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• 11. [Article] Mapping and managing poorly stocked Douglas-fir stands

  Declared out of print December 2009. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonst...

  Citation × Citation Citation Abstract Copy Title: Mapping and managing poorly stocked Douglas-fir stands Author: Green, Daniel, Emmingham, William H., Oregon State University. Extension Service, Bondi, Michael C. Declared out of print December 2009. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Mapping and managing poorly stocked Douglas-fir stands Author: Green, Daniel, Emmingham, William H., Oregon State University. Extension Service, Bondi, Michael C. Declared out of print December 2009. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 12. [Article] Predicting basal area growth in young-growth Douglas-fir using crown competition factor

  A comparison between crown competition factor and basal area as to their ability to predict future basal area growth was conducted. It was shown that for a single age and site combination there was no ...

  Citation × Citation Citation Abstract Copy Title: Predicting basal area growth in young-growth Douglas-fir using crown competition factor Author: Schaer, Charles W. A comparison between crown competition factor and basal area as to their ability to predict future basal area growth was conducted. It was shown that for a single age and site combination there was no real difference between the growth prediction ability of the two measures of stand density. It was shown that acceptable estimates of Crown Competition Factor can be obtained by grouping trees into broad diameter classes. Finally, it was shown that Crown Competition Factor and the average Competitive Stress Index for a stand are very highly correlated with each other. Title: Predicting basal area growth in young-growth Douglas-fir using crown competition factor Author: Schaer, Charles W. A comparison between crown competition factor and basal area as to their ability to predict future basal area growth was conducted. It was shown that for a single age and site combination there was no real difference between the growth prediction ability of the two measures of stand density. It was shown that acceptable estimates of Crown Competition Factor can be obtained by grouping trees into broad diameter classes. Finally, it was shown that Crown Competition Factor and the average Competitive Stress Index for a stand are very highly correlated with each other. Close

• 13. [Article] Juvenile development of Douglas-fir, red alder and snowbrush associations in Western Oregon

  The juvenile development of Douglas-fir, red alder and snowbrush associations was investigated in western Oregon. The relationship between Douglas-fir and red alder was studied and compared in the Coast, ...

  Citation × Citation Citation Abstract Copy Title: Juvenile development of Douglas-fir, red alder and snowbrush associations in Western Oregon Author: El Hassan, Babiker Ahmed The juvenile development of Douglas-fir, red alder and snowbrush associations was investigated in western Oregon. The relationship between Douglas-fir and red alder was studied and compared in the Coast, Willamette Valley and Cascade regions. Snowbrush- Douglas-fir stands were sampled in the western Cascades. Alder- Douglas-fir relationships were studied on clearcuts supporting at the same time mixtures of alder and Douglas-fir and open-grown Douglas-fir. Sites where snowbrush and Douglas-fir grew together were selected on the same basis. Total heights of alder and Douglas-fir were expressed as cumulative one-year growth measurements. Canopy height of snowbrush was measured at various ages to determine growth rate. Information pertaining to moisture, vegetation, slope, aspect, elevation and stand structure was recorded at each sample plot. The data were analyzed with the aid of a multiple regression program. Height and (height)² were treated as independent variables, and annual height increment as the dependent variable. Results indicate that early establishment of Douglas-fir is expected to aid its dominance-takeover and allow it to evade suppression by red alder. Douglas-fir trees growing on wet sites need to be established earlier than those on drier habitats for the same degree of suppression evasion. The rapid juvenile growth rate of red alder is a major threat for the successful establishment of Douglas-fir. Height growth curves of the two species intersected at an earlier age on non-wet as compared to wet sites. The two trees grow in direct competition up to about age 40 years on wet habitats, with alder able to suppress Douglas-fir during this period. Douglas-fir has virtually no chance áf survival when it is established concurrently with red alder or after its appearance. Snowbrush retards the growth of Douglas-fir trees during their first ten years of development. Trees that are delayed more than five years in establishment suffer a loss of more than 50% in total height as a result of the suppressive effect of the shrub. It is expected that the trees will compensate for some of this loss, but their growth may never equal that of comparable open-grown Douglas-fir developing under similar conditions. Title: Juvenile development of Douglas-fir, red alder and snowbrush associations in Western Oregon Author: El Hassan, Babiker Ahmed The juvenile development of Douglas-fir, red alder and snowbrush associations was investigated in western Oregon. The relationship between Douglas-fir and red alder was studied and compared in the Coast, Willamette Valley and Cascade regions. Snowbrush- Douglas-fir stands were sampled in the western Cascades. Alder- Douglas-fir relationships were studied on clearcuts supporting at the same time mixtures of alder and Douglas-fir and open-grown Douglas-fir. Sites where snowbrush and Douglas-fir grew together were selected on the same basis. Total heights of alder and Douglas-fir were expressed as cumulative one-year growth measurements. Canopy height of snowbrush was measured at various ages to determine growth rate. Information pertaining to moisture, vegetation, slope, aspect, elevation and stand structure was recorded at each sample plot. The data were analyzed with the aid of a multiple regression program. Height and (height)² were treated as independent variables, and annual height increment as the dependent variable. Results indicate that early establishment of Douglas-fir is expected to aid its dominance-takeover and allow it to evade suppression by red alder. Douglas-fir trees growing on wet sites need to be established earlier than those on drier habitats for the same degree of suppression evasion. The rapid juvenile growth rate of red alder is a major threat for the successful establishment of Douglas-fir. Height growth curves of the two species intersected at an earlier age on non-wet as compared to wet sites. The two trees grow in direct competition up to about age 40 years on wet habitats, with alder able to suppress Douglas-fir during this period. Douglas-fir has virtually no chance áf survival when it is established concurrently with red alder or after its appearance. Snowbrush retards the growth of Douglas-fir trees during their first ten years of development. Trees that are delayed more than five years in establishment suffer a loss of more than 50% in total height as a result of the suppressive effect of the shrub. It is expected that the trees will compensate for some of this loss, but their growth may never equal that of comparable open-grown Douglas-fir developing under similar conditions. Close

