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  • Aspen

    In fall, aspen ignite the landscape with leaves of yellow and gold. Walter Siegmund photo. Click to Enlarge Photo

    Newsletter Archives


June/July 2013

Across their range, aspen groves are in decline, and as they fade an invaluable wildlife habitat disappears. Bats, bears, deer, elk, beavers, rabbits and a splendid array of migrating and breeding birds all find food, nest sites and cover in their groves.

In Oregon, quaking aspen (Populus tremuloides) is found primarily east of the Cascades. Many organizations and individuals are working to conserve the species and everyone involved has the same message—the time to save our aspen is now.



Restorationist Gets Fired Up about Aspen
Aspen Groves Nurture Young Wildlife
Forest Service Works to Save Threatened Aspen Groves
OSU Professor Studies Hawks and Habitat on the Prairie
Restoring Aspen: One Grove at a Time
OHA Volunteers Fence Aspen Grove on Ochoco National Forest
Land Manager’s Guide to Aspen Management in Oregon
The Oregon Conservation Strategy and Aspen

Downy Woodpecker

The downy woodpecker prefers to nest in aspen. USFWS photo.
Click to Enlarge Photo


Forestry experts and biologists agree that the future of aspen in Oregon depends on protecting and enriching the groves we have.

“Aspen rarely regenerate from seeds. The new trees in aspen stands, called suckers, are part of a larger clone. They sprout from a common interconnected root system,” said Darin Stringer, a consulting restoration ecologist and forester.

Stringer is currently working with the Forest Service on the Glaze Forest Restoration Project near Sisters.

“The Glaze project encompasses some of the largest aspen stands in Central Oregon—the entire area is over 100 acres,” he said. “Aspen habitat in the state is exceedingly rare, it’s scattered far and wide and mostly in small acreages.”

There are several problems to address if the Glaze stand is to be rejuvenated, all of them familiar to those who work on aspen restoration: conifers that overpower the aspens, blocking light and draining water and nutrients; overeating of new sprouts by wildlife; and lack of fire.

Fencing groves to keep the large resident elk herd out of the grove until the trees are large enough to allow for browsing and thinning conifers are part of the restoration plan, as is controlled burning.

“Fire helps regenerate aspen. Historically, naturally caused fires perpetrated new growth. We need to recreate that to stimulate sprouting.”

Darin Stringer

Darin Stringer is working on the Glaze Forest Restoration Project.
Click to Enlarge Photo

The benefits of a healthy, vital aspen grove are huge. 

“It is an important habitat for both resident and migratory birds. One species closely connected to aspen is the red-naped sapsucker, which creates nest cavities and drills “sap wells” used by many species,” said Stringer.

The Forest Service, Oregon Wild, The Warm Springs Tribes and others are working on the Glaze Forest Restoration project.

Stringer contributed to the publication Land Manager’s Guide to Aspen Management in Oregon (pdf). Contact Darin.


Ask Oregon Department of Fish and Wildlife Biologist Craig Foster who’s doing aspen work in the Warner Mountains of Lake County and he will laugh and answer, “Who’s not?”

Conifer removal

Conifer removal to benefit aspen in the Warner Mountains of Oregon. ODFW photo. Click to Enlarge Photo

It’s an impressive list: US Forest Service, Bureau of Land Management, the Lake County Watershed Council, Collins Pine Company, Oregon Hunters Association, Natural Resource Conservation Service, Rocky Mountain Elk Foundation, Lakeview High School and ODFW.

“And I’ll probably hear from someone I forgot,” he added with that infectious laugh.

Foster, or Fozz, as he’s known, is interested in aspen groves as a fawning and calving ground for deer and elk as part of his work on the ODFW Mule Deer Initiative.

“An aspen grove has everything a doe needs to bring a fawn to heel in the first 30 days,” he said. “All the nutrients are there in the understory, and there is plenty of cover for it to hide.”

ODFW has treated about 300 acres, removing conifers to give the aspens more light, more room, more water—all the things they need to recover. Work is done by hand—trees are fallen with a chainsaw, bucked up and left on the ground, which provides nutrients to the soil and protects the stand from grazing animals.

“We don’t have significant grazing problems in the areas we’ve treated so far, mostly encroaching juniper, fir and pine,” he said, “but aspen restoration is not a one-size-fits-all deal. We are going to run into areas that need fencing. You have to look at each grove and design a prescription.

