Foliage injuries produced by disease-causing organisms or adverse environmental influences may be confined to leaves of a specific age occurring among the "perennial" foliage of coniferous trees. Inadequate information exists concerning the effectiveness of leaves of different ages in promoting the growth of forest trees. An experiment was conducted to assess the effects of artificial removal of foliage of different ages from white pine trees upon height and diameter growth, subsequent axial development and foliage vigor. Although the observations show that all three ages of foliage are utilized in the growth of white pine, it is indicated that during the growing season the one-year-old foliage may be more important than the two-year-old foliage or foliage produced during the current year.