Canadian Forest Service Publications
Estimating tree diameter and volume with a taper model and large-scale photo measurements. 2001. Hall, R.J.; Wang, Y.; Morgan, D.J. Northern Journal of Applied Forestry 18(4): 110-118.
Issued by: Northern Forestry Centre
Catalog ID: 20549
Large-scale photo (LSP) mensurational procedures were developed, in part, to reduce field costs by replacing much of the ground sampling with less expensive photo measurements. The conventional LSP approach uses photo measurements of tree height and crown area, which serve as independent variables in models, to predict tree diameter or volume. This study compared 18 linear and nonlinear model forms for estimating tree diameters and assessed the use of a provincial taper model to estimate total tree volume from LSP data. On average, linear models produce R2, root mean square error, and mean bias values that were at least equivalent to, if not statistically better than, nonlinear models for the range of data evaluated. For lodgepole pine, white spruce and a composite of two deciduous species (trembling aspen and balsam poplar), total volume estimates were not statistically different from those estimated from field measurements. A comparative analysis of LSP and field sampling costs suggests the use of taper models in LSP mensuration could save considerable cost and effort in data collection and model development. This finding may result in an increased use of LSP in operational forest inventory work.