Construction activity causes compaction of the soil which squeezes out oxygen and kills beneficial microbes and root hairs of trees and other plants. Prevent it - don’t allow it - use physical barriers. Build strong fences so contractors cannot access the root zone. Use coarse mulch on all work areas and areas of vehicle access (roads and parking). Three inches of coarse shredded native tree trimmings mulch is as effective as ¾” plywood at preventing compaction. The mulch also prevents tracking of mud and dirt into new construction.