i can't stop thinking about the redwoods. before this summer, i hadn't been there in quite a while, so i was awestruck anew at them. redwoods are awesome. they are superlative in size, incredible to see in person. they are masters of their environment, overseeing all other trees. they are like nothing else on the planet.
in looking for more specifics to understand redwoods, i turn to the dry but essential 1965 version of "Silvics of Forest Trees of the United States", old Ag Handbook No. 271, from the USFS. they have this to say in part about the fantastic coastal redwood, a.k.a. Sequoia sempervirens:
"This redwood belt...is an irregular coastal strip about 450 miles long and generally 5 to 35 miles wide. ... The frequent summer fogs which blanket the redwood region seem to be more important than the amount of precipitation in delineating the redwood type. ... The range of this tree is limited to areas where heavy summer fogs provide a humid atmosphere."
our friends at the USDA forest service (this edition compiled and revised by one H.A. Fowells) go on to explain to us several key facts, eventually: that redwood trees grow from sea level to about 3000' in elevation, but don't tolerate ocean winds, and so don't grow directly on or facing the ocean; that they reach their maximum development on alluvial soils (i.e., floodplains); that redwoods sprout from the stem or base if the top is damaged or removed; that they are, indeed, the tallest trees in the world, maxing out at 368' (in 1956); that redwood stands are dense, supporting nearly 1,000 stems per acre at 20 years; that redwood trees have no major tree-killing diseases; that old redwood stands show evidence of three major fires per 1000 years, but that old trees survive by virtue of their foot-thick bark. foot-thick! there's no exclamation points in the original, as you well may guess; Fowells et al do not let themselves tend toward exuberance. that's ok, because anyone reading it must pause at that statement, and exclaim to whomever is sitting near, while holding out their hands just so: foot thick bark! that is astounding!
the far more entertaining and poetic "A Natural History of Western Trees", by Donald Peattie, with an original copyright of 1950, at least attempts to capture more of what is so awe-inspiring about redwoods:
"In all the world there is no other forest growth like that of the Redwood. It is at once the tallest and the densest of stands - not dense like the jungle's tangled quantities of trees, lianas, and undergrowth, for the Redwood groves are spaciously open to your footsteps - but dense in the sheer volume of standing timber. ... The [transition into redwood forests] is like stepping into a cloister, one infinitely more spacious and lofty than any raised by man, and closing the door behind you on the bright secular world. ... Your footfalls make no sound on the needles and moss that have lain there for centuries. Your body makes no shadow in that green, lake-like diffused light. ... But this solemnity is not like that of a church or tomb; it is enlivened by the soft dispute of a stream with its bed... And now and then the treetops utter a slow, distant sea-hush, a sigh that passes, and then comes again, as if it were the breathing of a life beside which our lives are as a single day. ...
"And they are mighty past telling. Their enormously swelled bases are buttressed with great lynx-like claws, as if the trees gripped the earth to keep their balance. ..."
what does all this mean? well, from an ecological viewpoint, redwoods are specialists. they fit so thoroughly, so completely, in their narrow ecological niche, they survive only in this almost-coastal, fog-belt laden strip 5 to 30 miles wide and 450 miles long. fires are infrequent here, but when they come, redwoods survive by virtue of the incredible thickness of their bark. one sees many, many still-living trees where the bottom has been completely hollowed out; first the heartwood was weakened by fire, but the strong sapwood remains, keeping the tree alive. floods are frequent here, so redwoods have enormously spreading roots to anchor them firmly into soggy soil and let them take advantage of the nutrient-rich floodplain soil. should they topple over, they sprout back up again from all around the stem. given no windthrow, catastrophic fire, or other such disturbance, they can live over 2000 years.
actually, redwoods are more than specialists; they are master craftspeople. lots of plants are specialists; little particular species or variants of species that survive in small pockets here and there, where some certain condition is just right. what really separates the redwoods from the rest of the endemic plant crowd is the way they are able to parlay their special environment into the most spectacular growth possible. like most conifers, they are able to photosynthesize long into the winter season; in the dry summers, they capture fog and drip it down to the forest floor to the equivalent tune of an estimated several inches' worth of rain. they are so successful that redwood groves can support incredible amounts of woody biomass.
what does this have to do with climate change? sure, i care about climate change, believe it's human caused, believe we should do what we can to mitigate it, etc etc etc. i toe the party line, so to speak. but deep down inside, i can't get worked up about the possible disappearance of some of the more obscure species at risk. i understand why they are important; that we never know in advance the possible ripple effects of loss of a species. who knew a little rabbit could wreak havoc on australia, or that possums could almost single-handedly defoliate much of new zealand? i understand why we should care. i even get really excited when i see an unusual plant. i'm just saying that, deep down inside, i'm not convinced that every species is equally important for ecosystem functioning. i've also been coming to appreciate more and more the impermanence of all ecosystems; even the old-growth forests of the oregon coast range have fluctuated greatly over time, settling on thier current form as recently as 1,000 years ago. things come and go; they ebb and flow. mass species extinction should be avoided, of course. but in many specific instances, it's easy to imagine that an endemic species could disappear with nary a blip in the ecosystem overall.
ah, but the redwoods - those highly specialized masters! what if the climate changes, the fog declines, the fires and floods increase, new insects that can bore through the bark are able to migrate into their habitat? what then? my world, minus a special bluebell - not so different. but my world, minus the redwoods? that would be tragic. to never again stand in those groves, taller than any other on the planet, taller than imagining? to never again touch the crisscrossing bark? to have them as dinosaurs, existing only in dreams? to never again be able to lay down in that perfect cathedral, hearing only the distant hush of the ocean? that would be losing something, for everyone. and standing there, contemplating the possibility of the disappearance of such a marvelous thing, such an ancient craftsman as an old-growth redwood, i suddenly could motivate my lip service to worrying about climate change. climate change appears like a coming industrial revolution, with the potential to render obsolete so many of our natural master crafters.
in the aforementioned book "A Natural History of Western Trees", the author discusses the initial preservation of redwood groves (which began at the local and then the state level, not the national) with these final sentiments. can we rally round the redwoods once again, with the threat of the possible loss of their ecosystem this time instead of chainsaws?
"...For the members of some of the sponsoring organizations live in Iowa or Vermont, in Geeorgia or New York. The great majority of them are probably not persons of wealth at all. They gave anonymously, they gave purely, they gave to the future, to people yet unborn; they gave not only to the country but to the world. And they gave out of a deep religious feeling that the beauty and the age and greatness that here have risen from the earth to tower above us are holy and shall not be profaned."
amen to that, brother.