In the wake of our recent catastrophic fires, much can be written about the value of firescaping and its principles, and I will get to that subject in a moment, but first let me say a few words about tree maintenance.
The Santa Ana winds that spread the fires with lightning speed blew with hurricane force. Although nothing can compare to the property damage, much less loss of life, caused by the wind-driven fires, it’s worth taking a moment to discuss tree damage not only from the recent Santa Anas but from strong winds in general.
On my own block, a massive limb of a carob tree broke off and I was given the opportunity to examine it up close. If you see the massive branch of a tree that broke off in your neighborhood, perhaps you ask yourself the question: “There are plenty of big, thick tree branches up and down my street, so why did only this one break off?” The answer, more likely than not, is that the tree in question was improperly pruned. Where pruning cuts in a tree are improperly made, these cuts cannot properly heal and present an open invitation to pathogenic fungi. Once fungal spores get into an open wound where a faulty pruning cut was made, the interior of that branch could rot, weakening its attachment to the tree. In the particular case of the carob tree on my street, I noticed a poorly healed cut from a large branch that had been lopped off close to where the broken limb had been attached to the trunk.
It is also true, however, that leguminous trees such as carob have a tendency for limbs to die back for no apparent reason, but this tendency will only be exacerbated by improper pruning. The most popular leguminous tree known for dying back is mimosa or silk tree (Albizia julibrissin). It is famous for its rapid growth into an umbrella form but within a decade or less, branches will start dying back. From my experience, pruning it will only hasten its decline since it seems to have a weak immune system and pruning cuts are slow to heal, if they ever do.
The coral tree (Erythrina caffra) is a leguminous species that is particularly hazardous. Each time I drive down San Vicente Boulevard in Brentwood, whose median is planted with coral trees, I am reminded of this tree’s fragility. Don’t get me wrong: the coral tree is a magnificent, muscular-limbed species that loses its leaves in the winter and then, still in leafless condition, produces a breathtaking blanket of fiery orange flowers. The only problem with the coral tree is that it simply cannot support its own weight and must be pruned at least once a year. The best time to do this would be in March or April, following bloom so as not to sacrifice flower production, but the moment your coral tree looks top heavy, you should prune it, no matter what the season, even if that means pruning every six months.
I have seen many fallen or split-apart coral trees over the years, despite their having been pruned on an annual basis. If you look at the more mature coral trees on San Vicente Boulevard, you will notice that many trunks show scars where large branches have broken off. Because of their top-heaviness and brittle wood, coral trees don’t live long. Nevertheless, each time a coral tree on San Vicente Boulevard dies, it is replaced with another. Some would argue that a different, sturdier type of tree should be planted instead. Yet so beloved are the Brentwood coral trees by the surrounding residents that it has been written into the city’s specific plan that “no major alteration of the (San Vicente Boulevard) median strip shall occur without a public hearing.”
So how do you identify a successful pruning cut? It’s quite easy since such a cut produces wound wood, a raised layer of callus tissue around the cut. This tissue effectively seals off the wound from entrance of pathogenic organisms. As I walked down my street and examined the pruning cuts on various trees, most were without wound wood. When a cut is made flush with a trunk or any large branch, no wound wood can form. Incidentally, the practice of coating pruning cuts with a tar-like gooey substance has been discredited since it can trap moisture on the cut surface, prevent healing, and encourage decay. The best way to ensure your trees are properly pruned and to prevent hazardous breakage is to have a certified arborist visit your property on a yearly basis. To find a list of certified arborists in your area, go to isa-arbor.com. When you get there, click on “Find an Arborist” and enter your location.
Now for the tragic fires and what could be done to prevent them: The regulations we are obligated to follow are not enough to prevent a fire from engulfing our homes. For residents of Los Angeles County, at least, there is a legal mandate to maintain defensible space — the area around a structure that must meet certain brush clearance and firescape specifications — of only 200 feet. (For a full list of defensible space action items, do an Internet search for “LA County defensible space.”) However, when there are 80-mile-an-hour winds whipping up a blaze, a 200-foot measure of clearance is insufficient. Still, it is notable that one home on Iliff Street in Pacific Palisades remained standing even as neighboring homes burned, and its gravel-based garden may have had something to do with it. For a full description of the fire-retardant “passive design” of this home, go to mansionglobal.com and scroll down to “Passive Design May Have Saved This House.”
