Climatic factors affecting the tree‐ring width of Betula ermanii at the timberline on Mount Norikura, central Japan

Abstract

Takahashi et al. 2Tree-ring width chronology of Betula ermanii was developed at the timberline (2400 m a.s.l.) on Mount Norikura in central Japan, and climatic factors affecting the tree-ring width of B. ermanii were examined. Three monthly climatic data were used for the analysis (i.e., mean temperature, insolation duration, and sum of precipitation). The tree-ring width of B. ermanii was negatively correlated with December and January temperatures and with January precipitation prior to the growth. However, why high temperatures and much snow in winter had negative effects on the growth of B. ermanii is unknown. The tree-ring width was positively correlated with summer temperatures during June to August of the current year. The tree-ring width was also positively correlated with the insolation duration in July of the current year. On the contrary, the tree-ring width was negatively correlated with summer precipitation during July to September of the current year. However, these negative correlations of summer precipitation do not seem to be independent of temperature and insolation duration, i.e., much precipitation reduced the insolation duration and temperature. Therefore, it is suggested that much insolation duration and high temperature due to less precipitation in summer of the current year increase the radial growth of B. ermanii at the timberline.The results were also compared with those of our previous study conducted in the lower altitudinal limit of B. ermanii (approximately 1600 m a.s.l.) on Mount Norikura. This study suggests that climatic factors increasing the radial growth of B. ermanii differ between its upper and lower altitudinal limits.Key words: Betula ermanii; climatic conditions; dendrochronology; Mount Norikura; timberline; tree-ring width chronology. Takahashi et al. 3 INTRODUCTIONTimberlines are the most severe climatic conditions such as low temperature, strong winds and short growing season for plants along altitudinal gradients, and therefore, the regeneration of trees at the timberlines is supposed to be sensitive to climatic changes (e.g., Briffa & Osborn 1999;Kusnierczyk & Ettl 2002;Lloyd & Fastie 2002;Chapin et al. 2004;Daniels & Veblen 2004;Dullinger et al. 2004). For example, some researchers have discussed that frequent seedling establishment occurred in warmer and/or more mesic years near the timberlines (Kullman 1986;Taylor 1995;Kajimoto et al. 1998;Camarero & Gutiérrez 1999;Gervais & MacDonald 2000). In addition, many dendrochronological studies have revealed that radial growth of trees near the timberlines increased in ameliorated years with higher temperatures than the average (Ettl & Peterson 1995;Gostev et al. 1996;Buckley et al. 1997;Peterson & Peterson 2001;Wilson & Hopfmueller 2001). Trees may respond to climatic conditions more quickly in growth rather than seedling establishment. Thus, the growth is a useful indicator to examine how climatic conditions affect regeneration of trees at the timberlines. Although many researchers investigated the effects of climat...

Variability of climate–growth relationships along an elevation gradient in the Changbai Mountain, northeastern China

“…This view was confirmed in our study. Although our results were different from some previous studies that showed positive correlations of tree growth with temperature in the prior winter (Peterson and Peterson 1994;Pederson et al 2004;Fan et al 2009;Liang et al 2010), Takahashi et al (2005) showed that Betula ermanii was negatively correlated with December and January temperatures at the treeline in Japan. As for the negative associations of tree growth with the prior winter temperatures, it is possible that high temperatures could enhance respiration rates, which decreased the storage of the carbohydrate production (Pilcher and Gray 1982).…”

The altitudinal variability and temporal instability of the climate–tree-ring growth relationships for Changbai larch (Larix olgensis Henry) in the Changbai mountains area, Jilin, Northeastern China

“…Tree-ring width is commonly related to climate in both the previous year and current year (Bräuning 1999;Takahashi et al 2005;Savva et al 2006), which was also verified in this study. Generally, TRW was negatively associated with temperatures in the prior winter and the months before the growing season at all elevations (Fig.…”

Climatic response of Betula ermanii along an altitudinal gradient in the northern slope of Changbai Mountain, China

“…Above subalpine coniferous forest, it forms open woodlands of more than 300 m in vertical width, and invades to the uppermost limit of tree growth at nearly 2,100 m a.s.l., providing ideal places and materials for the dendroclimatical study (Wu et al 2009). Unfortunately, such studies on B. ermanii are in a shortage, and most of which were developed at upper tree-lines (Takahashi et al 2005;Yu et al 2005;Yu et al 2007), which could not give a thorough interpreting of the dendroclimatical features of Betula ermanii. With the objective to explore the climatic factors affecting variation in tree-ring growth and to identify whether these factors differ with altitude, we performed a dendroclimatic analysis on Betula ermanii in the northern slope of Changbai Mountain (41°31'-42°28' N, 127°9'-128°55' E).…”