Dawn light filters through fog between the trees. The scent of needles rises as the air warms. Leaves drip. Emily Burns walks between redwoods (Sequoia sempervirens) on the Californian coast.
Donning a helmet and harness, Emily clips onto a rope and climbs high into the canopy. As she ascends, the light brightens and the fog thins. Finally reaching a height of 72 metres, Emily stops and takes a photograph.
The very tops of trees emerge from a dense blanket of fog that stretches into the west, towards the Pacific ocean. Each night the fog rolls in off the ocean, inundating the trees in the coastal redwood forest. The trees intercept the fog, which can both drip off the tree crowns into the soils around the base of the trees, as well as be directly absorbed by the leaves into the entire tree crown, where it improves plant water status.
Emily, a Research Associate at UC Santa Cruz, Director of Science and Education at the Save the Redwoods League, and former graduate student of Todd Dawson’s lab at the University of California, Berkeley, had climbed into the canopy as part of a long term project exploring the ways fog impacts the water balance of the forest and the water relations of its plants.
“The aim of the research is to quantify the roles that fog water inputs play in the hydrology of coast redwood forests, and in the ecology and physiology of the plants that inhabit the redwood ecosystem,” says Todd Dawson, co-author of a Tansley review with Greg Goldsmith, published in New Phytologist.
The photograph on the cover of New Phytologist 219:4, Todd explains, documents how the regular occurrence of fog can inundate the entire coastal zone, an important source of water in an otherwise rainless Californian summer.
“Water is a key part of the hydrology and ecology of coastal redwood ecosystems,” adds Todd. “Both the redwoods themselves, as well as the understorey plants on the forest floor.”
Read the paper: Dawson, T. E. and Goldsmith, G. R. (2018) The value of wet leaves. New Phytologist. doi: 10.1111/nph.15307
The New Phytologist Trust