Early selection in Abies sachalinensis was studied to determine the best time to choose trees for breeding. By analyzing tree height and diameter at different ages, researchers found that selecting trees at 10-15 years old gives the highest genetic gain. This means choosing trees at this age leads to better growth and reduces costs compared to selecting trees at 5 years old. This study shows that selecting trees at the right time can improve the quality of forests and save money in the long run.