Nagoya University · Earth and Planetary Sciences
Professor Masaki Sano's research lab specializes in paleoclimatology and environmental science, focusing on tree-ring stable isotope analysis—particularly δ¹⁸O in cellulose—to reconstruct past hydroclimatic conditions across monsoon-affected regions of Asia. The lab emphasizes long-term climate variability, especially related to the Asian summer monsoon, using high-resolution tree-ring chronologies from diverse species and altitudes in the Himalayas, Southeast Asia, and the Russian Far East. Their work integrates dendroclimatology with climatic response modeling to understand monsoon dynamics, drought history, and climate-vegetation interactions over centuries. The lab also contributes to broader climate network development by expanding spatial coverage of tree-ring isotope data in data-sparse regions.
Figures are computed from collected data and may differ slightly.
A tree-ring δ 18 O chronology of Abies spectabilis from the Nepal Himalaya was established to study hydroclimate in the summer monsoon season over the past 223 years (ad 1778–2000). Response function analysis with ambient climatic records revealed that tree-ring δ 18 O was primarily controlled by the amount of precipitation and relative humidity during the monsoon season (June–September). Since tree-ring δ 18 O was simultaneously correlated with temperature, drought history in the monsoon season
We developed a 50‐year tree ring δ 18 O chronology for each of three tree species ( Juniperus indica , Larix griffithii , and Picea spinulosa ) using a total of 12 trees (four trees per species) from the Bhutan Himalaya. Despite originating from different species sampled at two different altitudes, the δ 18 O chronologies are highly correlated with one another ( r = 0.76–0.89). Response analyses reveal that tree ring δ 18 O values are controlled mainly by summer precipitation, irrespective of sp
A tree ring δ 18 O chronology is developed for the past 300 years (1705–2004) using 6 cypress trees from northern Vietnam to reconstruct long‐term hydroclimatic variations in the summer monsoon season. To the best of our knowledge, this is the first well‐replicated tree ring δ 18 O chronology from Southeast Asia, as well as the longest yet produced. Response analyses reveal that tree ring δ 18 O is significantly correlated with temperature, precipitation, and the Palmer Drought Severity Index (P
The oxygen isotope ratio (δ18O) of tree-ring cellulose is known to be a reliable proxy for hydroclimate in monsoon Asia. However, tree-ring δ18O data are still spatially and temporally limited, so a denser tree-ring network in Asia is required to better understand the dynamics of the monsoon circulation and its past variability. Here, we present a 242-year δ18O chronology calculated from five silver fir trees collected in the western (Indian) Himalaya, a region located on the northwestern periph
We developed a 378-year tree-ring-width chronology based on 110 core samples from 55 individual trees of Larix gmelinii (Rupr.) Rupr. growing in a wide open forest close to the tree line in the Kronotsky National Park. Reflecting strong climatic control over tree growth not only within the study area but also more extensively over central Kamchatka, our chronology was well correlated with those from other larch sites. Response analysis with 10-day mean temperature revealed that the ring width wa
Activity time allocations and diets of males and females in the pinguipedid fish Parapercis polyophthalma, which has haremic social groups dominated by single territorial males, were examined in shallow sandy areas at Iriomote Island, one of the Ryukyu Islands of Japan. During the day, males spent much less time foraging and more time engaging in social activities than did females, and actively patrolled the borders of their territories. Females, on the other hand, allocated most of their time t
Trees growing in the lowlands of Japan are not climatically stressed; consequently, ring-width patterns are weakly correlated between different trees. Therefore, dendrochronological studies in Japan based on ring widths rely largely on climatically stressed conifers growing in mountainous regions and/or at higher latitudes. In contrast, oxygen isotope ratios (δ18O) are well-matched between trees, irrespective of climatic stress, indicating that the huge amounts of wood excavated in Japan could p
ABSTRACT We present two new millennium-long tree-ring oxygen isotope chronologies for central and northern Japan, based on 9693 annually resolved measurements of tree-ring oxygen isotopes from 39 unearthed samples consisting mainly of Japanese cedar ( Cryptomeria japonica ). These chronologies were developed through cross-dating of tree-ring widths and δ 18 O data from multiple samples covering the periods 2349–1009 BCE (1341 yr) and 1412–466 BCE (947 yr) for central and northern Japan, respecti
AbstractWe have developed a 247-year ring-width chronology of Betura ermanii Cham. growing in an open canopy forest close to the tree line at a coastal site in southern Kamchatka. Climatic response analyses revealed that the ring width was primarily controlled by July–August temperature. The regression models that we used for statistical reconstruction passed the stringent calibration–verification tests used in dendroclimatology, resulting in the first quality-controlled tree-ring reconstruction
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