Effects of changing forest land definitions on forest inventory on the West Coast, USA
- 143 Downloads
A key function of forest inventory is to detect changes in the area of forest land over time, yet different definitions of forest land are used in different regions of the world. Changes in the definition of forest intended to improve international consistency can affect the ability to quantify true changes over time. The objective of this study was to evaluate the effects of a definitional change from relative stocking to canopy cover on the area classified as forest land and its relationship to species and forest density in California, Oregon, and Washington. Both western Juniper and ponderosa pine will yield higher estimates of forest land area using a canopy cover definition in comparison to a stocking-based definition, with the difference being most pronounced where land is marginally forested. The change in definition may result in an additional 146,000 ha of forest land identified on the West Coast. Measuring marginal forest lands with both metrics for the first cycle after implementation should make it possible to distinguish real change from definitional change.
KeywordsForest definition Forest inventory Relative stocking Canopy cover
- Andrews, H. J. (1932). Forest survey in the Douglas-fir region. Journal of Forestry, 30, 264–275.Google Scholar
- Andrews, H. J., & Cowlin, R. W. (1940). Forest resources of the Douglas-fir region. Misc. Pub. 389. Portland: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 169 p.Google Scholar
- Arner, S.L., Woudenberg, S., Waters, S., Vissage, J., MacLean, C., Thompson, & M. Hansen, M. (2001).National algorithm for determining stocking class, stand size class, and forest type for forest inventory and analysis plots. USDA Forest Service Northeastern Research Station Internal Rep., Newtown Square, PA, 10 p. http://www.fia.fs.fed.us/library/field-guides-methods-proc/docs/National%20algorithms.doc. Accessed 18 March 2013.
- Bechtold, W. A. (2004). Largest crown-width prediction models for 53 species in the western United States. Western Journal of Applied Forestry, 19, 245–251.Google Scholar
- Bechtold, W. A., & Patterson, P. L. (2004). The enhanced Forest Inventory and Analysis Program–national sampling design and estimation procedures (General Technical Report SRS-80). Asheville: USDA Forest Service, Southern Research Station.Google Scholar
- Crookston, N. L., & Stage, A. R. (1999). Percent canopy cover and stand structure statistics from the forest vegetation simulator. General Technichal Report RMRS-GTR-24 (p. 11). Ogden: USDA Forest Service, Rocky Mountain Research Station.Google Scholar
- Curtis, R. O. (1971). A tree area power function and related stand density measures for Douglas-fir. Forest Science, 7, 35–42.Google Scholar
- Gillespie, A. J. R. (1999). Rationale for a national annual forest inventory program. Journal of Forestry, 97, 16–20.Google Scholar
- Korhonen, I., Korhonen, K. T., Rautiainen, M., & Stenberg, P. (2006). Estimation of forest canopy cover: a comparison of field measurement techniques. Silva Fennica, 40(4), 577–588.Google Scholar
- Lettman, G. J., Azuma, D. L., Herstrom, A. A., McKay, N., & Robinson, T. J. (2009). Forest, farms, and people: land use change on non-federal land in Oregon, 1974–2005. Salem: Oregon Department of Forestry. 74 p.Google Scholar
- MacLean, C.D., & Bolsinger, C.L. (1973). Estimating productivity on sites with a low stocking capacity. U.S. Dept, Agric, Forest Service, Res. Pap. PNW-152, Portland, Oregon.Google Scholar
- McArdle, R. E., Meyer, W. H., & Bruce, D. (1961). The yield of Douglas-fir in the Pacific Northwest. Technical Bulletin #201, revised. Washington: US Department of Agriculture. 65 p.Google Scholar
- O’Brien, R. A. (1989). Comparison of overstory canopy cover estimates on forest survey plots. Research Paper INT-417. Ogden: USDA Forest Service, Intermountain Research Station. 5 p.Google Scholar
- Reineke, L. H. (1933). Perfecting a stand-density index for even-aged forests. Journal of Agricultural Research, 46, 627–638.Google Scholar
- United Nations Food and Agriculture Program (2008). Guidelines for country reporting to FRA 2010. Forest Resources Assessment Programme, Working Paper 143, 80 pp. http://www.fao.org/forestry/14097-0a8d9580c21c82a81175207120544e2b8.pdf. Accessed 18 March 2013.
- United Nations Food and Agriculture Program (2010). Global forest resources assessment, FRA 2010. Country Report, Vietnam 54 pp. http://www.fao.org/docrep/013/al664E/al664e.pdf. Accessed 18 March 2013.
- USDA Forest Service (1996). Forest health monitoring 1996 field methods guide. Internal Rep. Research Triangle Park, NC: U.S. Department of Agriculture, Forest Service, National Forest Health Monitoring Program. 128 p.Google Scholar
- USDA Forest Service. (2010). Forest Inventory and Analysis Program: field instructions for the annual inventory of Washington, Oregon, and California. Portland: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station.Google Scholar