“These are great wildlife habitats—and whether you are working for the deer or the woodpecker, it’s all good.”

ODFW Mule Deer Initiative, Contact Fozz.


Amy Markus

Amy Markus, Forest Wildlife Biologist, works to keep aspen stands on the Fremont-Winema healthy. USFS photo
Click to Enlarge Photo

“Aspen groves are biological hotspots for wildlife. They draw in a lot of wildlife species,” says Amy Markus, wildlife biologist for the Fremont-Winema National Forest. “You find a greater diversity of wildlife species in aspen than in surrounding dry forest conifer landscape.”

On the Fremont-Winema, aspen stands are dwindling. In the seventeen years, Markus has been working in the forest, she has seen the decline.

“Our stands are quite small. With the lack of fire, conifers have become more dense and are crowding out the aspen,” she says. “We have probably lost several small stands.”

To keep and expand what remains, Markus and her colleagues have just finished an aspen restoration strategy for the forest. “It will involve cutting conifers and doing some prescribed burning. Where appropriate, we will also consider changes in grazing strategies and fencing.”

Finding aspen stands that cover two acres or less is a challenge. Mapping is generally done by walking or driving an area. Biologists did get a boost two years ago, when a volunteer with the Rocky Mountain Elk Foundation flew the area in his private plane, identifying aspen groves. He flew in the fall when the aspen turn yellow and gold, making them easier to spot in the carpet of green forest.

Read Markus’ case study, Enhancing Aspen Woodlands on the Fremont-Winema National Forests, in Land Manager’s Guide to Aspen Management in Oregon (pdf).

Fremont-Winema National Forest, Contact Amy


Ferruginous Hawk
Ferruginous Hawks prefer to nest in aspen. USFS photo.
Click to Enlarge Photo

Dr. Pat Kennedy works in a rare and remote landscape, the Zumwalt Prairie, the largest remaining bunchgrass prairie in North America. The 160,000-acre grassland in northeast Oregon is primarily in private ownership, but The Nature Conservancy owns and manages 33,000 acres as a nature preserve, offering access and research opportunities.

Kennedy and colleagues Marcy Houle, Anne Bartuszevige, Ann Humphrey, Katie Dugger and John Williams recently completed a three-year study of hawk populations on the prairie. As a baseline, they revisited Marcy Houle’s seminal 1979-1980 study that documented for the first time the abundance of hawks in the area.

“Their abundance has not changed since Marcy’s study,” said Kennedy. “But some of the habitat is not doing so well, especially the aspen which is highly sought after for nest sites. All you have to do is stomp around out there for a while and you’ll see most of the stands are decadent, with little or no regeneration.

“What the decline in aspen means for the future of the hawks, we don’t know. We know the Ferruginous hawk prefers aspen for nesting. You can find a hawk nest in many groves, and we witnessed huge territorial disputes over the isolated pockets of aspen that are out there,” said Kennedy.

“While we don’t know how resilient Ferruginous Hawks are to landscape changes, we know they will nest in pines and large shrubs such as hawthorne, which are increasing on the landscape. So perhaps they will switch their preferences from aspen.”

Certainly grazing by cattle and elk is part of the cause of aspen decline, and fire suppression and climate change likely contribute, but the relative contribution of each factor to the decline is unknown.

“The prairie has been used to graze cattle since it was homesteaded, and before that the Nez Perce grazed horses here, so there is a rich history of hawks and livestock co-existing on the prairie,” she said.

Pat Kennedy
Researcher Pat Kennedy studies wildlife, habitat and livestock interactions. Pat Kennedy photo. Click to Enlarge Photo

“The results of this study suggest that the livestock management that occurred over the last 30 years or so has not negatively impacted the hawk populations. Whether or not their populations will be stable in the future is unknown.”

It is not a discussion Kennedy will shy away from. “Providing scientific evidence to help solve contentious policy issues is part of my job,” she said. “As an OSU scientist with an agricultural experiment station, I conduct studies to determine under what conditions agricultural production is and isn’t sustainable.”

As far as the aspen groves, Kennedy believes that while a number of people and organizations are working to protect and rejuvenate them with a wide variety of fencing and burning practices the effectiveness of these efforts has not been rigorously evaluated and the results have not been published in the scientific literature. 

“But we do know that aspen and many other woody species are disappearing throughout Oregon and the time to reduce these declines is now.”

