. Regeneration in mixed conifer shelterwood cuttings in the Cascade Range of eastern Oregon. Conifers; Forest regeneration Oregon; Forest regeneration Cascade Range. present (fig. 2). Slash in 69 shelterwood units was piled by machine and burned after the seed cut, and in 6 units it was not Figure shelterwood unit in the mixed conifer community contains an average of 16 trees and SO square feet of basal area per acre. Plots were within the pumice plateau region of south-central Oregon. Soils in this region are immature Regosols (Vitrandepts), developed from aerially deposite
. Regeneration in mixed conifer shelterwood cuttings in the Cascade Range of eastern Oregon. Conifers; Forest regeneration Oregon; Forest regeneration Cascade Range. present (fig. 2). Slash in 69 shelterwood units was piled by machine and burned after the seed cut, and in 6 units it was not Figure shelterwood unit in the mixed conifer community contains an average of 16 trees and SO square feet of basal area per acre. Plots were within the pumice plateau region of south-central Oregon. Soils in this region are immature Regosols (Vitrandepts), developed from aerially deposited dacite and rhyolitic pumice ejected from Mount Mazama (Crater Lake) about 6,500 years ago. These well-drained, coarse-textured soils have thin A horizons, low in fertility, which grade into un- weathered sand and gravel. A finer textured buried soil is found at a depth of 2 to 6 feet (Larsen 1976). METHODS Survey Design and Plot Selection The mountain hemlock and mixed conifer plant communities were considered separate populations. A record of shelterwood units harvested in 1973 or earlier in the two communities was obtained from the USDA Forest Service Regional Office in Portland, Oregon. Only units at least 5 years old were considered suitable for sampling so that reproduction would have had time to become established. The sampling unit was a square plot 10 acres in size. Therefore, all shelterwood areas 10 acres or larger and at least 5 years old were considered candidates for sampling. The total number of 10-acre plots in each plant community was then determined; fractional portions of 10-acre areas were ignored. In the mixed conifer community, 216 plots were available for sampling and 145 in the mountain hemlock community. I estimated that a total of about 75 plots could be sampled during the available time. There- fore, 45 plots were selectd at random from the total number in the mixed conifer community and 30 from the total in the mountain hemlock community. This resul
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Keywords: ., bookcentury1900, bookcollectionbiodiversity, booksubjectconifers
