Physical properties of black cottonwood and balsam poplar

Abstract

The objective of this study was to characterize selected properties of black cottonwood and balsam poplar to determine whether these species should be distinguished in their utilization. At present, black cottonwood is excluded from the "northern aspen" species group embraced by the National Lumber Grading Agency grading rules for dimension lumber and from use as core material in softwood plywood. Samples of black cottonwood were obtained from three sites in British Columbia. Samples of balsam poplar were obtained from three sites in Alberta. Ten tres were randomly selected from each site and a single 130 cm long bolt was collected immediately above breast height (1.36 m) from each tree. From two trees on each site, three additional bolts of the same length were collected immediately above the height positions located at 25, 50, and 75% of total tree height. The average basic specific gravity of the two species did not differ significantly (black cottonwood, 0.338; balsam poplar, 0.337) in this study. However, differences do exist between site averages, at least for black cottonwood. The initial green moisture contents differ significantly (black cottonwood, 160.5%; balsam poplar, 120.6%) and may be expected to affect their drying requirements differentially. For both species, the specific gravity increases and the green moisture content decreases with increasing height position in the tree. The average fiber length of black cottonwood is significantly longer than that of balsam poplar. The bending properties of strength and stiffness for black cottonwood were found to be significantly greater than for balsam poplar. Variation of these properties with height position in the tree was studied. Fiber length was found to decrease with increasing height position, while the bending strength properties were not affected by height position.

Implications of vertical distribution and within‐stand variation in moisture content for biomass estimation of some willow and hybrid poplar clones

“…However, different species may have different vertical MC profiles (cf. Kellogg & Swan 1986, Sennerby-Forsse 1989, and if stem sections from two stands with contrasting MC profiles are compared, the errors will be additive. Moreover, Salix usually has an MC of about 50% (Kenney et al 1990) and if an MC result (on fresh weight basis) is used to convert a biomass fresh weight estimate to a dry weight estimate, each percentage unit bias in the MC sample will lead to a twofold error in the dry weight estimate.…”

“…Differences in vertical MC between species have been shown for Populus (Kellogg & Swan 1986) and Salix (Stridsberg & Thörnqvist 1984, SennerbyForsse 1989; in which moisture content (when calculated on fresh weight basis) of different height sections varied by 1 to 9 percentage units.…”

“…To reduce the amount of biomass handled, a within-stem sampling procedure is often performed (e.g. Tamminen 1970, Sennerby-Forsse 1985, Kellogg & Swan 1986, Mosseler et al 1988). In short rotation forestry, grown for energy purposes, DC is often used to convert standing biomass results from a fresh weight basis to a dry weight basis (e.g.…”

Populus trichocarpa (Black Cottonwood) As a Model for Plant Genomic Studies: A Review

“…Poplars are dioecious, which means that the male and female blooms grow on different trees. To aid wind pollination, the flowers start blooming in drooping catkins before the leaves appear [8]. The fruits are small in size having thick-walled capsules which contain numerous tiny seeds covered in cottony tufts of silky hairs.…”

Determination of moisture content and basic specific gravity ofPopulus tremuloides(Michx.) andPopulus balsamifera(L.) logs using a portable near-infrared spectrometer

“…Kennedy (1965) reported BSG values for small clear samples of quaking aspen and balsam poplar grown in Canada of, respectively, 0.374 ± 0.024 and 0.372 ± 0.032. The BSG of balsam poplar in Alberta reported by Kellogg and Swan (1986) varies from 0.326 to 0.346 depending on the site. In western USA, a value of 0.38 ± 0.08 has been reported as BSG of quaking aspen (USDA Forest Service 1985).…”