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    Author(s): George T. Ferrell
    Date: 1983
    Source: Gen. Tech. Rep. PSW-72. Berkeley, Calif.: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Exp. Stn. 18 p
    Publication Series: General Technical Report (GTR)
    Station: Pacific Southwest Research Station
    PDF: Download Publication  (1.0 MB)


    Selected crown and bole characteristics were predictor variables in growth classification equations developed for California red fir, Shasta red fir, and white fir in northern California. Individual firs were classified on the basis of percent basal area increment (PCTBAI ) as Class 1 (≤ 1 pct), Class 2 (> 1 pct and ≤ 3 pct), or Class 3 (> 3 pct). Data from increment borings indicated that the equations accurately classified about 75 percent of trees at least 4 inches (10 cm) in diameter-at-breast-height (d.b.h. ), except those firs in stands seriously disturbed within the previous decade by logging, fire, or other influences. Because the growth classification equations use the same predictor variables as the risk equations, combined calculator programs can be designed to predict both growth class and risk of tree death. Properly used, the data from these classification systems should contribute to the sound management of California's true firs.

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    Ferrell, George T. 1983. Growth classification systems for red fir and white fir in northern California. Gen. Tech. Rep. PSW-GTR-72. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 18 p.


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    Abies concolor, Abies magnifica, California red fir, Shasta red fir, white fir, basal area increment

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