Effect of Site Quality, Light Environment and Mother Tree on Seed Germination and Seedling Growth of Melia azedarach

Abstract

Melia azedarach (Sendan) has been recently regarded as a promising silvicultural tree in Japan, since it produces straight trunk by bud pruning practices. The objective of this study is to clarify the effect of site quality, canopy openness (light environment) and mother tree on seed germination and seedling growth of Melia azedarach, which will provide important information on establishing its seeding silviculture. A sowing experiment from the same mother tree was conducted in fourteen forest sites from Nagano to Okayama Prefecture in springs of 2015 and 2016. Germination rates varied from 0 to 81％ and seedling height from 5 to 84 cm, depending on places. In April and May of 2016, fruits of Melia azedarach were sown in places with two levels of canopy openness. Germination rates, number of buds per fruit, and seedling height were all positively correlated with canopy openness. Another sowing experiment of three mother trees at a place showed that different provenances exhibited different seedling growth after a growing season. Therefore, it became clear that selection of site quality, light environment and mother tree are important in seeding silviculture of Melia azedarach.