Seed sowing density of some tree species of Caspian Forest at Pilambera nursery

Because there is not enough information on the percentage of seed germination of native broad-leaved species of Caspian Forests of lran, seed sowing is usually done with extra density. For this reason, most of the produced seedlings are thin and have low height and diameter growth rate. In case of sowing seeds with low density, the seedling production is not profitable due to few numbers of seedlings per area unit of nursery. The current trial was conducted, using Randomized Complete Blocks Design with three replicates for each species to obtain an ideal density of seed sowing and increase seedlings quality. Four species were tested including Quercus castaneifolia, Tilia begonifolia, Acer velutinum and Fraxinus excelsior. Four seed mass treatments per squar meter of nursery were applied for each species which differ for different species. The plot area was three squar meters. After measuring weight of 100 seeds of each species, the seed mass of each treatment was sawn inside of the plots along five rows. Only the seedlings grown on the three middle rows were considered and studied, leaving the first and the last rows as bufer lines. Space between the rows and between the plots was 20 and 30 cm, respectively. Two seed sowing seasons were planned: spring and autumn. According to the results achieved, autumn was the best, so all of the measurements and evaluations were made in that season. The differences between the seed density treatments were not significant, for all species. Best seed density for Q. castaneifolia, T. begonifolia, A. velutinum and F. excelsior was 500, 100, 40 and 50 g/cm2, respectively.