Timothy B. Harrington, Ph.D.
Forestry Sciences Laboratory
Olympia , WA 98512
My current work is exploring several research emphases: overstory and understory relationships in managed Douglas-fir forests; longer-term effects of vegetation control and logging debris manipulation on Douglas-fir plantation productivity; regeneration biology of Scotch broom; herbicide treatments for controlling invasive, nonnative plant species; and effects of logging debris and associated light quality on understory plants.
Biology and management of invasive, nonnative plant species; conifer seedling growth and physiology responses to microenvironment; restoration of understory plant communities in managed conifer forests; comparative growth and yield of Douglas-fir stands; and long-term effects of forest vegetation management and thinning on stand structure.
My past work has explored the physiology of Douglas-fir under different levels of competition from woody and herbaceous vegetation; bud production and shoot growth of Douglas-fir; shoot growth of southern pines; and restoration of longleaf pine communities in the southern United States.
Why This Research is Important
Invasive, nonnative plants threaten the biodiversity and many ecological functions of Pacific Northwest forests. Methods are needed to prevent or mitigate plant invasions to protect native plant and animal communities. Research on conifer regeneration is critical to appropriate management of public and private forest land to ensure steady production of the ecological services that society demands.
- Oregon State University, Ph.D. Silviculture, 1989
- Oregon State University, M.S. Forest Ecology, 1982
- Louisiana State University, B.S. Botany, 1980
Featured Publications & Products
- Harrington, Timothy B., Ph.D..; Tappeiner , John C., II. 2009. Long-term effects of tanoak competition on Douglas-fir stand development.
- Harrington, Timothy B., Ph.D..; Harrington, Constance A.; DeBell, Dean S. 2009. Effects of planting spacing and site quality on 25-year growth and mortality relationships of Douglas-fir (Pseudotsuga menziesii var menziesii)..
- Harrington, Timothy B., Ph.D. 2009. Seed germination and seedling emergence of Scotch broom (Cytisus scoparius).
- Harrington, Timothy B., Ph.D. 2011. Overstory and understory relationships in longleaf pine plantations 14 years after thinning and woody control.
- Devine, Warren D.; Harrington, Timothy B., Ph.D..; Terry, Thomas A.; Harrison, Robert B.; Slesak, Robert A.; Peter, David H.; Harrington, Constance A.; Shilling, Carol J.; Schoenholtz, Stephen H. 2011. Five-year vegetation control effects on aboveground biomass and nitrogen content and allocation in Douglas-fir plantations on three contrasting sites.
Publications & Products
- Harrington, Tim; Miller, Karl; Parks, Noreen. 2013. Restoring a disappearing ecosystem: the longleaf pine savanna.
- Harrington, Timothy B., Ph.D..; Slesak, Robert A.; Schoenholtz, Stephen H. 2013. Variation in logging debris cover influences competitor abundance, resource availability, and early growth of planted Douglas-fir.
- Devine, Warren D.; Footen, Paul W.; Strahm, Brian D.; Harrison, Robert B.; Terry, Thomas A.; Harrington, Timothy B., Ph.D. 2012. Nitrogen leaching following whole-tree and bole-only harvests on two contrasting Pacific Northwest sites.
- Peter, David H.; Harrington, Timothy B., Ph.D. 2012. Relations of native and exotic species 5 years after clearcutting with and without herbicide and logging debris treatments.
- Slesak, Robert A.; Schoenholtz, Stephen H.; Harrington, Timothy B., Ph.D. 2011. Soil carbon and nutrient pools in Douglas-fir plantations 5 years after manipulating biomass and competing vegetation in the Pacific Nortwest.
- Harrington, Timothy B., Ph.D. 2010. Manipulating stand structure of Douglas-fir plantations for wildlife habitat and wood production.
- Slesak, Robert A.; Schoenholtz, Stephen H.; Harrington, Timothy B., Ph.D. 2010. Soil respiration and carbon responses to logging debris and competing vegetation.
- Strahm, Brian D.; Harrison, Robert B.; Terry, Thomas A.; Harrington, Timothy B., Ph.D..; Adams, A.B.; Footen, Paul W. 2009. Changes in dissolved organic matter with depth suggest the potential for postharvest organic matter retention to increase subsurface soil carbon pools..
- Slesak, Robert A.; Schoenholtz, Stephen H.; Harrington, Timothy B., Ph.D..; Strahm, Brian D. 2009. Dissolved carbon and nitrogen leaching following variable logging-debris retention and competing-vegetation control in Douglas-fir plantations of western Oregon and Washington.
- Devine, Warren D.; Harrington, Timothy B., Ph.D. 2008. Belowground competition influences growth of natural regeneration in thinned Douglas-fir stands.
|More Scotch broom found where logging debris was removed|
Scotch broom, a nonnative, invasive species, is a severe competitor of young Douglas-fir.
|Presence of tanoak reduces Douglas-fir mortality from black-stain root disease|
Black-stain root disease is a native pathogen of conifers in the Pacific Northwest. The disease reduces growth and ultimately kills the infected ...
|Some Logging Debris Cover Boosts Growth of Douglas-fir Seedlings on Low-nutrient Site|
Stem growth of Douglas-fir seedlings with 40 percent debris cover and competing vegetation was greater than that of seedlings with zero or 80 pe ...