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Harvard Forest Symposium Abstract 2009

  • Title: Phenological monitoring across the northeastern US and adjacent Canada using a network of digital webcams
  • Primary Author: Andrew Richardson (Northern Arizona University)
  • Additional Authors: Bobby Braswell (University of New Hampshire - Main Campus); David Hollinger (USDA Forest Service); Julian Jenkins (University of New Hampshire - Main Campus)
  • Abstract:

    A collaborative research network to provide automated “near” remote sensing of canopy phenology across the northeastern US and adjacent Canada has been initiated. A pilot study (2006-2007) at the Bartlett Experimental Forest previously demonstrated the viability of tracking both spring green-up and autumn senescence based on relative changes in red, green, and blue (RGB) color channel brightness values extracted from networked digital camera (“webcam”) images. In 2008, we installed commercial-grade digital webcams at a dozen established research sites across the northeast, from Ontario and New York across to Maine, with most sites concentrated within a few degrees of 45°N. Two additional Midwestern sites were subsequently added to the network.

    At seven camera sites (Bartlett, Howland, Harvard Forest, Groundhog River, Chibougamau, University of Michigan Biological Station, and Morgan Monroe), ongoing measurements of carbon and water fluxes are being made with the eddy covariance method, which will enable us to directly link phenology to seasonal variation in ecosystem processes.

    In some cases, cameras were not deployed until after spring green-up, but at other sites, we obtained data on a full seasonal cycle (e.g., Harvard Forest; see seasonal trajectory of “greenness index”, showing rapid rise in greenness in spring, a gentle decline over the course of the summer, and then a rapid decline with autumn senescence at right).

    All cameras continue to be fully operational, and are in place and ready to observe the passing of the seasons in 2009. In future years, this network will yield a very rich (and unique) dataset on spatial and temporal patterns of canopy phenology across this region.

    Half hourly images are uploaded to a project web page (, which also features additional information about the project, including a protocol for camera deployment, download tools (so that the imagery is available to a wider community), site locations and contact information, etc. We are working towards developing on-the-fly analysis tools which will be used to process images as they are added to the archive so that the web page can display results in near-real time (along with corresponding MODIS data products).

    We have also begun archiving imagery from other collaborators (including NPS, USDA Forest Service, USGS, etc.) outside of the northeast region, in preparation for future continent-scale evaluation of satellite remote sensing phenology products.

  • Research Category: Ecological Informatics and Modelling, Physiological Ecology, Population Dynamics, and Species Interactions, Regional Studies

  • Figures:
  • NSRC Webcam Map.jpg