California bay (Umbellularia californica)

You might think of TreePeople as an organization whose sole mission is to plant more trees in Los Angeles. While that may have been true when the organization was founded four decades ago, and TreePeople can take credit for planting more than two million trees in this city, its reason for being has expanded in recent years. Today, TreePeople sees itself as an agent for radical change of the total urban environment, making close encounters with the natural world part of our everyday experience. Nearly 10,000 elementary students visited the TreePeople Center at Coldwater Canyon Park last year, learning first hand about the meaning of urban environmental stewardship and “the power of people, trees, and nature-based solutions to grow a sustainable Los Angeles.”
At TreePeople’s Center for Community Forestry, near the intersection of Coldwater Canyon Boulevard and Mulholland Drive, you will learn about a variety of water saving measures including, first and foremost, the simple act of planting a tree. The leaves and bark of a mature tree can store over 100 gallons of water. Multiply 100 gallons times the millions of trees that would make up the ultimate Los Angeles forest and not only have you saved an enormous quantity of water, but you have relieved your storm drains and sewage conduits of an incredible burden, lengthening the life of that system. A well-designed urban forest and extensive urban landscape could retain virtually all of the rainwater where it falls. Besides saving water, a major advantage of retaining rainwater in urban trees is reduction of ocean pollution. When rainwater runs down the street, it picks up chemical and hydrocarbon pollutants of every kind, all of which are eventually deposited in the Pacific.
At TreePeople’s Forestry Center, a giant cistern, capable of holding 216,000 gallons of water, was constructed so that, during the dry season, there would be sufficient water on site for irrigating the surrounding landscape. To me, the most intriguing aspect of the cistern is that the run-off water that goes into it is collected from a relatively small area, a modest parking lot and entrance driveway that, in total size, could not be more than a few thousand square feet. Without doing the math, it seems that a small cistern at the sloping end of any residential driveway, even if it collected nothing more than the water that fell on the driveway itself, would collect enough water to meet the annual irrigation requirements of a typical residential garden, especially if that garden featured California natives and other water thrifty plant species.
Keep in mind that, although annual rainfall in Los Angeles hovers around 15 inches, there are many, many years when we receive between 7 and 10 inches only, further underscoring the need for saving water which, properly stored in cisterns as well as in barrels situated under rain gutters, could be used throughout the dry season for garden irrigation.
Planting trees, you learn, is the least problematic aspect of urban forestry. Keeping those trees at peak health is a more complex enterprise. I met with Julie Prejean, Director of Forestry for TreePeople, who expressed concern about improper tree pruning in Los Angeles. “Topping, where a tree is reduced in size instead of being carefully thinned out, not only disfigures the tree,” she said, “but it results in rank growth that is prone to breakage. When you prune, never remove more than 25-30% of the tree,” she cautioned. “Trees should be allowed to reach and maintain their natural, mature height and shape. Trees should be only lightly thinned or laced out, and never be reduced in height. If a tree is too big for its location since, for example, it overhangs existing houses or other buildings, it should be removed and replaced with a tree whose mature height does not exceed that of nearby structures.”
Prejean directs a group of environmental stewards who not only plant and care for trees but recruit others to get involved. One of TreePeople’s major undertakings has been restoration of the Angeles National Forest watershed following the devastating conflagration of 2009, when 160,000 acres were burned. Angeles National forest provides more than 30% of LA County’s drinking water and more than 70% of its open space, so re-foresting it is a top priority of TreePeople. In the new year, many opportunities to plant tree seedlings in Angeles National Forest, as well to participate in other urban tree projects, are available. To take part in TreePeople projects, call (818) 623-4879 or visit www.treepeople.org.
You don’t have to be a tree hugger to advocate for planting more trees. The plain truth is that treescapes are more romantic, aromatic, and certainly easier to maintain than conventional landscapes, to say nothing of English gardens. If you ever visited Wrightwood, a community nestled in the Angeles National Forest, you would appreciate the look and feel of a true urban forest. The first time I visited Wrightwood, I had a sudden flash of how glorious an arboreal minded Los Angeles could be. Nothing but trees! I once visited Raleigh, North Carolina, and was similarly impressed by the ubiquitous pines that interlarded the yards and gardens there. Where trees are the main players on the urban landscape stage, feelings of calm and stability hold sway, and words like heritage and legacy are heard when talking about a city’s arboreal treasures.
Several memorable plants surround the TreePeople parking lot on Coldwater and Mulholland. These particular specimens do not appear to be receiving irrigation of any kind. At the entrance, a billowing myrtle (Myrtus communis) grows in the shade of some pines. Its dark green diamond foliage and abundance of purple-blue fruit provide ample evidence of its vitality. A rare winged elm (Ulmus thomasii) arches overhead. This elm species is native to the Midwest and completely absent from our local nursery trade. I wonder how it made the journey to Los Angeles but it is clearly thriving here. Branches are covered with unusual and irregular corky growth that botanists have dubbed “wings.” A huge California bay (Umbellularia californica) stands sentry at the northeast corner of the parking lot. I had never seen a California bay grow to such heights in Los Angeles before encountering this specimen. Underneath, robust clumps of coral bells (Heuchera sp.) are thriving on nothing but mulch. Heuchera are notorious for being short-lived, an inevitable consequence of over-irrigation. Apparently, if you just let coral bells go and grow, they can happily persevere for quite a few years, at least, as evidenced by the size of the unusually large clumps on display here.
Tip of the Week: Julie Prejean informed me of two perks available to Angelenos who are mulch- and money-minded. Free mulch is available through the Department of Sanitation and may be picked up at eleven locations throughout the city, five of which are in the San Fernando Valley. To find the location nearest you, visit www.lacitysan.org. Type “free mulch” in the search box and click the first link on the list that comes up. You can also receive a rebate of up to $3000 for converting your lawn into a drought tolerant garden. For more details, visit www.ladwp.com, click “residential rebates” and then “landscaping and irrigation.” In addition to receiving money for lawn conversions, rebates for installing water-smart irrigation controllers and water-saving sprinkler nozzles are also available.