Fog – Nature’s Foliar & Soil Input to Redwoods

Researchers state fog is a defining feature watering the coastal California redwood forest. Fog inputs via canopy drip in summer can constitute 30% or more of the total water input each year Dawson (1998). This natural phenomenon was imitated in Peru where they erected “fog catchers” to stave off a debilitating drought.

According to S.S.O BURGESS and T. E. DAWSON, foliar input of fog directly into the redwoods was also observed. “…sap transport reversed direction during heavy fog, with instantaneous flow rates in the direction of the soil peaking at approximately 5–7% of maximum transpiration rate. Isotopic analyses showed that up to 6% of a leaf’s water content could be traced to a previous night’s fog deposition…” Furthermore, wetting of the leaves at night, during their most active growth period, allowed for greater carbon fixation and contributed to faster growth rates and large size.

Orographic and Advection fog exist in coastal mountain regions where they rely on wind to move air over physical features (mountains or bands of cold water). Precipitation of fog droplets mostly occurs by horizontal interception on objects such as plant canopies, which are fairly permeable to the flow of air and have a large surface area, making them ideal fog interceptors. Another, more common type of fog occurs whenever radiative heat loss cools the Earth’s surface below the dew point of the surrounding air. Such ‘ground fogs’ tend to form on still nights (forming the mist of the morning).


The contribution of fog to the water relations of Sequoia sempervirens (D. Don): foliar uptake and prevention of dehydration  S. S. O. BURGESS & T. E. DAWSON




Study: Tracheid buckling buys time, foliar water uptake pays it back: Coordination of leaf structure and function in tall redwood tree.

Study: Within-crown plasticity in leaf traits among the tallest conifers

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