Seeking the Secrets of Old Growth

Andrews Photo_Students at Work
Undergraduate researchers at the Andrews Forest place a tracer dye into a stream while others wait downstream to record the tracer’s travel time. The team can then calculate flow rate in this reach of the stream. (Photo: Lina DiGregorio)

OREGON’S OLD-GROWTH FORESTS host thousands upon thousands of animal, plant and insect species: owls and beetles, mosses and ferns, salmon and salamanders, lichens and vines, spiders and songbirds, and trees that are older than the Aztecs and taller than Niagara Falls. For more than 60 years, the rich biological and physical connectivity of this forest and stream ecosystem has drawn hundreds of scientists with their sampling kits and measuring instruments to the Andrews Forest, a 16,000-acre watershed, including large stands of ancient Douglas fir, in the Cascades along the McKenzie Pass.

Now, these intensive studies of soil, water, air, growth, decomposition and human impacts, especially climate change, have been extended for another six years, thanks to a $6.7 million grant from the National Science Foundation.

“This sort of long-term focus is exceptionally rare,” notes Michael Paul Nelson, the nationally known environmental philosopher who leads the H.J. Andrews Forest Long-Term Ecological Research (LTER) program at Oregon State University. “Scientists don’t typically spend their careers unpacking the mysteries of a single place or a single relationship.”

This interdisciplinary research endeavor — the seventh iteration of the program — will investigate not only how air, water, and nutrients flow through the mountainous terrain, but also how changes in climate and land use affect forest and stream ecosystems. Interdisciplinary teams from OSU and the U.S. Forest Service’s Pacific Northwest Research Station will analyze records from weather stations and stream gauges that have been installed throughout the watershed. These data are critical to understanding temperature and precipitation variations across the landscape over long periods of time.

The scientists also will evaluate how the physical features of the landscape affect the organisms that live there. For example, they will study how pockets of cold air, which accumulate in low areas, influence tree health. Another question is how climate-induced drought stresses old-growth forests in relation to younger stands of trees. Also, by tracking the alignment of plant, animal and insect cycles, mismatches linked to alterations in climate and land use may be revealed.

“Many aspects of LTER7 will have broader social impacts,” Nelson says. “We will continue the strong tradition of fostering public engagement and producing policy-relevant knowledge in the area of ecosystem science. We’re engaging the public, resource managers and policymakers in studies of how changing social networks influence forest productivity. We’ll also analyze forest governance from the perspective of conservation ethics.”

Indeed, the scientific endeavor itself and how scientific understandings shape decision-making, will be under the microscope.

“The project will continue to delve into the long history of the Andrews Forest, which spans several policy shifts in forest management strategies, to understand how prevailing attitudes translate into action,” says Thomas Maness, dean of OSU’s College of Forestry. “The researchers will also evaluate how science influences forest policy by studying the relationship between specific management decisions and the use of scientific findings and logical reasoning.”

The Andrews Forest is open to the public. Through its Ecological Reflections project, the program partners with the Spring Creek Project for Ideas, Nature and the Written Word at Oregon State, to engage writers and artists. K-12 teachers and students use the forest as a learning lab. Citizen scientists, too, are welcome throughout the year.

Please contact Andrews LTER coordinator Lina DiGregorio at 541-737-8480 for more information and visit the website at