Temporal variation of tritium concentration in tree-ring cellulose over the past 50 years

<p>We use an interdisciplinary approach combining stable isotopes in tree rings, pollen data, ice cores from temperature-limited environment in the Siberian north and developed a comprehensive description of the climatic changes over the past 1500 years. We found that the Climatic Optimum Period was warmer and drier compared to the Medieval one, but rather similar to the recent period. Our results indicate that the Medieval Warm period in the Taimyr Peninsula started earlier and was wetter compared to the northeastern part of Siberia (northeastern Yakutia). Summer precipitation reconstruction obtained from carbon isotopes in tree-ring cellulose from Taimyr Peninsula significantly correlated with the pollen data of the Lama Lake (Andreev et al. 2004) and oxygen isotopes of the ice core from Severnaya Zemlya (Opel et al. 2013) recording wetter climate conditions during the Medieval Warm period compared to the northeastern part of Siberia. Common large-scale climate variability was confirmed by significant relationship between oxygen isotope data in tree-ring cellulose from the Taimyr Peninsula and northeastern Yakutia, and oxygen isotope ice core data from Severnaya Zemlja during the Medieval Warm period and the recent one. Finally, we showed that the recent warming on the Taimyr Peninsula is not unprecedented in the Siberian north. Similar climate conditions were recorded by stable isotopes in tree rings, pollen, and ice core data 6000 years ago. On the northeastern part of Siberia newly developed a 1500-year summer vapor pressure deficit (VPD) reconstruction showed, that VPD increased recently, but does not yet exceed the maximum values reconstructed during the Medieval Warm period. The most humid conditions in the northeastern part of Siberia were recorded in the Early Medieval period and during the Little Ice Age. However, the increasing VPD under elevated air temperature in the last decades affects the hydrological regime of these sensitive ecosystems by greater evapotranspiration rates. Further VPD increase will significantly affect Siberian forests most likely leading to drought even under additional access of thawed permafrost water.</p><p>This work was supported by the FP7-PEOPLE-IIF-2008 - Marie Curie Action: "International Incoming Fellowships" 235122 and "Reintegration Fellowships" 909122 &#8220;Climatic and environmental changes in the Eurasian Subarctic inferred from tree-ring and stable isotope chronologies for the past and recent periods&#8221; and the Government of Krasnoyarsk Kray and Russian Foundation for Basic Research and Krasnoyarsk Foundation 20-44-240001 &#8220;Adaptation of conifer forests on the north of the Krasnoyarsk region (Taimyr Peninsula) to climatic changes after extreme events over the past 1500 years&#8220; awarded to Olga V. Churakova (Sidorova).</p>

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Hydroclimate reconstruction in central Japan over the past four centuries from tree-ring cellulose δ 18 O

Quaternary International ◽

10.1016/j.quaint.2017.06.020 ◽

2017 ◽

Vol 455 ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Wataru Sakashita ◽

Hiroko Miyahara ◽

Yusuke Yokoyama ◽

Takahiro Aze ◽

Takeshi Nakatsuka ◽

...

Keyword(s):

Tree Ring ◽

Central Japan ◽

The Past ◽

Tree Ring Cellulose

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A 2600-year summer climate reconstruction in central Japan by integrating tree-ring stable oxygen and hydrogen isotopes

Climate of the Past ◽

10.5194/cp-16-2153-2020 ◽

2020 ◽

Vol 16 (6) ◽

pp. 2153-2172 ◽

Cited By ~ 1

Author(s):

Takeshi Nakatsuka ◽

Masaki Sano ◽

Zhen Li ◽

Chenxi Xu ◽

Akane Tsushima ◽

...

Keyword(s):

