Award Abstract # 1003050
Collaborative Research: Late Holocene Climate Variability from Stable Isotope Ratio Analysis of Coast Redwood Tree Ring Cellulose.

NSF Org: AGS
Division of Atmospheric and Geospace Sciences
Recipient: SOUTHERN OREGON UNIVERSITY
Initial Amendment Date: July 8, 2010
Latest Amendment Date: March 27, 2015
Award Number: 1003050
Award Instrument: Continuing Grant
Program Manager: David Verardo
AGS
 Division of Atmospheric and Geospace Sciences
GEO
 Directorate for Geosciences
Start Date: July 15, 2010
End Date: October 31, 2015 (Estimated)
Total Intended Award Amount: $635,739.00
Total Awarded Amount to Date: $635,739.00
Funds Obligated to Date: FY 2010 = $239,830.00
FY 2011 = $237,100.00

FY 2012 = $158,809.00
History of Investigator:
  • John Roden (Principal Investigator)
    rodenj@sou.edu
  • James Johnstone (Co-Principal Investigator)
Recipient Sponsored Research Office: Southern Oregon University
1250 SISKIYOU BLVD
ASHLAND
OR  US  97520-5001
(541)552-8662
Sponsor Congressional District: 02
Primary Place of Performance: Southern Oregon University
1250 SISKIYOU BLVD
ASHLAND
OR  US  97520-5001
Primary Place of Performance
Congressional District:
02
Unique Entity Identifier (UEI): GL1WH5BDCN74
Parent UEI:
NSF Program(s): Paleoclimate
Primary Program Source: 01001011DB NSF RESEARCH & RELATED ACTIVIT
01001112DB NSF RESEARCH & RELATED ACTIVIT

01001213DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s): 0000, 1304, EGCH
Program Element Code(s): 153000
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.050

ABSTRACT

This project aims to explore the relationship between atmospheric moisture and climate as recorded in trees. The researchers postulate that fog is a strongly integrative measure of interannual summer climate variability at the ocean-land-atmosphere interface of the U.S. Pacific Coast. They further suggest that there is strong coupling to coastal wind, sea-surface temperatures (SSTs), land temperatures, and the Pacific Decadal Oscillation (PDO).

The broad aim of the research is to assess changes in the nature of high-frequency (El Nino Southern Oscillation-scale) and multi-decadal (PDO) variability in the isotope records and to provide new information on the character of the Little Ice Age and Medieval Climate Anomaly on the U.S. Pacific coast.

The researchers argue that the climate of coastal northern California sets the stage for recovering a novel high-resolution paleoclimate record using stable isotopes from tree-rings. They propose to focus their attention on the Coast Redwood (Sequoia sempervirens [D. Don] Endl.), a long-lived tree species, with some individuals exceeding 2,000 years in age.

The researchers hypothesize that stable isotope analysis of ancient redwood tree rings could provide annually-resolved proxy information on large-scale climate mechanisms over the last 1,000 years and they aim to place warm-season changes in long-term context so that the range of natural and anthropogenic variations can be assessed.

This hypothesis is based on the team's previous research that established the feasibility of reconstructing climate, including northern California precipitation and fog in the spring and summer seasons, from the U.S. Pacific coast using stable isotope analysis of carbon and oxygen of redwood tree-ring cellulose. Their research also shows that over the past century, coastal northern California summer climate has changed substantially, including a ~33% reduction in fog frequency and a coastal SST increase of ~0.8°C.

The broader impacts involve pursuing a high risk research plan that could yield a new perspective on reconstructing climate from environmental and ecological data. The research could be of value to a broad range of users that include climatologists and forest managers. The project includes a strong collaboration between a non-PhD degree granting institution and a high performing research laboratory.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

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Voelker SL, JR Brooks, FC Meinzer, J Roden, A Pazdur, S Pawelczyk, P Hartsough,K Snyder, L Plavcova and J ?antr??ek "Reconstructing relative humidity from plant ?18O and ?D as deuterium deviations from the global meteoric water line." Ecological Applications , v.24 , 2014 , p.960
Voelker SL, JR Brooks, FC Meinzer, J Roden, A Pazdur, S Pawelczyk, P Hartsough,K Snyder, L Plavcova and J ?antr??ek "Reconstructing relative humidity from plant ?18O and ?D as deuterium deviations from the global meteoric water line." Ecological Applications , v.24 , 2014 , p.960

PROJECT OUTCOMES REPORT

Disclaimer

This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

Redwood trees (Sequoia sempervirens) represent some of the largest, oldest and tallest organisms on earth. Magnificent old-growth redwood forests are limited to coastal California within the fog belt and are considered endangered ecosystems. Variation in the frequency of marine-layer fog in northern California integrates inter-annual summer climate signals at the ocean-land-atmosphere interface of the U.S. Pacific Coast. The uptake of fog water represents an important resource for redwood forests. The stable isotopes of oxygen in fog water are distinct from rainfall and these signatures are preserved in the cellulose of redwood tree rings. Thus stable isotope analysis of ancient redwood tree rings could provide annually-resolved proxy information on important large-scale climate mechanisms dating back >1000 years.

The objective of this project is to develop millennial-scale reconstructions of climate variability by using oxygen and carbon stable isotope ratios from slabs of ancient redwood trees. Specifically, we hope to track changes in the periodicity of both high-frequency (i.e. drought, El Nino Southern Oscillation etc.) and multi-decadal (Pacific Decadal Oscillation, PDO) climate cycles during past climate anomalies (Medieval Warm Period and Little Ice Age). A primary goal is to place recent changes in fog frequency and sea surface temperatures over the last century into a long-term context so that the range of natural and anthropogenic variations can be assessed.

Already downed trees (from wind-throw and old age) that cross roads in National and State redwood preserves are cut to clear the road and provide a readily available surface from ancient trees that can be non-destructively sampled. We collected slabs from 11 redwood trees from five different sites in Northern California and southern Oregon (one was almost 1900 years old). From these samples we have precisely dated 7,073 individual rings using cross-dating techniques. We completed replicated (> 4 trees per year), sub-annually resolved (spring and summer conditions), 1,000-year carbon and oxygen isotope chronologies that represent >27,500 isotope measurements. In addition, to isotope data we produced extensive ring width chronologies that can be used to infer past growing conditions.    

The project has produced a number of valuable outcomes. One is our ability to cross-date ancient redwood slabs back to almost 2,000 years. This was considered extremely difficult to nearly impossible in the past due to numerous ring anomalies once these trees reach extreme old age. Another key outcome is the reconstruction of climate variation associated with the Pacific Decadal Oscillation (PDO). The PDO strongly impacts western North American climate and accurate sea surface temperature measurements do not go back far enough to characterize the periodicity and variability of this important climate feature. Our PDO reconstruction will add to sparse millennial scale reconstructions of PDO and aid climatologists as they model and predict future conditions. Our data can also provide information regarding regional drought and flooding events. Considering population and agricultural pressures on water resources in California any additional data on precipitation variability would be welcome. In addition to past variation, our results may provide some indications of future changes in water resources in a potentially warmer world for a state prone to drought.

 


Last Modified: 11/25/2015
Modified by: John Roden

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