Frank Davis

Dr. Frank Davis

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Research Focus & Metrics

Academic Career Length

43Years (1984-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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21 February 2016 in Global Change Biology
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Journal Article
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JCJames S. Clark
James S. Clark
LILouis Iverson
Louis Iverson
CWChristopher W. Woodall
Christopher W. Woodall
CACraig D. Allen
Craig D. Allen
DBDavid M. Bell
David M. Bell
NZNiklaus Zimmermann
Niklaus Zimmermann

30 March 2015 in Nature Geoscience
Verified
Journal Article
Closed access
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WAWilliam R. L. Anderegg
William R. L. Anderegg
AFAlan Flint
Alan Flint
CHCho-Ying Huang
Cho-Ying Huang
LFLorraine Flint
Lorraine Flint
JBJoseph A. Berry
Joseph A. Berry
CFChristopher B. Field
Christopher B. Field

1 January 1996 in Biological Conservation
Verified
Journal Article
Closed access
RCRichard L. Church
Richard L. Church
DSDavid M. Stoms
David M. Stoms
FDFrank Davis
Frank Davis

5 October 2012 in Global Change Biology
Verified
Journal Article
Closed access
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JFJanet Franklin
Janet Franklin
FDFrank Davis
Frank Davis
IMIKEGAMI Makihiko
IKEGAMI Makihiko
ASAlexandra Syphard
Alexandra Syphard
LFLorraine E. Flint
Lorraine E. Flint
LHLee Hannah
Lee Hannah

2 March 2016 in Nature Plants
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Journal Article
Closed access
WJWalter Jetz
Walter Jetz
JCJeannine Cavender-Bares
Jeannine Cavender-Bares
RPRyan Pavlick
Ryan Pavlick
DSDavid Schimel
David Schimel
FDFrank Davis
Frank Davis
SUSusan Ustin
Susan Ustin

6 October 2019 in Remote Sensing
Verified
Journal Article
Open access
PDF file
GFGeoffrey Fricker
Geoffrey Fricker
JVJonathan Ventura
Jonathan Ventura
JWJeffrey A. Wolf
Jeffrey A. Wolf
MNMalcolm North
Malcolm North
FDFrank Davis
Frank Davis
JFJanet Franklin
Janet Franklin
In this study, we automate tree species classification and mapping using field-based training data, high spatial resolution airborne hyperspectral imagery, and a convolutional neural network classifier (CNN). We tested our methods by identifying seven dominant trees species as well as dead standing trees in a mixed-conifer forest in the Southern Sierra Nevada Mountains, CA (USA) using training, validation, and testing datasets composed of spatially-explicit transects and plots sampled across a single strip of imaging spectroscopy. We also used a three-band ‘Red-Green-Blue’ pseudo true-color subset of the hyperspectral imagery strip to test the classification accuracy of a CNN model without the additional non-visible spectral data provided in the hyperspectral imagery. Our classifier is pixel-based rather than object based, although we use three-dimensional structural information from airborne Light Detection and Ranging (LiDAR) to identify trees (points > 5 m above the ground) and the classifier was applied to image pixels that were thus identified as tree crowns. By training a CNN classifier using field data and hyperspectral imagery, we were able to accurately identify tree species and predict their distribution, as well as the distribution of tree mortality, across the landscape. Using a window size of 15 pixels and eight hidden convolutional layers, a CNN model classified the correct species of 713 individual trees from hyperspectral imagery with an average F-score of 0.87 and F-scores ranging from 0.67–0.95 depending on species. The CNN classification model performance increased from a combined F-score of 0.64 for the Red-Green-Blue model to a combined F-score of 0.87 for the hyperspectral model. The hyperspectral CNN model captures the species composition changes across ~700 meters (1935 to 2630 m) of elevation from a lower-elevation mixed oak conifer forest to a higher-elevation fir-dominated coniferous forest. High resolution tree species maps can support forest ecosystem monitoring and management, and identifying dead trees aids landscape assessment of forest mortality resulting from drought, insects and pathogens. We publicly provide our code to apply deep learning classifiers to tree species identification from geospatial imagery and field training data.