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Full-Text Articles in Physical Sciences and Mathematics
Parallel Seasonal Patterns Of Photosynthesis, Fluorescence, And Reflectance Indices In Boreal Trees, Kyle R. Springer, Ran Wang, John A. Gamon
Parallel Seasonal Patterns Of Photosynthesis, Fluorescence, And Reflectance Indices In Boreal Trees, Kyle R. Springer, Ran Wang, John A. Gamon
School of Natural Resources: Faculty Publications
Tree species in the boreal forest cycle between periods of active growth and dormancy alter their photosynthetic processes in response to changing environmental conditions. For deciduous species, these changes are readily visible, while evergreen species have subtler foliar changes during seasonal transitions. In this study, we used remotely sensed optical indices to observe seasonal changes in photosynthetic activity, or photosynthetic phenology, of six boreal tree species. We evaluated the normalized difference vegetation index (NDVI), the photochemical reflectance index (PRI), the chlorophyll/carotenoid index (CCI), and steady-state chlorophyll fluorescence (FS) as a measure of solar-induced fluorescence (SIF), and compared these …
Parallel Seasonal Patterns Of Photosynthesis, Fluorescence, And Reflectance Indices In Boreal Trees, Kyle R. Springer, Ran Wang, John A. Gamon
Parallel Seasonal Patterns Of Photosynthesis, Fluorescence, And Reflectance Indices In Boreal Trees, Kyle R. Springer, Ran Wang, John A. Gamon
School of Natural Resources: Faculty Publications
Tree species in the boreal forest cycle between periods of active growth and dormancy alter their photosynthetic processes in response to changing environmental conditions. For deciduous species, these changes are readily visible, while evergreen species have subtler foliar changes during seasonal transitions. In this study, we used remotely sensed optical indices to observe seasonal changes in photosynthetic activity, or photosynthetic phenology, of six boreal tree species. We evaluated the normalized difference vegetation index (NDVI), the photochemical reflectance index (PRI), the chlorophyll/carotenoid index (CCI), and steady-state chlorophyll fluorescence (FS) as a measure of solar-induced fluorescence (SIF), and compared these …
A Remotely Sensed Pigment Index Reveals Photosynthetic Phenology In Evergreen Conifers, John A. Gamon, K. Fred Huemmrich, Christopher Y.S. Wong, Ingo Ensminger, Steven Garrity, David Y. Hollinger, Asko Noormets, Josep Peñuelas
A Remotely Sensed Pigment Index Reveals Photosynthetic Phenology In Evergreen Conifers, John A. Gamon, K. Fred Huemmrich, Christopher Y.S. Wong, Ingo Ensminger, Steven Garrity, David Y. Hollinger, Asko Noormets, Josep Peñuelas
School of Natural Resources: Faculty Publications
In evergreen conifers, where the foliage amount changes little with season, accurate detection of the underlying “photosynthetic phenology” from satellite remote sensing has been difficult, presenting challenges for global models of ecosystem carbon uptake. Here, we report a close correspondence between seasonally changing foliar pigment levels, expressed as chlorophyll/carotenoid ratios, and evergreen photosynthetic activity, leading to a “chlorophyll/carotenoid index” (CCI) that tracks evergreen photosynthesis at multiple spatial scales. When calculated from NASA’s Moderate Resolution Imaging Spectroradiometer satellite sensor, the CCI closely follows the seasonal patterns of daily gross primary productivity of evergreen conifer stands measured by eddy covariance. This discovery …