Giasson, M.-A.Ellison, AaronBowden, R. D.Crill, P. M.Davidson, E. A.Drake, J. E.Frey, S. D.Hadley, JulianLavine, M.Melillo, J. M.Munger, J. W.Nadelhoffer, K. J.Nicoll, L.Ollinger, S. V.Savage, K. E.Steudler, P. A.Tang, J.Varner, R. K.Wofsy, StevenFoster, DavidFinzi, A. C.2014-01-132013Giasson, M.-A., A. M. Ellison, R. D. Bowden, P. M. Crill, E. A. Davidson, J. E. Drake, S. D. Frey, et al. 2013. Soil respiration in a northeastern US temperate forest: A 22-year synthesis. Ecosphere 4 (11).2150-8925http://nrs.harvard.edu/urn-3:HUL.InstRepos:11510265To better understand how forest management, phenology, vegetation type, and actual and simulated climatic change affect seasonal and inter-annual variations in soil respiration (R\(_{s}\)), we analyzed more than 100,000 individual measurements of soil respiration from 23 studies conducted over 22 years at the Harvard Forest in Petersham, Massachusetts, USA. We also used 24 site-years of eddy-covariance measurements from two Harvard Forest sites to examine the relationship between soil and ecosystem respiration (R\(_{e}\)). R\(_{s}\) was highly variable at all spatial (respiration collar to forest stand) and temporal (minutes to years) scales of measurement. The response of R\(_{s}\) to experimental manipulations mimicking aspects of global change or aimed at partitioning R\(_{s}\) into component fluxes ranged from −70% to +52%. The response appears to arise from variations in substrate availability induced by changes in the size of soil C pools and of belowground C fluxes or in environmental conditions. In some cases (e.g., logging, warming), the effect of experimental manipulations on R\(_{s}\) was transient, but in other cases the time series were not long enough to rule out long-term changes in respiration rates. Inter-annual variations in weather and phenology induced variation among annual R\(_{s}\) estimates of a magnitude similar to that of other drivers of global change (i.e., invasive insects, forest management practices, N deposition). At both eddy-covariance sites, aboveground respiration dominated R\(_{e}\) early in the growing season, whereas belowground respiration dominated later. Unusual aboveground respiration patterns—high apparent rates of respiration during winter and very low rates in mid-to-late summer—at the Environmental Measurement Site suggest either bias in R\(_{s}\) and R\(_{e}\) estimates caused by differences in the spatial scale of processes influencing fluxes, or that additional research on the hard-to-measure fluxes (e.g., wintertime R\(_{s}\), unaccounted losses of CO\(_{2}\) from eddy covariance sites), daytime and nighttime canopy respiration and its impacts on estimates of R\(_{e}\), and independent measurements of flux partitioning (e.g., aboveground plant respiration, isotopic partitioning) may yield insight into the unusually high and low fluxes. Overall, however, this data-rich analysis identifies important seasonal and experimental variations in R\(_{s}\) and R\(_{e}\) and in the partitioning of R\(_{e}\) above- vs. belowground.en-USecosystem respirationeddy covarianceflux partitioningHarvard Forestphenologysoil respirationJournal Article2013-10-25M-A Giasson, AM Ellison, et al.2014-01-1310.1890/ES13.00183.1