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Dry-matter production and complete-tree utilization of lodgepole pine in Alberta

University of British Columbia

Lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) is a species of considerable importance to the forest economies of Alberta and the Interior of British Columbia. The objectives of the present thesis are: a. to present the results of studies of the dry-matter production, growth, and complete-tree utilization of 100-year-old lodgepole pine trees, b. to compare the yields of dry-matter from 100-year-old lodgepole pine stands grown under a variety of site and stand density conditions, and c. to compare the above-ground total standing crops of similarly aged lodgepole pine and Populus stands grown on similar sites. Tree and component weights of eighty-five, 100-year-old lodgepole pine trees from two average density stands and two-hundred and twenty-one, 100-year-old lodgepole pine trees from one high density stand located in southwestern Alberta were examined. Both graphical and regression techniques were used to develop allometric relationships between the component dry-weights and some easily measured tree characteristics. Of the independent variables tested, the combined variable of tree diameter at breast height squared times total tree height (D²H) was most closely associated with the component dry-weights. Reliable estimates of tree and component weights were obtained using the aforesaid independent variable. The systematic errors (underestimates) resulting from the use of logarithmic equations were examined and correction factors for these errors are presented. Estimates of component biomass were obtained using allometric equations, the stand-table and height-diameter data from eighty-eight of 100-year-old lodgepole pine trees covering a range of site and stand density condition. The combined variable of stand basal area times mean stand height (BA•H) was closely associated with most component dry-weights per acre. Although total tree and component biomass per acre were positively correlated with basal area per acre they were inversely related to number of stems per acre on a given site. Fresh- and dry-weight estimates, by component, were obtained from two paired, young lodgepole pine and Populus stands grown in west central Alberta. Equations for the estimation of the component dry-weights of young lodgepole pine trees are presented. For the sites examined, the above-ground total stand crop of the young lodgepole pine stands was substantially higher than that of similarly aged Populus stands grown on similar sites. Some possible reasons for these differences in productivity are discussed. Within and between tree variations in radial, cross-sectional area, and volume growth were examined for twenty, 100-year-old lodgepole pine trees. Ten trees were sampled from both a thinned and an unthinned stand. Although volume growth was found to be highly correlated with the amount of foliage, volume growth efficiency (growth per unit of foliage) was not related to tree size. Equations for relating the amount of growth at any point in the tree to the needle biomass at or above that point in the tree are presented. A large amount of within tree variation in growth was not accounted for by these relationships. Thinning did not appear to affect the pattern of growth of the trees examined. Suggestions for further research on the growth patterns as related to foliage biomass are presented. Ten pulp sample trees, two from each of the 4-, 6-, 8-, 10-, and 12-inch diameter classes, were collected from two average density, 100-year-old stands of lodgepole pine grown in southwestern Alberta. The oven-dry, bark-free weights of the merchantable stem (4.0-inch top), non-merchantable top (4.0- to 1.0-inch top), branch (> 1.0 inch diameter), and root-stump (> 1.0 inch diameter) components were measured for each tree. The relationships between the quantity of these components, expressed as a percentage of the oven-dry, bark-free full bole, and tree size are presented. The relationships between tree size, and the yield and quality of kraft pulp produced from each component are examined. A significant positive relationship was found between tree size and the unscreened yield of pulp from the full bole component only. No significant relationships were found between tree size or growth rate and pulp quality for any of the components. Variations in the yield and quality of kraft pulp at different locations within a single tree are examined and discussed. Because the yield and quality of pulp from the non-merchantable top was found to be relatively high and because quantity of this component per acre may be substantial in some stands, immediate consideration should be given to its utilization. Although the yield and quality of pulp from the root-stump system was found to be high, utilization of this component in the near future is doubtful because of the technical problems associated with extraction, cleaning, transporation, and processing. Similarly, utilization of branches in the near future is doubtful because of the low yield and quality of pulp from branchwood and because of the processing problems associated with its utilization. Nine highly suppressed, 100-year-old lodgepole pine trees from a high density stand in southwestern Alberta were collected for pulping studies. Kraft pulp yield and quality data are presented for the bole and root-stump components. The results demonstrate that the utilization of these small diameter trees for the manufacture of pulp depends upon economic harvesting and processing and not pulp yield and quality.

Text

2011-03-04

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http://hdl.handle.net/2429/32022

Forestry

University of British Columbia

Graduate