In total 16 branches of three individuals were cut in the field into 10 cm-long pieces and dried. Samples were sanded using sandpaper and decreasing grain size until the surface was even and the tree rings clearly visible and then scanned at 4800 dpi on a flatbed scanner. Tree rings were counted in Coorecorder (Cybis Elektronik & Data AB) at the oldest part and the middle pieces, and for the longest branch at four positions.