At its inception, Palo Alto was named after a 110-foot tall, over 1,000-years-old coast redwood tree called “El Palo Alto,” which loosely translates to “tall tree.” Today, in the midst of California’s drought, city staff and tree experts are encouraging residents to go back to their roots and care for these trees from which the city gets its name.
More than two-thirds of the city’s urban forest is situated on private property, according to Michael Hawkins, a certified arborist and program director of environmental nonprofit Canopy.
“(This) is why we encourage people to plant (and care for) new trees, which would replenish the trees we would lose from the drought,” he said.
Two of the main mistakes residents are making with their trees are overwatering or simply not watering at all, he said. Mature trees only need to be watered once a month or every month, according to Hawkins. Younger trees require watering weekly or biweekly, for at least the first three to five years. After which, they can be placed on a monthly watering cycle.
The worst tree-watering method, Hawkins said, is sprinklers because the water will likely evaporate before the tree has a chance to absorb it, especially during warmer temperatures. He recommends running drip emitters for more mature trees, specifically the Netafim brand, for about 90 minutes. They should be placed around the ring of the tree at the drip line where most roots are located. If residents don’t want to spend money on drip emitters, Hawkins recommends soaker hoses.
For younger trees, Hawkins said to water the tree by holding a large water bucket with holes drilled in the bottom over it. The holes help regulate flow and prevent water running into the streets.
As a last resort, if sprinklers must be used, they should run in early mornings or evenings and should be set to run only 30 minutes at a time, he said.
Depending on the density of the soil, trees can be watered up to once a week according to Ruben Green, president and consulting arborist at Evergreen Arborist Consultants.
“Water goes right to the root system for sandy soil. Heavy soil or expansive soil will go straight to the street,” he said.
He recommends taking a sample and crushing it in between fingers. The heavier soil is very similar to clay and can likely form a solid shape. Sandier or loamy soil, Green said, tends to fall apart and requires more frequent watering because the water passes through the soil much quicker than dense soil.
If there is any silver lining to the drought, Green believes residents are not overwatering their trees, which reduces the decay and diseases among them.
Green recommends not watering plants or bushes and reducing the amount of annual flowers.
“If it dies, it will be easy to replace,” he said. “The trees take decades and decades to replace.”
Trees are not one size fits all, Green adds. Residents who are looking to plant trees should consider how the tree will evolve during the next few decades.
“It has to be the right tree for the right place,” he said.
Green and Hawkins recommend planting trees such as the Chinese elm, silver linden and coast live oaks, and avoiding magnolia trees and Monterey pine. Coincidentally, the southern magnolia is the most common tree along Palo Alto’s streets. The next most common tree is the liquidambar.
According to Susan Rosenberg, a Canopy founder, every summer, Canopy staff and volunteers visit trees that have been planted by the city during the past five years and leave fliers for homeowners about tree care. She encourages residents who have questions about caring for these trees and their own to submit questions to Canopy’s Tree Hotline.
Despite the drought, trees are worth the water investment, Hawkins said.
“Everyone has been really focused on preserving water and a lot of trees have been suffering as a result,” he said. “It’s important that we don’t lose them as assets.”
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Muna Sadek is an editorial intern at the Palo Alto Weekly.
Muna Sadek is an editorial intern at the Palo Alto Weekly.
Muna Sadek is an editorial intern at the Palo Alto Weekly.