05 January 2011


Coast redwoods (Sequoia sempervirens) need a lot of moisture to grow to 115.61 meters/379 feet in height and up 8 meters/26 feet in circumference and to survive for nearly two millennia.

They harvest it from a rainy season and a foggy season—both of which roll in from the Pacific. Redwoods are ocean giants.

(Photo by Jason Sturner, courtesy Wikimedia Commons.)

Some interesting research on the fog ecology in a redwood forest was published in this 1998 paper in Oecologia. Turns out that in the process of capturing ocean fog for themselves, redwoods also provide it for their forest neighbors.

During the summer months when fog was most frequent, the isotopic data indicated that between 8-34% of the water used by the coast redwood, Sequoia sempervirens, and between 6-100% of the water used by the understory vegetation came from fog precipitation after it had dripped from the tree foliage into the soil. Direct uptake of fog by plant foliage was not quantified. Fog-collector and foliar interception data showed that between 22-46% of the moisture input to the ecosystem was due to the presence of the Redwood trees themselves (interception input); when trees were absent, interception input declined by 19-40% These data show that not only are plants of coastal redwood forests using a high proportion of fog precipitation but that the presence of the trees has a real influence on the magnitude of water input from fog precipitation.

(Photo by Naotake Murayama, courtesy Wikimedia Commons.)

Poets often know the science before scientists do. Here's part of Robinson Jeffer's 1928 poem, The Summit Redwood:

Only stand high a long enough time your lightning
     will come; that is what blunts the peaks of
But this old tower of life on the hilltop has taken
     it more than twice a century, this knows in
Cell the salty and the burning taste, the shudder
     and the voice.

                      The fire from heaven; it has
     felt the earth's too
Roaring up hill in autumn, thorned oak-leaves tossing
     their bright ruin to the bitter laurel-leaves,
     and all
Its under-forest has died and died, and lives to be
     burnt; the redwood has lived. Though the fire
It cored the trunk while the sapwood increased. The
     trunk is a tower, the bole of the trunk is a
     black cavern,
The mast of the trunk with its green boughs the
     mountain stars are strained through
Is like the helmet-spike on the highest head of an
     army; black on lit blue or hidden in cloud
It is like the hill's finger in heaven. And when the
     cloud hides it, though in barren summer, the
Make their own rain.

(Photo by Scott Catron, courtesy Wikimedia Commons.)

The paper:
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