Category Archives: Plant Health

Scientists make inroads against tree-killing pests

Early detection increases the chances of eradicating pests

January 24, 2023

by Randall Oliver
Read article at farmprogress.com
https://www.farmprogress.com/insects/scientists-make-inroads-against-tree-killing-pests
 
John Kabashima/UCANR
 
An adult male red striped weevil. John Kabashima/UCANR

Trees provide shade to keep us cool, produce oxygen for us to breathe and calm our nerves. Numerous studies have demonstrated that even brief contact with trees and green spaces can provide significant human health benefits such as reductions in blood pressure and stress-related hormones. Trees also reduce noise and visual pollution, help manage storm water runoff, reduce erosion and provide habitat for birds and wildlife. Trees naturally capture carbon, helping to offset the forces of climate change. They also increase the value of our properties and communities. In short, trees are essential to our well-being.

Unfortunately, invasive pests pose an ongoing threat to California’s forests in both urban and wildland settings. Invasive insects such as goldspotted oak borer and invasive shothole borers have killed hundreds of thousands of trees in Southern California and are continuing to spread. Meanwhile, other pests and diseases such as Mediterranean oak borer and sudden oak death are killing trees in Northern California.

While the situation may sound dire, it is not hopeless. Of course, the best way to stop invasive pests is to prevent them from entering the state, as the California Department of Food and Agriculture has done on many occasions. For example, several months ago, CDFA border inspectors seized a load of firewood containing spotted lanternfly eggs (a pest that is causing extensive damage on the East Coast). When pests do sneak in, the next defense is to catch them early before they become established. Finally, even if pests do become established, they can be managed if not completely eradicated.

A few examples may help to illustrate why invasive tree pests deserve action, but not panic.

Red striped palm weevil eradicated in Laguna Beach

When red striped palm weevil, a highly destructive palm pest native to Indonesia, was discovered in Laguna Beach in October 2010, a working group was quickly formed to develop a management plan. The small but diverse group included international palm weevil experts, research scientists from University of California Riverside, CDFA and U.S. Department of Agriculture, UC Cooperative Extension personnel from San Diego, Orange and Los Angeles counties and county entomologists from the agricultural commissioner’s offices in Orange and San Diego counties.

The resulting response included a pheromone-based trapping program, public advisory and targeted insecticide treatments. Within two years, additional trapping and inspections could not find any signs of continued infestations. Early detection was key to the success: the infestation in Laguna Beach was identified early, so the weevil population was still relatively small. In addition, Laguna Beach is geographically isolated, the local climate is much cooler than the weevil’s place of origin, and the eradication effort was well funded by state and federal agencies. Eliminating invasive pests where such conditions are not present may prove more difficult.

Invasive shothole borers attack Disneyland

The Disneyland Resort in Anaheim contains 16,000 trees and over 680 different tree species. When park officials identified an infestation by invasive shothole borers in 2016, their initial attempts at vanquishing the insects with pesticides produced mixed results. Then, they consulted with experts from UC Riverside and UC Cooperative Extension and together designed and followed an integrated pest management program that included monthly ground surveys, a trapping program that helped to detect infestation hot spots and find and remove the source of beetles, and occasional pesticide treatments on selected trees. The park went from a large number of beetles in 2017 to very low levels today. There are still some beetles, but resulting damage is extremely low, and although monitoring programs continue, the park’s landscape team has been able to turn its focus elsewhere.

Goldspotted oak borer spotted in Weir Canyon

When goldspotted oak borer was confirmed in Orange County’s Weir Canyon in 2014, a team from Irvine Ranch Conservancy, the organization that manages the area on behalf of Orange County Parks, sprang into action. UC Cooperative Extension and the US Forest Service assisted IRC in developing a management program, and over the ensuing years, IRC has actively collaborated with OC Parks, The Nature Conservancy, OC Fire Authority, and CAL FIRE to control the existing infestation and stop its spread. IRC has surveyed the oaks in the area yearly to monitor the infestation and guide each year’s management actions.

