Canadian Forest Service Publications

Sensitivity of predictions of merchantable tree height, log production, and lumber recovery to tree taper. 2013. Li, C.; Barclay, H.; Huang, S.; Hans, H.; Ghebremusse, S. The Forestry Chronicle 89(6):741-751.

Year: 2013

Issued by: Northern Forestry Centre

Catalog ID: 35321

Language: English

CFS Availability: Order paper copy (free), PDF (request by e-mail)

Mark record


Tree taper models characterize the change in diameter from the bottom to the top of a tree, thereby contributing to the estimation of tree volume. This paper examines the sensitivity of predictions of merchantable height defined as the tree height at a given top diameter inside bark (DIB) determined by the utilization standard, log production, and lumber recovery to the eight parameters in Kozak’s (1988) tree taper model. We found that predictions of merchantable height and log production were sensitive to two parameters, whereas predictions of the percentage of lumber recovery were sensitive to one parameter. Because the three measures examined in this study are not very sensitive to tree taper, especially the percentage of lumber recovery that is of most concern to the forest industry, together with the relatively small variations in tree taper parameters across Canada and the limited contribution of tree taper to characterizing the value of lumber recovery at the stand scale, one could infer that it may be possible to develop a single Canadian national softwood tree taper model for predicting forest product variables such as log production and percentage of lumber recovery from forest inventory.

Plain Language Summary

This paper reflected our first step in an effort to estimate potential forest products such as logs and lumber directly from data about forest inventory. Good estimates would improve decision-making for optimal use of wood resources. We analyzed typical tree inventory data such as diameter at breast height and total tree height using a mathematical model (Kozak’s taper model) to calculate merchantable tree height and log production. We also estimated lumber recovery (percentage of lumber yield) using Optitek, an industrial software package for optimizing sawmill operations. Results showed that some parameters from the models fairly closely predicted merchantable height, log production, and lumber recovery. Combined with other research results, these findings indicate that a single softwood tree taper model could be used across Canada to predict forest product yield from forest inventory data.