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    Author(s): P.H. Cochran; W. Lopushinsky; P.D. McColley
    Date: 1986
    Source: Res. Note PNW-RN-445. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 12 p
    Publication Series: Research Note (RN)
    Station: Pacific Northwest Research Station
    PDF: View PDF  (394 KB)


    Nitrogen concentration in current year needles of Pacific silver fir (Abies amabilis Dougl. ex Forbes) showed a significant (P<0.05) 1.9-fold increase after fertilization with sulfated urea (40-0-0-6), compared with a nonsignificant 1.3-fold increase in Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) and a significant (P<0.05) 2.5-fold increase in bracken fern (Pteridium aquilinum (L.) Kuhn.). Nitrogen concentration in needles of unfertilized Pacific silver fir (0.99 percent) indicated a deficiency of nitrogen, whereas the concentration in Douglas-fir (1.35 percent) was above threshold levels. Total sulfur concentration in needles ranged from 0.05 to 0.09 per-cent for both species, with no significant effect of fertilization. Fertilization resulted in increased needle surface area for Pacific silver fir. Diameter growth of the trees, stand basal area growth, and volume growth were all increased by fertilization. More trees on the fertilized plots had broken tops, and rates of height growth for undamaged trees were greater for the fertilized plots; but the difference attributed to fertilization was not quite significant at the 5-percent level of probability.

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    Cochran, P.H.; Lopushinsky, W.; McColley, P.D. 1986. Effect of operational fertilization on foliar nutritent content and growth of young Douglas-fir and Pacific silver fir. Res. Note PNW-RN-445. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 12 p


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    Foliar analysis, nitrogen fertilizer response, increment, Pacific silver fir, Douglas-fir

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