Data-driven strategies for accurate volume-to-biomass conversions

Abstract

ABSTRACT This document presents a method for estimating conversion factors from volume to green weight and from volume to oven dry weight using ratio and linear and nonlinear regression estimators, and the results of its use in nine raw materials, including roundwood from harvest and sawmill offcuts. Although no differences were detected in either the value or accuracy of the linear factors, the linear estimator tended to have slightly higher accuracy than the ratio estimator. Linear conversion factors obtained using regression through the origin were accurate, especially those for roundwood. In general, the conversion factors from volume to green weight were more precise than those from volume to dry weight. Conversion factors from volume to dry weight are useful only in situations in which the moisture range of application is like that used for obtaining those average factors. In addition, given that the green volume-weight factor can be adjusted to the observed moisture in the raw material for which dry weight is intended to be determined, it is advisable to concentrate efforts on this type of factor in future studies. Nonlinear regression estimators are an alternative to linear regression estimators through the origin for determining conversion factors from volume to dry weight. In all the analyzed raw materials, a decrease in the conversion factor from volume to dry weight was observed as the moisture content increased. This is an unexpected outcome that cannot be explained by the variables recorded in this study.