To reduce the spread of the infestation, IRC removed more than 100 severely infested oaks in the first few years of management (no severely infested oaks have been found in the last few years of surveys). Additionally, more than 3,000 tree trunks have been sprayed annually in the late spring to kill emerging adult beetles and newly hatched offspring.

In the most recent survey of the oaks in Weir Canyon, the IRC team found only 12 trees with new exit holes, and most of those had just one to two exit holes per tree, which is an extremely low number. With the situation well under control, IRC is now considering modifying its annual spraying program and adapting other less aggressive treatment options. Finally, IRC has been actively planting acorns to mitigate losses due to the removals as well as the Canyon 2 Fire of 2016.

As these brief examples demonstrate, insect pest infestations can be managed or even eradicated if caught early enough. Early detection not only increases the chances of success, but also minimizes the cost of pest management efforts.

What you can do to prevent infestation

While management actions will vary depending on the insect or disease, species of tree and location, there are a few steps that will lead to greater success in fighting tree pests and diseases.

  • Keep your trees healthy. Proper irrigation and maintenance go a long way toward keeping trees strong and resistant to pests and diseases.

  • Check your trees early and often for signs and symptoms of tree pests and diseases. These may include entry/exit holes, staining, gumming, sugary build-ups, sawdust-like excretions, and branch or canopy dieback. Use available tools like the UC IPM website to determine probable causes of the problems.

  • Talk with experts (arborists, pest control advisers, researchers and advisors from the University of California and other institutions), and report pest findings to your county Agricultural Commissioner.

  • Evaluate the extent of tree damage and determine a management plan. Remove severely infested branches and trees that may be a source of insect pests that can attack other trees.

  • Properly manage infested wood and green waste. Chip wood and other plant materials as small as possible. Solarization or composting can further increase the effectiveness of chipping. It is generally best to keep those materials close to where they originated, but if you absolutely need to move them, first make sure the facility where they will be sent is equipped to process them. Always tightly cover materials while in transit. If working with a tree care professional, insist that proper disposal is part of the job requirements.

  • Many invasive tree pests can survive in down wood for long periods. When buying or collecting firewood, always obtain it as close as possible to where you are going to burn it and leave leftover firewood in place.

Randall Oliver is UC Statewide IPM Program Communications Coordinator.

Source: University of California Division of Agriculture and Natural Resources

Tree Survey at Pasadena’s Arlington Garden

Why a tree survey?

by William Hallstrom (Arlington Garden volunteer)
Aug 27, 2021

For the past few months, most of the volunteer crew at Arlington Garden have spent at least some of their time wrapping the trunks of each of the garden’s trees with the kind of soft tape measure you might use for sewing, looking up to the highest branches and pacing underneath them while jotting down notes. It’s all part of the tree survey, one of the recent volunteer projects at the garden, whose goal is to determine how much carbon is being sequestered by the trees in Arlington Garden.

Arlington Garden Communications & Volunteer Manager Andrew Jewell says the idea for the tree survey began from a need for some real data to help bolster a proposal. “We set out to quantify the effect the garden has on various environmental measures including atmospheric carbon, the urban heat island effect, rainwater capture,” he says. This would require human effort, which was facilitated by the growth of the volunteer program in recent months.

Arborist Jonathan Flournoy came out to the garden on Tuesday, June 21nd and walked us through the basic process. It’s pretty simple. Teams of volunteers are assigned parts of the garden to work in. Teams of two people work well—one person can take measurements and the other can record them. READ MORE: https://www.arlingtongardenpasadena.com/2021/08/27/why-a-tree-survey/?mc_cid=6b9fafac4a&mc_eid=137d77d9e0

12 Reasons Not to Use Artificial Turf

By Rebecca Latta

Thinking of replacing a lawn and considering alternatives?
Make sure not to choose artificial turf. Read on to learn why.

