. Regeneration in mixed conifer and Douglas-fir shelterwood cuttings in the Cascade Range of Washington. Methods. Figure 2.—Shelterwood unit in the Douglas-fir type. Mixed conifer plots exhibited greater diversity of species, and no single species dominated the overstory. Grand fir and Douglas-fir each accounted for about 23 percent of the overstory; western larch and mountain hemlock each comprised 16 percent. Other species were Engel- mann spruce—9 percent, ponderosa pine—6 percent, and western hemlock— 3 percent. Pacific silver fir, western redcedar, lodgepole pine, and western white pine w
. Regeneration in mixed conifer and Douglas-fir shelterwood cuttings in the Cascade Range of Washington. Methods. Figure 2.—Shelterwood unit in the Douglas-fir type. Mixed conifer plots exhibited greater diversity of species, and no single species dominated the overstory. Grand fir and Douglas-fir each accounted for about 23 percent of the overstory; western larch and mountain hemlock each comprised 16 percent. Other species were Engel- mann spruce—9 percent, ponderosa pine—6 percent, and western hemlock— 3 percent. Pacific silver fir, western redcedar, lodgepole pine, and western white pine were also present but only in small numbers, each amounting to less than 1 percent of the overstory. Slash on all plots in the Douglas-fir type was piled by machine and burned after the seed cut. In the mixed conifer type, slash was piled and burned on 23 of 26 plots; on 2 plots, unmerchantable material was yarded; on 1 plot, slash was not treated. Survey Design and Plot Selection Douglas-fir and mixed conifer types were considered separate populations. A record of shelterwood units harvested in 1976 or earlier in these timber types in east-side Ranger Districts of the Gifford Pinchot and Wenatchee National Forests was obtained from the USDA Forest Service Regional Office (Pacific North- west Region) in Portland, Oregon. Only units at least 5 years old were considered suitable for sampling so that reproduction would have had time to become estab- lished. Plot size was 10 acres; thus, all shelterwood units of this size or larger and at least 5 years old were potential plots. I estimated that a total of about 40 plots could be sampled during the available time. Therefore, 26 plots were selected at random from the total number (196) in the mixed conifer type and 14 from the total (65) in the Douglas-fir type, resulting in a sampling intensity of about 13 and 22 percent, respectively. Candidate sample plots were rejected if the shelterwood unit was direct seeded to trees or
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