- Author: Jeannette E. Warnert
As the amount of sunlight falling on trees is reduced with the change in the seasons, trees go into dormancy and require less water than during the hot summer months. But in exceptionally dry conditions, a tree many not have enough stored moisture to survive until drought conditions improve. Tree advocates and water officials urge homeowners to educate themselves on effective tree care to ensure their trees' survival in the months ahead--especially if California's extended dry period continues this winter.
Representatives of the Sacramento Tree Foundation, California Center for Urban Horticulture (CCUH) at UC Davis, UC Cooperative Extension and the California Department of Water Resources (DWR) say a return of normal rainfall this winter might be enough to sustain trees without special care and watering. However, with no way to know how long the current drought will continue, the advocates say knowing when and where to water a tree can be the difference between its life and death.
"We are seeing locations in California where trees are dying because they haven't been watered adequately," said CCUH Director Dave Fujino. "While homeowners are trying to save water by letting lawns die, they need to continue watering their nearby trees."
Chuck Ingels, UC Cooperative Extension horticulture advisor, urged homeowners to follow these steps:
- Dig into the soil 6 to 8 inches at a tree's drip line--the area immediately below the widest part of the leaf canopy; if the soil feels dry and crumbly, it needs water.
- Apply water slowly and uniformly using low-volume application equipment, such as a soaker hose that circles the tree at the drip line. Allow water to saturate the soil to a depth of 8 to 12 inches.
- Allow the soil to dry between waterings; for most mature trees, one or two deep waterings per month is adequate. Fewer waterings--and perhaps none--are needed during the cooler and potentially wet winter months.
- Add mulch (leaves or wood chips) between the trunk and drip line to retain the soil's moisture.
- Reduce competition for water by removing weeds and grass within 4 feet of a tree's trunk.
Anne Fenkner, Greenprint Regional Coordinator, Sacramento Tree Foundation, said trees are essential to the health and beauty of residences and entire communities throughout the state. "Trees provide food for people and animals and shade that helps make hot climates livable," she said. "We owe it to ourselves, our children, their children and the trees themselves to help them get through this extraordinarily dry period. When water supplies are limited, priority should be given to trees, then shrubs and perennials and lastly to lawn and annuals."
Julie Saare-Edmonds, DWR's Landscape Program Manager, said Californians are responding to the call in January by Governor Edmund Gerald Brown Jr. to reduce their water usage by 20 percent.
But if a homeowner has allowed a lawn to dry up during the drought, trees growing in that lawn may not be getting enough water and may need more to help them transition into winter dormancy.
Anne Fenkner said trees have varying water needs depending on their species, age, size, slope of the ground beneath them and other factors. Homeowners can nurture their trees and improve their health by understanding tree care principles:
- Older established trees may be starved for water as well as younger trees. The low rainfall last winter did not replenish the soil moisture adequately and they may need a moisture boost before winter.
- Avoid fertilizing trees now; it will stimulate new growth at the wrong time of year.
- When planting new trees, choose species wisely. Consult a local urban forestry group such as the Sacramento Tree Foundation or check the Arboretum All-Stars list at UC Davis. We don't know how long the drought will last, so consider selecting drought-resistant varieties and delaying planting until drought conditions improve. If the drought worsens in 2015, investments in new trees may be lost.
- Improve the quality of the soil in which the trees grow. Aerate lawns so the roots of mature trees have good access to water and oxygen.
- Consult the UC Cooperative Extension Master Gardeners or a certified arborist if you have questions about the health of a mature tree.
Additional advice on caring for trees can be found at these websites:
- Statewide UC Master Gardener Program
- California Center for Urban Horticulture
- California ReLeaf
- California Urban Forests Council
- UC Davis Arboretum All-Stars
- CAL FIRE
- Author: Jeannette E. Warnert
"I had the same experience that most people did," Gable said.
Banks began the 2014 summer gardening season like most home gardeners, full of hope and enthusiasm. But as fall approached she found herself with "a few spindly stalks of okra, a tangle of barren melon vines and a pepper plant loaded with misshapen pods."
Gable and another UC Cooperative Extension advisor, Janet Hartin, chalked up this year's garden frustrations in part to the state of California's water woes.
"A lot of people are calling and want to rip out their whole garden and just put in native plants," Hartin told the columnist.
But she and Gable assured the writer that vegetables are well worth the water it takes to grow them.
"...By growing fruits and vegetables, you're decreasing your carbon footprint," Gable said. "You're not using pesticides, not making trips to the grocery store... The environmental and health benefits of home gardens are lasting and important."
Gable offered some suggestions to improve the chances for success:
- Add compost to the soil to provide nutrients and increase water-holding capacity
- Switch to water-conserving drip irrigation
- Insulate the soil surface with a thick layer of mulch
- Make careful planting decisions
"(Gable) steered me to a bevy of experts who take questions by email and phone through the University of California's Cooperative Extension Master Gardener Program. I've bookmarked local planting guides and advice online at http://www.ucanr.edu," Banks wrote.
To read the Los Angeles Times article by Banks, click here.
- Author: Dohee Kim
Donald R. Hodel, environmental horticulture advisor, is the recipient of the 2014 Horticulturist of the Year award from the Southern California Horticultural Society. The distinguished award recognizes his lifetime of contributions to Southern California horticulture, including his applied research projects that helped to improve practices in the selection and management of landscape plants and trees.
Hodel will receive the award on September 13, 2014 at the Los Angeles County Arboretum and Botanic Garden.