• 14. [Article] Comparative development of a thinned and a natural Douglas-fir stand from 45 to 60 years of age

  An understanding of the dynamics of individual tree and stand growth, development, and structural patterns during the immature formative years of a commercial species is essential to determine correct ...

  Citation × Citation Citation Abstract Copy Title: Comparative development of a thinned and a natural Douglas-fir stand from 45 to 60 years of age Author: Groman, William A. An understanding of the dynamics of individual tree and stand growth, development, and structural patterns during the immature formative years of a commercial species is essential to determine correct thinning practices necessary to attain desired objectives. This study compared a natural, medium-site Douglas-fir stand and an adjacent similar stand released by a severe crown thinning in 1955 at 45 years of age. Individual tree measurement and classification data collected in 1955 and in 1970 from all stems 1.5 inches and larger on permanent one-acre research plots within each stand were used to compare growth and developmental changes occurring during the interval. In addition, the Douglas-fir on both plots were measured in 1970 with a Barr and Stroud optical dendrometer to determine volumetric and morphological differences. The interplot and intraplot characteristics manifested during and at the end of the 15-year period on each study area were examined. Structural changes of crown classes and components were delineated and investigated. Regression analyses were performed to compare basal area growth rates and volume similarities or differences by crown classes within and between the plots. After 15 years, the thinned stand was superior in site index, stand restructuring for dominance, basal area growth, and d.b.h.- volume relationships based on total cubic foot volume inside bark. Neither the ratio of live crown length to total height nor defect due to crown breakage and resulting Fomes cajanderi had an influence on subsequent crown class movement or basal area growth rate. Mortality was caused by suppression, and occurred in the intermediate and overtopped crown classes. The dynamics and magnitude of crown class movement, especially stability in the dominant class and the proportion of upward movement by the intermediate and codominant classes were greater than previously observed in other studies. This phenomenon has a major impact on silvicultural decisions, and warrants further intensive investigation. Intermediate trees showed the greatest vertical crown class movement; overtopped trees were candidates for mortality in the near future. The greatest actual basal area growth on an individual tree basis occurred in the dominant class on the thinned plot, but the larger codominants and the smaller dominants from the same plot exhibited superior potential for response to release with proportionally larger basal area increases. All crown classes except overtopped on the thinned study area were capable o relatively greater basal area growth than their unthinned counterparts. Fifteen years after release, the volumes of the dominant and codominant trees on the thinned area were significantly greater than the dominants and codominants of corresponding d.b.h.s on the unthinned plot. The d.b.h., height, crown length, and crown surface area were also substantially greater in these crown classes on the thinned plot. At 60 years of age, both plots were forming into three crown classes--a dominant, a codominant, and an intermediate-overtopped group based on crown class structure, basal area growth, and volume characteristics. The thinned stand, however, had relatively superior characteristics in these categories. The need for intensive periodic remeasurement of single-tree plots to determine the effects of genetics, tree physiology, microsite, and the spatial-distribution relationship on growth and development is discussed. Title: Comparative development of a thinned and a natural Douglas-fir stand from 45 to 60 years of age Author: Groman, William A. An understanding of the dynamics of individual tree and stand growth, development, and structural patterns during the immature formative years of a commercial species is essential to determine correct thinning practices necessary to attain desired objectives. This study compared a natural, medium-site Douglas-fir stand and an adjacent similar stand released by a severe crown thinning in 1955 at 45 years of age. Individual tree measurement and classification data collected in 1955 and in 1970 from all stems 1.5 inches and larger on permanent one-acre research plots within each stand were used to compare growth and developmental changes occurring during the interval. In addition, the Douglas-fir on both plots were measured in 1970 with a Barr and Stroud optical dendrometer to determine volumetric and morphological differences. The interplot and intraplot characteristics manifested during and at the end of the 15-year period on each study area were examined. Structural changes of crown classes and components were delineated and investigated. Regression analyses were performed to compare basal area growth rates and volume similarities or differences by crown classes within and between the plots. After 15 years, the thinned stand was superior in site index, stand restructuring for dominance, basal area growth, and d.b.h.- volume relationships based on total cubic foot volume inside bark. Neither the ratio of live crown length to total height nor defect due to crown breakage and resulting Fomes cajanderi had an influence on subsequent crown class movement or basal area growth rate. Mortality was caused by suppression, and occurred in the intermediate and overtopped crown classes. The dynamics and magnitude of crown class movement, especially stability in the dominant class and the proportion of upward movement by the intermediate and codominant classes were greater than previously observed in other studies. This phenomenon has a major impact on silvicultural decisions, and warrants further intensive investigation. Intermediate trees showed the greatest vertical crown class movement; overtopped trees were candidates for mortality in the near future. The greatest actual basal area growth on an individual tree basis occurred in the dominant class on the thinned plot, but the larger codominants and the smaller dominants from the same plot exhibited superior potential for response to release with proportionally larger basal area increases. All crown classes except overtopped on the thinned study area were capable o relatively greater basal area growth than their unthinned counterparts. Fifteen years after release, the volumes of the dominant and codominant trees on the thinned area were significantly greater than the dominants and codominants of corresponding d.b.h.s on the unthinned plot. The d.b.h., height, crown length, and crown surface area were also substantially greater in these crown classes on the thinned plot. At 60 years of age, both plots were forming into three crown classes--a dominant, a codominant, and an intermediate-overtopped group based on crown class structure, basal area growth, and volume characteristics. The thinned stand, however, had relatively superior characteristics in these categories. The need for intensive periodic remeasurement of single-tree plots to determine the effects of genetics, tree physiology, microsite, and the spatial-distribution relationship on growth and development is discussed. Close

