Tree phenology and carbon dioxide fluxes - use of digital photography for process-based interpretation at the ecosystem scale

Ahrends, Hella E.; Etzold, Sophie; Kutsch, Werner L.; Stöckli, Reto; Brügger, Robert; Jeanneret, François; Buchmann, Nina; Eugster, Werner (2009). Tree phenology and carbon dioxide fluxes - use of digital photography for process-based interpretation at the ecosystem scale. Climate research, 39(3), pp. 261-274. Oldendorf (Luhe) (D): Inter-Research 10.3354/cr00811

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Vegetation phenology is an important indicator of climate change and climate variability and it is strongly connected to biospheric–atmospheric gas exchange. We aimed to evaluate the applicability of phenological information derived from digital imagery for the interpretation of CO2 exchange measurements. For the years 2005–2007 we analyzed seasonal phenological development of 2 temperate mixed forests using tower-based imagery from standard RGB cameras. Phenological information was jointly analyzed with gross primary productivity (GPP) derived from net ecosystem exchange data. Automated image analysis provided reliable information on vegetation developmental stages of beech and ash trees covering all seasons. A phenological index derived from image color values was strongly correlated with GPP, with a significant mean time lag of several days for ash trees and several weeks for beech trees in early summer (May to mid-July). Leaf emergence dates for the dominant tree species partly explained temporal behaviour of spring GPP but were also masked by local meteorological conditions. We conclude that digital cameras at flux measurement sites not only provide an objective measure of the physiological state of a forest canopy at high temporal and spatial resolutions, but also complement CO2 and water exchange measurements, improving our knowledge of ecosystem processes.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geography > Physical Geography > Unit Climatology
08 Faculty of Science > Institute of Geography

UniBE Contributor:

Ahrends, Hella Ellen; Brügger, Robert and Jeanneret, François

ISSN:

0936-577X

Publisher:

Inter-Research

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 15:21

Last Modified:

11 Sep 2017 08:09

Publisher DOI:

10.3354/cr00811

Web of Science ID:

000270489600009

BORIS DOI:

10.7892/boris.36390

URI:

https://boris.unibe.ch/id/eprint/36390 (FactScience: 204571)

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