Is fog important and why?

The California Redwood's leaves capture and channel the fog water droplets. They can actually trap more water than they can use so provide water for other plants.

Todd Dawson of UC Berkeley has studied the trees to find "a 100' tall redwood tree can gather the equivalent of four inches of rain". During the dry summer, with only fogs, the trees gather water to provide about 1/2 the annual water needed by the forest