Skip to main content
U.S. flag

An official website of the United States government

Andrew Gray

Andrew Gray
Research Ecologist, Team Leader
Resource Monitoring and Assessment
3200 SW Jefferson Way
Corvallis, OR 97331-8550
United States
Current Research
My research focuses on understanding the drivers affecting forest growth and disturbance at multiple spatial and temporal scales, and how these affect carbon sequestration, forest structure, and species' distributions. I pursue these questions through the application of regionally-comprehensive forest monitoring datasets combined with satellite trend detection and modeled climate and physiographic variables. I am reconstructing changes in carbon through time as it moves between pools in forest ecosystems. Other ongoing studies include improving our ability to predict tree canopy cover using tree measurements,  estimating the extent of regional wildlife habitat, determining rates and patterns of land use change, and digitizing detailed county-level forest type maps from the 1930s.
Past Research
My past research has included investigations of long-term vegetation response to canopy gaps in mature conifer forests, applications of adaptive management studies in coastal Oregon, effects of fire and prescribed burning on regeneration and soil moisture in Sierran mixed conifer, and regional distribution and abundance of invasive species.
Research Interest
  • Effects of disturbance and management on forest composition and structure
  • Accurate accounting of changes in forest sector carbon stores
  • Conditions and trends of Washington's forest resources
Why This Research Is Important
My work is important because forest inventories provide an unbiased examination of forest conditions and trends across large regions and multiple ownerships. The proper collection, compilation, and analysis of inventory data provides a solid factual bedrock to inform policymakers and managers and supports additional modeling studies that evaluate the potential impacts of future changes in management and environment.
  • Oregon State University, Ph.D., Forest Ecology, 1995
  • University of Washington, M.S., Forest Ecology, 1990
  • University of Washington, B.S., Environmental Studies, 1985
Professional Organizations
  • Member,  Society of American Foresters (SAF),  2018 - Current
  • Member,  Ecological Society of America,  1990 - Current
  • Deputy Coordinator,  International Union of Forestry Research Organizations,  2014 - Current
  • Member,  International Association for Landscape Ecology,  1992 - Current
  • Member,  Northwest Scientific Association,  1990 - Current
Featured Publications
Other Publications
Citations of Non-Forest Service Publications
  • Gray, A. N. and T. A. Spies. 1996. Gap size, within-gap position, and canopy structure effects on conifer seedling establishment. Journal of Ecology 84:635-645.

  • Gray, A. N. and J. F. Franklin. 1997. Effects of multiple fires on the structure of southwestern Washington forests. Northwest Science 71:174-185.

  • Gray, A. N. 2000. Adaptive ecosystem management in the Pacific Northwest: a case study from coastal Oregon. Conservation Ecology [online] 4:6.

  • Monleon, V. J., A. I. Gitelman, and A. N. Gray. 2002. Multi-scale relationships between coarse woody debris and presence/absence of western hemlock in the Oregon Coast Range. Pages 311-318 in C. Gatsonis, A. Carriquiry, A. Gelman, D. Higdon, R. Kaas, D. Pauler, and I. Verdinelli, editors. Case Studies in Bayesian Statistics, Volume VI. Springer-Verlag, New York.
  • Vance, N., A. Gray, and R. Haberman. 2002. Congruent management of multiple resources: proceedings from the Wood Compatibility Initiative workshop. USDA Forest Service Pacific Northwest Research Station, Portland, OR. General Technical Report PNW-GTR-563

  • Lindh, B. C., A. N. Gray, and T. A. Spies. 2003. Responses of herbs and shrubs to reduced root competition under canopies and in gaps: a trenching experiment in old-growth Douglas-fir forests. Canadian Journal of Forest Research 33:2052-2057.

  • Gray, A. N. and C. Miller. 2006. Vegetation change in the Blue River Landscape Study: 1998-2005. Pacific Northwest Research Station, U.S. Department of Agriculture, Forest Service, Corvallis, OR. unpublished report on file at,

  • Rudis, V. A., A. N. Gray, W. McWilliams, R. O'Brien, C. Olson, S. Oswalt, and B. K. Schulz. 2006. Regional monitoring of non-native plant invasions with the Forest Inventory and Analysis program. Pages 49-64 in R. E. McRoberts, G. A. Reams, P. C. Van Duesen, and W. H. McWilliams, editors. Proceedings of the 6th Annual Forest Inventory and Analysis Symposium. USDA Forest Service, Denver, CO.


