Canadian Forest Service Publications

Canadian national taper models. 2013. Ung, C.-H.; Guo, X.J.; Fortin, M. For. Chron. 89:211-224.

Year: 2013

Issued by: Laurentian Forestry Centre

Catalog ID: 34713

Language: English

Availability: PDF (request by e-mail)

Mark record


Work was done to gather stem taper data for most forest tree species across Canada. They were used for producing taper models to be applied for the purposes of the national forest inventory and for regional purposes when regional taper models are not available. The models are based on squared DBH and on measured or predicted tree height. A taper equation based on the dimensional analysis approach was adopted to fit Canadian national taper models using the collected data. The model parameters were estimated using a mixed model for taking into account variance heterogeneity and within-tree autocorrelation. In spite of the different protocols for data collection, the accuracy of the proposed stem taper models is similar to that found in previous studies. Consequently, the models seem suitable for pre-harvest estimation of sawlog volume nationally or regionally.

Plain Language Summary

The taper of a tree is a characteristic of the stem, which decreases in diameter from bottom to top. Tree taper data is used to maximize the value of processed wood while making it possible to calculate wood volume from any crosscut in the tree.

Using taper data gathered by the Canadian Forest Service, researchers developed taper models in which the inputs are two measurements available from all forest inventory data in Canada: tree diameter at breast height (1.3 m above the ground) and height.

The accuracy of these national taper models is similar to that found in previous studies. These models, however, have the advantage of being standardized throughout Canada, thus facilitating compilations and comparisons of wood production between Canada's forest regions.