• 15. [Article] The inter-relationship of salmonberry and Douglas-fir in cutover areas

  The inter-relationship of salmonberry and Douglas-fir on cutover areas was investigated in the Coast Range of western Oregon. Animal influences affecting the survival of Douglas-fir in a salmonberry habitat ...

  Citation × Citation Citation Abstract Copy Title: The inter-relationship of salmonberry and Douglas-fir in cutover areas Author: Allen, Hollis H. The inter-relationship of salmonberry and Douglas-fir on cutover areas was investigated in the Coast Range of western Oregon. Animal influences affecting the survival of Douglas-fir in a salmonberry habitat were also investigated. The autecology of salmonberry was considered first by formulating a mathematical model to characterize the lateral encroachment of the shrub on an opening containing a Douglas-fir seedling or sapling. The height response of Douglas-fir along with its general physiological condition were examined under different degrees of competition imposed by salmonberry. The response of salmonberry s growth to the development of Douglas-fir was also generally described. Data were obtained in cutover and burned areas containing several age-classes of salmonberry that had Douglas-fir seedlings or saplings interspersed within the shrubs. For the purpose of characterizing the lateral encroachment of salmonberry by a model, origins of the shrub stems and the shrubs' area of occupancy around an opening were mapped. A ratio of the area of an initial opening before brush encroachment and the area after brush encroachment was used to give a relative size of opening value This ratio served as the dependent variable in the model. Average maximum heights of the shrubs, the initial size of the opening, time or age of salmonberry, and the number of stem origins or clumps of salmonberry were used as the independent variables, The data were analyzed with the aid of a multiple regression program. Height increments that had accrued in 1968 on Douglas-fir seedlings were examined under conditions ranging from total suppression by salmonberry to no suppression. Data were obtained from 1, 950 two-year-old nursery seedlings (Douglas-fir) that gave an index of animal damage with respect to succession. The findings indicate that the mathematical model formulated is deficient in its prediction ability although it is useful in that it gives a first approximation to the growth characteristics of salmonberry. The growth in height of the shrubs and the initial size of the opening are especially important variables in determination of encroachment. Suppression by salmonberry substantially reduces the growth of Douglas-fir. Moreover, seedlings dominated by salmonberry or even in close proximity to the shrub are frequently damaged by rabbits. Results reveal that the succession of salmonberry on cutover areas causes an increased frequency of damage to Douglas-fir seedlings. Seedlings that are planted early will have a much better chance of avoiding suppression by the brush and will be less likely to be severely damaged by rabbits, at least during the first year. The interrelationship of salmonberry and biotic influences are formidable to the establishment of Douglas-fir, both because of salmonberry' s fast growth and the increasing rabbit damage to seedlings with increasing age of the shrub. Title: The inter-relationship of salmonberry and Douglas-fir in cutover areas Author: Allen, Hollis H. The inter-relationship of salmonberry and Douglas-fir on cutover areas was investigated in the Coast Range of western Oregon. Animal influences affecting the survival of Douglas-fir in a salmonberry habitat were also investigated. The autecology of salmonberry was considered first by formulating a mathematical model to characterize the lateral encroachment of the shrub on an opening containing a Douglas-fir seedling or sapling. The height response of Douglas-fir along with its general physiological condition were examined under different degrees of competition imposed by salmonberry. The response of salmonberry s growth to the development of Douglas-fir was also generally described. Data were obtained in cutover and burned areas containing several age-classes of salmonberry that had Douglas-fir seedlings or saplings interspersed within the shrubs. For the purpose of characterizing the lateral encroachment of salmonberry by a model, origins of the shrub stems and the shrubs' area of occupancy around an opening were mapped. A ratio of the area of an initial opening before brush encroachment and the area after brush encroachment was used to give a relative size of opening value This ratio served as the dependent variable in the model. Average maximum heights of the shrubs, the initial size of the opening, time or age of salmonberry, and the number of stem origins or clumps of salmonberry were used as the independent variables, The data were analyzed with the aid of a multiple regression program. Height increments that had accrued in 1968 on Douglas-fir seedlings were examined under conditions ranging from total suppression by salmonberry to no suppression. Data were obtained from 1, 950 two-year-old nursery seedlings (Douglas-fir) that gave an index of animal damage with respect to succession. The findings indicate that the mathematical model formulated is deficient in its prediction ability although it is useful in that it gives a first approximation to the growth characteristics of salmonberry. The growth in height of the shrubs and the initial size of the opening are especially important variables in determination of encroachment. Suppression by salmonberry substantially reduces the growth of Douglas-fir. Moreover, seedlings dominated by salmonberry or even in close proximity to the shrub are frequently damaged by rabbits. Results reveal that the succession of salmonberry on cutover areas causes an increased frequency of damage to Douglas-fir seedlings. Seedlings that are planted early will have a much better chance of avoiding suppression by the brush and will be less likely to be severely damaged by rabbits, at least during the first year. The interrelationship of salmonberry and biotic influences are formidable to the establishment of Douglas-fir, both because of salmonberry' s fast growth and the increasing rabbit damage to seedlings with increasing age of the shrub. Close

