Post-clearcut dynamics of carbon, water and energy exchanges in a mid-latitude, temperate forest environment

Temperate forests store a large amount of carbon vulnerable to release from climate change, disturbance and land conversion processes.  Temperate forests also play an important role in regulating earth’s climate system via the biogeophysical effects of shortwave and longwave radiative fluxes and evapotranspiration.  Although earth system models provide important clues to the biogeochemical and biogeophysical effects of land change, the precise changes are poorly understood in part because of a lack of field measurements.  Flux tower contrasts and age-sequences offer a valuable approach to documenting how these balances change with disturbance and recovery processes, though such a sequence has thus far been lacking in New England.  This study quantifies such variation and identifies underlying mechanisms with detailed observations from an intensely instrumented site in a post-clearcut environment undergoing rapid vegetative regrowth typical of New England and located within the Harvard Forest Long-Term Ecological Research site (HF LTER).  In central and western MA, harvest rates average about 1.4% per year, similar to that of heavily managed forests of the southeast.  Though the average harvesting intensity is modest in this region, about one fifth involves clearcut practices.  Using the first three years of data from a flux tower deployed in a recently clearcut site we have begun to address the questions: How do GEP, R_eco, and NEP vary with vegetation recovery in a post-clearcut environment of New England?  Is there a sustained decrease in evapotranspiration following clearing and how rapidly does evapotranspiration recover with vegetation regrowth?  And how do gross and net radiative fluxes vary seasonally and annually in the early years following forest clearing?