Distribution ofAcer palmatum seedlings under the crown of the maternal tree

To investigate the relationship between crown width of a parent plant and seedling distribution, seedling ages and sizes, and their distances from the maternal tree were surveyed under a maple (Acer palmatum) crown at Chungdam Park, Chungdam-dong, Kangnam-gu, Seoul, in 1998. Maple crown width increased 33.0 cm per year during the eight-year study. Seedlings ranged from 1 to 10 years old; their density was highest the third year, and decreased with age. Seedling-distribution ranges from the parent plant were 43 cm to 487 cm, and seedling density was highest at the border of the parent plant canopy. One-year-old seedlings were distributed broadly, but the main distribution areas became more distant from the maternal plant with seedling age. Seedling heights increased with age; differences between two consecutive ages were significant at the 0.1% level for ages less than 5 years, but not for over 6 years. For seedlings of the same age, heights were similar, but short under the tree crown, but were varied and taller outside the crown. The variation in seedling height increased with age and distance from the parent plant In particular, seedlings older than 5 years that were distributed outside the crown showed conspicuous variations among distance classes. Therefore, maple seedlings were distributed to an appropriate distance at which their growth could be supported by the understory-light environment. This study demonstrated that newA. palmatum trees are not recruited from the seedlings growing beneath the crown but from those that grow vigorously outside the crown.