Integrating tree-ring and sample plot data to reconstruct annual estimates of ecosystem productivity
The primary methods for obtaining field measurements of forest ecosystem productivity are currently sample plots, eddy covariance, and tree-ring measurements. Of these, tree-ring measurements are the most suitable method for obtaining long-term (multi-decadal) data. These data are used to make inferences about the magnitude and direction of future trends as well as the causes of past inter-annual variability. However, they provide only a tree-level index of productivity and do not typically provide data on mortality rates. It is not known whether and how tree-ring data are related to stand-level measures such as net primary production. Detailed regional studies are required to develop and validate methods for scaling data from tree-level ring-widths to estimates of annual productivity for stands or ecosystems. These studies can be used to inform methodologies for integrating tree-ring and plot data into landscape-level assessments of ecosystem productivity, either by developing new empirical models or providing validation data sets to assess process-based models. The results of this research will be integrated into the next-generation tools used by Canada’s National Forest Carbon Monitoring, Accounting, and Reporting System. Currently, this system uses empirical growth curves that represent average past growing conditions but do not account for inter-annual variability or long-term trends in stand dynamics that affect annual GHG emissions and removals.
Regional studies of tree-ring and sample plot data to be integrated into methodologies to assess stand- or ecosystem-level productivity