  • Schroeder, T. A., A. Gray, M. E. Harmon, D. O. Wallin, and W. B. Cohen. 2008. Estimating live forest carbon dynamics with a Landsat-based curve-fitting approach. Journal of Applied Remote Sensing 2:023519.

  • Azuma, D. L., J. Menlove, and A. N. Gray. 2009. Reserved and Roadless Forests. Pages 16-18 in W. B. Smith, P. D. Miles, C. H. Perry, and S. A. Pugh, editors. Forest Resources of the United States, 2007. US Deparment of Agriculture Forest Service, Washington D.C.

  • Christensen, G.A.; Gray, A.N.; Kuegler, O.; Yost, A. 2019. Oregon Forest Ecosystem Carbon Inventory: 2001-2016. Salem, OR: Oregon Department of Forestry. 343 p.
  • Christensen, G.A.; Gray, A.N.; Kuegler, O.; Tase, N.A.; Rosenberg, M.; Loeffler, D.; Anderson, N.; Stockmann, K.; Morgan, T.A. 2019. AB 1504 California Forest Ecosystem and Harvested Wood Product Carbon Inventory: 2017 Reporting Period. Sacramento, CA: California Department of Forestry and Fire Protection. 552 p.
  • Watts, A.; Gray, A.N.; Whittier, T.R. 2017. There’s Carbon in Them Thar Hills: But How Much? Could Pacific Northwest Forests Store More? 195. Portland, Oregon: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 6 p.
  • Christensen, G.A.; Gray, A.N.; Kuegler, O.; Tase, N.A.; Rosenberg, M. 2017. AB 1504 California Forest Ecosystem and Harvested Wood Product Carbon Inventory: 2006 – 2015. Sacramento, CA: California Department of Forestry and Fire Protection. 390 p. (“under AB 1504 Report” at:
Research Highlights

Working with Cal Fire to monitor carbon sequestration in California

Year: 2018
Forest Service scientists partnered with California’s Department of Forestry and Fire Protection (Cal Fire) to develop a carbon inventory essential for assessing the state’s progress toward meeting its carbon sequestration target via California’s forest sector. They found that California forests are...

Scientists model four-state region to estimate carbon pools and flux over large domains

Year: 2017
Variation in climate, disturbance regime, and forest management strongly influence terrestrial carbon sources and sinks.

Scientists analyze trends in tree growth to assess change in Interior Alaska’s spruce forest

Year: 2017
Tree-ring analysis adjusted for age-related changes in growth indicate that recent growth of black and white spruce in Interior Alaska is near the historic mean, but lower than a peak in growth in the mid-1900s.

Wetter, warmer conditions will likely favor biomass accumulation in Douglas-fir

Year: 2017
Conversely, continued accumulation of forest biomass in drier regions may be more limited.

Ground-based Estimates of Fire Severity Reveal Information Undetected by Satellite Imagery Analyses

Year: 2016
A new study provides a broad-scale characterization of the extent of relatively low-severity fires and small fires, including prescribed fires, not previously available. Fire-severity classifications based on tree mortality, combined with remotely sensed and management information on timing and trea...

Equations Used to Estimate Regional Tree Biomass and Carbon can be Improved

Year: 2015
Developing nationally consistent methods for defining, measuring, and calculating biomass components will improve the reliability and application of biomass and carbon estimation. Sampling trees across the full range of forest conditions is also important. Forest Service researchers recommend collec...

Increasing Development Near Public Forest Lands in Washington and Oregon Has Implications for Public Land Management and Fire Suppression

Year: 2014
Areas bordering public forest land in Washington and Oregon are showing substantial increases in development, with the number of structures on private lands near almost all types of public forest more than doubling between the 1970s and 2000s.

Net Forest Carbon in Oregon Increased Slightly During the Last Decade

Year: 2014
Gains in forest carbon through tree growth and afforestation in the Pacific Northwest were offset by fire, insects, cutting, and deforestation.

Forest and Agricultural Land Area Declines in Washington State While Residential and Urban Land Use Increases Over Past 30 years

Year: 2013
Station scientists and partners assessed changes in land use and housing density across Washington state from 1976 to 2006. They found that the population in Washington increased by 2.5 million people, leading to the conversion of 1.16 million acres of forest and agricultural land to residential and...