Effects of prior growth on oak tree and stand growth response to drought-defoliation disturbance

Authors

• Jillian D. Dyer, University of Connecticut
• Robert Bagchi, University of Connecticut
• Audrey Barker Plotkin, Harvard Forest
• James Mickley, University of Connecticut
• Keenan J. Rivers, University of Connecticut
• Maya Sagarin, University of Connecticut
• Danielle N. Tanzer, University of Connecticut
• Robert T. Fahey, University of Connecticut

Document Type

Article

Publication Date

12-1-2026

Abstract

Novel disturbance interactions associated with global change drivers are increasingly affecting forested ecosystems. Understanding of how pre-disturbance tree and forest conditions affect growth and mortality outcomes of disturbance interactions is needed to better predict and manage for potential impacts. We aimed to determine how prior growth rates, as an indicator of tree vitality, affected growth and mortality of oaks (Quercus sp.) during a 2015–2018 drought- spongy moth (Lymantria dispar) defoliation interaction. Increment core data from canopy trees at 35 sites in Massachusetts (n = 164 trees) and Connecticut, USA (n = 492 trees) were used to reconstruct growth prior to disturbance. These data along with site, stand, and disturbance characteristics (e.g., topography, soil, stand density, and defoliation severity) and individual tree characteristics (DBH, species, crown class) were related to growth and mortality. Prior growth was not strongly related to oak mortality rates at the stand level or mortality probability at the individual tree level. Stand-level growth during disturbance and growth resistance (growth during disturbance relative to prior growth) were both predicted by a combination of defoliation frequency and prior growth. At the individual tree level, growth during the disturbance and growth resistance were related to prior growth in combination with crown position. Our results suggest that growth response during this disturbance interaction was associated with legacies of prior growth, but that mortality associated with this drought-defoliation event was not strongly impacted by pre-disturbance growth rates. Improved understanding of how legacies of pre-disturbance forest conditions affect growth responses will aid managers in predicting and managing for resistance to novel disturbance interactions.

Publication Title

Forest Ecology and Management

Recommended Citation

Dyer, J., Bagchi, R., Plotkin, A., Mickley, J., Rivers, K., Sagarin, M., Tanzer, D., & Fahey, R. (2026). Effects of prior growth on oak tree and stand growth response to drought-defoliation disturbance. Forest Ecology and Management, 621. http://doi.org/10.1016/j.foreco.2026.124229
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p2/2951