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• 1. [Article] Growth and yield of western larch under controlled levels of stocking in the Blue Mountains of Oregon

  Repeated thinning to five growing-stock levels resulted in widely differing tree sizes and volumes per acre after 30 years. Largest trees but the least cubic-volume yield per acre were produced in the ...

  Citation × Citation Citation Abstract Copy Title: Growth and yield of western larch under controlled levels of stocking in the Blue Mountains of Oregon Author: Cochran, P.H. Repeated thinning to five growing-stock levels resulted in widely differing tree sizes and volumes per acre after 30 years. Largest trees but the least cubic-volume yield per acre were produced in the heaviest thinning level, whereas highest board-foot yields were found in intermediate thinning levels. partial defoliation by larch casebearer (Coleophora Iaricella Hubner), drought, and top damage from ice occurred, and site trees grew less in height than expected during the 30-year study. Curvilinear increases in periodic annual increments of both basal area and cubic volume generally occurred with increasing stand density, but increments dropped off at the highest stand densities for some periods. Anticipated patterns for these increments were found after fitting a model that included stand density index, height increments of site trees, and dummy variables for periods as independent variables. heavy thinning did not increase the age of culmination of cubic-volume means annual increment as expected. Thinning stands of larch to densities as low as 50 percent of 'normal' results in little loss of basal-area growth, a moderate loss in volume production, and a large increase in tree diameter. Thinning is necessary in many larch stands to maintain vigorous, rapidly growing trees. Title: Growth and yield of western larch under controlled levels of stocking in the Blue Mountains of Oregon Author: Cochran, P.H. Repeated thinning to five growing-stock levels resulted in widely differing tree sizes and volumes per acre after 30 years. Largest trees but the least cubic-volume yield per acre were produced in the heaviest thinning level, whereas highest board-foot yields were found in intermediate thinning levels. partial defoliation by larch casebearer (Coleophora Iaricella Hubner), drought, and top damage from ice occurred, and site trees grew less in height than expected during the 30-year study. Curvilinear increases in periodic annual increments of both basal area and cubic volume generally occurred with increasing stand density, but increments dropped off at the highest stand densities for some periods. Anticipated patterns for these increments were found after fitting a model that included stand density index, height increments of site trees, and dummy variables for periods as independent variables. heavy thinning did not increase the age of culmination of cubic-volume means annual increment as expected. Thinning stands of larch to densities as low as 50 percent of 'normal' results in little loss of basal-area growth, a moderate loss in volume production, and a large increase in tree diameter. Thinning is necessary in many larch stands to maintain vigorous, rapidly growing trees. Close

• 2. [Article] Reduction in growth of pole-sized Ponderosa pine related to a Pandora moth outbreak in central Oregon

  A pandora moth (Coloradia pandora Blake) outbreak began in 1991 in a ponderosa pine (Pinus ponderosa Dougl. ex. Laws) spacing study area that also included scattered sugar pine (P. lambertiana Dougl). ...

