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• 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] Does photosynthetic bark have a role in the production of core vs. outer wood?

  This paper hypothesizes a correlation in some species between the cambial age of transition from core (juvenile) to outer (mature) wood and the cambial age of transition from photosynthetic to non-photosynthetic ...

  Citation × Citation Citation Abstract Copy Title: Does photosynthetic bark have a role in the production of core vs. outer wood? Author: Gartner, B. L. This paper hypothesizes a correlation in some species between the cambial age of transition from core (juvenile) to outer (mature) wood and the cambial age of transition from photosynthetic to non-photosynthetic bark. Secondly, this paper hypothesizes that the relationship is causal: a signal produced in relation to the photosynthetic bark affects wood development a few millimeters away. It is further hypothesized that the photosynthetic periderm is replaced by a non-photosynthetic one at light levels below its light compensation point. In Tsuga heterophylla and Pseudotsuga menziesii var. menziesii, the cambial age at which the first periderm dies (the base of photosynthetic bark) ranges from 16 to 33 and 12 to 43 years, respectively, for four Oregon Coast Range populations. These values are in the same range as the cambial ages of transition from core to outer wood, as shown by literature values and data reported here on tracheid length in T. heterophylla. In both species, the cambial age at the base of the live crown is not coincident with, nor consistently higher or lower than, the height of the lowest photosynthetic bark. Data presented here are consistent with the photosynthetic bark hypothesis of formation of core wood, but manipulative studies are needed to further explore the relationship. Title: Does photosynthetic bark have a role in the production of core vs. outer wood? Author: Gartner, B. L. This paper hypothesizes a correlation in some species between the cambial age of transition from core (juvenile) to outer (mature) wood and the cambial age of transition from photosynthetic to non-photosynthetic bark. Secondly, this paper hypothesizes that the relationship is causal: a signal produced in relation to the photosynthetic bark affects wood development a few millimeters away. It is further hypothesized that the photosynthetic periderm is replaced by a non-photosynthetic one at light levels below its light compensation point. In Tsuga heterophylla and Pseudotsuga menziesii var. menziesii, the cambial age at which the first periderm dies (the base of photosynthetic bark) ranges from 16 to 33 and 12 to 43 years, respectively, for four Oregon Coast Range populations. These values are in the same range as the cambial ages of transition from core to outer wood, as shown by literature values and data reported here on tracheid length in T. heterophylla. In both species, the cambial age at the base of the live crown is not coincident with, nor consistently higher or lower than, the height of the lowest photosynthetic bark. Data presented here are consistent with the photosynthetic bark hypothesis of formation of core wood, but manipulative studies are needed to further explore the relationship. Close

• 3. [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

• 4. [Article] Effects of pruning on wood density and tracheid length in young Douglas-fir

  To study whether pruning young Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) hastens the transition from juvenile to mature wood, we investigated the effects on wood properties in an ...

