Establishment by Seeds and Maintenance by Ramets in Elaeagnus umbellate Population

한국산 보리수나무 개체군의 종자에 의한 정착과 라메트에 의한 유지

The establishment by seeds and the maintenance by ramets of the autumn olive (Elaeagnus umbellata) population were investigated in the Namhansansung Provincial Park, Jungbu-myun, Kwangju-gun, Kyunggi-do. Seed production and germination rate were 3, 300 $seeds{\cdot}m^{-2}{\cdot}yr^{-1}$ and 52%, respectively. The ramet formation in the population was classified into 4 types: stump type, creeping root type, lateral root type and secondary creeping root type. The subterranean creeping roots were 0.1~1.0 m in length, 4.5~14.0 mm in diameter and 0.06~0.2 m in soil depth. The number of ramets formed from a node was 1~21. The subterranean roots spread $5~509cm^2{\cdot}plant^{-1}{\cdot}yr^{-1}$, which began to be produced from 7~9 year-old individuals. The number of stems was 1~67 per stump, which was reduced by self-thinning from 2 to 14 year-old trees. The frequency distribution of stem diameter$(D_{30})$ showed a reverse J-shaped curve, suggesting that this population be maintained perpetually by their own ramets.