Combining Ring Counting and Ring Width for Estimating Height in Stem Analysis

This article presents a general conceptual framework for seven methods of estimating the height to a given age by stem analysis, which involves estimates of periodical annual increment in height. To estimate the height, a fraction of the periodical increment in height, which is cumulated in a time fraction of the respective period, is assigned to every hidden tip. Traditional methods of height estimation in stem analysis can be grouped into two broad sets, depending on how the time fraction associated with every hidden tip is determined. By combining time fractions from both groups, two mixed methods were derived and compared with traditional methods to determine the most advantageous method under variations in the crosscut intensity and regularity along the stem and variations in the regularity of current annual increments in total height and stem radius throughout the tree's life. The combined methods were more accurate than traditional methods when sampling schemes that involve long distances between crosscuts are carried out and especially when sampling combines variable distances between crosscuts. If a sample were available, simultaneously combining crosscuts at varying distances taken from trees having varying degrees of irregularities in stem radius and height increments, the combined methods would surpass traditional methods in accuracy.