Oxygen and carbon isotopic ratios of tree-ring cellulose in a conifer-hardwood mixed forest in northern Japan

Abstract

Oxygen and carbon isotopic ratios (δ 18 O and δ 13 C) were analyzed for cellulose extracted from tree rings of 5 oak trees (Quercus crispula) and 4 fir trees (Abies sachalinensis) standing in a 1 ha plot of a sub-boreal conifer-hardwood mixed forest, northern Japan. 18 O, the inter-annual variations in δ 13 C did not possess any common trends among individual trees for either Q. crispula or A. sachalinesis, suggesting that the ecological effects, such as spatial heterogeneities in δ 13 C and/or concentration of CO 2 in canopy air and/or competition for light with neighboring trees, regulate the δ 13 C of photosynthetic products in each tree. Seasonal variations of the δ 18 O and δ 13 C within annual tree rings of Q. crispula showed random and cyclic characteristics, respectively. The difference between the annual patterns of δ 18 O and δ 13 C supports the idea that δ 18 O is controlled by some environmental factors, which change from year to year, but δ 13 C is primarily governed by physiological conditions of the tree itself, which repeat regularly in every growing season. The historical variation in δ 18 O of tree-ring cellulose in Q. crispula has negative correlations with those in both of winter and summer precipitation amounts, whereas it does not show any relationship with temperature, probably due to multiple source areas of water vapor for the precipitation at the studied area. Because the δ 18 O of precipitation in northern Japan is positively correlated with air temperature, the correlation between δ 18 O and winter precipitation suggests that, in a year of heavy snowfall, the soil in this forest retains larger amount of lower δ 18 O water derived from snowmelt, which is taken by roots of Q. crispula in summer. On the other hand, the negative correlation with summer precipitation cannot be elucidated by the δ 18 O of rainfall, but must be explained by a higher relative humidity in the growing season in a year of larger summer rainfall. Our results confirm the potential of δ 18 O of tree-ring cellulose to reconstruct past climate in a forest with a heavy snowfall, and suggest the importance of the hydrological knowledge in an atmosphere-soil-plant system for the utilization of treering δ 18 O in paleoenvironmental purposes.

Alpha-cellulose extraction procedure for the tropical tree sungkai (Peronema canescens Jack) by using an improved vessel for reliable paleoclimate reconstruction

“…The procedure reported by Nakatsuka et al (2004), which was modified after Green (1963) and Loader et al (1997), was adopted in our study.…”

“…Moreover, it has high sensitivity to its environment and is therefore suitable for paleoclimate reconstruction (Oobayashi et al, 1992). Furthermore, to improve the speed of cellulose extraction from tree-ring samples to a marked degree, we introduced an improved extraction vessel originally developed by Nakatsuka et al (2004). Using it, we evaluated the cellulose extraction time for our Sungkai sample.…”

“…1) improved by Nakatsuka et al (2004) based on a previous report by Loader et al (1997). A slender Teflon tube (8 and 6 mm external and internal diameters, respectively) was cut to about 150 mm length.…”

Synchronized Northern Hemisphere climate change and solar magnetic cycles during the Maunder Minimum

“…In humid and temperate regions, variations in tree-ring width and its carbon isotopic composition (δ 13 C) often show large discre-pancies between different individual trees mainly due to ecological competition in forest areas of high population density. However, even in these circumstances the interannual variations in tree-ring δ 18 O are well correlated among different trees and accurately reflect the regional hydroclimate variations (33). The annual time resolution is sufficient to investigate climate periodicities at the decadal scale and to reveal the response time of climate to changes in solar activity.…”

“…To our knowledge, this is the first paper to compare tree-ring cellulose δ 18 O directly with tree-ring Δ 14 C. Tree-ring δ 18 O is correlated negatively with relative humidity and positively with δ 18 O in precipitation (31). Because δ 18 O in precipitation is negatively correlated with the amount of precipitation in monsoon areas (32), the tree-ring δ 18 O can be a reliable proxy for past relative humidity and/or amount of precipitation in Japan (33)(34)(35). In humid and temperate regions, variations in tree-ring width and its carbon isotopic composition (δ 13 C) often show large discre-pancies between different individual trees mainly due to ecological competition in forest areas of high population density.…”