The Development and Use of Isoscapes to Determine the Geographical Origin of <em>Quercus</em> spp. in the United States

The stable isotope ratios of oxygen, hydrogen, carbon and sulfur from extracted wood of 87 samples of oaks from the United States were analysed. Relationships with climate variables and the stable isotope ratios of the 69 training dataset samples were investigated to a monthly resolution using long-...

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Main Authors: Charles J. Watkinson, Peter Gasson, Gareth O. Rees, Markus Boner
Format: Article
Language:English
Published: MDPI AG 2020-08-01
Series:Forests
Subjects:
Online Access:https://www.mdpi.com/1999-4907/11/8/862
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author Charles J. Watkinson
Peter Gasson
Gareth O. Rees
Markus Boner
author_facet Charles J. Watkinson
Peter Gasson
Gareth O. Rees
Markus Boner
author_sort Charles J. Watkinson
collection DOAJ
description The stable isotope ratios of oxygen, hydrogen, carbon and sulfur from extracted wood of 87 samples of oaks from the United States were analysed. Relationships with climate variables and the stable isotope ratios of the 69 training dataset samples were investigated to a monthly resolution using long-term monthly mean climate data from NASA and the University of East Anglia’s Climate Research Unit, in conjunction with forecast data for hydrogen and oxygen isotope ratios in precipitation. These relationships were used to construct model isoscapes for oxygen, hydrogen, carbon and sulfur for US oak with the aim of using them to forecast isotopic patterns in areas that were not sampled and predict values in samples not used to construct the models. The leading predictors for isoscape generation were oxygen isotope ratios in January precipitation for oak oxygen isotope ratios, hydrogen isotope ratios in July precipitation for oak hydrogen isotope ratios, water vapour in April for carbon isotope ratios, and reflected shortwave radiation in March in combination with sulfate concentration in May for oak sulfur isotopes. The generated isoscapes can be used to show regions an unknown sample may have originated from with a resolution dependent on the rarity of the stable isotope signature within the United States. The models were assessed using the data of 18 samples of georeferenced oak. The assessment found that 100% of oxygen, 94% of hydrogen, 78% of carbon, and 94% of sulfur isotope ratios in the 18 test dataset samples fell within two standard deviations of the isoscape models. Using the results of the isoscapes in combination found that there were 4/18 test samples which did not fall within two standard deviations of the four models, this is largely attributed to the lower predictive power of the carbon isoscape model in conjunction with high local variability in carbon isotope ratios in both the test and training data. The method by which this geographic origin method has been developed will be useful to combat illegal logging and to validate legal supply chains for the purpose of good practice due diligence.
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spelling doaj.art-72cf4e6da5c148bf9b4717a35e64d6be2023-11-20T09:28:58ZengMDPI AGForests1999-49072020-08-0111886210.3390/f11080862The Development and Use of Isoscapes to Determine the Geographical Origin of <em>Quercus</em> spp. in the United StatesCharles J. Watkinson0Peter Gasson1Gareth O. Rees2Markus Boner3Agroisolab UK Ltd., Greets House Road, Welburn YO60 7EP, UKJodrell Laboratory, Royal Botanic Gardens, Kew, Richmond TW9 3DS, UKAgroisolab UK Ltd., Greets House Road, Welburn YO60 7EP, UKAgroisolab GmbH, Prof.-Rehm-Str. 6, D-52428 Jülich, GermanyThe stable isotope ratios of oxygen, hydrogen, carbon and sulfur from extracted wood of 87 samples of oaks from the United States were analysed. Relationships with climate variables and the stable isotope ratios of the 69 training dataset samples were investigated to a monthly resolution using long-term monthly mean climate data from NASA and the University of East Anglia’s Climate Research Unit, in conjunction with forecast data for hydrogen and oxygen isotope ratios in precipitation. These relationships were used to construct model isoscapes for oxygen, hydrogen, carbon and sulfur for US oak with the aim of using them to forecast isotopic patterns in areas that were not sampled and predict values in samples not used to construct the models. The leading predictors for isoscape generation were oxygen isotope ratios in January precipitation for oak oxygen isotope ratios, hydrogen isotope ratios in July precipitation for oak hydrogen isotope ratios, water vapour in April for carbon isotope ratios, and reflected shortwave radiation in March in combination with sulfate concentration in May for oak sulfur isotopes. The generated isoscapes can be used to show regions an unknown sample may have originated from with a resolution dependent on the rarity of the stable isotope signature within the United States. The models were assessed using the data of 18 samples of georeferenced oak. The assessment found that 100% of oxygen, 94% of hydrogen, 78% of carbon, and 94% of sulfur isotope ratios in the 18 test dataset samples fell within two standard deviations of the isoscape models. Using the results of the isoscapes in combination found that there were 4/18 test samples which did not fall within two standard deviations of the four models, this is largely attributed to the lower predictive power of the carbon isoscape model in conjunction with high local variability in carbon isotope ratios in both the test and training data. The method by which this geographic origin method has been developed will be useful to combat illegal logging and to validate legal supply chains for the purpose of good practice due diligence.https://www.mdpi.com/1999-4907/11/8/862isoscapestimber forensicsstable isotope ratio mass spectrometrygeographic originoakEUTR
spellingShingle Charles J. Watkinson
Peter Gasson
Gareth O. Rees
Markus Boner
The Development and Use of Isoscapes to Determine the Geographical Origin of <em>Quercus</em> spp. in the United States
Forests
isoscapes
timber forensics
stable isotope ratio mass spectrometry
geographic origin
oak
EUTR
title The Development and Use of Isoscapes to Determine the Geographical Origin of <em>Quercus</em> spp. in the United States
title_full The Development and Use of Isoscapes to Determine the Geographical Origin of <em>Quercus</em> spp. in the United States
title_fullStr The Development and Use of Isoscapes to Determine the Geographical Origin of <em>Quercus</em> spp. in the United States
title_full_unstemmed The Development and Use of Isoscapes to Determine the Geographical Origin of <em>Quercus</em> spp. in the United States
title_short The Development and Use of Isoscapes to Determine the Geographical Origin of <em>Quercus</em> spp. in the United States
title_sort development and use of isoscapes to determine the geographical origin of em quercus em spp in the united states
topic isoscapes
timber forensics
stable isotope ratio mass spectrometry
geographic origin
oak
EUTR
url https://www.mdpi.com/1999-4907/11/8/862
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