Hasan Malik started a tree-planting enterprise when he was a high school student. Now his non-profit, Northeast Tree Tenders, has 60 to 70 volunteers who have planted more than 270 trees in front of people's houses, in their yards — even in business parks and commercial strips. His mission: restoring the tree canopy in Northeast Philadelphia. Homeowners pay $15 (if they have it) and the trees are supplied by the Pennsylvania Horticultural Society. "They get a great deal: We break up the concrete, plant the trees, come out and prune and mulch, leave them instructions," he said. "We have only lost 16 trees in three years. We think we're better than the pros."