Allometry of winter buds in beech (Fagus sylvatica L.) natural regeneration with respect to its volume and dry weight estimation.

Abstract

Allometric relationships among bud’s fresh volume (V), length (L), maximal diameter (MD), basal
diameter (BD), and dry weight (W) in beech (Fagus sylvatica L.) saplings manifest strong mutual correlations. These correlations depend on the bud type determined by bud position on shoot, shoot type and shoot position in crown. However, in most cases the differences among the bud types are not distinct – individual types can be classified into several overlapping groups. The bud type significantly influences bud shape characterised by the ratios of BD to MD, and BD to L; on the other hand, it has no influence on MD/L and bud density (V/W). Influence of accessible light on bud shape and density also depends on bud type. For non-destructive estimation of V and W, we have prepared a regression model using as independent variable the volume of cylinder enclosing the bud (Vcyl). This model could explain 98% of the variation in V and W, with a relative accuracy of 6.4% for V, and 5.4% for W (P = 0.95). The performance of the model was verified by a test allowing us to conclude that the model outputs are comparable with directly measured values.