A 370-year dendroecological history of an old-growth Abies– Acer – Quercus forest in Hokkaido, northern Japan Marc D. Abrams, Carolyn A. Copenheaver, Kazuhiko Terazawa, Kiyoshi Umeki, Mika Takiya, and Nobuhiro Akashi Abstract: Dendroecological techniques were used to study the dynamics and species recruitment patterns, spanning nearly four centuries, for a mesic, montane, old-growth forest in Hokkaido, northern Japan. The forest is dominated by Abies sachalinensis (Masters), Acer palmatum (Thunb.), Quercus mongolica var. grosseserrata (Rehd.), and Cercidiphyllum japonicum (Sieb.). From 1620 to 1750 and 1820 to 1840, Q. mongolica exhibited continuous recruitment into the overstory. A lack of recruitment for all tree species from 1750 to 1820 followed a 1739 volcanic eruption 200 km from the study area. Release events for individual trees occurred almost every decade of the stand history, indicating that frequent small-scale disturbances coupled with infrequent large-scale disturbances, impact tree growth and species recruitment. From 1870 to 1950, canopy recruitment of Abies and Acer dominated the forest, while recruitment of Quercus ceased. These later successional species appeared to be replacing Quercus, suggesting that the syndrome of declining oak dominance is an increasingly global phenomenon. However, successional patterns in the forest are difficult to predict because intensive deer browsing has recently prevented canopy recruitment of all tree species and the possibility of future large-scale disturbances, such as fire and volcanic eruption. Résumé : Des techniques dendroécologiques ont été utilisées pour étudier la dynamique et les patrons de recrutement des espèces, sur près de quatre siècles, d’une vieille forêt montagnarde mésique de l’île de Hokkaido, dans le nord du Japon. La forêt est dominée par l’Abies sachalinensis (Masters), l’Acer palmatum (Thunb.), le Quercus mongolica var. grosseserrata (Rehd.) et le Cercidiphyllum japonicum (Sieb.). De 1620 à 1750 et de 1820 à 1840, le Q. mongolica a montré un recrutement continu dans l’étage dominant. Le manque de recrutement de toutes les espèces entre 1750 et 1820 a suivi une éruption volcanique qui s’est produite en 1739, à 200 km de l’aire étudiée. Le dégagement des arbres individuels s’est produit presque à chaque décennie de l’histoire du peuplement, indiquant que de fréquentes perturbations à petite échelle, combinées à des perturbations peu fréquentes à grande échelle, avaient un impact sur la croissance des arbres et le recrutement des espèces. De 1870 à 1950, le recrutement dans la canopée d’Abies et d’Acer a dominé la forêt, tandis que celui du Quercus a cessé. Ces dernières espèces successionnelles semblaient être en train de remplacer le Quercus, suggérant que le syndrome du déclin de la dominance du chêne est un phénomène de plus en plus global. Toutefois, les patrons de succession forestière sont difficiles à prédire à cause du broutage du cerf, qui a récemment empêché le recrutement dans la canopée de toutes les espèces arborescentes, et à cause de la possibilité que surviennent dans le futur des perturbations à grande échelle, telles que les feux et les éruptions volcaniques. [Traduit par la Rédaction] Abrams et al. 1899 Introduction Over the past decade, dendroecological techniques have become an important tool in the study of stand dynamics and ecological history (Fritts 1976; Fritts and Swetnam 1989). From tree-ring chronologies, researchers have been able to reconstruct the historical development of forests in terms of species recruitment patterns, periodicity and intensity of dis- turbances, the impacts of yearly climatic variation and ex- treme weather phenomena, and populations and successional dynamics (Canham 1985; Foster 1988; Frelich and Graum- lich 1994; Abrams and Orwig 1995; Abrams et al. 1995). Coupling tree-ring chronologies, age structure, and land-use history has proven to be a particularly robust approach for understanding long-term variation in forest dynamics and history (Foster 1988; Abrams and Orwig 1995; Abrams et al. 1997). Stand dynamics is an important subject of ecological re- search in Japan, and these studies have provided a substan- tial data base of information on the regeneration ecology and population structure of forests, particularly in relation to canopy gaps (Nakashizuka 1984; Yamamoto 1989; Kubota 1995; Namikawa 1996). However, there have been very few dendroecological studies conducted in Japan, despite the fact that most trees produce distinct annual rings. A few recent papers have reported on the age structure of trees in old- growth forests and the effects of climatic factors on radial Can. J. For. Res. 29: 1891–1899 (1999) © 1999 NRC Canada 1891 Received July 6, 1999. Accepted August 5, 1999. M.D. Abrams 1 and C.A. Copenheaver. School of Forest Resources, Ferguson Building, Pennsylvania State University, University Park, PA 16802 U.S.A. Kiyoshi Umeki, Mika Takiya, Kazuhiko Terazawa, and Nobuhiro Akashi. Hokkaido Forestry Research Institute, Bibai, Hokkaido 079-0198, Japan. 1 Corresponding author. e-mail: agl@psu.edu