October 2021 - Trees

treesDue to wildfire, disease, and drought, California now leads the nation in loss of tree cover. Most, but not all of this loss has occurred in uninhabited forest lands. Our own Santa Cruz Mountains saw devasting tree loss during the CZU fires last year. Wildland forests may recover to some degree on their own. But trees in the urban landscape face challenges that wildland trees don’t. Trees growing near houses, driveways, and streets require more water due to the heat-trapping effect of the urban landscape.  Drought adds to these stresses. Conversely, trees help mitigate the heat effects of roofs and roads and so their continued presence is a major environmental benefit, in addition to cleaning our air and water, making our streets quieter, and improving our property values. Water for trees is undoubtedly a beneficial use of our water resources. Please follow these guidelines from the California Urban Forests Council to water trees wisely so we can continue enjoying the wide range of benefits that trees offer.

  • Young trees. Water young trees twice a week with about 5 gallons of water, using a bucket or hose. The roots of younger trees are less established and need easy access to water to develop deep roots.
  • Mature trees. If you are noticing water stress in mature trees, then water the ‘drip zone’ area directly beneath the foliage and shaded by the tree. Apply the equivalent of about an inch of water once a week in several places around the drip zone. It takes about 2/3 of a gallon to cover 1 square foot in an inch of water. You don’t need to wet the entire drip zone. Selectively soaking portions of the drip zone will get water to the roots and promote healthier trees. Water should soak into the ground rather than running off. Create small depressions if your soil needs help allowing water to infiltrate and add mulch all around to lower soil temperature and reduce water evaporation.
  • Deciduous trees. The critical time for water is late winter into spring when buds and leaves are forming. Watering deciduous trees and fruit trees later in summer and fall could be a waste as they begin going dormant.
  • The right time. Water early in the morning or after the sun has set. This is when trees replace the water they have lost during the day and less water is lost to evaporation.
  • The right tree. California natives like Oaks usually need no supplemental water. Chose California native trees and drought-tolerant trees over lawns to provide long-term value. Visit watersavingplants.com for lots of native and drought-tolerant tree choices.