Accurate tree positions play a vital role in precision forestry and environmental sciences. In this study, we propose an accurate, efficient, and adaptable method for tree localization by integrating heading, diameter at breast height (DBH), and ultra-wideband technology. The proposed method is simple to implement in different forest environments and can determine the position of each tree within a few seconds. Compared with traditional field measures, such as laser rangefinders and inclinometers, the proposed approach is more efficient. In comparison with commonly used measures, such as terrestrial laser scanning (TLS) and mobile laser scanning (MLS), the proposed method is more cost-effective and easier to implement, making it particularly suitable for natural forests that are remote from roads yet require accurate measurements. Field experiments were conducted in a managed boreal forest in southern Finland, characterized by minimal understory vegetation and good visibility, where a total of 50 trees were mapped. Experimental results indicate that the proposed method can accurately determine tree positions with an RMSE of 0.12 m and an MAE of 0.11 m.