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A simple stem taper model with mixed effects for boreal black spruce

Summary

Published in European Journal of Forest Research 128(5): 505-513

We simplified Kozak's taper model by setting the inflection point at 1.3 m (dbh) without losing accuracy and precision. The simplification was required to facilitate the estimation of the covariance parameters when using a mixed-effects method. This method was necessary to take into account the correlation among multiple diameter measurements on an individual stem. The simple stem taper model was fitted to an extended data set collected across the province of Québec, Canada. Comparison of the predicted stem taper and the derived stem volume with those obtained using existing models showed a comparable predictive power for the simple model. Including a prediction of the tree random effects based on supplementary diameter measurements of the bole improves the predictive ability of the model around the extra diameter observation. This model offers welcome simplicity as a means of predicting tree taper at coarse resolution for planning tree harvesting.

Sector(s): 

Forests

Categorie(s): 

Scientific Article

Theme(s): 

Forestry Research, Forests, Silviculture

Departmental author(s): 

Lambert, Marie-Claude

Author(s)

LEJEUNE, Geneviève, Chhun-Huor UNG, Mathieu FORTIN, Xiao Jing GUO, Marie-Claude LAMBERT and Jean-Claude RUEL

Year of publication :

2009

Format :

PDF available upon request

Keywords :

Picea mariana, silviculture and yield of natural forests - softwood stands, random effects, black spruce, stem taper, variable-exponent taper equation

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