Response of a 110-year-old Douglas-fir stand to urea and ammonium nitrate fertilization

Constance A. Harrington; Richard E. Miller

Treesearch

Response of a 110-year-old Douglas-fir stand to urea and ammonium nitrate fertilization

Informally Refereed

Authors:

Constance A. Harrington, Richard E. Miller

Year:

1979

Type:

Research Note

Station:

Pacific Northwest Research Station

Source:

Res. Note PNW-RN-336. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 8 p

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Abstract

Basal area response to 150 pounds of nitrogen per acre applied as urea or ammonium nitrate was monitored on 1/5-acre plots for 4 years in a recently thinned, 110-year-old, site II, Douglas-fir stand. Nitrogen fertilization significantly increased growth. Basal area increment was increased 59 percent over the controls by ammonium nitrate and 37 percent by urea. The difference in response between urea and ammonium nitrate was statistically significant. Crown class had a highly significant influence on basal area growth of individual trees; however, the increases in growth due to fertilization were not significantly different by crown class.

Keywords

Nitrogen fertilizer response, increment (basal area), urea, ammonium nitrate, Douglas-fir, Pseudotsuga menziesii

Citation

Harrington, Constance A.; Miller, Richard E. 1979. Response of a 110-year-old Douglas-fir stand to urea and ammonium nitrate fertilization. Res. Note PNW-RN-336. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 8 p.