Steven Sader, Ph.D., a professor of forest resources and director of the Maine Image Analysis Laboratory at the University of Maine, will talk on “Mapping and Monitoring 40+ Years of Forest Change in Maine’s North Woods,” at a MDI Science CafA© to be held at McKay’s Public House, 231 Main St., Bar Harbor, at 5:30 p.m. on Wednesday, April 6. The talk will address NASA and University of Maine initiatives using satellite imagery to manage Maine’s forest landscape.