• 16. [Article] Developing an equation for making estimates of diameter inside bark at various heights up the stem in Douglas-fir

  The purpose of this thesis was to develop a suitable multiple regression equation for making estimates of diameter inside bark at various heights up the bole in Douglas-fir (Pseudotsuga menziesii (Mirb.) ...

  Citation × Citation Citation Abstract Copy Title: Developing an equation for making estimates of diameter inside bark at various heights up the stem in Douglas-fir Author: Faqir Mohammad Khan The purpose of this thesis was to develop a suitable multiple regression equation for making estimates of diameter inside bark at various heights up the bole in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)tree. Data on 237 and 302 trees from Black Rock Forest Management Research Area, Polk County, Oregon, and scattered plots in the State of Washington respectively were analysed in a stepwise regression procedure. The results of regression analyses showed that: a) Direct estimation of diameter inside bark at various upper stem points yield better results than expressing it as a ratio of diameter outside bark as practised previously. b) Diameter inside bark at various heights up the stem has a high positive correlation with its respective diameter outside bark, and a negative correlation with height itself. c) Bark ratio at breast height has been found to have a positive correlation with such ratio at upper stem points; both are negatively related to tree age. Regression equations are presented for estimating diameter inside bark at various upper stem points. These equations are recommended for practical use under stand conditions comparable to those from where the original data were obtained. Title: Developing an equation for making estimates of diameter inside bark at various heights up the stem in Douglas-fir Author: Faqir Mohammad Khan The purpose of this thesis was to develop a suitable multiple regression equation for making estimates of diameter inside bark at various heights up the bole in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)tree. Data on 237 and 302 trees from Black Rock Forest Management Research Area, Polk County, Oregon, and scattered plots in the State of Washington respectively were analysed in a stepwise regression procedure. The results of regression analyses showed that: a) Direct estimation of diameter inside bark at various upper stem points yield better results than expressing it as a ratio of diameter outside bark as practised previously. b) Diameter inside bark at various heights up the stem has a high positive correlation with its respective diameter outside bark, and a negative correlation with height itself. c) Bark ratio at breast height has been found to have a positive correlation with such ratio at upper stem points; both are negatively related to tree age. Regression equations are presented for estimating diameter inside bark at various upper stem points. These equations are recommended for practical use under stand conditions comparable to those from where the original data were obtained. Close

• 17. [Article] Habitat relationships of birds and young-growth Douglas-fir in northwestern California

  Ninety-one species of birds were surveyed in grass/forb, early and late shrub/sapling, pole, and medium sawtimber stages of young-growth Douglas-fir in northwestern California; patterns of bird distribution ...

