Climate responses of ring widths and radial growth phenology of Betula ermanii, Fagus crenata and Quercus crispula in a cool temperate forest in central Japan

Abstract

Climate responses of radial growth of major hardwood species growing in a cool temperate forest in Japan were clarified by dendrochronological analysis combining the phenology observation of radial growth. To better understand which climate factors limit the radial growth of major hardwood species growing in a cool temperate forest in Japan, we clarified the phenology of radial growth and developed ring width residual chronologies for Betula ermanii, Fagus crenata and Quercus crispula at Takayama, an LTER research site located in central Japan. We inspected stem tissue for division of cambial cells in the early stage of wood formation and examined the cumulative radial growth by the wounding method. The onset of cambial cell division in Q. crispula was observed to be about 2 weeks earlier than in the other species. Wood formation in the final part of the tree ring occurred approximately 1 month earlier in B. ermanii than in the other species. The correlation analysis was performed between chronologies and moving averages of 31-day climate data with a 1-day lag. The periods which revealed significant correlations with climate factors were categorized into the previous growing season, previous autumn, just before the current growing season and current growing season according to their characteristic responses and the phenology of wood formation and leaves. The negative correlations between ring width of all the species and mean and minimum temperatures of previous year’s autumn, when the growth ending of ring width and leaf coloring occurred, suggested that temperature may have affected the respiration rate and/or prolonged the start of leaf fall, resulting in variations of radial growth through the consumption of photosynthetic products. On the other hand, different responses to climate were observed among species during the other phenological periods.