Wind River Canopy Crane

Crane Closing Down but Long-Term Research Continues

On May 27th, the Wind River Canopy Crane gondola took one of its last trips into the old-growth forest canopy at the Wind River Experimental Forest in southeast Washington.  Along for the ride were Wind River Canopy Crane Research Facility (WRCCRF) Site Director Ken Bible, SFR Director of Student and Academic Services Michelle Trudeau and her husband Lorne, UW News and Information Assistant Director Sandra Hines, and The Columbian reporter Kathie Durbin. The 25-story construction crane used since 1995 to investigate such things as how Pacific Northwest forests absorb carbon dioxide, obtain sufficient water, and resist attacks by pests and diseases is being pruned back to just the tower.  

After assessing the prospects of continued research funding and the cost of maintenance and operation, the crane’s partners—the University of Washington and the U.S. Forest Service Pacific Northwest Research Station—agreed to remove the crane’s jib arm, probably sometime this summer.  Gone will be the ability to carry a gondola with researchers and instruments from the bottom to the top of trees as tall as 220 feet in a 560-foot circle, the farthest reach of any of the nine forest canopy research cranes operating in the world today.   The 230-foot tower, fitted with a diverse array of sensors, will remain — these sensors connect the facility to three national networks (AmeriFlux, a network of gas exchange measurements in North, Central, and South America; BASIN (Biosphere-Atmosphere Stable Isotope Network); and COSMOS (Cosmic Ray
Soil Moisture Observing System). 

The tower’s sensors have been collecting data about such things as carbon dioxide absorption and release and air flow since 1999, one of the longest, continuously collected data sets of carbon flux from a forest. Work at the crane site produced some of the first data to substantiate what SFR Professor and WRCCRF Director Jerry Franklin and other scientists suspected in the 1980s:  that old-growth Douglas-fir forests weren’t emitting more carbon than they were absorbing.  “Data collected at the crane site revealed that old growth forests are sinks for carbon,” says Franklin, who was the prime mover in the 1990s for landing the $1 million project. At the Wind River site, data show that the forest is takes up more carbon  than it releases through year round respiration and decay.

Other scientific discoveries facilitated by the crane have included seminal research on the structure of forest canopies, the physiology of northwestern tree species, carbon and water cycles in forests, forest productivity and health, and the contributions of forest canopies to biodiversity, including birds, bats, and insects. Researchers and students using the crane have generated more than 300 scientific publications.  Important research results include:

  • Pacific Northwest Research Station ecologist Rick Meinzer’s work in collaboration with faculty and former students from the UW and Oregon State Universty showed how very tall trees get the water they need to survive centuries of environmental extremes. During annual cycles of summer drought, trees rely on internal water storage to stabilize the supply of water to foliage high in the canopy, and on their deep roots to bring water close to the surface to feed shallow roots that might otherwise die every summer.
  • The complexity of older canopies—with branches and foliage from the bottom to the top of trees—is one reason older forests are good at taking up carbon dioxide, research at the crane showed.  The canopies of older forests are much deeper than those of younger forests, which is one of the reasons why older forests have more “leaf area” than younger forests.
  • As to the puzzle of how old growth Douglas-firs can thrive for centuries after they stop growing taller and their crowns stop getting fuller, research conducted by SFR Professor David Ford at the crane showed the significance in older trees of new branch, twig, and foliage production from dormant ("epicormic") buds located on bole and branches, which are stimulated to become active. This mechanism allows Douglas-firs to replace portions of or even entire crowns that have been lost due to damage or shading.
  • Research at the crane has revealed some of the ecosystem advantages of complex forest canopies and insight into how younger forests might be managed for more complexity if we wish.

“The crane taught us a lot,” says Bible, “but research on carbon dynamics and climate change is moving toward studies that are regional to global in scope. We are probably at a point where there’s not a whole lot more we can learn from using the crane as a research tool.  But the tower with its sensors and the ongoing work on the ground will continue to yield new knowledge.”  A growing number of partners, ranging from the National Oceanic and Atmospheric Administration to the Smithsonian Institution Global Earth Observatories, count on carbon flux and isotope data being collected at the Wind River facility from the tower. The Wind River Experimental Forest, been a research site for over 100 years; studies have been conducted on nursery practices, seedling survival and growth, genetics, and ecology.   And recently the site was chosen as the Pacific Northwest core site for the National Ecological Observatory Network, known as NEON, a major new initiative of the National Science Foundation.

The crane has also provided educational opportunities for thousands of K-12 and college students, teachers, and natural resource professionals, sometimes on site and, on occasion, through electronic “field trips” that have reached millions. “One of the things I’ll miss,“ says Bible, “is the sense of excitement and wonder on the faces of people seeing the old-growth forest canopy from this perspective for the first time. That sense of discovery is a powerful inspiration for scientists and laypersons alike.”  His sentiments are shared by Franklin and many others who have worked at the site over the years.

An eight-person gondola carried researchers, equipment, and an "arbornaut," on board to insure passengers' safety. Photo: Mary Levin.


Sudent helpers on a herbivory research study use a grid to estimate how much of the tree's foliage has been consumed by herbivores. Photo: WRCCRF Image Archive.


Inspecting the crane's counterweight jib. Photo: Mary Levin.