Artificial turf:

  • Creates a barrier to soil moisture, potentially harming nearby plants
  • Promotes higher soil temperatures, which can burn underlying roots
  • Is composed of plastic which eventually degrades, leaving harmful particles in the soil
  • Deprives plant roots of needed air circulation
  • Suffocates beneficial soil microorganisms which are essential for plant health
  • Kills earthworms and beneficial insects that live in soil
  • Reduces soil fertility by creating a barrier to beneficial leaf litter
  • Takes the place of excellent lawn-alternative ground covers, such as native plants
  • Reduces opportunities for native wildlife, such as pollinators, to thrive
  • Takes the place of permeable and sustainable paving alternatives
  • Promotes the out-of-date notion that a lawn is necessary to enhance a property’s appearance
  • It’s fake and it looks fake. There are many beautiful, practical and sustainable alternatives that are worth investigating!

US cities are losing 36 million trees a year. Here’s why it matters and how you can stop it

By Amy Chillag, CNN
Updated 12:44 PM ET, Wed September 18, 2019

If you’re looking for a reason to care about tree loss, this summer’s record-breaking heat waves might be it. Trees can lower summer daytime temperatures by as much as 10 degrees Fahrenheit, according to a recent study.

But tree cover in US cities is shrinking. A study published last year by the US Forest Service found that we lost 36 million trees annually from urban and rural communities over a five-year period. That’s a 1% drop from 2009 to 2014.

If we continue on this path, “cities will become warmer, more polluted and generally more unhealthy for inhabitants,” said David Nowak, a senior US Forest Service scientist and co-author of the study.

Nowak says there are many reasons our tree canopy is declining, including hurricanes, tornadoes, fires, insects and disease. But the one reason for tree loss that humans can control is sensible development.

The most effective way to tackle climate change? Plant 1 trillion trees

The most effective way to tackle climate change? Plant 1 trillion trees

“We see the tree cover being swapped out for impervious cover, which means when we look at the photographs, what was there is now replaced with a parking lot or a building,” Nowak said.

More than 80% of the US population lives in urban areas, and most Americans live in forested regions along the East and West coasts, Nowak says.

“Every time we put a road down, we put a building and we cut a tree or add a tree, it not only affects that site, it affects the region.”

The study placed a value on tree loss based on trees’ role in air pollution removal and energy conservation.

Why you should be forest bathing (and we don't mean shampoo)

Why you should be forest bathing (and we don’t mean shampoo)

The lost value amounted to $96 million a year.

Nowak lists 10 benefits trees provide to society:

Heat reduction: Trees provide shade for homes, office buildings, parks and roadways, cooling surface temperatures. They also take in and evaporate water, cooling the air around them. “Just walk in the shade of a tree on a hot day. You can’t get that from grass,” Nowak said. To get the full temperature benefit, tree canopy cover should exceed 40% of the area to be cooled, according to a recent study in the Proceedings of the National Academy of Sciences. “A single city block would need to be nearly half-covered by a leafy green network of branches and leaves,” the authors wrote.

Air pollution reduction: Trees absorb carbon and remove pollutants from the atmosphere.

Energy emissions reduction: Trees reduce energy costs by $4 billion a year, according to Nowak’s study. “The shading of those trees on buildings reduce your air conditioning costs. Take those trees away; now your buildings are heating up, you’re running your air conditioning more, and you’re burning more fuel from the power plants, so the pollution and emissions go up.”

Water quality improvement: Trees act as water filters, taking in dirty surface water and absorbing nitrogen and phosphorus into the soil.

Flooding reduction: Trees reduce flooding by absorbing water and reducing runoff into streams.

Noise reduction: Trees can deflect sound, one reason you’ll see them lining highways, along fences and between roads and neighborhoods. They can also add sound through birds chirping and wind blowing through leaves, noises that have shown psychological benefits.

