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Estimation of the parameters in the allometric equation by fitting a simple linear regression to the logarithmically transformed variables results in biased estimates of the arithmetic mean. This bias expressed as a percent of the mean approaches the limit −(1 − e−σ2/2) (100) as n increases. An adjusted estimator developed by Finney rather than the one given by Baskerville should be used when s2 is large and n is small. A change of measurement scale of the x or y variables presents no difficulty, but problems arise if variables are transformed to logarithms other than base e.

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Predicting volume directly from stump dimensions is useful in many situations, such as timber trespass. In the present study, equations for predicting diameter at breast height (dbh) and tree volume from stump diameter outside bark were developed for three economically important tree species in the forest region of Bucak, Turkey. Diameter at breast height was estimated with relatively high accuracy using a simple linear model. Tree volume was estimated with high precision using an exponential equation. Weighted linear and non-linear least squares methods were used to consider heteroscedasticity observed in the volumeÁstump diameter relationships. The results of a non-linear extra sum of squares method and of the F test indicated that different equations are needed for estimating dbh and tree volume from stump diameter outside bark for different species.