Saturday, August 04, 2007

The beginnings of canopy science

kw: book reviews, nonfiction, natural history, trees

In a post in May (Scientists that can write?) I reviewed a collection of essays and single chapters by a number of scientists who write well indeed. The Wild Trees: A Story of Passion and Daring by Richard Preston was one such chapter extract. The chapter was a fair sample of the book's excellence of writing and storytelling.

Steve Sillett's first ascent of a redwood was far from auspicious. He really ought to have died. He and a friend jumped from the top of a 70-footer to grab a small branch on the trunk of a 300-footer. Such "epicormic" branches are usually weakly attached. This one was strong enough to hold the two of them, though it also harbored a wasp nest. They free-climbed the rough bark cliff to a stronger branch and ascended to the tree's crown. Preston doesn't mention how they got back down, but I assume they managed to jump back to the smaller tree, garnering a few more stings along the way. The things 19-year-olds do! His life exemplifies the cynical definition of "expert": someone who has gotten away with really risky stuff more often than you have.

From such a beginning, Sillett grew to become a major figure in canopy research in the tallest forests. Ironically, after learning arborist rope techniques, and experimenting to adapt them to trees reaching nearly 400 feet, he is very finicky about safety with his colleagues, including Preston, who caught the tall tree bug after an interview with Sillett, went to an arborist school in Atlanta, and practically forced himself upon the scientist.

Though (now Dr.) Sillett is the central (human) figure of the book, the author includes brief developmental biographies of a number of prominent tall tree researchers, some that have used cranes and dirigibles, and others who also use ropework.

But the real heroes are the trees. The tallest redwoods (Sequoia sempervirens) are probably the tallest trees on earth today. The tallest currently known is 379 feet (115.5 m) tall. But some "mountain ash" (Eucalyptus regnans) in Australia are nearly as tall, and there were reports in the early 20th Century of Douglas-fir (Pseudotsuga menziesii) trees that measured 400 feet (122 m) after felling...though exaggeration is likely. All these species grow in temperate rain forests, and are more than twice as tall as all but a very few tropical trees.

Whatever the species, the crown of a tall tree begins at about half the tree's total height. Few branches, if any, are found on the first hundred to 150 feet of a 300-foot tree. Just getting a drawline over the first substantial branch of such a tree requires a good eye with a crossbow, and several to many attempts. The crown itself is a maze of branches, vertical shoots off the branches that are often the size of "ordinary" trees, and a fractal structure that makes the crown seem a forest all in itself. Indeed, Sillett's wife got lost in a crown once, tied herself to a branch, and radioed her husband for help. He was no more than fifty feet away, but took twenty minutes to find her.

Such a crown is an ecosystem, one that is now thought to contain more than half the total subaerial species on the planet. The catalog of species that are either endemic to tree crowns or rare elsewhere grows daily, including lichens, mosses, liverworts, many kinds of insects and mites, that all compete for space with more familiar species such as huckleberry and other epiphytes. Some large crowns host entire small forests of shorter tree species.

As one who had to send my kid up a 20-foot ladder to install a rope swing a few years ago, I must admire these folks from a least 300 feet! They are learning what such ecosystems have to offer, as such forests are becoming vanishingly rare.


M. D. Vaden of Oregon said...

Quite a good book to read - The Wild Trees.

But oh how I wish I could show people the trees Preston writes about so they could compare those groves to his writing style.

Grove of Titans & Atlas Grove

Oddly - I would have found at least one grove within 6 months even if I never read the book. I go off trail, and the Grove of Titans would have been in the 5th or 6th location that I would have explored since I had just finished venturing off Hiouchi trail already.

I'm not into trying to find new champions. Just seeing what's in the forest to enjoy and take photographs.


M. D. Vaden

M. D. Vaden of Oregon said...

Recently, after visiting two groves and some trees mentioned in The Wild Trees:

Grove of Titans & Atlas Grove

I added a comment to my page in the above link about wear and tear. Wear and tear to titan redwoods by researchers.

My visits have revealed that the groves are not as remote as Preston described with orchestrated vocabulary. And the researchers are not the initial trickle of visitors.

Apparently, the researchers may be the ones having the greater impact and wear and tear on these trees.

Buds can sprout anywhere on a redwood, and today's bud rubbed off in a climb, is tomorrow's leader stem replacement not existing. It's virtually impossible to climb a tree without interrupting something. Even in Preston's writing, and document reports I've found, epiphytes have been stepped on, some limbs knocked loose, some life forms removed. All the way from the needles Sillett's wife removed for their wedding ring patterns, to Canopy soil mat samples removed and taken to a lab.

In consideration that these largest titans have other visitors, and should be the most pristine, we need to consider the "untouched" nature of the habitat.

The university staff are storing PVC and hardware in cavities of the trunks like storage sheds covered with needles. Irrigation type flags with bright colors decorate the soil around several trees among the ferns. Ropes are left suspended and draping from upper limbs.

And once more, consider the wear and tear of climbers scrambling through the trees and draping climbing gear.

It may be appropriate at this time, for the researchers to abandon the oldest ESTABLISHED epiphytic growth, and move to trees of near equal height where the growth is beginning. To spread out the wear and tear.

Then, maybe climb the titans at 10 to 50 year intervals, rather than yearly or frequent intervals.


M. D. Vaden of Oregon