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Abstract
Measurement error in the Forest Inventory and Analysis work of the Pacific Northwest Station was estimated with a recently implemented blind plot measurement protocol. A small subset of plots was revisited by a crew having limited knowledge of the first crew's measurements. This preliminary analysis of the first 18 months' blind plot data indicates that ranges of variation can be quite large. When blind plot results were summarized to facilitate comparisons with established tolerance standards, we found that diameters at breast height for trees > 20 inches d.b.h., heights for trees < 60 feet tall, and counts of down wood pieces did not meet standards in over 10 percent of cases. However, azimuths for condition class boundaries, diameters for trees < 20 inches d.b.h., heights for trees > 60 feet tall, and understory vegetation cover estimates by life form were within tolerance limits at least 90 percent of the time.
Parent Publication
Citation
Melson, Susanna; Azuma, David; Fried, Jeremy S. 2002. A first look at measurement error on FIA plots using blind plots in the Pacific Northwest. In: McRoberts, Ronald E.; Reams, Gregory A.; Van Deusen, Paul C.; Moser, John W., eds. Proceedings of the Third Annual Forest Inventory and Analysis Symposium; Gen. Tech. Rep. NC-230. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Research Station: 11-20