"I'm honored to receive this award from the Southern California Horticulture Society. It's nice confirmation and recognition of my body of work in and contribution to the landscape and tree care industry," said Hodel.
Hodel has been with UC Cooperative Extension for more than 30 years and is an international authority in palm horticulture and taxonomy. His research has taken him to places all over the world, including Mexico, Central America, South America, Hawaii and the South Pacific, and Southeast Asia. He has authored and co-authored more than 500 publications about identification, selection and management of plants. He has also authored and co-authored eight books, including Exceptional Trees of Los Angeles.
Hodel earned his master's degree in tropical horticulture from the University of Hawaii in Honolulu and his bachelor's degree in ornamental horticulture from Cal Poly in Pomona.
- Author: Pamela Kan-Rice
Now, they have a new online resource to consult about urban farming. Last week, the University of California Division of Agriculture and Natural Resources launched a website to provide practical, science-based information for urban agriculture.
At the website ta http://ucanr.edu/urbanag, visitors will find information on raising livestock, crop production, marketing and policies for farming in their backyards, on a few acres, at a school or in a community setting.
Rachel Surls, a UC Cooperative Extension advisor in Los Angeles County, and a team including UCCE farm advisors, policy and advocacy experts, urban planners, agricultural economists and others created the new urban agriculture website in response to the results of a UC survey of urban farmers in California.
"Our team interviewed urban farmers around the state about their challenges and successes, and what information they really needed as they got started," said Surls, who specializes in sustainable food systems. "Based on their needs, we looked for science-based educational materials that would be helpful and packaged them into this website.
"The site will be a resource for urban farmers who are selling what they grow, as well as school and community gardeners, and folks who are keeping some backyard chickens and bees. We also intend it to be a resource for local policy makers who are making decisions that impact farming in California cities."
Many urban farmers are beginning farmers, according to Surls. "They need basic information on planting, pests and irrigation, as well as information that's more specific to farming in the city," she said. "For example, they must navigate local laws and regulations that impact farming which include zoning and health codes."
The UC ANR Urban Agriculture website also advises urban farmers about environmental issues that they may encounter.
"Urban soils can sometimes be contaminated and may need testing and remediation," Surls said. "Farming close to neighbors in the city can also bring special challenges."
She encourages people to check back for updates as the Urban Ag website continues to grow.
"We'll also share stories about urban farms around California and news around the state about urban agriculture policies and initiatives." Surls said.
For more information, please contact Rachel Surls at (626) 586-1982, firstname.lastname@example.org.
For 100 years, University of California Cooperative Extension researchers and educators have been drawing on local expertise to conduct agricultural, environmental, economic, youth development and nutrition research that helps California thrive. UC Cooperative Extension is part of the University of California Division of Agriculture and Natural Resources. To learn more about UC Cooperative Extension services in Los Angeles County, please visit http://celosangeles.ucanr.edu.
- Author: Jeannette E. Warnert
- Author: Dohee Kim
Long before European settlers arrived in America, the Los Angeles River was an important source of food and water for native peoples. Europeans settled the Los Angeles area in part because of the river and fertile alluvial soils it provided. The river and its tributaries frequently flooded and changed course, forming wide alluvial floodplains that extended across southern Los Angeles from modern day Santa Monica to Long Beach. When Los Angeles began its transition to teeming metropolis and settled these flat floodplains, the river's natural characteristics led to disastrous flooding.
In the interest of saving lives and property, civil engineers sloped the banks and encased them in more than 30 miles of concrete, a move that completely altered the fishery. In 2010, UC Cooperative Extension completed research that indicated life is still capable of being sustained in the LA River, despite the concrete and influx of pollutants from local storm drains and sewage treatment plants.
Working with Friends of the Los Angeles River, an organization interested in restoring the LA River to a more natural state, UCCE natural resources advisor Sabrina Drill surveyed the fish population in the river's eight-mile Glendale Narrows area, a section that, because of its underlying geology, was left with a natural bottom. The researchers discovered a diverse and bountiful fish population in this stretch of the river.
"To our surprise and delight, toxicity reports show the small number of fish we tested to be free of mercury and have extremely low levels of PCBs," Drill said. "This may not be true for the rest of the river. Glendale Narrows is one of the cleanest sections, probably because the natural river bottom cleans itself and because of the high quality effluent coming out of upstream water reclamation plants."
The survey identified eight species of fishes, none of them native, plus tadpoles and red swamp crayfish in the river. The eight fish species are: fathead minnow, carp, black bullhead, Amazon sailfin catfish, mosquito fish, green sunfish, largemouth bass and tilapia. They hail from Africa, South America, Eastern North America and Asia.
Whether reestablishment of native species to the river is possible remains to be seen, and may not be the most important factor in river restoration.
"Difficult though it may be, you can't make the LA River what it used to be simply by digging up the concrete," Drill said. "Because of all the development, the water we import, and changes in hydrology, temperature, and water quality, it's not the same system it was before people settled here."
According to Drill, large-scale habitat restoration and restoration of some historical floodplains will dramatically enhance the ecological function and natural beauty of the Los Angeles River.
Drill has also served as part of the Technical Advisory Committee for the City of Los Angeles/U.S. Army Corps of Engineers project to restore and revitalize portions of the LA River since 2008. Recently, she began field work to update to the Los Angeles River Fish Study, which she co-authored in 2008.
To view a video about fishing in the LA River, click here. The seven-minute documentary, created by film maker Megan McCarty, includes an interview with Drill.