UBC Theses and Dissertations
Yield and volume tables for aspen in central and northern Alberta MacLeod, William Kenneth
Even-aged well stocked aspen stands in Northern Alberta were sampled in order to derive "normal" yields per acre for number and size of trees, basal area, and various measures of volume. The stands occur chiefly on three qualities of site which have been classified into Pair, Medium and Good by the average height of dominant trees at 80 years. Exceptionally high mortality per decade is characteristic in fully stocked young aspen stands and the relation of number of trees per acre to average diameter is markedly different from the trends found by investigators for other species., A table of stand density units was constructed to permit the, rapid calculation of stand-density index when average diameter and number of trees per acre have been determined. The mean annual cubic volume growth on medium sites is maximum at age 40. For merchantable cubic and board feet, growth reaches a peak at 85 and 130 years respectively. Data from two other regions show that the amount of cull is high in aspen trees above 80 years of age, this indicates that the wood should be utilized before a stand-age of 130 years is reached if maximum return in board foot volume is desired. By 140 years aspen stands show signs of breaking up. The hardwood stands measured were composed mainly of aspen but both white birch and black poplar occurred on many of the plots. The growth of the black poplar is only slightly less than that for the aspen. It has consistently lower volumes per tree which permits the use of aspen volume tables when correction factors are applied.
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