Environmental Management

, Volume 41, Issue 6, pp 949–958 | Cite as

Monitoring Plant Phenology Using Digital Repeat Photography

  • Michael A. CrimminsEmail author
  • Theresa M. Crimmins


Repeated observations of plant phenology have been shown to be important indicators of global change. However, capturing the exact date of key events requires daily observations during the growing season, making phenologic observations relatively labor intensive and costly to collect. One alternative to daily observations for capturing the dates of key phenologic events is repeat photography. In this study, we explored the utility of repeat digital photography for monitoring phenologic events in plants. We provide an illustration of this approach and its utility by placing observations made using repeat digital imagery in context with local meteorologic and edaphic variables. We found that repeat photography provides a reliable, consistent measurement of phenophase. In addition, digital photography offers advantages in that it can be mathematically manipulated to detect and enhance patterns; it can classify objects; and digital photographs can be archived for future analysis. In this study, an estimate of greenness and counts of individual flowers were extracted by way of mathematic algorithms from the photo time series. These metrics were interpreted using meteorologic measurements collected at the study site. We conclude that repeat photography, coupled with site-specific meteorologic measurements, could greatly enhance our understanding environmental triggers of phenologic events. In addition, the methods described could easily be adopted by citizen scientists and the general public as well as professionals in the field.


Digital imaging Image processing Meteorologic monitoring Phenology Repeat photography RGB 



This work was funded by a grant to M. Crimmins from the University of Arizona Foundation Faculty Small Grants Program. Comments from three anonymous reviewers improved the manuscript and are appreciated.


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Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  1. 1.Department of Soil, Water, and Environmental ScienceThe University of ArizonaTucsonUSA
  2. 2.Office of Arid Lands StudiesThe University of ArizonaTucsonUSA

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