A cloud forest is a forest that gets a substantial amount of moisture from clouds or fog. In Sutro Cloud Forest, it’s around 30% or more. Through the summer, the forest lies in the clouds and captures the moisture from it.
A Cloud forest? In San Francisco?
It’s not so surprising. Here’s a quote from the website of the San Francisco Botanical Garden:
“… [There are] striking similarities between coastal California’s climate and that of mountainous areas in the tropics. The temperature variation between day and night and between summer and winter is not very great in the tropics, even on tropical mountains. Coastal California also has moderate temperatures year round due to the ocean’s strong influence – San Francisco is sometimes referred to as “the air-conditioned city.” Cloud forests are found at elevations where water in moist rising air masses condenses creating a shroud of mist and fog. The high moisture levels are comparable to northern California’s wet winters while a cool ocean current off the coast creates summer fog which softens our Mediterranean summer drought to the extent that it moves inland. Views from atop tropical mountains are remarkable in their resemblance to panoramic summer views of the Bay area with thick fog advancing and retreating below higher hills and mountains.”
[Edited to Add Feb 2013: Click HERE to read about how this ecosystem works.]