Northern California loves its trees. To the people who care about them most, every elm or oak lost feels like a jab to the heart.
That made California’s prolonged drought particularly difficult for the staff and volunteers at the Sacramento Tree Foundation. Not only did trees die slow deaths from drought, but healthy trees are being removed in the interest of saving water.
And when the storms came, more trees fell victim, particularly those already weakened by drought. Although Northern California may be out of drought in 2017, trees will continue to die from drought’s continued after-effects.
“While we are thrilled residents are saving water and installing drought-tolerant landscapes, we are very concerned about the tree canopy loss along with it,” said Ray Tretheway, the foundation’s executive director, during last year’s drought. “The drought has already killed so many trees in the region in the last few years, and it is so hard to see residents removing more for the sake of only water savings. The loss of tree canopy to our region is not worth the water savings gained.”
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Residents can save water and their trees, Tretheway said.
“Both are very compatible. You can have a balance,” he said.
In the city of trees, Tretheway worries about our shrinking urban forest.
“Our trees definitely are in danger, particularly from the effect of four-plus years of drought,” Tretheway said. “Under state water conservation mandates, we need to redouble our efforts to save water. But we also need to redouble our efforts to save existing trees and plant new ones. We have a deficit of tree canopy.”
By the foundation’s estimates, about 17 percent of the six-county greater Sacramento area is covered with trees, Tretheway said.
“We need about 35 percent canopy cover – more than double our present canopy.”
Before the drought, Sacramento’s tree population totaled about 1.7 million within city limits. Overall, Sacramento County had an estimated 6 million trees, including 1.92 million in rural orchards and wilderness.
Every five years, volunteers count trees in a botanical census that also surveys other vegetation and land use. Tretheway frets what they will find.
“Tree canopy loss is a very costly problem, not only in expensive tree removal, but also in the loss of all the benefits trees provide,” Tretheway said. “Our tree canopy provides an immense range of health, energy, environmental and economic benefits. Trees improve air and water quality. Trees provide shade to the landscape and reduce water needs. They help keep your home cooler, slow stormwater runoff and help recharge groundwater and reduce soil erosion. And trees add value – sometimes thousands of dollars’ worth – to your home and neighborhood.
“Tree canopy takes a long time to grow, and the larger the canopy, the greater the benefits. (The drought) has already harmed and killed too many trees. It will take 10, 20 or even 40-plus years to regrow the tree canopy and to regain the lost benefits.”
Many homeowners are converting their traditional turf-based landscapes to water-wise alternatives. That has put “lawn trees” – those ornamental trees planted in the middle of a grassy area – at risk. They’re accustomed to all that sprinkler water used to irrigate the lawn. When that water is turned off, they become really stressed. Many lawn trees don’t survive the transition.
“We see poor practices,” Tretheway said. “Homeowners may not be fully informed as they transition to drought-tolerant landscapes.”
Those lawn trees also develop shallow roots – instead of deep strong roots. That makes them more likely to fall down during storms, as seen throughout the Sacramento region in January. Hundreds of trees, weakened by drought, were knocked down by high winds after winter storms saturated the soil.
In addition, the most common drought-tolerant plants require full sun – something they don’t get under a large, shady tree.
“Please don’t forget there are many wonderful low-water users that also like shade and can grow well under existing trees,” Tretheway said. Some of his favorites for “dry shade” include coral bells, sticky monkey flower and Douglas iris.
Jeanne Cunningham, a longtime SacTree volunteer who works part time on the foundation’s staff, tackled this balancing act in her own front yard.
“My redbud and crabapple are now in full bloom and just gorgeous,” she said last spring.
Her Antelope home originally had all lawn and a lonely Bradford pear planted in the middle of the turf.
“When we first moved in (20-plus years ago), all we had was the pear tree,” she said. “It was trimmed to be a lollypop tree.”
In transitioning her garden to a drought-tolerant landscape, Cunningham initially worked around the pear tree. “Then, there was a big storm and it fell over. Mother Nature decided on her own that tree had to go.”
In its place, Cunningham planted three other trees that fit her low-water landscape: pomegranate, crabapple and redbud. All three trees bloom heavily in spring, adding to the colorful front yard.
“We get fruit from the pomegranate,” she said. “I make jelly.”
In summer, Cunningham irrigates most of the front yard twice a week via a drip system. She uses the “bucket method” to deep-water her trees every other week.
“It’s easy; no muss, no fuss,” she said. “You take a 5-gallon bucket and drill an eighth-inch hole in the bottom. Place the bucket just inside the dripline (the edge of the tree’s canopy) and fill it with water. The water soaks slowly into the soil. When the bucket is empty, move it to another spot and fill again. It’s much better than letting the hose run. You can forget (the hose) and end up wasting a lot of water.”
Wood-chip mulch keeps the soil evenly cool over tree roots and retains moisture.
“Our big message to homeowners is not just to water trees but to mulch them,” Tretheway said. “That’s really important to help them survive. We’re in a brand-new era. Nobody intentionally wants to put their trees at risk. But we’re working to save them, tree by tree, home by home. We’re all learning.”