Search

Search Results

• 1. [Article] Wood density of young-growth western hemlock: relation to ring age, radial growth, stand density, and site quality

  Breast-high stem sections were sampled from 56 western hemlock (Tsuga heterophylla (Raf.) Sarg.) trees growing in 15 plots representing a wide range of tree and site conditions in northwestern Oregon. ...

  Citation × Citation Citation Abstract Copy Title: Wood density of young-growth western hemlock: relation to ring age, radial growth, stand density, and site quality Author: Marshall, D. D., Gartner, B. L., Singleton, R., DeBell, D. S. Breast-high stem sections were sampled from 56 western hemlock (Tsuga heterophylla (Raf.) Sarg.) trees growing in 15 plots representing a wide range of tree and site conditions in northwestern Oregon. Growth and wood density traits of individual rings were measured via X-ray densitometry, and relationships of ring density and its components to age and growth rate were analyzed. Ring density was highest (0.49 g/cm3) near the pith, declined to 0.40 g/cm3 at age 10, remained stable to about age 25, and then increased gradually and remained between 0.43 and 0.44 g/cm3 from age 38 to 45 and beyond. A negative influence of rapid growth on whole ring density was greatest at young ages and diminished with time, becoming nonsignificant beyond age 30. Earlywood density, latewood density, and latewood proportion were all negatively related to ring width at young ages, but by age 21–25, latewood proportion was the only component of ring density that remained significantly diminished by increased growth rate. Residual differences in wood density (after age and growth rate were considered) did not appear to be related to either stand density or site class. Overall, young-growth hemlock trees are relatively uniform in wood density and likely to be more so if grown in intensively managed stands. Title: Wood density of young-growth western hemlock: relation to ring age, radial growth, stand density, and site quality Author: Marshall, D. D., Gartner, B. L., Singleton, R., DeBell, D. S. Breast-high stem sections were sampled from 56 western hemlock (Tsuga heterophylla (Raf.) Sarg.) trees growing in 15 plots representing a wide range of tree and site conditions in northwestern Oregon. Growth and wood density traits of individual rings were measured via X-ray densitometry, and relationships of ring density and its components to age and growth rate were analyzed. Ring density was highest (0.49 g/cm3) near the pith, declined to 0.40 g/cm3 at age 10, remained stable to about age 25, and then increased gradually and remained between 0.43 and 0.44 g/cm3 from age 38 to 45 and beyond. A negative influence of rapid growth on whole ring density was greatest at young ages and diminished with time, becoming nonsignificant beyond age 30. Earlywood density, latewood density, and latewood proportion were all negatively related to ring width at young ages, but by age 21–25, latewood proportion was the only component of ring density that remained significantly diminished by increased growth rate. Residual differences in wood density (after age and growth rate were considered) did not appear to be related to either stand density or site class. Overall, young-growth hemlock trees are relatively uniform in wood density and likely to be more so if grown in intensively managed stands. Close

• 2. [Article] Wood density and fiber length in young populus stems: relation to clone, age, growth rate, and pruning

  Cross-sectional disks were cut at two stem heights (1.5 m and 3.0 m) from 9-year-old trees of three Populus clones grown in an intensively-cultured plantation in western Washington. At age 1.5 years, when ...

  Citation × Citation Citation Abstract Copy Title: Wood density and fiber length in young populus stems: relation to clone, age, growth rate, and pruning Author: Gartner, B. L., Singleton, R., Harrington, C. A., DeBell, D. S. Cross-sectional disks were cut at two stem heights (1.5 m and 3.0 m) from 9-year-old trees of three Populus clones grown in an intensively-cultured plantation in western Washington. At age 1.5 years, when the trees averaged 3.4 m tall, half of the trees were pruned by removing all branches below 1.8 m. Ring width, wood density, and fiber length were measured for each ring. Pruning had no effect on mean ring width or wood properties, averaged over the entire disk or on rings produced during the 2nd through the 4th years. Averaged over all trees, wood density of the 1.5 m sample was 0.37 g cm-3 during the first 3 years, decreased somewhat at age 4 or 5, and then increased to an average of 0.45 g cm-3 at age 9. Fiber length increased from 0.57 mm at age 1 to nearly 1.0 mm at age 9. Averaged over all disks at 1.5 m, clones differed significantly in ring width, wood density, and fiber length. Mean values for the two wood properties at 3.0 m were slightly lower than those at 1.5 m and did not differ significantly among clones. Within clone correlations between ring width and wood density or fiber length or between wood properties were low, and generally non significant or inconsistent. Title: Wood density and fiber length in young populus stems: relation to clone, age, growth rate, and pruning Author: Gartner, B. L., Singleton, R., Harrington, C. A., DeBell, D. S. Cross-sectional disks were cut at two stem heights (1.5 m and 3.0 m) from 9-year-old trees of three Populus clones grown in an intensively-cultured plantation in western Washington. At age 1.5 years, when the trees averaged 3.4 m tall, half of the trees were pruned by removing all branches below 1.8 m. Ring width, wood density, and fiber length were measured for each ring. Pruning had no effect on mean ring width or wood properties, averaged over the entire disk or on rings produced during the 2nd through the 4th years. Averaged over all trees, wood density of the 1.5 m sample was 0.37 g cm-3 during the first 3 years, decreased somewhat at age 4 or 5, and then increased to an average of 0.45 g cm-3 at age 9. Fiber length increased from 0.57 mm at age 1 to nearly 1.0 mm at age 9. Averaged over all disks at 1.5 m, clones differed significantly in ring width, wood density, and fiber length. Mean values for the two wood properties at 3.0 m were slightly lower than those at 1.5 m and did not differ significantly among clones. Within clone correlations between ring width and wood density or fiber length or between wood properties were low, and generally non significant or inconsistent. Close