Time Series ◽

Tree Ring ◽

Isotope Ratios ◽

Tree Age ◽

Central Japan ◽

The Past ◽

Summer Climate ◽

Age Trends ◽

Past Summer ◽

Tree Ring Cellulose

Abstract. Oxygen isotope ratios (δ18O) of tree-ring cellulose are a novel proxy for summer hydroclimate in monsoonal Asia. In central Japan, we collected 67 conifer wood samples, mainly Chamaecyparis obtusa, with ages encompassing the past 2600 years. The samples were taken from living trees, archeological wood, architectural wood, and buried logs. We analyzed stable isotope ratios of oxygen (δ18O) and hydrogen (δ2H) in tree-ring cellulose in these samples (more than 15 000 rings in total) without using a pooling method and constructed a statistically reliable tree-ring cellulose δ18O time series for the past 2500 years. However, there were distinct age trends and level offsets in the δ18O record, and cellulose δ18O values showed a gradual decrease as an individual tree matures. This suggested it is difficult to establish a cellulose δ18O chronology for low-frequency signals by simple averaging of all the δ18O time series data. In addition, there were opposite age trends in the cellulose δ2H, and δ2H gradually increased with tree age. There were clear positive correlations in the short-periodicity variations between δ18O and δ2H, probably indicating a common climate signal. A comparison of the δ18O and δ2H time series in individual trees with tree-ring width suggested that the opposite age trends of δ18O and δ2H are caused by temporal changes in the degree of post-photosynthetic isotope exchange with xylem water (physiological effect), accompanied by changes in stem growth rate that are influenced by human activity in the forests of central Japan. Based on the assumptions that cellulose δ18O and δ2H vary positively and negatively with constant proportional coefficients due to climatological and physiological effects, respectively, we solved simultaneous equations for the climatological and physiological components of variations in tree-ring cellulose δ18O and δ2H in order to remove the age trend. This enabled us to evaluate the climatic record from cellulose δ18O variations. The extracted climatological component in the cellulose δ18O for the past 2600 years in central Japan was well correlated with numerous instrumental, historical, and paleoclimatological records of past summer climate at various spatial and temporal scales. This indicates that integration of tree-ring cellulose δ18O and δ2H data is a promising method to reconstruct past summer climate variations on annual to millennial timescales, irrespective of the growth environment. However, analytical and statistical methods need to be improved for further development of this climate proxy.

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Reconstruction of multi-millennial summer climate variations in central Japan by integrating tree-ring cellulose oxygen and hydrogen isotope ratios

10.5194/cp-2020-6 ◽

2020 ◽

Cited By ~ 1

Author(s):

Takeshi Nakatsuka ◽

Masaki Sano ◽

Zhen Li ◽

Chenxi Xu ◽

Akane Tsushima ◽

...

Keyword(s):

Time Series ◽

Tree Ring ◽

Isotope Ratios ◽

Growth Effect ◽

Climate Variations ◽

Central Japan ◽

The Past ◽

Summer Climate ◽

Age Trends ◽

Tree Ring Cellulose

Abstract. Oxygen isotope ratios (δ18O) of tree-ring cellulose are a novel proxy of summer hydroclimate in monsoonal Asia. In central Japan, we collected 67 conifer wood samples, mainly Chamaecyparis obtusa, with ages encompassing the past 2,600 yr. The samples were taken from living old trees, excavated archeological wood, old architectural wood, and naturally buried logs. We analyzed stable isotope ratios of oxygen (δ18O) and hydrogen (δ2H) in tree-ring cellulose in these samples without using a pooling method, and constructed a statistically reliable tree-ring cellulose δ18O time-series for the past 2,500 yr. However, there were distinct age trends and level offsets in the δ18O record, and cellulose δ18O values showed a gradual decrease as an individual tree matures. This suggested it is difficult to establish a cellulose δ18O chronology for low-frequency signals by simple averaging of all the δ18O time-series data. However, there were opposite age trends in the cellulose δ2H, and δ2H gradually increased with tree age. There were clear positive correlations in the short periodicity variations between δ18O and δ2H, probably indicating a common climate signal. A comparison of the δ18O and δ2H time-series in individual trees with tree-ring width suggested that the opposite age trends of δ18O and δ2H are caused by temporal changes in the degree of post-photosynthetic isotope exchange with xylem water, accompanied by changes in stem growth rate (growth effect) that are influenced by human activity in the forests of central Japan. Based on the assumptions that cellulose δ18O and δ2H vary positively and negatively with constant proportional coefficients due to climate variations and the growth effect, respectively, we solved simultaneous equations for the climatological and physiological components of variations in tree-ring cellulose δ18O and δ2H in order to remove the age trend (growth effect). This enabled us to evaluate the climatic record from cellulose δ18O variations. The extracted climatological component in the cellulose δ18O for the past 2,600 yr in central Japan was well correlated with numerous instrumental, historical, and paleoclimatological records of past summer climate at various spatial and temporal scales. This indicates that integration of tree-ring cellulose δ18O and δ2H data is a promising method to reconstruct past summer climate variations on annual to millennial time-scales, irrespective of the growth affect. However, analytical and statistical methods need to be improved for further development of this climate proxy.

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Temporal Variation of Carbon-14 Concentration in Tree-ring Cellulose for the Recent 50 Years

Journal of Nuclear and Radiochemical Sciences ◽

10.14494/jnrs2000.6.2_135 ◽

2005 ◽

Vol 6 (2) ◽

pp. 135-138 ◽

Cited By ~ 12

Author(s):

Yoshimune Yamada ◽

Kaeko Yasuike ◽

Kazuhisa Komura

Keyword(s):

Temporal Variation ◽

Tree Ring ◽

Carbon 14 ◽

Tree Ring Cellulose

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Spatio-temporal Variation Characteristics of Surface Net Radiation in China over the Past 50 Years

Geo-information Science ◽

10.3724/sp.j.1047.2013.00001 ◽

2013 ◽

Vol 15 (1) ◽

pp. 1 ◽

Cited By ~ 8

Author(s):

Yangzi GAO ◽

Honglin HE ◽

Li ZHANG ◽

Qianqian LU ◽

Guirui YU ◽

...

