Dozens of arborists donated their time, resources and expertise on Saturday to help spruce up Buffalo's Delaware Park. They spent much of the day removing hazardous trees and broken branches, and pruning and fertilizing other trees. It's a big project. The Olmsted Parks Conservancy is responsible for maintaining 15,000 trees in the Olmsted Parks and parkways throughout the city. Volunteers from private tree companies taking part say they don't mind donating their efforts because it helps the community.