Evidence of increased net ecosystem productivity associated with a longer vegetated season in a deciduous forest in south‐central Indiana,USA |
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| Authors: | DANILO DRAGONI HANS PETER SCHMID CRAIG A WAYSON HENRY POTTER C SUSAN B GRIMMOND JAMES C RANDOLPH |
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| Institution: | 1. Department of Geography, Indiana University, Bloomington, IN, USA;2. Atmospheric Environmental Research, Karlsruhe Institute for Technology (KIT/IMK‐IFU), Garmisch‐Partenkirchen, Germany;3. USDA Forest Service, Newtown Square, PA, USA;4. Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA;5. Department of Geography, King's College London, London, United Kingdom;6. School of Public and Environmental Affairs, Indiana University, Bloomington, IN, USA |
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| Abstract: | Observations of net ecosystem exchange (NEE) of carbon and its biophysical drivers have been collected at the AmeriFlux site in the Morgan‐Monroe State Forest (MMSF) in Indiana, USA since 1998. Thus, this is one of the few deciduous forest sites in the world, where a decadal analysis on net ecosystem productivity (NEP) trends is possible. Despite the large interannual variability in NEP, the observations show a significant increase in forest productivity over the past 10 years (by an annual increment of about 10 g C m?2 yr?1). There is evidence that this trend can be explained by longer vegetative seasons, caused by extension of the vegetative activity in the fall. Both phenological and flux observations indicate that the vegetative season extended later in the fall with an increase in length of about 3 days yr?1 for the past 10 years. However, these changes are responsible for only 50% of the total annual gain in forest productivity in the past decade. A negative trend in air and soil temperature during the winter months may explain an equivalent increase in NEP through a decrease in ecosystem respiration. |
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| Keywords: | carbon cycle climate change eddy‐covariance leaf senescence phenology |
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