Plantations vs. Advance Regeneration: Height Growth Comparisons for Southwestern Oregon

Abstract

Model projections of newly planted Douglas-fir (Pseudotsuga menziesii) seedlings grown under three competition regimes were compared across three site classes with growth of three height classes of Douglas-fir and white fir (Abies concolor) advance regeneration for 20 years following overstory removal. Plantations growing without competition were projected to grow about as fast as advance regeneration on the best sites and slower on the poorer sites. However, over the 20-year period, the projected height of planted trees exceeded only that of released small white fir. Competing vegetation reduced projected plantation growth, thus increasing the height advantage of advance regeneration over planted trees after 20 years. Comparisons such as these are influenced by the time required to establish new plantations, competition faced by released and planted trees, and the species composition, vigor, and initial height of the advance regeneration. These results suggest that managing advance regeneration may be a viable reforestation alternative in southwestern Oregon, particularly on poorer sites. West. J. Appl. For. 7(2):44-47