Reciprocal distribution of two congeneric trees, Betula platyphylla var. japonica and Betula maximowicziana, in a landscape dominated by anthropogenic disturbances in north-eastern Japan

Oxford

2005

2057-2068

Sonderdruck

12931S

40002915

Information has been compiled on disturbance regimes and the life-history characteristics of Betula platyphylla var. japonica (Miq.) Hara and B. maximowicziana Regel to investigate the impact of humans on the present distribution patterns of these two congeneric tree species. Main conclusions: The earlier reproductive maturity and the shorter life span of B. platyphylla var. japonica indicate a shorter population cycle than that for B. maximowicziana. The latter would be excluded from grasslands that were burned frequently, as a result of the longer time span before initial reproduction and its poor sprouting ability. In contrast, B. platyphylla var. japonica would be excluded from old-growth forests, where disturbance was infrequent, owing to its shorter life span and lack of a persistent seed bank.Keywords: Age at reproduction, anthropogenic disturbances, Betula maximowicziana, Betula platyphylla, birch, distribution pattern, land use, life history, life span, northeastern Japan