Trees of cloud forests contribute to water yield by precipitating water from clouds onto needles, a process known as 'fog drip.'


"Cloud forests, which are dense tracts of evergreens rising thousands of meters above sea level, contribute to yield, but in a novel manner: they literally comb water from the clouds. In the Cascade Mountains of Oregon and other coastal slopes or mountain summits, for instance, firs are often shrouded in swirls of fog or immersed in wind-driven clouds. Water condensing on the needles and dripping to the ground can increase precipitation enormously. From the mountainous forests of Hawaii to the Bavarian Alps, trees can sometimes scavenge more moisture from the clouds than the clouds yield directly as rainfall. Cutting such forests not only decreases streamflow but often changes the functioning and character of the landscape…When Yale University botanist Hubert Vogelmann studied the area [southeast coast of Mexico which had been cleared of forests] he found that the gulf winds still drive moist fogs across the slopes, even in the dry season. Without trees to intercept the fog drops, however, this moisture simply evaporates as it sweeps inland over the now-arid ground." (Baskin 1997:85-86)

Work of Nature: How the Diversity of Life Sustains UsJanuary 1, 1997
Yvonne Baskin

Coast RedwoodSequoia sempervirensSpecies