  Citation × Citation Citation Abstract Copy Title: Habitat relationships of birds and young-growth Douglas-fir in northwestern California Author: Marcot, Bruce G. Ninety-one species of birds were surveyed in grass/forb, early and late shrub/sapling, pole, and medium sawtimber stages of young-growth Douglas-fir in northwestern California; patterns of bird distribution and abundance were related to habitat conditions and even-age silvicultural treatments. Seven species (band-tailed pigeon, western wood pewee, dusky flycatcher, western bluebird, fox sparrow, purple finch, and evening grosbeak) have probably increased in population size or distribution since extensive clearcutting in the study area began in the early 1950's. Six species (Hammond's flycatcher, chestnut-backed chickadee, red-breasted nuthatch, brown creeper, golden-crowned kinglet, and hermit warbler) are restricted to forest stages and probably have decreased in population size or distribution. Abundances of various species were associated with presence of a forest overstory, hardwood stem density, deciduous foliage volume, height and patchiness of shrub cover, number plant species, and snag density. Slope angle and distance to permanent water or to the next nearest similar habitat type explained some variation in abundance of a few species. The grass/forb stage had the lowest number of bird species and lowest total density, while the late shrub/sapling stage had the highest; species composition varied markedly across the young-growth stages. Cluster analysis defined Shrub stage specialists and forest stage Specialists. Seasonal patterns of permanent resident species suggested that the shrub stage specialists are most limited in distribution during winter, and that their winter distributions may reflect optimal ("source") habitat. In contrast, forest stage specialists showed no seasonal changes of distribution, or were more restricted in distribution during the breeding season. All phases of the clearcutting system, including site preparation, stocking control, intermediate treatments, and final harvest, greatly affect stand conditions. No one stand condition, young-growth stage, or silvicultural treatment provided best habitat for all bird species. Simplification of forest stand structure by reduction or elimination of hardwoods, snags, and large diameter softwoods, could lead to low within-stand but high between-stand diversity of vegetation and bird assemblages. Even-age silvicultural systems, however, can integrate management objectives for timber production and bird habitat. Title: Habitat relationships of birds and young-growth Douglas-fir in northwestern California Author: Marcot, Bruce G. Ninety-one species of birds were surveyed in grass/forb, early and late shrub/sapling, pole, and medium sawtimber stages of young-growth Douglas-fir in northwestern California; patterns of bird distribution and abundance were related to habitat conditions and even-age silvicultural treatments. Seven species (band-tailed pigeon, western wood pewee, dusky flycatcher, western bluebird, fox sparrow, purple finch, and evening grosbeak) have probably increased in population size or distribution since extensive clearcutting in the study area began in the early 1950's. Six species (Hammond's flycatcher, chestnut-backed chickadee, red-breasted nuthatch, brown creeper, golden-crowned kinglet, and hermit warbler) are restricted to forest stages and probably have decreased in population size or distribution. Abundances of various species were associated with presence of a forest overstory, hardwood stem density, deciduous foliage volume, height and patchiness of shrub cover, number plant species, and snag density. Slope angle and distance to permanent water or to the next nearest similar habitat type explained some variation in abundance of a few species. The grass/forb stage had the lowest number of bird species and lowest total density, while the late shrub/sapling stage had the highest; species composition varied markedly across the young-growth stages. Cluster analysis defined Shrub stage specialists and forest stage Specialists. Seasonal patterns of permanent resident species suggested that the shrub stage specialists are most limited in distribution during winter, and that their winter distributions may reflect optimal ("source") habitat. In contrast, forest stage specialists showed no seasonal changes of distribution, or were more restricted in distribution during the breeding season. All phases of the clearcutting system, including site preparation, stocking control, intermediate treatments, and final harvest, greatly affect stand conditions. No one stand condition, young-growth stage, or silvicultural treatment provided best habitat for all bird species. Simplification of forest stand structure by reduction or elimination of hardwoods, snags, and large diameter softwoods, could lead to low within-stand but high between-stand diversity of vegetation and bird assemblages. Even-age silvicultural systems, however, can integrate management objectives for timber production and bird habitat. Close

• 18. [Article] Two studies of Acer macrophyllum : I. The effects of bigleaf maple on soils in Douglas-fir forests : II. The ecology of bigleaf maple seedling establishment and early growth in Douglas-fir forests

  Bigleaf maple (Acer iaacrophyllunt) is a deciduous, persistent, sprouting species that frequently accounts for as much as 20% of the basal area in Douglas-fir forests. Because of the lack of knowledge ...

