Dripping My Way Through the Forest

For anyone interested in water, a rain-gauge is not only an essential tool and toy, but a great topic for cocktail party chit-chat. Did you know, for example, that one can actually overlook 30 to 60 inches of "rain"?

I live on a high ridge dividing a hotter, dryer inland plain from the more temperate, wetter Pacific Ocean climate some five miles to the west. The non-drought average rainfall on top of my cloud-scraping ridge is about 60 inches per year.

Shortly after moving here, I noticed that a foggy summer evening produced the sound of steady rain beneath the tallest trees—even though a meadow 20 feet away remained bone-dry. I soon learned that in my Mediterranean coastal zone, summer "rain," consisting of droplets of condensed fog, is a frequent occurrence

In this climate, with its summer fogs and winter rains, moist air condenses on the leaves of plants and forms droplets like the hot-weather "sweat" on a bottle of cold soda. The collective needles of the Douglas fir trees near my house offer an immense surface area for this condensation.

I set up a rain-gauge beneath the tallest (125 -foot) Douglas fir tree, and over six years I've discovered that this single tree gathers one or more inches of "rain" each summer night during heavy fogs, and half-again to twice the year-round "rain" of the adjacent open meadow. The month of August usually produces six inches of summer fog drip, or an amazing 163,000 gallons per acre of tree foliage!

To utilize nature's original "drip irrigation" and take direct advantage of this free rain, I plant beneath the dripline of the Douglas firs near my patio The difficulty is finding plants that are somewhat drought-tolerant, shade-loving and deer-resistant. So far my list includes most of the varieties of Daphne (Daphne spp.); wild ginger (Asarum caudatum); native Western ferns; foxgloves (Digitalis spp.); huckleberry (Vaccinium ovatum); Forget-me-nots (Myosotis scorpioides); salal from Northern CA, OR and WA (Gaultheria shallon); the native thimbleberry (Rubus parviflorus); Euryops pectinatus (gets leggy, must have late evening light); and various ornamental grasses. Soon to be infiltrated by Rhododendrons spp., Azaleas spp., and bear berries (Mahonia spp.)

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