In this article from the Marin Independent Journal, Nick Crawford, sales arborist for Davey's San Francisco office, gives readers tips for keeping their trees healthy during drought.
Posted: June 5, 2015
By PJ Bremier
Wondering how your trees will survive the drought? Nicholas Crawford, a board-certified master arborist for the Davey Tree Expert Co. whose territory includes Marin County offers some timely tips:
• Know your tree. Crawford divides trees into three categories: those with high, moderate or low water requirements.
Redwoods fall into the high water use category; citrus, maples, broadleaf evergreens and gingkoes are in the moderate range, and low water users include eucalyptus, pines and native oaks.
Even so, low-water use trees need water. “They can survive drought conditions, but we had an unseasonably warm winter and that combination is stressing out native oaks,” he says. And, when a tree is stressed, it’s wide open for fatal pests or diseases.
In general, for the health of the tree, low water-using ones should be slowly deep-watered once every three months when it’s hot, and dry and moderate ones should be watered once a month.
A recommendation for high water users, such as a redwood tree, he says, “is a tough one because they could use so much water. They’re used to much wetter environments.”
• Location, location, location. “It’s hard to give a general answer on how much water any tree needs,” he says. “An arborist can take a look at the whole landscape to help you figure that out.”
For example, you can have multiple microclimates within your garden or a tree could be planted next to asphalt causing it to bake in the sun or it could be in a protected location on the north side.
• Water ways. “People I talk to are really trying to do whatever they can,” he says. “They shower with a bucket and pour it on a tree. A bucket of water may be fine for container plants, but it’s negligible for a tree.”
First thing, Crawford says, is “water trees in the morning to minimize evaporation.” Then, water slowly, so there is less run-off.
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