  Citation × Citation Citation Abstract Copy Title: Two studies of Acer macrophyllum : I. The effects of bigleaf maple on soils in Douglas-fir forests : II. The ecology of bigleaf maple seedling establishment and early growth in Douglas-fir forests Author: Fried, Jeremy Steven Bigleaf maple (Acer iaacrophyllunt) is a deciduous, persistent, sprouting species that frequently accounts for as much as 20% of the basal area in Douglas-fir forests. Because of the lack of knowledge of the role of bigleaf maple in Douglas-fir forest ecosystems and the problems that it poses as a vigorous competitor to commercial conifer seedlings, two studies were undertaken to determine its possible effects on forest soils, and to gain insight into the seedling establishment phase of its life cycle. Soil chemical and physical properties and forest floor and litterfall weights, nutrient content and forest floor turnover rates under bigleaf maple and Douglas-fir (Pseudotsuga !nenziesii) were compared on five sites on the eastern margin of the Oregon Coast Range. Litterfall weight and nutrient content were greater under maple on virtually every site for every macro and micro-nutrient. Forest floor biomass and nutrient content were extremely variable, much more so than litterfall, and there were no significant differences among the two species. However, turnover rates for forest floor biomass and nutrients were significantly faster under maple for every nutrient on every site. Bulk density of mineral soil was also highly variable with significant differences on only two sites. Soil nitrogen was generally greater under maple and there was a trend towards greater potassium under maple also. Amounts of calcium, magnesium and phosphorous showed no consistent trends. Soil organic matter content under maple was significantly greater than under Douglas-fir on 4 of 5 sites. The greater soil nutrients and organic matter under maple may be attributed to the more rapid forest floor turnover in that system. The establishment phase of bigleaf maple, a ubiquitous, deciduous hardwood in western Oregon's Douglas-fir forests, was studied in a variety of stands ranging from 1 to 150 years of age to identify those stages in Douglas-fir forest succession where bigleaf maple is most likely to become successfully established from seed. Germination rates of seed protected from rodents averaged from 30 to 40 % in all environments but typically less than 2 % of the unprotected seed germinated, indicating that seed predators play an important role in regulating seedling establishment. Seedling survival was highly dependent on light arid mortality after one growing season was particularly high in stands with greater than 90 % overstory cover. At least half of the first year mortality was due to browsing by burrowing rodents and invertebrates, with dessication as the second greatest cause of mortality during the first year. On plots that were monitored over two growing seasons, overwinter mortality was the second most frequent classification. Seedling survival was not related to soil moisture content or soil moisture tension. The highest survival rates (90 %) were in clearcuts and very open stands and the lowest (0 %) were in dense, young, conifer stands. Maple establishment in clearcuts will likely only be successful if seedlings escape shading by competing shrubs arid herbs. Optimum long term survival is most likely in Douglas-fir stands over 40 years of age. Title: Two studies of Acer macrophyllum : I. The effects of bigleaf maple on soils in Douglas-fir forests : II. The ecology of bigleaf maple seedling establishment and early growth in Douglas-fir forests Author: Fried, Jeremy Steven Bigleaf maple (Acer iaacrophyllunt) is a deciduous, persistent, sprouting species that frequently accounts for as much as 20% of the basal area in Douglas-fir forests. Because of the lack of knowledge of the role of bigleaf maple in Douglas-fir forest ecosystems and the problems that it poses as a vigorous competitor to commercial conifer seedlings, two studies were undertaken to determine its possible effects on forest soils, and to gain insight into the seedling establishment phase of its life cycle. Soil chemical and physical properties and forest floor and litterfall weights, nutrient content and forest floor turnover rates under bigleaf maple and Douglas-fir (Pseudotsuga !nenziesii) were compared on five sites on the eastern margin of the Oregon Coast Range. Litterfall weight and nutrient content were greater under maple on virtually every site for every macro and micro-nutrient. Forest floor biomass and nutrient content were extremely variable, much more so than litterfall, and there were no significant differences among the two species. However, turnover rates for forest floor biomass and nutrients were significantly faster under maple for every nutrient on every site. Bulk density of mineral soil was also highly variable with significant differences on only two sites. Soil nitrogen was generally greater under maple and there was a trend towards greater potassium under maple also. Amounts of calcium, magnesium and phosphorous showed no consistent trends. Soil organic matter content under maple was significantly greater than under Douglas-fir on 4 of 5 sites. The greater soil nutrients and organic matter under maple may be attributed to the more rapid forest floor turnover in that system. The establishment phase of bigleaf maple, a ubiquitous, deciduous hardwood in western Oregon's Douglas-fir forests, was studied in a variety of stands ranging from 1 to 150 years of age to identify those stages in Douglas-fir forest succession where bigleaf maple is most likely to become successfully established from seed. Germination rates of seed protected from rodents averaged from 30 to 40 % in all environments but typically less than 2 % of the unprotected seed germinated, indicating that seed predators play an important role in regulating seedling establishment. Seedling survival was highly dependent on light arid mortality after one growing season was particularly high in stands with greater than 90 % overstory cover. At least half of the first year mortality was due to browsing by burrowing rodents and invertebrates, with dessication as the second greatest cause of mortality during the first year. On plots that were monitored over two growing seasons, overwinter mortality was the second most frequent classification. Seedling survival was not related to soil moisture content or soil moisture tension. The highest survival rates (90 %) were in clearcuts and very open stands and the lowest (0 %) were in dense, young, conifer stands. Maple establishment in clearcuts will likely only be successful if seedlings escape shading by competing shrubs arid herbs. Optimum long term survival is most likely in Douglas-fir stands over 40 years of age. Close

