Conserving Water AND Saving Trees
Smart Tree Watering Guidelines
Trees are the most valuable component of our green infrastructure because of the benefits they provide and the investment they represent. As summer temperatures increase after a wet, cool early summer, trees will need to be irrigated to assure they thrive.
We are asking citizens to conserve water, but not at the expense of their trees. A large percentage of our city's trees need summer water, and we can't afford to lose the shade, beauty and environmental benefits they provide.
Water conservation and tree preservation are not incompatible goals. Canopy offers advice on how to achieve both:
- Visit the Canopy Tree Library to determine how much water your tree needs or to select a drought tolerant species for your planting.
- Read our step-by-step instructions on how you can preserve trees and conserve water.
- Consult our watering guidelines for practical tree watering recommendations
- Read three case studies for concrete examples of water conservation situations and their solutions.
Noticing signs of water related stress
It is important to identify and relieve water related stress promptly, especially during dry months. Leaves of a tree will show identifiable symptoms like browning of leaf edges, poor or stunted new growth in the spring, die-back of leaves, twigs and branches, or "Sunburn." Surburn presents with brown patches in the middle of the leaf, which can occur during hot spells when the tree cannot uptake water as quickly. Learn how to take a "moisture sample."
Frequency of watering
You should infrequently yet deeply water your trees in the most efficient manner possible. Keep in mind that if the weather is hotter or cooler or if your watering area is shaded or particularly hot, your frequency of watering will change. Click to expand the table.
Newly Planted Trees
In Palo Alto, it is the responsibility of residents to care for young street trees until they are "established." If you have a young street tree, you have probably received a postcard from Canopy about your responsibility to water your tree. Young trees require special attention because they are vulnerable. You need to saturate the soil with water to a depth of 12 inches below the soil surface, and widely enough to include the entire root ball. Use ten to fifteen gallons per young tree or per inch of trunk diameter will suffice. During summer, water once per week and during winter water once per month.
Dry California Native Oaks
Our native oaks do not require and do not tolerate irrigation in the dry months. If irrigation is applied near their trunk during the dry season, oak root fungus will grow through the combination of warmth and moisture, which in turn will cause the tree to die. As Canopy and the City continue to plant drought-tolerant trees that will match our region's rainfall levels, we ask that you help us appropriately care for these new trees on the block.
The City of Palo Alto and Canopy have planted thousands of new street trees in the last fifteen years. To assure that these trees survive to maturity, it is important to consider summertime watering needs. We are happy to answer any questions (please always feel welcome to call our Tree Hotline: 650-964-6110 x1), but the most important element is community participation in providing trees a regular and appropriate supply of water.