• 3. [Article] Effects of live crown on vertical patterns of wood density and growth in Douglas-fir

  It would be valuable economically to know what are the biological triggers for formation of mature wood (currently of high value) and (or) what maintains production of juvenile wood (currently of low value), ...

  Citation × Citation Citation Abstract Copy Title: Effects of live crown on vertical patterns of wood density and growth in Douglas-fir Author: Gartner, B. L., Johnson, G. R., North, E. M., Singleton, R. It would be valuable economically to know what are the biological triggers for formation of mature wood (currently of high value) and (or) what maintains production of juvenile wood (currently of low value), to develop silvicultural regimes that control the relative production of the two types of wood. Foresters commonly assume the bole of softwoods produces juvenile wood within the crown and mature wood below. We tested that assumption by comparing growth ring areas and widths and wood density components of the outer three growth rings in disks sampled from different vertical positions of 34-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees. The 18 trees were sampled from one site and had a wide range of heights to live crown. Most of the variance (63–93%) in wood characteristics (growth ring area: total, earlywood, latewood; growth ring width: total, earlywood, latewood; latewood proportion: by area, width; and ring density: total, earlywood, latewood) was due to within-tree differences (related to age of the disk). Stepwise regression analysis gave us equations to estimate wood characteristics, after which we analyzed the residuals with a linear model that included whether a disk was within or below the crown (defined as the lowest node on the stem with less than three live branches). After adjusting for tree and disk position, only 2–10% of the residual variation was associated with whether the disk was in or out of the live crown. There were no statistically significant differences at p = 0.05 between a given disk (by node number) in versus out of the crown for any of the factors studied. Moreover, the wood density characteristics were not statistically significant at p = 0.30. This research suggests that there was no effect of the crown position on the transition from juvenile to mature wood as judged by wood density. Therefore, we found no evidence to support the concept that tree spacing and live-branch pruning have a significant effect on the cambial age of transition from juvenile to mature wood in Douglas-fir trees of this age. Title: Effects of live crown on vertical patterns of wood density and growth in Douglas-fir Author: Gartner, B. L., Johnson, G. R., North, E. M., Singleton, R. It would be valuable economically to know what are the biological triggers for formation of mature wood (currently of high value) and (or) what maintains production of juvenile wood (currently of low value), to develop silvicultural regimes that control the relative production of the two types of wood. Foresters commonly assume the bole of softwoods produces juvenile wood within the crown and mature wood below. We tested that assumption by comparing growth ring areas and widths and wood density components of the outer three growth rings in disks sampled from different vertical positions of 34-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees. The 18 trees were sampled from one site and had a wide range of heights to live crown. Most of the variance (63–93%) in wood characteristics (growth ring area: total, earlywood, latewood; growth ring width: total, earlywood, latewood; latewood proportion: by area, width; and ring density: total, earlywood, latewood) was due to within-tree differences (related to age of the disk). Stepwise regression analysis gave us equations to estimate wood characteristics, after which we analyzed the residuals with a linear model that included whether a disk was within or below the crown (defined as the lowest node on the stem with less than three live branches). After adjusting for tree and disk position, only 2–10% of the residual variation was associated with whether the disk was in or out of the live crown. There were no statistically significant differences at p = 0.05 between a given disk (by node number) in versus out of the crown for any of the factors studied. Moreover, the wood density characteristics were not statistically significant at p = 0.30. This research suggests that there was no effect of the crown position on the transition from juvenile to mature wood as judged by wood density. Therefore, we found no evidence to support the concept that tree spacing and live-branch pruning have a significant effect on the cambial age of transition from juvenile to mature wood in Douglas-fir trees of this age. Close