We assessed tree mortality and volume loss resulting from recent or current jack pine budworm defoliation in jack pine (Pinus banksiana) stands in the northern Lower Peninsula and the Upper Peninsula of Michigan. Budworm defoliation ranged from negligible to relatively high in some stands. Annual radial growth, topkill and mortality resulting from budworm defoliation or other causes were determined in replicated plots in over 75 stands. Relationships between site and stand inventory variables and tree growth and mortality were examined. Coarse woody debris was quantified in each stand to determine how jack pine budworm defoliation affects fire hazard. The reason for the landscape scale quantification of outbreaks is to validate the Lake States Jack Pine Budworm Decision Support System (JPBW DSS) so that it can be applied to other areas besides the eastern U.P.