind of “packing” of species within a small space that contributes to the high biodiversity of tropical cloud forests. Defined simply by they way that it grows, an epiphyte is any plant that grows on another plant (except for plants that are parasitic, like mistletoe). Because they don’t send roots into the soil, epiphytes must have adaptations that allow them to obtain water and nutrients from the air. This is why they are so common in cloud forests, which are often bathed in moisture throughout the day. So, epiphytes and cloud forests are closely linked to each other.
Last week I met a researcher, Greg Goldsmith, who is finishing up his PhD. He has been studying cloud forests for a while and recently collaborated on an interesting way to teach other people about them using high-quality photographs stitched together to make 360-degree panoramic images that you can explore. You should definitely take a look at the website: Canopy in the Clouds. It may take some time to upload the images, but it’s worth it. See if you can find the incredible video clip of a resplendent quetzal swallowing a very large seed! (OK … it’s also on vimeo, which is easier to link to from here.)
Recently, Greg has been studying the ways that trees (not epiphytes) are able to survive through the dry season up here in Monteverde, and he’s documenting some interesting things. For example, he’s got great data to demonstrate that many trees are capable of taking up water through their leaves from the air … as long as they are water stressed. This is incredible since we are taught almost without exception that trees can take water into their tissues only through their roots. Any basic biology textbook will tell you this. However, if water is limiting (and it is definitely can be during the dry season) it makes sense that it benefits a tree to be able to use moisture from the air to survive and grow, and trees that are better able to do this will pass along this trait to their offspring.
Epiphytes are an entirely different story (at least we think so) because there are a wide range of interesting structures that epiphytes use to absorb water from the air or collect it in vessels in order to grow in the dry environment up in the branches of a tree. So … here are a few photos of cloud forests and epiphytes that have been piling up in my camera.