Canadian Forest Service Publications

An analysis of measures of density in even-aged balsam fir and jack pine stands. 1964. Vézina, P.E. Forestry Chronicle 40(4): 474-481.

Year: 1964

Issued by: Laurentian Forestry Centre

Catalog ID: 16179

Language: English

Availability: PDF (request by e-mail)

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The concept of stand density in relation to thinning is examined and its development over the years is discussed. Present difficulties of objectively measuring stand density are recognized and probable future trends towards the development of better formulae to express stand density are outlined. Researchers should continue to collect information on interrelationships among stand variables. Certain merits accrue from description of stand density in terms of variables, such as crown closure, that can be measured with some precision from aerial photographs. Conversely, valid estimates of crown closure which are often difficult to obtain by means of devices from the ground, could be predicted from stand density. Three stand variables, used as expressions of stand density, were tested in crown closure simple regressions in even-aged, unmanaged stands of balsam fir (Abies balsamea (L.) Mill.) and jack pine (Pinus banksiana Lamb.). These are: total number of trees, number of trees 4 inches and up, and basal area per acre. The strongest relationship found was the one where crown closure is compared with basal area; it was stronger for jack pine than for balsam fir. This was explained by differences in tolerance among the two species. The significance of these relationships for the stand development, and the feasibility of using height-and diameter-based indices as measures of growing stock in studies of yield are discussed.