USDA Forest Service

Pacific Northwest Research Station

Pacific Northwest Research Station
1220 SW 3rd Ave.
Portland, OR 97204

(503) 808-2100

US Forest Service

H.J. Andrews Experimental Forest

Rock formation in H J Andrews Experimental Forest.Introduction

Since its establishment in 1948, the H. J. Andrews Experimental Forest has been a site of intensive and extensive research on watershed processes; forest ecology, especially structure, composition, and function of old-growth Douglas-fir forests and plantation; forest-stream interactions; biological diversity; processes, rates, and controls on nutrient and carbon cycling; and history and effects of natural and management disturbance processes. The research at H. J. Andrews featured studies of management effects in the 1950s and 1960s, and then supplemented applied studies with ecosystem research under the International Biological Program in the 1970s, and the National Science Foundation’s Long-Term Ecological Research (LTER) program since 1980. The close working relationship between research and management communities (under the auspices of the Cascade Center for Ecosystem Management and the Central Cascades Adaptive Management Area) have resulted in testing and development of new management approaches to forest stands and landscapes as well as streams and riparian zones. The H. J. Andrews is a Biosphere Reserve in UNESCO’s Man and the Biosphere program. Research activities extend over a much broader area, including use of Research Natural Areas (RNA), wilderness areas, and other lands.


The climate at the H. J. Andrews is cool and wet in winter and warm and dry in summer. Annual precipitation is about 2,500 mm at low elevations, falling mainly as rain at low elevations and as snow at upper elevations.


Soils are primarily Inceptisols, with local areas of Alfisols and Spodosols derived from mainly andesite volcanic bedrock. Surface horizons are commonly loamy but may be stony at depth and shallow on steep slopes.

Tall trees in H J Andrews Experimental Forest


Douglas-fir-western hemlock forest dominates at lower elevations and Pacific silver fir forest at upper elevations. Forest age classes include 150- and 500-year-old stands developed after wildfire, and plantations dominated by Douglas-fir established after clearcutting since 1950. Other forest types and age classes exist in neighboring areas, including within RNAs.

Long-Term Data Bases

Numerous long-term data bases are available on the H. J. Andrews Web site. These include the amount and chemistry of precipitation and streamflow from three sets of experimental watersheds; vegetation change in plots of various types, including 1-ha mapped reference stands representing the vegetation types of the areas; and data from long-term experiments, such as the 200-year log decomposition experiment.

Research, Past and Present

Studies in the first two decades of the H. J. Andrews’s history emphasized basic characterization of the forests and soils and analysis of effects of forestry practices, including effects of clearcutting with and without burning and various partial cutting practices on nutrients, streamflow, and sediment yield from small watersheds. In the 1970s, ecosystem studies expanded the characterization of patterns of and controls on vegetation across the landscape, stream ecology, disturbance processes, and hydrology and nutrient cycling within small watersheds. Basic work on old-growth forests and northern spotted owl ecology took place during this decade. Since 1980, research under the LTER program has focused on the question “how do land use (principally forestry and roads), natural disturbances (principally fire and floods), and climate variability affect key ecosystem properties, especially hydrology, biological diversity, and carbon dynamics”?

Major Research Accomplishments and Effects On Management

Science at the H. J. Andrews has contributed greatly to our understanding of conifer forests of the region and globe. Work on old-growth forests, forest-stream interactions, roles of coarse woody debris in terrestrial and stream systems, and interactions of geophysical and ecological systems has yielded important advances. Perhaps the most distinctive feature has been the close link between research and land management and policy in areas such as the development of new approaches to management of forest stands, riparian zones, road systems, landscapes, dead wood, and species conservation.

Facilities at H J Andrews Experimental Forest


The H. J. Andrews is managed cooperatively by the Pacific Northwest Research Station, Oregon State University, and Willamette National Forest. Research and education activities involve collaborators from many other institutions.

Research Opportunities

The H. J. Andrews is managed as an open national and international research and education resource. There are many research and education opportunities. Contact the director or participating scientists for further information.


The H. J. Andrews is located 50 miles east of Eugene, Oregon, in the Cascade Mountains and is a 2-hour drive from Corvallis, where many scientists working at the forest have main offices. The headquarter facilities include office, laboratory, and living facilities.
Lat. 44° 11' 55" N, long. 122° 14' 41" W

Contact Information

Dr. Sherri Johnson
Corvallis Forestry Sciences Laboratory
3200 SW Jefferson Way
Corvallis, OR 97331
Tel: (541) 758-7771

1Information has been updated since original publication.

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US Forest Service - Pacific Northwest Research Station
Last Modified: Wednesday,27July2016 at12:34:40CDT

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