Tree-ring data sourced in a forest inventory context

Tree-ring time series data offer a lifelong, annually resolved record of a tree’s growth, making them a valuable source of information on aboveground woody biomass accumulation and hence carbon sequestration in forests. However, tree-ring data have traditionally been generated with sampling protocols biased towards climate-sensitive trees, to meet the goal of reconstructing past climate (i.e., for paleoclimatology). Since 2016, I’ve been collaborating with the US Forest Service’s Forest Inventory and Analysis (FIA) program in the Interior West region to develop a spatial network of tree-ring time series data that is relatively unbiased and representative, because they were sourced in the FIA’s network of forest inventory plots. With this data network, we showed that the sensitivity of tree growth to climate variability is 41-59% greater when estimated from the International Tree-Ring Data Bank (a public repository of tree-ring time series) compared to the forest inventory tree-ring collection, leading to an overestimate of the negative impact of climate change on tree growth (Klesse et al. 2018). We have made the case for adding systematic tree-ring sampling in the national forest inventories of Canada, the US, and Mexico to create a continental-scale tree-ring data network to help resolve key uncertainties about the future of the land carbon sink, improve forest carbon accounting, and better guide nature-based climate mitigation strategies. A recording of a talk delivered at AGU in December, 2021 is available here.