The Oregon State University Research Forests are a valuable asset for long-term research projects

Sometimes, the best strategy for scientific work is to play the long game – because a short-term study can’t always offer the same insights as a multi-year endeavor.

That’s one of the many reasons that the OSU Research Forests are such an asset. They provide a venue for researchers to run long-term studies that can offer meaningful insights into an array of research questions that examine forestry practices, forests, and ecosystems.

Here are a few examples of the long-term research projects that started years ago in the Research Forests – and are still happening today – but couldn’t have happened at all, without a place to watch science unfold over decades.  

Purple Martin Habitat Patrol

The purple martin is picky about where it lives. It likes to nest in a good hole – like a dead tree cavity. And, it also needs an open canopy for foraging insects.

While this large swallow maintains a healthy population on the East Coast, it’s a “critical” sensitive species in Oregon – and could be listed as an endangered or threatened species if its population declines more. It would’ve been difficult – if not impossible – to find a purple martin in the Willamette Valley a decade and a half ago.

But, in the late 2000s, Joan Hagar, research wildlife biologist with the United States Geological Survey (USGS) and affiliate faculty in the department of forest ecosystems and society, turned to the Research Forests to encourage purple martin habitat in the Willamette Valley. And, she set up a study to monitor how the bird’s population changed over time.

She set up artificial nests in regenerative harvest sites in the McDonald and Dunn research forests to coax purple martins into the forest. Nearby snags would eventually create lasting habitat for the birds, but they needed a few years to decompose into an ideal purple martin home. OSU initially created these snags after tree harvests, in order to provide dead wood for woodpeckers to turn into cavities, which would become homes for purple martins. The recently harvested area provided a prime habitat for insects, which the purple martins feed on.

Since setting up the nests, Hagar has been monitoring the state of the purple martin population and its use of managed forests for habitat. To do this, her team bands birds every year and monitors their nesting habits when they return from their winter migration. She says the Research Forests – and plenty of time – are vital components for this study.

“Birds can see a lot of annual variation, especially migratory birds, so you can’t always see patterns until you collect a lot of data,” she said. “By observing them for multiple years, you can see trends more clearly.”

The purple martins have thrived in the Research Forests, where they can access the maintained snags for habitat – and beyond that, they’ve helped provide insights into how other species fare when dead and decomposing trees are purposely left for habitat and biodiversity. There’s a large collection of species in the Pacific Northwest that relies on cavities in dead trees for habitat.

“Purple martins are a great indicator species for how a whole suite of species is faring in this habitat,” Hagar explained.

COF Integrated Research Project

Back in 1989, a team of COF researchers and resource managers decided to launch a long-term study to investigate alternatives to clearcutting. They wanted to learn whether they could retain features of mature and old-growth Douglas-fir forests through a variety of types of timber harvests.

To initiate the study, they applied four different silviculture treatments across 33 different stands in the Research Forests and monitored how these treatments affected economic, social, and ecological factors over time. They published a summary of their initial findings in 2005.

Klaus Puettmann, professor in the department of forest ecosystems and society, assumed responsibility for the study a little over a decade ago, mainly to continue to facilitate teaching and research opportunities on this land – and advocated for its value as a long-term resource.

He explains that while active research has slowed in these stands over time, they provide a huge opportunity for education and research as the installations contain forest structures that are unique in the region. He personally brings a number of his classes to these stands on the Research Forests because they’re such a great resource for teaching.

“They offer examples of a wide range of forest conditions and hold great value for researchers and teachers who want to consider a multitude of forestry approaches,” Puettmann says. “We just don’t have many examples of these treatments in the region, especially so close by and accessible for our students.”

One of the greatest benefits of this project is for researchers and educators who want to investigate how certain treatments affect a forest over longer time periods. This could be especially helpful for questions related to how factors like climate change have affected forests, Puettmann explains.

 “They can consult the database to see if the inventory matches their research needs – and potentially launch their project with the help of decades of data,” he said.

Mature Forest Management

For the last 25 years, OSU researchers have examined how mature forests change through different levels of thinning and understory treatment. Mature forests are stands of older and larger trees, often Douglas-fir, that resemble old growth. It’s a project that was inspired by the timber wars of the 1990s, the struggles over logging and old-growth protection, to help researchers understand how mature forests and certain tree species develop through different approaches to forest management.

“This project is so valuable for answering post-timber wars questions about forest development and how we can use different kinds of silvicultural treatments for functions other than managing plantations of trees,” said John Bailey, professor in the departments of forest engineering, resources and management and forest ecosystems and society.

The project has let researchers explore questions about the best conditions for Douglas-fir growth, how thinning in different intensities and ways affects understory vegetation, and how the use of herbicides affects the growth of saplings. They’ve utilized both the McDonald and Dunn and the Blodgett Research Forests for this work.

The researchers have published a number of findings over the course of the project, and the treatments continue to be beneficial for researchers looking to explore new issues, Bailey says. Researchers can draw from 25 years of data to consider issues like carbon storage in a forest or how plant biodiversity in the understory is impacted by herbicides.

“As new questions come up, we can keep looking at this data through different lenses,” he said.

One of Bailey’s personal research interests is how thinning and understory treatment affect wildfire spread. He can consult the decades of data to investigate how different types of thinning and understory treatment affects fuel hazards for wildfires.

“Long-term studies are great for providing a time arc of data to look at as new issues and new angles emerge,” he said.