Keyword(s):

Temporal Variation ◽

Net Radiation ◽

The Past ◽

Variation Characteristics ◽

Spatio Temporal

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Supporting Restoration Decisions through Integration of Tree-Ring and Modeling Data: Reconstructing Flow and Salinity in the San Francisco Estuary over the Past Millennium

Water ◽

10.3390/w13152139 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2139

Author(s):

Paul H. Hutton ◽

David M. Meko ◽

Sujoy B. Roy

Keyword(s):

San Francisco ◽

Tree Ring ◽

San Francisco Estuary ◽

Salinity Intrusion ◽

Estuarine Ecosystem ◽

Freshwater Flow ◽

The Past ◽

Decadal Scale ◽

Tree Ring Data ◽

Past Millennium

This work presents updated reconstructions of watershed runoff to San Francisco Estuary from tree-ring data to AD 903, coupled with models relating runoff to freshwater flow to the estuary and salinity intrusion. We characterize pre-development freshwater flow and salinity conditions in the estuary over the past millennium and compare this characterization with contemporary conditions to better understand the magnitude and seasonality of changes over this time. This work shows that the instrumented flow record spans the range of runoff patterns over the past millennium (averaged over 5, 10, 20 and 100 years), and thus serves as a reasonable basis for planning-level evaluations of historical hydrologic conditions in the estuary. Over annual timescales we show that, although median freshwater flow to the estuary has not changed significantly, it has been more variable over the past century compared to pre-development flow conditions. We further show that the contemporary period is generally associated with greater spring salinity intrusion and lesser summer–fall salinity intrusion relative to the pre-development period. Thus, salinity intrusion in summer and fall months was a common occurrence under pre-development conditions and has been moderated in the contemporary period due to the operations of upstream reservoirs, which were designed to hold winter and spring runoff for release in summer and fall. This work also confirms a dramatic decadal-scale hydrologic shift in the watershed from very wet to very dry conditions during the late 19th and early 20th centuries; while not unprecedented, these shifts have been seen only a few times in the past millennium. This shift resulted in an increase in salinity intrusion in the first three decades of the 20th century, as documented through early records. Population growth and extensive watershed modification during this period exacerbated this underlying hydrologic shift. Putting this shift in the context of other anthropogenic drivers is important in understanding the historical response of the estuary and in setting salinity targets for estuarine restoration. By characterizing the long-term behavior of San Francisco Estuary, this work supports decision-making in the State of California related to flow and salinity management for restoration of the estuarine ecosystem.

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Tree Vitality and Forest Health: Can Tree-Ring Stable Isotopes Be Used as Indicators?

Current Forestry Reports ◽

10.1007/s40725-021-00137-8 ◽

2021 ◽

Cited By ~ 1

Author(s):

Paolo Cherubini ◽

Giovanna Battipaglia ◽

John L. Innes

Keyword(s):

Air Pollution ◽

Stable Isotopes ◽

Tree Ring ◽

Forest Decline ◽

Forest Health ◽

Stress Factors ◽

Tree Vitality ◽

The Past ◽

Physiological Processes

Abstract Purpose of Review Society is concerned about the long-term condition of the forests. Although a clear definition of forest health is still missing, to evaluate forest health, monitoring efforts in the past 40 years have concentrated on the assessment of tree vitality, trying to estimate tree photosynthesis rates and productivity. Used in monitoring forest decline in Central Europe since the 1980s, crown foliage transparency has been commonly believed to be the best indicator of tree condition in relation to air pollution, although annual variations appear more closely related to water stress. Although crown transparency is not a good indicator of tree photosynthesis rates, defoliation is still one of the most used indicators of tree vitality. Tree rings have been often used as indicators of past productivity. However, long-term tree growth trends are difficult to interpret because of sampling bias, and ring width patterns do not provide any information about tree physiological processes. Recent Findings In the past two decades, tree-ring stable isotopes have been used not only to reconstruct the impact of past climatic events, such as drought, but also in the study of forest decline induced by air pollution episodes, and other natural disturbances and environmental stress, such as pest outbreaks and wildfires. They have proven to be useful tools for understanding physiological processes and tree response to such stress factors. Summary Tree-ring stable isotopes integrate crown transpiration rates and photosynthesis rates and may enhance our understanding of tree vitality. They are promising indicators of tree vitality. We call for the use of tree-ring stable isotopes in future monitoring programmes.

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