• 19. [Article] Silvicultural impacts of sheep grazing in Oregon's Coast Range

  A three-year investigation was conducted during 1980-1982 to evaluate the potential of using herded sheep as a silvicultural tool to suppress brush in Douglas-fir (Pseudotsuga menziesii) plantations of ...

  Citation × Citation Citation Abstract Copy Title: Silvicultural impacts of sheep grazing in Oregon's Coast Range Author: Leininger, Wayne C. A three-year investigation was conducted during 1980-1982 to evaluate the potential of using herded sheep as a silvicultural tool to suppress brush in Douglas-fir (Pseudotsuga menziesii) plantations of Oregon's Coast Range. Sheep browsing of Douglas-fir was highest in May soon after bud break. Averaged over the 2 years of grazing, sheep consumed 28% of the Douglas-fir current year's growth (CYG) in two May-grazed plantations. Browsing was generally light (2% CYG) during July and August. Browsing of terminal leaders by sheep decreased as seedling height increased. Less than 3% of the study trees were mechanically impacted by sheep. In a 2-year-old plantation in which seedlings were heavily browsed by sheep in both May and August, annual height and mean diameter increment were reduced by sheep grazing. However, annual mean diameter increment was 8 to 17% higher in the grazed portion of three 4-6-year-old study plantations. Survival of regeneration over the 2 years of investigation was high in all study plantations and was unaffected by grazing. Increased available nitrogen deposited as urine in grazed plantations may have contributed to the increased diameter growth. Vegetational composition of sheep diets varied by year, season, and plantation age class. Averaged over the 2 years of grazing, graminoids and forbs were nearly equal, at approximately 40% each, in sheep diets from older plantations. In contrast, diets of sheep in young grass seeded plantations averaged 70% graminoids and only 16% forbs. Ferns were a minor component (<2%) of sheep diets in both plantation age classes. Browse averaged 15 and 12% of sheep diets in older and younger plantations, respectively. Douglas-fir comprised less than 3% of sheep diets throughout the grazing season. Weight gains followed seasonal trends typical of sheep grazing non-irrigated hill pasture in western Oregon. Average daily gain (ADG) of ewes and lambs during the 1981 grazing season was -.03 and .12 kg/sheep/day, respectively. Yearling ewes gained .08 kg/ewe/day in the 1982 gazing season. Death losses were relatively low, averaging 3% for the ewes and 5% for the lambs in 1981 and 2% for the yearlings in 1982. Title: Silvicultural impacts of sheep grazing in Oregon's Coast Range Author: Leininger, Wayne C. A three-year investigation was conducted during 1980-1982 to evaluate the potential of using herded sheep as a silvicultural tool to suppress brush in Douglas-fir (Pseudotsuga menziesii) plantations of Oregon's Coast Range. Sheep browsing of Douglas-fir was highest in May soon after bud break. Averaged over the 2 years of grazing, sheep consumed 28% of the Douglas-fir current year's growth (CYG) in two May-grazed plantations. Browsing was generally light (2% CYG) during July and August. Browsing of terminal leaders by sheep decreased as seedling height increased. Less than 3% of the study trees were mechanically impacted by sheep. In a 2-year-old plantation in which seedlings were heavily browsed by sheep in both May and August, annual height and mean diameter increment were reduced by sheep grazing. However, annual mean diameter increment was 8 to 17% higher in the grazed portion of three 4-6-year-old study plantations. Survival of regeneration over the 2 years of investigation was high in all study plantations and was unaffected by grazing. Increased available nitrogen deposited as urine in grazed plantations may have contributed to the increased diameter growth. Vegetational composition of sheep diets varied by year, season, and plantation age class. Averaged over the 2 years of grazing, graminoids and forbs were nearly equal, at approximately 40% each, in sheep diets from older plantations. In contrast, diets of sheep in young grass seeded plantations averaged 70% graminoids and only 16% forbs. Ferns were a minor component (<2%) of sheep diets in both plantation age classes. Browse averaged 15 and 12% of sheep diets in older and younger plantations, respectively. Douglas-fir comprised less than 3% of sheep diets throughout the grazing season. Weight gains followed seasonal trends typical of sheep grazing non-irrigated hill pasture in western Oregon. Average daily gain (ADG) of ewes and lambs during the 1981 grazing season was -.03 and .12 kg/sheep/day, respectively. Yearling ewes gained .08 kg/ewe/day in the 1982 gazing season. Death losses were relatively low, averaging 3% for the ewes and 5% for the lambs in 1981 and 2% for the yearlings in 1982. Close

• 20. [Article] Growth behavior of Douglas-fir reproduction in the shade of managed forest in the interior Coast Range of Oregon

  During the past 20 years, repeated thinning of a Douglas-fir forest, now 65 years old, has allowed desired limits of basal area to be maintained. In the process, the understory environment has altered ...

