A destructive sampling method to estimate the age of first-order branches is presented. The proposed method can be applied only to living tree species showing annual growth rings. The implementation requires an estimate of total tree height development applying stem analysis techniques and the measurement of stem height and insertion angle for a sample of first-order branches. The developed procedure allows estimating the age and year of branch formation, and the maintenance of branches within the death and live crown. It can be considered an alternative to branch dissection methods. The algorithms’ implementation is illustrated for a 48-year old Nothofagus obliqua (Mirb.) Oerst. tree.