  Citation × Citation Citation Abstract Copy Title: Reduction in growth of pole-sized Ponderosa pine related to a Pandora moth outbreak in central Oregon Author: Pacific Northwest Research Station (Portland, Or.), Cochran, P.H. A pandora moth (Coloradia pandora Blake) outbreak began in 1991 in a ponderosa pine (Pinus ponderosa Dougl. ex. Laws) spacing study area that also included scattered sugar pine (P. lambertiana Dougl). The relation of defoliation to five tree spacings (with and without understory vegetation) was examined, and stand growth reduction due to defoliation was estimated. Defoliation generally increased as spacing varied from 2 to 5.7 meters and then decreased as spacing increased to 8 meters. Partial defoliation in 1992 reduced stand volume growth, while partial defoliation in 1994 reduced height growth during 1990-94. Basal area growth of nonefoliated sugar pine and partially defoliated ponderosa pine trees outside the outbreak area. Ratios of annual basal area increments for nondefoliated trees to annual increments of partially defoliated ponderosa pine sharply increased after the outbreak. Basal area annual increments of sample trees were reduced by 25 prcent in the first growing season after defoliation (1992), 30 percent the second year after defoliation (1993), and 63 percent after the second defoliation (1994). Title: Reduction in growth of pole-sized Ponderosa pine related to a Pandora moth outbreak in central Oregon Author: Pacific Northwest Research Station (Portland, Or.), Cochran, P.H. A pandora moth (Coloradia pandora Blake) outbreak began in 1991 in a ponderosa pine (Pinus ponderosa Dougl. ex. Laws) spacing study area that also included scattered sugar pine (P. lambertiana Dougl). The relation of defoliation to five tree spacings (with and without understory vegetation) was examined, and stand growth reduction due to defoliation was estimated. Defoliation generally increased as spacing varied from 2 to 5.7 meters and then decreased as spacing increased to 8 meters. Partial defoliation in 1992 reduced stand volume growth, while partial defoliation in 1994 reduced height growth during 1990-94. Basal area growth of nonefoliated sugar pine and partially defoliated ponderosa pine trees outside the outbreak area. Ratios of annual basal area increments for nondefoliated trees to annual increments of partially defoliated ponderosa pine sharply increased after the outbreak. Basal area annual increments of sample trees were reduced by 25 prcent in the first growing season after defoliation (1992), 30 percent the second year after defoliation (1993), and 63 percent after the second defoliation (1994). Close

• 3. [Article] Lodgepole pine development after early spacing in the Blue Mountains of Oregon

  Seedlings were thinned to spacings of 5, 9, 12, 15, and 18 feet and measured periodically. Twenty-seven years after treatment, quadratic mean diameters increased curvilinearity (p < or = 0.05) as spacing ...

  Citation × Citation Citation Abstract Copy Title: Lodgepole pine development after early spacing in the Blue Mountains of Oregon Author: Dahms, Walter G., Cochran, P.H. Seedlings were thinned to spacings of 5, 9, 12, 15, and 18 feet and measured periodically. Twenty-seven years after treatment, quadratic mean diameters increased curvilinearity (p < or = 0.05) as spacing increased, but total height did not differ significantly (p < or = 0.05) with spacing. Corresponding basal areas decreased curvilinearly (p < or = 0.05), and cubic volumes decreased linearly (p < or = 0.05) as spacing increased. All periodic annual increments differed with period or age. Periodic annual increments for mean diameter and basal area varied curvilinearly (p < or = 0.05), whereas volume increments varied linearly (p < or = 0.05) with spacing for each period. Height increments were greatest at intermediate spacing during some periods, at wide spacings during other periods, and at the narrowest spacing during one period. Crown widths increased (p < or = 0.05) as spacing widended. Fifty percent crown cover as attained at a stand density index of about 80 for all spacings. Simulation to a breast high age of 100 years indicated that most merchantable cubic volume was produced at the 6-foot spacing but that the 12-, 15-, and 18-foot spacings produced about the same board-foot volume. Title: Lodgepole pine development after early spacing in the Blue Mountains of Oregon Author: Dahms, Walter G., Cochran, P.H. Seedlings were thinned to spacings of 5, 9, 12, 15, and 18 feet and measured periodically. Twenty-seven years after treatment, quadratic mean diameters increased curvilinearity (p < or = 0.05) as spacing increased, but total height did not differ significantly (p < or = 0.05) with spacing. Corresponding basal areas decreased curvilinearly (p < or = 0.05), and cubic volumes decreased linearly (p < or = 0.05) as spacing increased. All periodic annual increments differed with period or age. Periodic annual increments for mean diameter and basal area varied curvilinearly (p < or = 0.05), whereas volume increments varied linearly (p < or = 0.05) with spacing for each period. Height increments were greatest at intermediate spacing during some periods, at wide spacings during other periods, and at the narrowest spacing during one period. Crown widths increased (p < or = 0.05) as spacing widended. Fifty percent crown cover as attained at a stand density index of about 80 for all spacings. Simulation to a breast high age of 100 years indicated that most merchantable cubic volume was produced at the 6-foot spacing but that the 12-, 15-, and 18-foot spacings produced about the same board-foot volume. Close