Initial and continued effects of a release spray in a coastal Oregon Douglas-fir plantation.

Richard E. Miller; Edmund L. Obermeyer

doi:10.2737/PNW-RP-487

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Initial and continued effects of a release spray in a coastal Oregon Douglas-fir plantation.

Informally Refereed

Authors:

Richard E. Miller, Edmund L. Obermeyer

Year:

1996

Type:

Research Paper

Station:

Pacific Northwest Research Station

DOI:

https://doi.org/10.2737/PNW-RP-487

Source:

Res. Pap. PNW-RP-487. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 11 p

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Abstract

Portions of a 4-year-old Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) plantation were sprayed with herbicide. Five years after spraying, we established 18 plots and used several means to determine retrospectively that six plots probably received full spray treatment and six others received no spray. Various portions of the remaining six plots probably were sprayed. Herbicide reduced number and size of red alder (Alnus rubra Bong.), increased number and size of planted Douglas-fir, damaged terminal shoots of Douglas-fir resulting in more abnormal boles and branching, and increased number of volunteer conifers. Fifteen of the eighteen plots were thinned. In the subsequent 6 years, thinned plots that had received full release at age 4 averaged 9 percent more volume growth (all species) than plots not released.

Keywords

Conifer release, plantation growth, herbicide damage, Pseudotsuga menziesii, Alnus rubra, Tsuga heterophylla, Picea sitchensis, precommercial thinning, Oregon Coast Ranges

Citation

Miller, Richard E.; Obermeyer, Edmund L. 1996. Initial and continued effects of a release spray in a coastal Oregon Douglas-fir plantation. Res. Pap. PNW-RP-487. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 11 p