Proper management of uneven-aged interior Douglas-fir (Pseudotsuga menziesii var. glauca) stands is important for British Columbia’s central and southern interior. These stands constitute one of main components of the operable forest land in these areas, with easy access from main roads and towns. This study focused on the growth of uneven-aged Douglas-fir stands after pre-commercial thinning (spacing), with an impetus to improve upon current management practices. Data were collected from 24 permanent sample plots which were established near Williams Lake, British Columbia in 1989; thinning took place between 1990 and 1991. Three measurements have been made post-treatment: 1993, 1997 and 2004. The plot data were used to analyze different growth responses among three different spacing regimes (standard, 3 m clumped and 5 m clumped spacing) and a control. Analyses were performed at both the stand and tree level. The growth of basal area per ha, quadratic mean dbh, volume per ha and Lorey’s height were used for stand level analyses. At the tree level, dbh, height, basal area and volume were the variables of interest. At the stand level, mortality increased (7.1 to 107.1 stems/ha) and ingrowth decreased (2.4 to 8.6 stems/ha) for the second growth period (1997-2003), compared to the first growth period (5.8 to 107.1 stems/ha and 5.0 to 12.4 stems/ha, respectively). No significant differences in annual growth of quadratic mean dbh, basal area and volume per ha and Lorey’s height were noted between the different spacing regimes and the control. At the individual tree level, the 5 m clumped spacing regime usually had the highest dbh, basal area and volume growth for both growth periods. The one exception was for height growth, when analyzed using mixed-effects modeling, where no significant differences were found. Trees on the other two spacing regimes also had higher growth in dbh, basal area, and volume than trees on the control plots. The positive growth response to the spacing treatments at the single tree level was obtained without a reduction in growth at the stand level. This growth increase will result in the residual trees reaching larger sizes more quickly than they would have with no treatment, leading to improved mule deer winter range habitat and higher timber values.

Several acoustic techniques have been used to determine elastic and damping properties of trees, logs and beams. Time of flight (TOF) measurements in the outerwood of 14-year-old Pinus radiata trees showed that pruning operations increased the outerwood stiffness by up to 25% compared with unpruned trees. However, at the most 5% to 10% of the increased stiffness can be explained by the fact that the outerwood of the pruned trees is free of knots, as TOF measurements are little affected by knots. Thus, it is not known what causes the increase of outerwood stiffness in the pruned trees. One possible explanation could be a smaller microfibril angle (MFA) in the S2 layer of the outerwood cells, which would cause a significant increase in stiffness. Thinning operations decreased the outerwood stiffness by up to 8%. In small Eucalyptus nitens and Pinus radiata logs, which had branch nodes and nodal whorls at specific locations, MOE calculations (using the resonance technique) based on different harmonics gave different results. This indicates that defects do interact with acoustic waves. Acoustic tests on laminated beams with artificial defects (holes filled with dowels) at specific locations also had a significant impact on the MOE. Moreover, it was evident that the damping ratio (evaluated from the Q- factor) of the beams increased with increasing diameter of the holes. However, it was found that holes in laminated beams decreased stiffness while branch nodes and nodal whorls increased stiffness. This shows that relatively small defects, occupying a small volume of the beam, have an impact on acoustic measurements. It is not appropriate to base the MOE calculation on a single harmonic, considering that different harmonics investigate different parts of the specimen

Proper management of uneven-aged interior Douglas-fir (Pseudotsuga menziesii var. glauca) stands is important for British Columbia’s central and southern interior. These stands constitute one of main components of the operable forest land in these areas, with easy access from main roads and towns. This study focused on the growth of uneven-aged Douglas-fir stands after pre-commercial thinning (spacing), with an impetus to improve upon current management practices. Data were collected from 24 permanent sample plots which were established near Williams Lake, British Columbia in 1989; thinning took place between 1990 and 1991. Three measurements have been made post-treatment: 1993, 1997 and 2004. The plot data were used to analyze different growth responses among three different spacing regimes (standard, 3 m clumped and 5 m clumped spacing) and a control. Analyses were performed at both the stand and tree level. The growth of basal area per ha, quadratic mean dbh, volume per ha and Lorey’s height were used for stand level analyses. At the tree level, dbh, height, basal area and volume were the variables of interest. At the stand level, mortality increased (7.1 to 107.1 stems/ha) and ingrowth decreased (2.4 to 8.6 stems/ha) for the second growth period (1997-2003), compared to the first growth period (5.8 to 107.1 stems/ha and 5.0 to 12.4 stems/ha, respectively). No significant differences in annual growth of quadratic mean dbh, basal area and volume per ha and Lorey’s height were noted between the different spacing regimes and the control. At the individual tree level, the 5 m clumped spacing regime usually had the highest dbh, basal area and volume growth for both growth periods. The one exception was for height growth, when analyzed using mixed-effects modeling, where no significant differences were found. Trees on the other two spacing regimes also had higher growth in dbh, basal area, and volume than trees on the control plots. The positive growth response to the spacing treatments at the single tree level was obtained without a reduction in growth at the stand level. This growth increase will result in the residual trees reaching larger sizes more quickly than they would have with no treatment, leading to improved mule deer winter range habitat and higher timber values.

Thesis (Ph. D.)--University of Tennessee, 2007. / Cover title. Includes bibliographical references. Also available via Internet.

Thesis (M.S.)--University of Nevada, Reno, 2007. / "August, 2007." Includes bibliographical references. Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2007]. 1 microfilm reel ; 35 mm.

Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Thesis (M.S.)--Auburn University, 2004. / Abstract. Vita. Includes bibliographical references.

Thesis (M.S.)--Oregon State University, 1997. / Typescript (photocopy). Includes bibliographical references (leaves 80-84). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1999. / Typescript (photocopy). Includes bibliographical references (leaves 67-74). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1999. / Typescript (photocopy). Includes bibliographical references (leaves 91-92). Also available on the World Wide Web.