  Citation × Citation Citation Abstract Copy Title: Growth behavior of Douglas-fir reproduction in the shade of managed forest in the interior Coast Range of Oregon Author: Del Rio, Ernest During the past 20 years, repeated thinning of a Douglas-fir forest, now 65 years old, has allowed desired limits of basal area to be maintained. In the process, the understory environment has altered sufficiently to allow Douglas-fir reproduction to establish in abundance. The forest is located on the east side of the Coast Range, north of Corvallis, Oregon. A study was undertaken to examine growth patterns of understory trees in relation to microenvironment, physical attributes of the tree and time. This information would help determine how long a tree can be maintained at a given level of shade and still function properly. This information also would add to the understanding of modification of growth strategies for survival. To characterize the understory environments of the three thinning intensities (23 to 30, 30 to 37 and 37 to 44 m2/ha basal area), measurements were made of plant moisture stress, evaporative demand, air and soil temperature, light and vegetative cover. Light measured at seedling crown best separated the environments; light was found to increase with a decrease in stand basal area, averaging 5, 8 and 12 percent of daily sun for the three thinning levels. Trees, randomly selected, ranged in height from 10 cm to 1.5 m and in age from 4 to 15 years. Parameters measured included leader growth for the past two seasons, diameter growth, above-ground biomass, height and age. Bud phenology and beginning of cambial activity were also observed. Development of buds in the spring was inversely related to light while renewed cambial activity was directly related to tree size and light. Increments of height and diameter growth were found to increase with light and tree height. Linear differences in average leader and diameter growth and above-ground biomass production were found between the three intensities of thinning, with trees under the heaviest thinning growing most. Average growth is predictable for at least two years. However, rates of leader growth and biomass production, in relation to growth of the previous year and leaf biomass, were not different for individual trees from the three understory environments. A balance of foliar to stem bioniass was maintained by understory trees. Physical characteristics of the tree accounted for most of the variation in growth. As thinning of young Douglas-fir becomes a widespread management practice, it can be expected that, in similar vegetation types, Douglas-fir seedlings will establish naturally in the understory. If the new forest is established at final harvest several years in lag time may be saved; regeneration problems often associated with clear-cutting will be alleviated, planting costs reduced or eliminated, and the forest gene pool maintained. Title: Growth behavior of Douglas-fir reproduction in the shade of managed forest in the interior Coast Range of Oregon Author: Del Rio, Ernest During the past 20 years, repeated thinning of a Douglas-fir forest, now 65 years old, has allowed desired limits of basal area to be maintained. In the process, the understory environment has altered sufficiently to allow Douglas-fir reproduction to establish in abundance. The forest is located on the east side of the Coast Range, north of Corvallis, Oregon. A study was undertaken to examine growth patterns of understory trees in relation to microenvironment, physical attributes of the tree and time. This information would help determine how long a tree can be maintained at a given level of shade and still function properly. This information also would add to the understanding of modification of growth strategies for survival. To characterize the understory environments of the three thinning intensities (23 to 30, 30 to 37 and 37 to 44 m2/ha basal area), measurements were made of plant moisture stress, evaporative demand, air and soil temperature, light and vegetative cover. Light measured at seedling crown best separated the environments; light was found to increase with a decrease in stand basal area, averaging 5, 8 and 12 percent of daily sun for the three thinning levels. Trees, randomly selected, ranged in height from 10 cm to 1.5 m and in age from 4 to 15 years. Parameters measured included leader growth for the past two seasons, diameter growth, above-ground biomass, height and age. Bud phenology and beginning of cambial activity were also observed. Development of buds in the spring was inversely related to light while renewed cambial activity was directly related to tree size and light. Increments of height and diameter growth were found to increase with light and tree height. Linear differences in average leader and diameter growth and above-ground biomass production were found between the three intensities of thinning, with trees under the heaviest thinning growing most. Average growth is predictable for at least two years. However, rates of leader growth and biomass production, in relation to growth of the previous year and leaf biomass, were not different for individual trees from the three understory environments. A balance of foliar to stem bioniass was maintained by understory trees. Physical characteristics of the tree accounted for most of the variation in growth. As thinning of young Douglas-fir becomes a widespread management practice, it can be expected that, in similar vegetation types, Douglas-fir seedlings will establish naturally in the understory. If the new forest is established at final harvest several years in lag time may be saved; regeneration problems often associated with clear-cutting will be alleviated, planting costs reduced or eliminated, and the forest gene pool maintained. Close