Early survival and growth of planted Douglas-fir with red alder in four mixed regimes [report]

Marshall D. Murray, Richard E. Miller
1986 unpublished
Murray, Marshall D.; Miller, Richard E. Early survival and growth of planted Douglas-fir with red alder in four mixed regimes. Res. Pap. PNW-366. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station; 1986. 13 p. To quantify between-species interactions, we measured and compared survival and growth of planted Douglas-fir and associated planted and volunteer red alder at a location on the west side of the Cascade Range in Washington. The planted alder
more » ... re wildlings dug either from a nearby area or from a distant, coastal site and interplanted into a 3-year-old Douglas-fir plantation. The volunteer alder became established in year 1; these were cut at year 3 or 7 depending on the regime tested. The data indicated no apparent advantage in using nonlocal red alder to reduce aboveground competition with Douglas-fir at this location. Survival of both sources of interplanted alder was high, and the average diameter and height were similar through plantation age 10. Retaining about 1 100 volunteer alder per hectare (445/acre) through plantation age 7 had no measurable positive or negative effect on the associated Douglas-fir. When alder densities are less than about 1 250/ha (500/acre), silviculturists can safely delay alder control on most average or below-average site quality land until 6 to 8 years after planting Douglas-fir. This reduces alder sprouting and permits combining complete or partial control of alder with precommercial thinning of associated Douglas-fir. To ensure timely control, periodic observations of Douglas-fir red alder mixtures are necessary, however.
doi:10.2737/pnw-rp-366 fatcat:5avo7zn4znafnkxdcamrjobqi4