Ring width of a given year can be highly variable throughout the cross
section of a stem. This is especially true for roots. Therefore, the entire
circumference of tree rings is often needed for studies focusing on specific
reactions of individual trees on certain environmental conditions. Also, ring
reconstructions are of interest for biomass calculations estimated by the
cross-sectional area.The aim of the study is thus to reconstruct tree rings of
cross sections within a 3D root-surface model, which will be the basis for an
upcoming 3D root-development model. A FARO Scan Arm was used for the
acquisition of the 3D root structure (Technologies Inc.,2010). Afterwards
ring-width data was measured along 4 radii per cross section and the resulting
ring boundaries were integrated into the 3D root model. A weighted
interpolation algorithm was used to reconstruct entire ring-width profiles of
the cross sections. The algorithm considered the ring-width variations of the
adjacent radii as well as the outer shape of the cross section. Hence, the
intention was to estimate ring width around the root circumference using ring
widths measured along 4 radii and the surface dimensions of roots.
Interpolated ring-width data was compared to the measured tree-ring data as a
control for the developed interpolation algorithm. Comparisons between
modelled and empirical values showed a mean absolute error of about 0.06mm
deviation, and with a few exceptions the growth patterns could be accurately
simulated. This has permitted additional radii measurements to be replaced by
modelinterpolations.