Keep trees healthy and strong. Need a new tree? Pick the right one for future water use and shade needs.
By Debbie Arrington
Guest Writer
What a difference a wet 
winter makes. Following three years of drought, heavy winter rains gave local trees a much needed deep soaking. All that water refreshed our urban forest.
“Most trees are doing a lot better – they’re showing a lot of growth and look very healthy,” says Alex Binck, community arborist for the Sacramento Tree Foundation (SacTree). “Especially trees that have been in decline for the last several years such as redwoods; those trees are flush with new growth and just look a lot greener.”
Binck has a special relationship with hundreds of Sacramento-area trees; he played a direct role in their planting. As a community forester, he helped residents pick out and site trees as part of SacTree’s Sacramento Shade program. In partnership with SMUD, the program offers free trees to all SMUD customers. The extra shade can lower electricity consumption (and energy bills) during intense summer heat. Urban trees also clean air and help cool neighborhoods.
Sacramento Shade is a great opportunity to add (or replace) valuable trees to your landscape. Those same winter storms took a dramatic toll on many trees—particularly eucalyptus and elms, Binck notes. Now is a good time to put the right tree in the right place.
“Sacramento Shade’s most popular tree is the Shantung maple; people love its fall color,” Binck says. “It’s medium size, a little larger than a Japanese maple.”
SacTree experts such as Binck are currently studying which Sacramento trees did best (and worst) after our wet winter. They’re also trialing new tree varieties. Their observations will help shape recommendations for the Sacramento Shade program.
“With wild weather swings, we’re really trying to look at which trees are doing well and which are not,” Binck says.
That wet aspect can be bad for trees native to dry habitats. Sacramento area trees have to withstand too much rain as well as too little.
“If you experiment with desert species, be careful,” he says. “Even if heat and drought adapted; wet soil can be challenging, especially wet clay soil. They just don’t like it.”
Desert Museum palo verde, for example, demands excellent drainage and sandy soil; that species does not like standing water.
Binck’s observations so far? Valley oaks are loving this year. “They tolerate both drought and wetter conditions. They can stand in four feet deep of water for weeks, then be bone dry in August. They’re big trees, though, and do need some space.”
California live oaks are doing well, too, as are olives. Binck recommends both of those trees; they’re well adapted to our climate but can take the weather swings, too. They also keep their foliage year round.
“Originally, we only had deciduous trees in the shade program and concentrated on energy savings,” Binck says, “but we now consider the holistic benefits of trees and added a few evergreens such as olive and live oak.”
Binck likes to recommend trees he knows will grow well here, not just now but for years to come.
“The reasons I like them: They’re adapted to our climate,” he says.
Binck’s short list of favorites: Zelkova (Zelkova serrata), a tough urban shade tree with great fall color; fern pine (Afrocarpus falcatus), a graceful African evergreen ornamental tree that’s neither fern nor pine; and desert willow (Chilopsis linearis), a small tree native to Southern California with beautiful trumpet-shaped blooms.
About two dozen varieties of trees are currently available via the Sacramento Shade program.
“When you meet with a community forester, you come up with a plan together and decide where each tree should go and the appropriate type for each area,” Binck.
Keep trees happy
This summer, concentrate on helping your trees maintain their recent health gains. Although soil moisture may be good now, Sacramento’s notorious heat can bake away that moisture quickly.
“We had a phenomenal year with a lot of rainfall and soil moisture,” Binck notes, “but we had years of moisture deficit. We’ll be back into dry conditions by late summer. There definitely will be soil stress by the end of summer.”
Trees—especially younger or newly transplanted trees—are at their most vulnerable when weather changes from cool to hot rapidly—a common occurrence in the Sacramento region in June, Binck says. “Especially that first big heat wave after nice, cool weather. Look at temperatures and increase irrigation if temperatures are going to spike.
“Trees seem to adapt to temperature changes over time, but that first heat can be challenging,” he adds. “With climate change, we expect to see more dramatic swings. For trees, dramatic swings can be more stressful.”
- Irrigate thoughtfully this summer. Check soil moisture with a probe or moisture meter before automatically turning on the sprinklers. Trees prefer deep, infrequent irrigation; it encourages deep roots.
- Remember to water trees at their dripline—the farthest reach of their foliage—and not their trunks; their thirsty roots are at that outer edge.
- To retain moisture during hot summer months, make sure to mulch. Binck recommends wood chips such as those available free from SMUD. Leave a wide circle 4 inches away from the trunk to avoid crown rot.
For more on the Sacramento Shade Program including the online application: https://sactree.org/programs/free-shade-trees/. For more tips visit BeWaterSmart.info/trees or sactree.org.
Debbie Arrington is a longtime home and garden reporter and co-author of the blog Sacramento Digs Gardening: https://sacdigsgardening.californialocal.com/
