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Harvard Forest REU Symposium Abstract 2011
- Title: Do physiological changes at leaf level explain seasonal changes in remotely sensed canopy greenness?
- Author: Bridget A Darby (Boston University)
- Abstract:
The Phenocam network is a network of digital cameras used to analyze phenological events and track canopy greenness levels throughout the growing season. As a near surface remote sensing platform it acts as an intermediary between leaf level measurements and satellite based remote sensing products. The cameras typically document a rapid increase in canopy greenness after leaf out, which peaks in early summer and gradually declines thereafter. Open questions remain, however, as to whether the observed changes in canopy greenness are directly related to changes in leaf physiology, or changes in canopy structure. The goal of this study was to determine if a correlation exists between the physiological changes occurring at leaf-level and the seasonal greenness as measured by the cameras. Such relationships may also allow for leaf level changes to be estimated indirectly using images from the Phenocam network, and better inform our interpretation of remotely sensed satellite products. We sampled the leaves of three species: red oak (Quercus rubra), red maple (Acer rubrum) and yellow birch (Betula alleghaniensis) at Harvard Forest (MA, USA) directly surrounding a Phenocam. Leaf mass per area and fluorescence were measured for each leaf, along with spectral indices of reflectance and transmission. Preliminary results show that changes in leaf mass per area and photosynthetic capability at leaf-level appear to reflect trends in the GCC data. Further study through the end of the growing season is expected to confirm these results.
- Research Category: Physiological Ecology, Population Dynamics, and Species Interactions
