Temporal variation in species recruitment and dendroecology of an old-growth white oak forest in the Virginia Piedmont, USA

摘要

The composition and temporal variation in species recruitment were examined in relation to annual dendrochronological data to determine the historical development and successional history of an old-growth mixed-oak (Quercus) forest in northern Virginia, USA. A ridge site in the upland Piedmont, along the Potomac River, was used to survey the old-growth forest, which is dominated by Q. alba, Q. rubra, Liriodendron tulipifera, Fagus grandifolia and Carya glabra. The present age structure indicates that the oldest Q. alba established between 1748 and 1790. All tree species other than Q. alba in the forest were <110 yr old, excluding a 166-yr-old Nyssa sylvatica. Q. alba had fairly continuous recruitment between 1740 and 1925. Peak recruitment of Q. rubra and C. glabra occurred between 1900 and 1930. Since 1930, tree recruitment in the forest has been dominated by Fagus, Liriodendron, and Acer rubrum. Releases in radial growth, indicative of moderate- and small-scale disturbances, occurred in most ofthe oldest trees during the last 200 yr. The master tree-ring chronology exhibited a sharp decline from 1837 to 1844, associated with an extremely cold period in the region, followed by a general increase from 1850 to 1930; growth remained high from 1930 to 1998. The shift in dominance from white oak to red oak to mixed-mesophytic tree species after 1900 is consistent with successional variation in other oak forests in the mid-Atlantic region.