Thinning effects on seedling's biomass of Fraxinus excelsior L. and Acer velutinum Boiss in Nursery

Successful afforestation in destroyed forest areas and forest development requires high quality seedling production in nursery which can grow in adverse conditions, establish and be a dominant over competition with other species. One of the most important activities in nursery which has great effect on seedling quality is thinning. This research was conducted in North of Iran, Mazandaran province, nursery No.1 of Nekachoob company (chalmardy Nursery) to evaluate effects of thinning on quality and quantity of seedling characteristics of Acer insigne and Fraxinus excelsior in different thinning spaces (5, 10, 15, 20 cm and control) using CRB design. The results showed that thinning had significantly effect on leaf dry weight, stem dry weight, root dry weight, biomass. Thinning 20 cm treatment had the greatest impact on the examined factors in both species that increased with increasing distance in thinning. According to the results, the best space for Acer insigne was 15 cm thinning treatment and 20 cm for Fraxinus excelsior. The results of this study could be used for nursery.