Southeast Asian tree rings and hydroclimate: recent developments and future prospects” with Brendan Buckley
Originally presented 16 Sep 2017
The April 2017 E2C featured three of the young scientists from the LDEO Tree Ring Lab describing some of the innovative techniques, such as Blue Light Intensity, and research in which they are engaged. In this follow-up talk by Brendan Buckley, Lamont Research Professor and one of the long-time TRL scientists, will provide a preview of the talk he will present two days later as the opening of this year’s Biology and Paleoenvironment Seminar Series.
“Southeast Asian tree rings and hydroclimate: recent developments and future prospects” is co-authored by Brendan M. Buckley, Rosanne D’Arrigo, Caroline Ummenhofer, and Kyle Hansen.
VIEW THE SLIDESHOW FOR THIS PRESENTATION
Twenty years of tree-ring research in Southeast Asia has resulted in near-millennial length reconstructions of the regional hydroclimate using the rare cypress (Fokienia hodginsii) found growing along the length of the Annamite Range from 12˚ – 23˚ N latitude. These records led to discoveries of severe climate anomalies that gripped the region and contributed to the demise of the Khmer at Angkor by the early 15th century, and the collapse of all major polities of the Indochina Peninsula by the late 18th century. Three published records of spring (March – May) hydroclimate from north, central and southern Vietnam Fokienia represent the most robust and well-replicated tree ring records from anywhere in the global tropics, with two additional Fokieniarecords from north and central Vietnam currently in preparation for publication. Additional Fokienia collections from Lao PDR are being developed. We have also developed teak records from Myanmar, Thailand and Indonesia, and multiple records from Pinus species from Myanmar, Thailand, Cambodia and Laos.
This talk focuses on new developments in the methods we use to analyze tropical tree ring data. We are now able to account for discrete seasonal reconstructions of climate beyond the spring season, and include variability of the summer, autumn and winter seasons. In particular, Blue Light Intensity (BLI) is a proxy for wood density, and has been widely used in the high latitude forests where summer temperature dominates the growth response. We apply this technique to the earlywood of Fokienia hodginsii samples from Vietnam and find a response to winter (Dec-Apr) temperature strong enough to allow for robust statistical reconstruction. We interpret these results as reflecting a cavitation-avoidance response of this species, such that higher than average temperature during the annual winter dry period results in a reduction of lumen diameters during the springtime flush of growth (an interpretation supported by ongoing ecophysiological research).
Stable isotope analyses of δ18O from Fokienia and Pinus species are revealing summer hydroclimate seasonality (May-Sep), while earlywood and latewood measurements from Pseudotsuga sinensis from northern Vietnam reflect autumn rainfall. The ability to analyze discreet seasonal climate variability from the tropics is new, and is a major development for studies of climate over Southeast Asia.
VIEW THE INTRODUCTORY SLIDESHOW “LEARNING FROM TREE RINGS”
PREVIOUS E2C PRESENTATIONS FROM THE LDEO TREE RING LAB
We have enjoyed many talks with TRL scientists during the past 15+ years. View these for additional resources and links.
“More than How Old? Understanding Climate Changes from Tree Rings” with Mukund Palat Rao, Daniel Bishop, and Rose Oelkers (Apr 2017)
“Trees, Climate, and Societal Relevance: A Case Study in Mongolia” with Caroline Leland and Mukund Palat Rao (Sep 2014)
“Droughts, Dzud and Archaeology in Mongolia: A Tree Ring Perspective” with Nicole Davi (Jan 2011)
“Transects and Tree Rings at LDEO” with Brendan Buckley (May 2008)
“Tree Rings and Climate Change” with Nicole Davi (Jan 2005)
“Learning from Tree Rings” with Nicole Davi (Dec 2003)
Special Features
LDEO Scientist Ted Koscinsky provided this fascinating video and webpage called “Wood Swimmer”:
Daily Motion video Daily Motion webpage
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