  Citation × Citation Citation Abstract Copy Title: Effects of pruning on wood density and tracheid length in young Douglas-fir Author: Gartner, B. L., Robbins, J. M., Newton, M. To study whether pruning young Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) hastens the transition from juvenile to mature wood, we investigated the effects on wood properties in an intensively managed young plantation in the Coast Range of Oregon. Ten years after trees were pruned to a fixed height (3.4 or 5.5 m), we investigated the effects on wood density (in 12 trees per pruning treatment, two or three treatments per age class, three age classes, and two heights for a total of 168 cores) and tracheid length (in four trees per treatment, one height and age class only, for 12 trees total). The trees were 13, 16, and 18 years old when pruned in 1988. Removal of 50% of the live crown in young trees caused a small one-year decline in growth ring width at breast height, but removal of 30% of the live crown did not. In partial contrast, pruning caused no detectable effect on wood density at breast height, presumably because the branches were in the lower crown, and were not contributing much to the growth of the bole. Pruning caused a small increase in wood density at the upper height (5.3 m) in the youngest age class (for which this 5.5 m pruning would be removing vigorous live branches at this height) but not in the medium age class (for which the pruning would be removing lower live crown at this height) or in the oldest age class (for which there would have been no live branches at 5.5-m). Pruning the youngest trees caused a 3–4 year increase in tracheid length at breast height. In summary, pruning had very small or no effect on growth ring width, density, or tracheid length; but the effects that it had were the ones expected if pruning accelerated the transition from juvenile to mature wood. The larger benefit of pruning, especially if done early in rotation, is to shorten branch healing time and provide for a longer period of clear wood production. Title: Effects of pruning on wood density and tracheid length in young Douglas-fir Author: Gartner, B. L., Robbins, J. M., Newton, M. To study whether pruning young Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) hastens the transition from juvenile to mature wood, we investigated the effects on wood properties in an intensively managed young plantation in the Coast Range of Oregon. Ten years after trees were pruned to a fixed height (3.4 or 5.5 m), we investigated the effects on wood density (in 12 trees per pruning treatment, two or three treatments per age class, three age classes, and two heights for a total of 168 cores) and tracheid length (in four trees per treatment, one height and age class only, for 12 trees total). The trees were 13, 16, and 18 years old when pruned in 1988. Removal of 50% of the live crown in young trees caused a small one-year decline in growth ring width at breast height, but removal of 30% of the live crown did not. In partial contrast, pruning caused no detectable effect on wood density at breast height, presumably because the branches were in the lower crown, and were not contributing much to the growth of the bole. Pruning caused a small increase in wood density at the upper height (5.3 m) in the youngest age class (for which this 5.5 m pruning would be removing vigorous live branches at this height) but not in the medium age class (for which the pruning would be removing lower live crown at this height) or in the oldest age class (for which there would have been no live branches at 5.5-m). Pruning the youngest trees caused a 3–4 year increase in tracheid length at breast height. In summary, pruning had very small or no effect on growth ring width, density, or tracheid length; but the effects that it had were the ones expected if pruning accelerated the transition from juvenile to mature wood. The larger benefit of pruning, especially if done early in rotation, is to shorten branch healing time and provide for a longer period of clear wood production. Close

• 5. [Article] Do gymnosperm needles pull water through the xylem produced in the same year as the needle?

  The original was published at http://www.amjbot.org/.

  Citation × Citation Citation Abstract Copy Title: Do gymnosperm needles pull water through the xylem produced in the same year as the needle? Author: Gartner, B. L., Maton, C. The original was published at http://www.amjbot.org/. Title: Do gymnosperm needles pull water through the xylem produced in the same year as the needle? Author: Gartner, B. L., Maton, C. The original was published at http://www.amjbot.org/. Close

• 6. [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

• 7. [Article] Sinuous stem growth in a Douglas-fir (Pseudotsuga menziesii) plantation: growth patterns and wood-quality effects

  Stem sinuosity is thought to negatively impact wood quality, but no studies have characterized its vertical and radial effects on wood properties. Here we study wood quality along the entire stem in 25-year-old ...

  Citation × Citation Citation Abstract Copy Title: Sinuous stem growth in a Douglas-fir (Pseudotsuga menziesii) plantation: growth patterns and wood-quality effects Author: Darbyshire, R.L., Spicer, R., Gartner, B. L. Stem sinuosity is thought to negatively impact wood quality, but no studies have characterized its vertical and radial effects on wood properties. Here we study wood quality along the entire stem in 25-year-old plantation grown Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) trees (32 trees total) that had been scored for sinuosity at age 12. We also study compression wood formation in the radial direction for one internode that had been scored for sinuosity at age 12 and subsequently produced 13 more annual rings. Trees with highly sinuous leaders at age 12 were more likely to be sinuous in other years, and developed more slope of grain defect (approximately 15% log volume) than less sinuous trees, but did not differ in the size of the pith-containing core. Leaders originally scored as highly sinuous developed more compression wood than control trees but only near the pith. Internode length did not differ among sinuosity classes. The size of the pith deviations (radial distance from centreline) remained constant up the stem despite a decline in internode length. However, the frequency of pith deviations was highest at 10–15 years, when internode length reached a peak. The relationship between temporal patterns of growth rate, sinuosity, and tree biomechanics deserves further attention. Title: Sinuous stem growth in a Douglas-fir (Pseudotsuga menziesii) plantation: growth patterns and wood-quality effects Author: Darbyshire, R.L., Spicer, R., Gartner, B. L. Stem sinuosity is thought to negatively impact wood quality, but no studies have characterized its vertical and radial effects on wood properties. Here we study wood quality along the entire stem in 25-year-old plantation grown Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) trees (32 trees total) that had been scored for sinuosity at age 12. We also study compression wood formation in the radial direction for one internode that had been scored for sinuosity at age 12 and subsequently produced 13 more annual rings. Trees with highly sinuous leaders at age 12 were more likely to be sinuous in other years, and developed more slope of grain defect (approximately 15% log volume) than less sinuous trees, but did not differ in the size of the pith-containing core. Leaders originally scored as highly sinuous developed more compression wood than control trees but only near the pith. Internode length did not differ among sinuosity classes. The size of the pith deviations (radial distance from centreline) remained constant up the stem despite a decline in internode length. However, the frequency of pith deviations was highest at 10–15 years, when internode length reached a peak. The relationship between temporal patterns of growth rate, sinuosity, and tree biomechanics deserves further attention. Close

