Climatic Factors Affecting the Growth of Larix cajanderi in the Kamchatka Peninsula, Russia

Abstract Tree-ring width chronology of larch (Larix cajanderi) was developed in the lowland in the central part of the Kamchatka Peninsula in Russia, and climatic factors affecting the growth of larch were examined by using monthly temperature, precipitation and water deficit [(potential evapotranspiration) - (precipitation)]. Eighteen disks oflarch were examined, and a tree-ring index was developed by using five-year moving averages. Tree-ring indexes of sampled trees were positively correlated with each other, suggesting that many trees grew synchronously. A standardized tree-ring index (RI) was developed from A.D. 1840 to 1996 by averaging tree-ring indexes among sampled trees in each year. A correlation test revealed that RI was negatively correlated with precipitation in April in the current year. In addition, RI was positively correlated with precipitation and negatively with water deficit during the growing season (June-September) in the previous year. This was probably due to low precipitation in this region: mean precipitation during the growing season was only 171 mm, and water deficit was 183 mm. Therefore, drought stress during the growing season is an important factor affecting the growth of larch in the lowland of the central Kamchatka. Key words: Climatic factor; Kamchatka Peninsula; Larix cajanderi; Tree ring Introduction The regeneration of trees at the timberline or in boreal forests is supposed to be sensitive to climate change, and therefore, tree-ring information there is useful for re-constructing past climates. Many attempts have been conducted to reveal effects of climatic changes on tree growth and to re-construct past climate by analyzing tree rings (e.g., Sweda and Takeda 1993, Yasue et al. 1996, Gindl 1999). Several researchers reported that tree growth and recruitment rates increased in ameliorated years than the average in boreal forests or at the timberline (Kullman 1986; Steijlen and Zackrisson 1987; Hofgaard 1993; Kullman 1993; Taylor 1995; Camarero and Gutierrez 1999). Most of these studies have been conducted in the Scandinavia Peninsula, North America and the northwestern part of Russia. However, there have been few studies in the eastern part of Russia. Recently, tree-ring chronological studies have been started in the Kamchatka Peninsula in the Russian Far East. In the central part of the Kamchatka Peninsula, larch (Larix cajanderi Mayr.) is a long-lived species