Regarding gravel-based gardens, it may be useful to consider the installation of Zen gardens in fire-prone areas. Zen gardens may consist of nothing but large rocks or boulders and a few plants, if any, surrounded by pea gravel. The boulders represent giant tortoises or the islands of Japan and the gravel represents the surrounding ocean. Stepping stones in pathways alternate in a fashion that mimics the goofy walk of plover birds. Evergreen plants are evenly pruned since, gazing at a natural landscape from afar, the vegetation that you see reveals itself in discrete, symmetrical forms. Gravel is regularly raked since the patterns created represent waves or currents of water. Plants selected may have naturally compact or symmetrical forms and are chosen more for that quality than flowering capacity, although azaleas and dwarf Indian hawthorns, which flower for a single season, are often included. A Zen garden is informed by constancy and predictability, creating a tranquil atmosphere that allows for escape from the chaos of urban life.
There is an approach to wide-scale brush clearance and no army of weed whackers or mechanical equipment of any kind is needed to get the job done. I am talking about goats. Michael Choi and his family own and operate Fire Grazers Incorporated. They started with a herd of 50 goats that has expanded to a burgeoning population of 1,000. “We have more business than we can handle,” Choi told me. When I asked if brush clearance by his goats could have stopped our recent fires from causing so much damage, he replied, “The goats could at least have cleared enough brush to grant more time between the start of the fire and the arrival of firefighters.” To learn more about Choi’s services, go to goatsrock.com. Maybe we need to add a few thousand more goats to brush management in order to more effectively stop wildfires before they get out of control.
Regarding the availability of water — not only to put out fires but to sustain farmers and gardeners — there is a question about the seriousness of government when it comes to saving it. The last two Los Angeles winters were the wettest back-to back winters since 1888-1890, but none of that water went into any kind of new reservoir. In 2014, California voters passed a $7.5 billion bond meant to fund projects that would expand California’s water storage and delivery systems. To date, not a single such project has been started. Then there is the obstinate refusal to desalinate the ocean. In Israel, for comparison’s sake, 85% of drinking water is desalinated seawater, but none of Los Angeles water is in that category. And Israel recycles 90% of its wastewater, while only 2% of Los Angeles wastewater is recycled, although a new project at the Tillman Water Reclamation plant in the Sepulveda Basin is set to increase that percentage. At the Tree People headquarters in Coldwater Canyon Park (12601 Mulholland Drive, Beverly Hills), the driveway there has a cistern below it that catches runoff from winter rains. In the future, home designs may incorporate this feature, whether the water stored is used for fighting fires or irrigating plants. An urban watershed garden on site includes elements for saving rainwater and maximizing its use in the garden.
California native of the week: Wright’s beebrush or Oreganillo (Aloysia wrightii) is an evergreen to semi-deciduous shrub that grows in desert to woodland habitats to a height and girth of six feet. It is covered with short, white flower spikes that attract birds and solitary bees from late summer into fall. Roundish in form, Its oval leaves, less than an inch long, are used as an oregano substitute. Lemon verbena (Aloysia tryphilla) is a non-native relative, available in your nursery’s herb section, that is prized for its leaves’ unmatched lemon fragrance. Oreganillo is highly aromatic too and would make a wonderful addition to an herb, drought tolerant, aromatic, or native plant garden but, unfortunately, is not widely available in the nursery trade. If anyone knows of a source for this plant or its seeds, please advise.
Does anyone live in a wildfire area whose firescaping may have helped prevent damage to their home? If so, please send your story to joshua@perfectplants.com so I can share it with readers here. Your questions, comments, concerns, and successes are always welcome.