Protection from UV radiation: Trees absorb 96% of ultraviolet radiation, Nowak says.

Improved aesthetics: Ask any real estate agent, architect or city planner: Trees and leaf cover improve the looks and value of any property.

Improved human health: Many studies have found connections between exposure to nature and better mental and physical health. Some hospitals have added tree views and plantings for patients as a result of these studies. Doctors are even prescribing walks in nature for children and families due to evidence that nature exposure lowers blood pressure and stress hormones. And studies have associated living near green areas with lower death rates.

Wildlife habitat: Birds rely on trees for shelter, food and nesting. Worldwide, forests provide for a huge diversity of animal life.

Planning for trees

Gardening becomes healing with horticultural therapy

Gardening becomes healing with horticultural therapy

Nowak says there’s a downside to trees too, such as pollen allergies or large falling branches in storms, “and people don’t like raking leaves.” But, he says, there are ways cities and counties can manage trees to help communities thrive. “You can’t just say ‘we’re not going to have forests.’ We might as well manage and work with the trees.”

“You don’t want a tree in the middle of a baseball field. It’s very difficult to play sports if you have trees in the way. Or trees in the middle of freeways.”

Nowak says we can design and manage tree canopies in our cities to help “affect the air, to affect the water, to affect our well-being.”

Urban forests especially need our help to replace fallen trees. Unlike rural areas, it is very difficult for trees to repopulate themselves in a city environment with so much pavement and asphalt.

“A lot of our native trees can’t actually find a place to drop an acorn so they can regenerate,” explains Greg Levine, co-executive director for Trees Atlanta.

“That’s why the community has to go in and actually plant a tree because the areas just aren’t natural anymore.”

'America's Amazon' is at risk

‘America’s Amazon’ is at risk

The job is not complete when the saplings take root. Organizations like Trees Atlanta and their volunteers plan most of their year to care for these young trees until they’re mature enough to thrive on their own.

“We try to prune trees for 10 years to make sure they get a good healthy structure.” Levine adds. “We also add mulch around trees to help keep the moisture in the ground so the tree doesn’t dry up. We have to have a lot of patience with planting trees around pavement, making sure that they can rise to the challenge. “

How you can help stop tree loss

Protect what you have: Nowak says the first step is caring for the trees on your own property. “We think we pay for our house, and so we must maintain it. But because we don’t pay for nature, we don’t need to. And that’s not necessarily true.”

Prune the dead limbs out of your trees: If they’re small enough, do it yourself or hire a company. The risk of limbs damaging your house is significantly lowered when there’s tree upkeep, Nowak said.

Notice where your trees may be in trouble: Often, you can observe when something’s wrong, such as when branches are losing leaves and breaking or when mushrooms are growing at the base or on the trees. You can also hire an arborist or tree canopy expert to assess the health of your trees on an annual basis. Or you can contact your local agricultural extension office for advice.

Don’t remove old trees if it’s not necessary: Instead, try taking smaller actions like removing branches. “It takes a long time for these big trees to get big: 50 to 100 years. And once they’re established, they can live a long time. But taking a big tree out and saying ‘we’ll replant,’ there’s no guarantee small trees will make it, and it will take a very long time to grow.”

Allow trees to grow on your property: Although everyone’s aesthetic is different, it’s the cheap way to get cooler yards and lower energy bills. It’s also an inexpensive approach to flood and noise control.

Nowak says he laughs when his neighbors wonder why their property doesn’t have more trees, because “I hear people running their lawn mowers.” Fallen seeds need a chance to implant, and constant mowing prevents that. If you don’t like where a seedling is growing, you can dig it up and plant it or a new tree where you like.

Educate yourself about trees and get involved: Many cities have tree ordinances that seek to protect very old, significant trees. You can get involved by attending city council meetings. You can also help your city plant trees by joining local nonprofit groups.

