Urban Forest
Type of Development
New Development, Restoration
Topography
Hills, Valley, Baylands
Longevity
Environment
Natural Habitat, Urban
Maintenance
Low
Cost
1:8 cost/benefit ratio. $100–$570 per tree with long term maintenance costs included (Nrc Solutions)
Overview
Tree canopies are tree communities of native or ecologically suited trees planted throughout cities to reduce climate change impacts. Trees establish healthy hydrologic circulation by capturing and storing water within soils, filtering out pollutants, and recharging clean groundwater through their base. Trees with deep root systems have a large capacity to capture water from storm runoff and flooding events. Tree canopies provide shade and healthy air, while also reducing average temperatures.
Function
Planting trees will detain water runoff from storms and floods, create shade and moisture, and will generally reduce temperatures.
Benefit
Tree canopies' root systems capture excessive amounts of water runoff and effectively filter out pollutants from the hydrologic system. Trees sequester carbon, increasing healthy air in their vicinity and resulting increased overall community health. Green spaces create opportunities for community gatherings and are proven to increase mental health. Shade from trees reduces heat by up to 3-4 degrees during the day and as much as 11-22 degrees during the night. Further management of urban forests reduces wildfire risk and increases drought tolerance. Agroforestation increases soil nutrients, reduces erosion of soils, and generally increases the socioeconomic prosperity and value of crops. Tree groves protect rivers by intercepting rainfall and strengthening banks. The added nutritional value of trees, specifically native ones, reestablishes habitats by reducing weed growth and encouraging native organisms to thrive locally. Additional benefits include muffling traffic noise, removing pollutants and dirt from the air, and reducing cooling costs through direct shading of buildings.
Dependency
Development Considerations
Forty percent tree cover is recommended. However, on average Santa Clara has only 11% tree coverage (https://services.sccgov.org). Trees require sunlight, water, and space. Planting times should be scheduled to experience mild climates for the first few months, right before Santa Clara's rainy season.
Environmental Considerations
Type of tree, space available, type of soil, planting schedule
Maintenance Consideration
Five years of maintenance may be required to protect small trees from animals, weeds, and humans. Additional attention after extreme weather events are required in the first five years of planting. However, after 5 years there is little to no maintence required. Tracking projects is always important for future projects.
Cost Considerations
1:8 cost/benefit ratio. $100–$570 per tree with long term maintenance costs included (Nrc Solutions)
Case Studies
Urban Forest “Vision Solano”
Sustainable Solano's Urban Forest “Vision Solano” project aims to green Solano County with trees and plants that support diverse ecosystems and provide shade, food, and habitat for wildlife. For this project, Sustainable Solano planted 60 trees in 2018 and 2019 throughout Shelter Solano, a local Fairfield homeless shelter, using a grant from the California ReLeaf Social Equity Tree Planting Program. These efforts converted the 3.5-acre area into a resilient, mixed-canopy urban forest complete with California native drought-tolerant trees and fruit trees. Community members participated in the creation of this urban forest while learning about sustainable landscaping practices and urban forestry for local communities.
