@Article{ToomeyFFHKSBBBBBBCHMMMMPPTWZR:2015:GrInDi,
author = "Toomey, M. and Friedl, M. A. and Frolking, S. and Hufkens, K. and
Klosterman, S. and Sonnentag, O. and Baldochhi, D. D. and
Bernacchi, C. J. and Biraud, S. C. and Bohrer, G. and Brzostek, E.
and Burns, S. P. and Coursolle, C. and Hollinger, D. Y. and
Margolis, H. A. and McCaughey, H. and Monson, R. K. and Munger, J.
W. and Pallardy, S. and Phillips, R. P. and Torn, M. S. and
Wharton, S. and Zeri, Lui Marcelo de Mattos and Richardson, A.
D.",
affiliation = "{Harvard University} and {Department of Earth and Environment} and
{University of New Hampshire} and {Ghent University} and {Harvard
University} and {Universit{\'e} de Montre{\'a}l} and {University
of California} and {University of Illinois at Urbana-Champaign}
and {Lawrence Berkeley National Laboratory} and {Ohio State
University} and {Indiana University} and {University of Colorado}
and {Universit{\'e} Laval} and {USDA Forest Service} and
{Universit{\'e} Laval} and {Queen's University} and {University
of Arizona} and {Harvard University} and {University of Missouri}
and {Indiana University} and {Lawrence Berkeley National
Laboratory} and {Lawrence Livermore National Laboratory} and
{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Harvard
University}",
title = "Greenness indices from digital cameras predict the timing and
seasonal dynamics of canopy-scale photosynthesis",
journal = "Ecological Applications",
year = "2015",
volume = "25",
number = "1",
pages = "99--115",
month = "Jan.",
keywords = "Deciduous broadleaf forest, Digital repeat photography, Evergreen
needleleaf forest, Grassland, Gross primary productivity,
PhenoCam, Phenology, Photosynthesis, Seasonality.",
abstract = "The proliferation of digital cameras co-located with eddy
covariance instrumentation provides new opportunities to better
understand the relationship between canopy phenology and the
seasonality of canopy photosynthesis. In this paper we analyze the
abilities and limitations of canopy color metrics measured by
digital repeat photography to track seasonal canopy development
and photosynthesis, determine phenological transition dates, and
estimate intra-annual and interannual variability in canopy
photosynthesis. We used 59 site-years of camera imagery and net
ecosystem exchange measurements from 17 towers spanning three
plant functional types (deciduous broadleaf forest, evergreen
needleleaf forest, and grassland/crops) to derive color indices
and estimate gross primary productivity (GPP). GPP was strongly
correlated with greenness derived from camera imagery in all three
plant functional types. Specifically, the beginning of the
photosynthetic period in deciduous broadleaf forest and
grassland/crops and the end of the photosynthetic period in
grassland/crops were both correlated with changes in greenness;
changes in redness were correlated with the end of the
photosynthetic period in deciduous broadleaf forest. However, it
was not possible to accurately identify the beginning or ending of
the photosynthetic period using camera greenness in evergreen
needleleaf forest. At deciduous broadleaf sites, anomalies in
integrated greenness and total GPP were significantly correlated
up to 60 days after the mean onset date for the start of spring.
More generally, results from this work demonstrate that digital
repeat photography can be used to quantify both the duration of
the photosynthetically active period as well as total GPP in
deciduous broadleaf forest and grassland/crops, but that new and
different approaches are required before comparable results can be
achieved in evergreen needleleaf forest.",
issn = "1051-0761",
language = "en",
urlaccessdate = "27 abr. 2024"
}