The only absolutely accurate method of measuring a tree’s height is to climb
into its crown and drop a tape measure from the top. Sillett delayed his ascent
for two weeks, until the end of the nesting season of the marbled murrelet,
an endangered seabird that inhabits the area. Then he assembled a team to climb
Hyperion and verify its status as the world’s tallest tree.
With Atkins, Taylor, and Sillett’s wife, Marie Antoine, beside him, Sillett
tied fishing line to an arrow. Using a crossbow, he shot the arrow over a branch
in the lower crown of the tree. Then he tied a nylon cord to one end of the
fishing line and, pulling on the other end, hoisted the cord over the branch.
Finally, he attached a climbing rope to the cord and pulled the rope over the
branch. After tying off one end to a nearby tree, Sillett attached mechanical
ascenders to the hanging end of the rope, and began to pull himself up toward
the first branch.
"The lowest branch in a big redwood," says Sillett, "is higher
than the tallest branch of almost any other tree in any other forest on earth.
And once you get up there, you realize you’ve got almost another 200 feet to
reach the top."
The crown of such a giant is a gnarled mass of limbs, with bridges of living
and dead wood running horizontally from branch to branch, forming a natural
structure of struts and girders. Upon reaching the first branch, Sillett set
up an elaborate rig of ropes and carabiners, which he used to pull himself up
from limb to limb, into the heart of the crown. There, Sillett found blackened
chambers in the trunk, hollowed out by an ancient, high-reaching forest fire.
"It’s another world, almost another planet up there," Sillett told
me. "There’s a lot of biological diversity that’s unexpected. On limbs
and in crotches, you get these huge accumulations of rich, wet soil, hundreds
of feet off the ground. We found salamanders, earthworms, aquatic crustaceans,
huge huckleberry bushes, even other trees growing on soil mats. It’s literally
a hanging rainforest garden."
Before Taylor and Atkins began finding exceptionally tall specimens high on
mountainsides, Sillett and most other experts believed that the tallest redwoods
would grow only in alluvial flats, the silty flood plains near creeks.
"There were taller trees up higher all along, of course," Atkins says.
"But the ones in the low, flat areas were what people happened to see,
because getting onto the remote mountainsides was so challenging."
The fact that Hyperion is located in such an unlikely place suggests to researchers
that its height was not such an anomaly. Of particular interest to Sillett is
the question of the physiological limits of a tree’s height. In other words,
how high can a redwood grow?
Trees suck water upward through microscopic pipes called xylem. As water molecules
evaporate from the pores of leaves at the top of the tree, other molecules are
pulled up from the roots to replace them, in a journey that takes a few weeks
from root to treetop. Redwoods, more than any other tree, can move water to
great heights, against tremendous forces of gravity and frictional resistance.
But at a certain height, the tension of the water column begins to overstress
Sillett’s team has used centrifuges to artificially create tension in xylem,
and has demonstrated that the limit to a redwood’s height is about 410 feet
in southern Humboldt County. In the wetter, cooler northern part of the county,
where Redwood National Park is located, Sillett’s preliminary research indicates
that the limit may be considerably higher.
"What we’ve discovered about the redwoods’ physiology indicates that they
can grow a lot higher than the ones we’ve found," says Sillett. "Which
brings up a sobering thought. Now that 96 percent of the old-growth redwood
landscape is lost, we understand that, even in our lifetimes, we almost certainly
had trees over 400 feet. And we cut them down."
ACCORDING TO SILLETT’S measurements, Hyperion’s height is 379.1 feet. Chris
Atkins believes that the chance of finding an even taller tree is less than
one percent. "There are so few places we haven’t been through," he
told me. "Then again, there are a couple of basins we haven’t seen yet,
and there are rumors of tall trees up there. We’re hoping to get in there in
the next few months."
We were talking over the phone, a couple of weeks after my trip to Humboldt
County. Toward the end of a long conversation, Atkins asked me where we had
hiked. I named the creek basin we had explored on our last day.
"Wow," he said. "You managed to find your way into one of the
most spectacular groves on earth." He asked a few more questions, regarding
how far up the creek we went, which side we climbed, how high we went. After
I described the location, Atkins was silent for what seemed like a long time.
"You were in the right place," he said finally. "You probably
walked right past it."
I shivered when I heard that. Later, as I looked at some of Katzman’s pictures,
I recalled that final day when, pausing to rest on a bed of pine needles, I
was overcome by a feeling of insignificance that grew until it became strangely
For all I knew, I was sitting in Hyperion’s shadow. But at that moment, the
pursuit of a single tree–even the tallest one on earth–seemed inconsequential.
The real object of my quest was all around me, a mass of immortal columns strong
and generous enough to support the sky.
I’d come here looking for a tree, and discovered a forest.
Tom Clynes has climbed, saved, and now measured trees for BACKPACKER.