USA NPN National Phenology Network

Taking the Pulse of Our Planet

You are here

Effects of seasonal variation of photosynthetic capacity on the carbon fluxes of a temperate deciduous forest

TitleEffects of seasonal variation of photosynthetic capacity on the carbon fluxes of a temperate deciduous forest
Publication TypeJournal Article
Year of Publication2013
AuthorsMedvigy, D, Jeong, S-J, Clark, KL, Skowronski, NS, Schäfer, KVR
JournalJournal of Geophysical Research: Biogeosciences
Date Published12/2013
Abstract

Seasonal variation in photosynthetic capacity is an important part of the overall seasonal variability of temperate deciduous forests. However, it has only recently been introduced in a few terrestrial biosphere models, and many models still do not include it. The biases that result from this omission are not well understood. In this study, we use the Ecosystem Demography 2 model to simulate an oak-dominated stand in the New Jersey Pine Barrens. Two alternative model configurations are presented, one with seasonal variation of photosynthetic capacity (SPC-ON) and one without seasonal variation of photosynthetic capacity (SPC-OFF). Under typical climate conditions, the two configurations simulate values of monthly gross primary productivity (GPP) as different as 0.05 kg C m−2 month−1 in the early summer and 0.04 kg C m−2 month−1 in the fall. The differences between SPC-ON and SPC-OFF are amplified when there is temporal correlation between photosynthetic capacity and climate anomalies or disturbances. Warmer spring temperatures enhance GPP in SPC-ON more than in SPC-OFF, but warmer fall temperatures enhance GPP in SPC-OFF more than in SPC-ON. Defoliation by gypsy moth, a class of disturbance that typically happens in late spring in the New Jersey Pine Barrens, has a disproportionately negative impact on GPP in SPC-ON. It is concluded that including seasonal variation of photosynthetic capacity in models will improve simulations of monthly scale ecosystem functioning as well as of longer-term responses to climate change and disturbances.

URLhttp://onlinelibrary.wiley.com/doi/10.1002/2013JG002421/pdf
DOI10.1002/2013JG002421
Journal of Geophysical Research: Biogeosciences
12/2013