One of two main reason: 1. It's likely that your request for a tree does not fall under the areas we currently plant in. Our tree planting efforts are focussed in neighborhoods that have the lowest tree canopy as we want trees to be equitably distributed in all of San Francisco. 2. If your request is in a neighborhood we plant in, then ask your neighbors to complete the Tree Request Form. The more interest we see in a block, the sooner we start planning a block planting in the area. It takes us 4 to 6 months to plan a block planting .