A Huge Lift For Treetop Researchers Canopy Crane Boosts Old-Growth Study

A little buckshot was handy in the past when scientists wanted to sample the treetops for research experiments. Just blast away, and pick up whatever fell.

Cherry pickers would do, if the tree wasn’t too tall.

Towers and catwalks could be built, but it was pretty labor-intensive. The truly adventurous launched dirigibles and lowered rubber rafts onto the tops of the trees. Scientists reached over the sides of the rafts to pick samples.

It worked, but only with a flat spot to set the raft on.

Now, there’s the Wind River Canopy Crane, a 25-story research tool used by scientists to soar to the tops of old-growth trees, opening a whole new realm of research.

The crane is in the Gifford Pinchot National Forest, in southwest Washington near the Columbia River Gorge.

Last used to build a public library in San Francisco, the crane was purchased secondhand in 1995 by the U.S. Forest Service for $620,000.

It’s the tallest research crane there is, one of only three in the world. The other two are used to study tropical forests in Panama and Venezuela.

Scientists at Washington State University are using the Wind River crane to sail around the treetops this summer, sampling branches as part of a study of global climate change. It’s one of dozens of experiments made possible by the crane.

“A lot of the work that was done before the crane was ground-level work. But with the crane, we have access to any tree, at any height,” said Shelley Pressley, a WSU graduate student conducting an experiment with the crane.

In the first two years of operation, about 45 projects have been completed, involving more than 70 researchers and a dozen organizations from the Environmental Protection Agency to the Smithsonian Environmental Research Center.

The findings can be used to better manage forests of any age. They help answer questions about insects and diseases, plants and animals, and the structure of the canopy itself.

Studying the canopy is important to understand how forests thrive.

Examining a forest without looking at the top is like determining the health of people by looking at their feet.

Canopy research is easier than ever, but it’s still not for the fainthearted.

Scientists climb into a yellow metal basket the size of a loveseat that dangles at the end of a cable hung from the crane. The basket, called a gondola, can slide across the bar of the crane. A cable can move the gondola up and down. And the whole shebang can rotate 360 degrees.

The crane is controlled by an operator in a tiny cab way up where the horizontal bar is pinned to the vertical rise of the crane.

Before swooping around the tree canopy, scientists don hard hats, strap into harnesses clipped to the gondola, then call the operator on a radio to ask to be whisked to the treetops.

Almost silently, the gondola glides up and up and up, from the forest floor to the middle canopy of 400-year-old hemlocks and firs. Then all the way to the top, and then even higher, to hover, looking down on the tops of giant trees where the wind whistles free. When it reaches the top of its range, the gondola gives a little lurch as it settles on the cable. The old hands aboard hardly notice.

From way up there, the trees are like a sea of broccoli tops, a rolling, rumpled blanket of green that stretches to the horizon.

The crane is in a stand of old growth Douglas fir and Western hemlock typical of the forests that once covered much of Western Washington. The oldest trees are estimated to be about 500 years old, and the tallest reach 220 feet.

The University of Washington and two branches of the U.S. Forest Service formed a partnership to erect the 250-foot crane in 1995. Researchers pay the university $185 an hour for its use to cover operating costs.

The crane allows researchers repeated, easy access to the same spot if they like, to gather data for long-term experiments. The basket can be lowered in a 550-foot circle, providing fingertip access to about 300 trees in 6 acres of old-growth canopy.

For researchers, that’s where the action is. The tips of branches are where budding, growth and most photosynthesis takes place. And the canopy, where the treetops interlace with the sky, is where a host of complicated interactions unfold.

The exchange of gases between the branches and the atmosphere affects everything from the air temperature to its purity.

The work being done by Pressley, the WSU graduate student, is intended to help scientists understand how much hydrocarbon forests contribute to the earth’s atmosphere. Hydrocarbons are a component of smog linked to global warming.

To understand how to counteract pollution, researchers have to know more about its source, which of those sources can be manipulated and curtailed, and which occur naturally.

To gather samples of the canopy, Pressley reaches over the edge of the gondola, dangling more than a hundred feet up, and grasps the tiny branches.

She keeps careful records of each sample taken from two trees that are part of her study: a 183-foot Douglas fir and a 160-foot hemlock. She’s been to the same sampling spots on the trees more than 70 times since May.

It’s patient, meticulous work. And it would have been impossible without the crane, Pressley said. “The crane is invaluable. It opens a whole new frontier.”

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