This R package is designed for efficiently recording the shape of all annual rings in a tree trunk cross-section. It interpolates the annual rings (L2) between representative annual ring lines (L) from the annual ring points (P) and representative annual ring lines inputted on radii measured in GIS software (‘Qgis’). A “representative annual ring” refers to the annual rings that characterize the shape of the outer circumference and the cross-section of the disc, requiring fewer rings the closer their shape is to a perfect circle. Although annual rings grow concentrically around the pith, their shape is not perfectly circular. Traditionally, dendrochronology and tree-ring analysis have evaluated tree growth based on the width of the annual rings. However, with the advancement of image analysis technologies, there has been an increasing number of studies evaluating growth based on the area of the annual rings. Most of these studies have focused on conifer plantation samples, where the annual rings are clearly defined. However, this package also enables the recording of annual ring shapes in trees from natural forests, where the ring shapes are more complex. It should be noted, however, that currently, information regarding the shape of the annual rings needs to be manually inputted, which can be labor-intensive.
** see also ** https://www.sanchikanri.com/treering/TreeRingShape.html