Changes in Buteo Hawk Territory Occupancy over Several Decades on a Privately-Managed Bunchgrass Prairie in Northeast Oregon, Pat Kennedy et al, Oregon State University, Department of Fisheries and Wildlife will be available early next year.  Contact Pat


Aspen Stand

Healthy aspen stands are wildlife hotspots. Martyne Reesman photo.
Click to Enlarge Photo

Tim Lillebo knows a lot about aspen. His enthusiasm and knowledge reflect the 38 years he has spent working to protect native habitats and species. Based in Bend, Lillebo works for Oregon Wild and collaborates with public agencies and conservation groups on restoration projects.

For a number of years, he has worked with the US Forest Service on aspen restoration, and while progress is being made, he can tell you how much more needs to be done.

“It’s serious. We need to do something big, and we need to do it now,” he said. “We are losing aspen stands every year that aren’t coming back.

“The aspen we have been pretty well hammered by grazing—past and present—and we’ve got some water table and conifer problems and road development in the bottomlands. So, there is not a standard restoration plan. We have to look at each site and ask, what is the root cause of the problem?”

To do this, Lillebo works with seven Forest Service collaboration groups, assessing pockets of aspen across Eastern Oregon. “We use a decision tree—something I’m trying to get time to formalize—to decide what action to take. Are the sprouts getting eaten off? Are the trees being shaded out by conifers? Is there enough water? Then we decide what to do.” 

Are they making progress? “We are making some headway, but the loss over the last 100 years has been so dramatic, that if we save one stand, we are making progress.”

Lillebo’s publication, Restoring eastern Oregon’s dry forests (pdf): A practical guide for ecological restoration. It is available for download on the Oregon Wild website.


Volunteers fenced an aspen grove on a grazing allotment. Eric Brown photo. Click to Enlarge Photo

About two dozen volunteers from the Capitol, Bend and Ochoco chapters of the Oregon Hunters Association spent a Saturday in June building a fence around a 5-acre aspen grove on Little Summit Prairie in the Ochoco National Forest to protect it from browsing by cattle, deer and elk.

“The grove is on a grazing allotment and the fence is mainly for keeping the cattle out,” said Rick Stutheit, Vice-President of the OHA Capitol Chapter. “They go into the grove and eat the small trees and new shoots.”  

Cows, elk and deer can prevent healthy groves from regenerating because of the way aspens spread. Root suckers rise from a shared root system and grow into trees. If the new growth is stunted or removed, the stands will eventually be lost.

The US Forest Service supplied the fencing materials and the OHA volunteers provided the labor for the project. Rick Stutheit, OHA, and Paul Smith, USFS, managed the project.


Nicole Strong
Nicole Strong, OSU Extension educator, is planning workshops and tours to support aspen management in the state. Click to Enlarge Photo

Land Manager’s Guide to Aspen Management in Oregon

A free guide to aspen management for landowners is available through Oregon State University Extension Services.

“Aspen, and hardwoods in general, can be overlooked by land managers,” said Nicole Strong, a Senior Instructor in Forestry and Natural Resources for Extension Services. “This publication gives practical advice from aspen experts who work in the state.”

It includes information on ecology, assessing habitat, deciding what actions to take and best management practices and resources.

Limited print manuals are currently available from your local OSU Extension office. Stay tuned for information on upcoming aspen management workshops occurring throughout eastern and central Oregon in spring 2014. Land manager's guide to aspen management in Oregon. Contact Nicole.



The Oregon Conservation Strategy and Aspen

Aspen woodlands are a Strategy Habitat in the Northern Basin and Range and Blue Mountains ecoregions. Aspen are also found in the East Cascades ecoregion. The limiting factors in aspen woodlands are: altered fire regimes and juniper encroachment; lack of reproduction; degraded understories; fragmentation and mapping limitations.

Here are some aspen stories from past issues of the newsletter.



On the Ground newsletter archives


The Oregon Conservation Strategy provides a blueprint and action plan for the long-term conservation of Oregon’s native fish and wildlife and their habitats through a voluntary, statewide approach to conservation. It was developed by ODFW with the help of a diverse coalition of Oregonians including scientists, conservation groups, landowners, extension services, anglers, hunters, and representatives from agriculture, forestry and rangelands.

Meg Kenagy
Oregon Conservation Strategy Communications coordinator
(503) 947-6021

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