Data from: Variable effects of climate on forest growth in relation to climate extremes, disturbance, and forest dynamics
Itter, Malcolm S., Michigan State University
Finley, Andrew O., Michigan State University
D'Amato, Anthony W., University of Vermont
Foster, Jane R., University of Minnesota
Bradford, John B., United States Geological Survey
Published Jan 30, 2017 on Dryad.
Cite this dataset
Itter, Malcolm S. et al. (2017). Data from: Variable effects of climate on forest growth in relation to climate extremes, disturbance, and forest dynamics [Dataset]. Dryad. https://doi.org/10.5061/dryad.18pm5
Changes in the frequency, duration, and severity of climate extremes are forecast to occur under global climate change. The impacts of climate extremes on forest productivity and health remain difficult to predict due to potential interactions with disturbance events and forest dynamics—changes in forest stand composition, density, size and age structure over time. Such interactions may lead to non-linear forest growth responses to climate involving thresholds and lag effects. Understanding how forest dynamics influence growth responses to climate is particularly important given stand structure and composition can be modified through management to increase forest resistance and resilience to climate change. To inform such adaptive management, we develop a hierarchical Bayesian state space model in which climate effects on tree growth are allowed to vary over time and in relation to past climate extremes, disturbance events, and forest dynamics. The model is an important step toward integrating disturbance and forest dynamics into predictions of forest growth responses to climate extremes. We apply the model to a dendrochronology data set from forest stands of varying composition, structure, and development stage in northeastern Minnesota that have experienced extreme climate years and forest tent caterpillar defoliation events. Mean forest growth was most sensitive to water balance variables representing climatic water deficit. Forest growth responses to water deficit were partitioned into responses driven by climatic threshold exceedances and interactions with insect defoliation. Forest growth was both resistant and resilient to climate extremes with the majority of forest growth responses occurring after multiple climatic threshold exceedances across seasons and years. Interactions between climate and disturbance were observed in a subset of years with insect defoliation increasing forest growth sensitivity to water availability. Forest growth was particularly sensitive to climate extremes during periods of high stem density following major regeneration events when average inter-tree competition was high. Results suggest the resistance and resilience of forest growth to climate extremes can be increased through management steps such as thinning to reduce competition during early stages of stand development and small-group selection harvests to maintain forest structures characteristic of older, mature stands.
Northeastern Minnesota Tree Growth Data
Annual radial growth increment data for 2,291 trees located in 35 stands in and around Superior National Forest in northeastern Minnesota. Data includes stand-level measurements including water balance variables and years since cohort initiation.