EFFECTS OF SITE PREPARATION TIME ON SEED GERMINATION AND SEEDLING SURVIVAL RATE IN MIXED SPECIES CONIFER FOREST STANDS IN GIRESUN, TURKEY

摘要

This study was undertaken to investigate the effects of the year of site preparation relative to that of large-scale seed dispersal on seed germination and seedling survival success for natural regeneration of oriental spruce in a mixed forest of oriental spruce (Picea orientalis) and Caucasian fir (Abies nordmanniana) in the Pa?akonagi region of Giresun province, Turkey. Two ecologically similar sites, both 120 years of age with an area of 12 ha (site 20) or 15 ha (site 21) were selected. Seed-tree cutting, site preparation and soil tillage activities were performed in "site 20" in 2014, which was a low seed year, and in "site 21" in 2015, which was an abundant seed year, respectively. Oriental spruce trees at both sites dispersed an average of 363 seeds/m~2 in the abundant seed year of 2015, and 92,840 and 143,704 oriental spruce seedlings per ha germinated from these seeds in 2016 in sites 20 and 21, respectively. Seedling number decreased significantly until May 2018 by 34.04% and 49.82% in "site 20" and 21, respectively (P<0.05). The greatest significant decrease took place during the first winter germination occurred. Taller and stockier seedlings occurred at "site 21" where site preparation and soil tillage was carried out in the same year as seed dispersal (P<0.05).