by Brad Lancaster © 2014
Got fog? Plant and grow living fog-harvesters or become one yourself, and you’ll end up increasing your rainfall—or at least your fogfall.
Many native plants that grow in areas where fog is a regular occurrence have adapted their leaf structure to harvest fog. The fog gathers/precipitates on the rough/fine surface area of the leaves then drips/rains down to the soil as “fog precipitation.” The coastal redwood tree (Sequoia sempervirens) is an excellent example of the impact of this phenomenon; one study in northern California found that on average 34% of the annual hydrologic input was fog-drip off the redwood trees themselves, while in areas without the redwood trees, fog accounted for only 17% of the water input. These data demonstrate that the trees significantly influence the volume of fog-water entering the system.1 The study also found that in summer when fog was most frequent, and rainfall was absent, about 19% of the water within the redwoods—and about 66% of the water within the understory plants—came from fog after it had dripped from the leaves of the trees.2
Fog-drip from trees can be, and has been, harvested in cisterns to provide drinking water, as was the traditional practice with the “rain tree” (Ocotea foetens)3 of Hierro, otherwise known as the “holy tree,” or “garoe,” which grows in laurel-forest habitat at elevations between 400 and 1400 meters in Madeira, Azores, and the Canary Islands.4
Click here […] to continue reading this blog post in its entirety on my website, HarvestingRainwater.com.
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1. “Fog in the California Redwood Forest: Ecosystem Inputs and Use by Plants,” by T.E. Dawson, Oceologia, 1998. http://link.springer.com/article/10.1007%2Fs004420050683#page-2, accessed 7-21-2014.
2. “Fog in the California Redwood Forest: Ecosystem Inputs and Use by Plants,” by T.E. Dawson, Oceologia, 1998. http://link.springer.com/article/10.1007%2Fs004420050683#page-2, accessed 7-21-2014.
3. The Laurel or Bay Forests of the Canary Islands, C.A. Schroeder, Department of Biology, University of California, Los Angeles. California Avocado Society 1989 Yearbook 73:145-147. http://www.avocadosource.com/CAS_Yearbooks/CAS_73_1989/CAS_1989_145.htm, accessed 7-21-2014.
4. Ocotea foetens, Wikipedia, http://en.wikipedia.org/wiki/Ocotea_foetens, accessed 7-21-2014