Pruning Trees a. All pruning shall be performed under supervision of a certified arborist. Pruning standards shall conform to ISA standards specified in the Urban Forest Program of the City Department of Recreation and Parks. Prune trees (1) to select and develop permanent scaffold branches that are smaller in diameter than the trunk or branch to which they are attached and that have vertical spacing from 18 to 48 inches and radial orientation so as to not overlay one another; (2) to eliminate diseased or damaged growth; (3) to eliminate narrow, V-shaped branch forks that lack strength;