• 8. [Article] Impact of the foliar pathogen Swiss needle cast on wood quality of Douglas-fir

  Many stands of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) near coastal areas of Oregon and Washington are heavily infected with the foliar pathogen causing Swiss needle cast (SNC) disease, and ...

  Citation × Citation Citation Abstract Copy Title: Impact of the foliar pathogen Swiss needle cast on wood quality of Douglas-fir Author: Gartner, B. L., Johnson, G. R., Grotta, A. T., Downes, G. Many stands of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) near coastal areas of Oregon and Washington are heavily infected with the foliar pathogen causing Swiss needle cast (SNC) disease, and yet there is very little research on the resulting wood quality. Modulus of elasticity (MOE), modulus of rupture (MOR), microfibril angle (MFA), wood density, latewood proportion, and sapwood moisture content were examined in 20- to 28-year-old trees from 15 stands that were infected with varying intensities of SNC. SNC severity was quantified by measuring needle retention, the number of needle cohorts retained at three crown levels. Correlations between disease severity and wood properties were examined at both the stand and within-stand levels. Trees from heavily infected stands (needle retention <2 years) had higher MOE, wood density, and latewood proportion and lower sapwood moisture content than trees from healthier stands. Breast-height age (BHage) was also correlated with these properties, but age alone did not explain all of the increases. MFA was not associated with SNC severity. Within stands, needle retention was not associated with MOE or MOR. The increase in latewood proportion in diseased stands appears to be the driving factor behind their increase in stiffness (MOE). Ring width decreased with decreased needle retention, and the examined wood properties generally showed stronger correlations with ring width than with needle retention. Title: Impact of the foliar pathogen Swiss needle cast on wood quality of Douglas-fir Author: Gartner, B. L., Johnson, G. R., Grotta, A. T., Downes, G. Many stands of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) near coastal areas of Oregon and Washington are heavily infected with the foliar pathogen causing Swiss needle cast (SNC) disease, and yet there is very little research on the resulting wood quality. Modulus of elasticity (MOE), modulus of rupture (MOR), microfibril angle (MFA), wood density, latewood proportion, and sapwood moisture content were examined in 20- to 28-year-old trees from 15 stands that were infected with varying intensities of SNC. SNC severity was quantified by measuring needle retention, the number of needle cohorts retained at three crown levels. Correlations between disease severity and wood properties were examined at both the stand and within-stand levels. Trees from heavily infected stands (needle retention <2 years) had higher MOE, wood density, and latewood proportion and lower sapwood moisture content than trees from healthier stands. Breast-height age (BHage) was also correlated with these properties, but age alone did not explain all of the increases. MFA was not associated with SNC severity. Within stands, needle retention was not associated with MOE or MOR. The increase in latewood proportion in diseased stands appears to be the driving factor behind their increase in stiffness (MOE). Ring width decreased with decreased needle retention, and the examined wood properties generally showed stronger correlations with ring width than with needle retention. Close

• 9. [Article] Fiber length in young hybrid Populus stems grown at extremely different rates

  Length of libriform fibers was measured in rings 2 7 at breast height in 7-year-old hybrid poplar stems from two clones (11-11, a Populus trichocarpa Torr. & Gray ´ P. deltoides Bartr. ex Marsh. hybrid; ...

