Distribution pattern of coniferous seedlings after a partial harvest along a creek in a Canadian Pacific northwest forest

Abstract

In managed forests, partial harvest within riparian areas is one way to provide harvest opportunities and maintain some of the functions of riparian vegetation. We examined the response of coniferous seedlings to a 50 %-partial harvest in a second-growth, coniferous riparian forest in the Pacific Northwest. Partial canopy opening facilitated the establishment of Tsuga heterophylla and Thuja plicata, but Pseudotsuga menziesii did not show the same tendency. Results suggested that differences in seedling establishment were related to differences in light. Increased light availability also stimulated growth of Rubus spectabilis, especially in moist sites, and the dense cover precluded establishment of coniferous seedlings. Once R. spectabilis was established, continued stem recruitment maintained a dense stable cover, and even intense disturbance did not affect the stability of the populations. R. spectabilis would be a major competitor to constrain conifer seedlings to regenerate in riparian zones. Although Gaultheria shallon extended their cover, competition from dense G. shallon was not as severe as from R. spectabilis.