Comparison of Tree-Ring and Eddy-Covariance Derived Annual Ecosystem Production Estimates for Jack Pine and Trembling Aspen Forests in Saskatchewan, Canada
Agricultural and Forest Meteorology
Reliable projections of future carbon (C) dynamics are essential to resource management decision making under a changing climate. Additional corroborative data may reduce uncertainty in C flux estimates. Here we use a tree-ring based hybrid biometric modelling approach to estimate annual ecosystem production at jack pine (Pinus banksiana) and aspen (Populus tremuloides and Populus balsamifera) plots co-located with eddy-covariance installations in the boreal forest of Saskatchewan, Canada for a 28 year (1985 to 2012) period. Correspondence between tree-ring and eddy-covariance derived estimates was better for jack pine (14-year overlap, 1999 to 2012) than aspen (16-year overlap, 1997 to 2012), and better for some C fluxes than others. In particular, tree-ring estimates of annual and cumulative net ecosystem production were larger than eddy-covariance derived estimates for the overlapping period. Allometric equations, belowground production, and biomass turnover could neither be confirmed nor ruled out as causes of discrepancy, but a lower stand density and higher carbon use efficiency would together reduce observed differences for aspen. Tree-ring based estimates of biomass increment or net primary production showed good temporal correspondences with both current and previous year eddy-covariance analogues, and net and gross primary production. Similar comparisons for net ecosystem production and heterotrophic respiration had mixed results. This study improves on previous work by comparing independent estimates of the same fluxes quantities and demonstrates the value of tree-ring data for evaluating C flux estimates.
Metsaranta, J., S. Mamet, J. Maillet, and A. Barr. 2021. Comparison of tree-ring and eddy-covariance derived annual ecosystem production estimates for jack pine and trembling aspen forests in Saskatchewan, Canada. Agricultural and Forest Meteorology 307:108469.