  Citation × Citation Citation Abstract Copy Title: Fiber length in young hybrid Populus stems grown at extremely different rates Author: Gartner, B. L., DeBell, J. D., DeBell, D. S. Length of libriform fibers was measured in rings 2 7 at breast height in 7-year-old hybrid poplar stems from two clones (11-11, a Populus trichocarpa Torr. & Gray ´ P. deltoides Bartr. ex Marsh. hybrid; and D-01, of unknown taxonomic identity) grown in a controlled test of three spacings (0.5, 1.0, and 2.0 m) on an irrigated and fertilized site in western Washington. In each clone, samples included a very wide range of cambial growth rates, with ring widths from 1 to 19 mm. Growth rate, expressed in several ways, had no consistent effect on fiber length within rings of the same age for rings 2 6. For ring 7, however, there were positive correlations between most growth rate measures and fiber length. Whole-disk fiber length increased with overall growth rate as measured by stem diameter; this apparent anomaly is caused by the fact that fast-growing trees have more of their basal area concentrated in rings further from the pith than do slower growing trees, and these rings have longer fibers compared with rings closer to the pith. Title: Fiber length in young hybrid Populus stems grown at extremely different rates Author: Gartner, B. L., DeBell, J. D., DeBell, D. S. Length of libriform fibers was measured in rings 2 7 at breast height in 7-year-old hybrid poplar stems from two clones (11-11, a Populus trichocarpa Torr. & Gray ´ P. deltoides Bartr. ex Marsh. hybrid; and D-01, of unknown taxonomic identity) grown in a controlled test of three spacings (0.5, 1.0, and 2.0 m) on an irrigated and fertilized site in western Washington. In each clone, samples included a very wide range of cambial growth rates, with ring widths from 1 to 19 mm. Growth rate, expressed in several ways, had no consistent effect on fiber length within rings of the same age for rings 2 6. For ring 7, however, there were positive correlations between most growth rate measures and fiber length. Whole-disk fiber length increased with overall growth rate as measured by stem diameter; this apparent anomaly is caused by the fact that fast-growing trees have more of their basal area concentrated in rings further from the pith than do slower growing trees, and these rings have longer fibers compared with rings closer to the pith. Close

• 10. [Article] Effect of growth rate on the anatomy, specific gravity, and bending properties of wood from 7-year-old red alder (Alnus rubra)

  Understanding the association between growth rate and wood properties is of practical importance to maximizing and sustaining wood and fiber production. Anatomical characteristics, specific gravity, and ...

  Citation × Citation Citation Abstract Copy Title: Effect of growth rate on the anatomy, specific gravity, and bending properties of wood from 7-year-old red alder (Alnus rubra) Author: Milota, M. R., Gartner, B. L., Lei, H. Understanding the association between growth rate and wood properties is of practical importance to maximizing and sustaining wood and fiber production. Anatomical characteristics, specific gravity, and bending properties were determined at breast height for thirty 7-year-old trees with varying growth rates, from a red alder (Alnus rubra Bong.) plantation. Wood was sampled from the growth ring with a cambial age of 5 years. Growth varied from 2.0 to 9.3 mm/year (ring width), or 264 to 3350 mm2/year (ring area). We analyzed the relationship between growth rate, in terms of both annual ring width and area, and each wood property. Because both measures of growth rate yielded the same qualitative results, we only used ring width in our analyses. Regression analysis showed that growth rate had no effect on specific gravity, the modulus of elasticity in bending, the modulus of rupture in bending, fiber diameter, or the proportion of growth ring that was fiber or vessel. Fiber length, vessel diameter, and ray proportion, however, were positively correlated with growth rate. Fiber-wall thickness and axial parenchyma proportion decreased slightly with growth rate. The results indicate that the growth rate of A. rubra trees can be increased through silvicultural practices with few negative effects on wood and fiber quality, at least in the juvenile wood zone of the stem. Title: Effect of growth rate on the anatomy, specific gravity, and bending properties of wood from 7-year-old red alder (Alnus rubra) Author: Milota, M. R., Gartner, B. L., Lei, H. Understanding the association between growth rate and wood properties is of practical importance to maximizing and sustaining wood and fiber production. Anatomical characteristics, specific gravity, and bending properties were determined at breast height for thirty 7-year-old trees with varying growth rates, from a red alder (Alnus rubra Bong.) plantation. Wood was sampled from the growth ring with a cambial age of 5 years. Growth varied from 2.0 to 9.3 mm/year (ring width), or 264 to 3350 mm2/year (ring area). We analyzed the relationship between growth rate, in terms of both annual ring width and area, and each wood property. Because both measures of growth rate yielded the same qualitative results, we only used ring width in our analyses. Regression analysis showed that growth rate had no effect on specific gravity, the modulus of elasticity in bending, the modulus of rupture in bending, fiber diameter, or the proportion of growth ring that was fiber or vessel. Fiber length, vessel diameter, and ray proportion, however, were positively correlated with growth rate. Fiber-wall thickness and axial parenchyma proportion decreased slightly with growth rate. The results indicate that the growth rate of A. rubra trees can be increased through silvicultural practices with few negative effects on wood and fiber quality, at least in the juvenile wood zone of the stem. Close