Volunteer or donate to tree planting and research organizations:

CNN’s Christopher Dawson contributed to this story.

Memorial for a Venerated Oak

By Rebecca Latta

A ceremony marked the passing of the sentinel oak at Sunland-Tujunga Library on January 13.

A farewell ceremony at Sunland-Tujunga Library on January 13 marked the end of the life of a beloved friend to many, a majestic Coast Live Oak tree that stood in front of the library for decades. Its passing was celebrated by a gathering of staff, patrons, and friends, who bid it a fond farewell with speeches and poems recited especially for the occasion by two community poets. The poetic tributes to the tree appear at the end of this article.

For nearly five years, the library and the City of Los Angeles had worked to save the tree. But in spite of their efforts, the oak continued to decline. When the tree was near death, it had to be removed for safety reasons. The sad demise of the nearly 60-foot tree was recorded on January 13 by photographer Gary Leonard:

Why should we care so much about one old oak tree? The library’s tree was estimated to be between 100 and 150 years old, representing our local history. Indigenous peoples once used oaks for food, fuel, and shelter. Spanish explorers noted their numbers and named nearby places after them: “Encino” is Spanish for “live oak,” “los robles” means “valley oak.” Oaks provide homes for songbirds, squirrels and owls. Of course, oaks provide comforting shade. And, they are beautiful. There’s nothing like a magnificent oak to connect us with nature. Children and fond memories grow under such old trees, so it’s natural that we come to love them, and grieve when we lose them.

There’s a happy ending to this oak story. As the old oak was cleared away, its branches were chipped to prepare the ground for three young, healthy Coast Live Oaks that took its place.

Three young Coast Live Oaks will reside in the space where the venerable oak once thrived. The trio will grow up with the community and become landmarks in their own right.

Even though the Sunland-Tujunga community treasured their old tree, the three new saplings will grow to be landmarks for those who come after us, bringing the site full circle to delight the next generation.

Oak Care Tips

  • A majestic oak in its native habitat prefers undisturbed soil and a thick carpet of its own dropped leaves surrounding its trunk. An oak surrounded by lawn, flower beds or ivy can die from overwatering, fungal disease, damage from mowers and other hazards. Excavating or paving too near the tree can likewise cause an early death by damaging sensitive roots and exposing them to too much heat.
  • Though winter is the best time to prune deciduous trees (those that drop their leaves) summer is the best time to prune evergreen live oaks Quercus agrifolia (coast live oak) or Quercus wislizeni (interior live oak.) Live oaks drop a few leaves throughout the year and are never bare. They have adapted over eons to California’s hot, dry summer weather by switching to a slower growth cycle when less water is available. So August and September are the best months to trim your live oaks. Beware of over-pruning. If trimmers overdo it, trees can become stressed, causing them to decline and die. Remember, foliage feeds the tree. Removing too much of it puts the tree on a starvation diet.
  • Consult a certified arborist and your city planning department for guidance on tree issues. If you wish to cut limbs from your trees, or grade or build near them, you’ll need a permit. Oaks and certain other tree species are protected by law, so check with your city first. An oak can never regrow a limb lost to a bad cut.
  • Oaks are a natural asset. They’re also a valuable community asset. If you’re lucky enough to own oaks, they are your valuable asset, and you are their steward. Oaks add value to your property, provide privacy, offer shade to lower your air conditioning costs—and save water costs since they’re drought-tolerant. You’ll want to take good care of them.

Old Oak of Sunland/Tujunga Library
On the Occasion of Laying the Tree to Rest, Jan. 13, 2020

By Alice Pero ©2020
Published by permission of the author

Old oak, you have watched us long
While we trampled the underbrush
Nearly 100 years
You watched
While we turned forest floors
Into highways and sidewalks
Finding comfort in books
Inside cool walls of cement
And stone

Once you baffled the sun*
With your thick, fertile branches
Your Old Women** friends
Teaching us the prayers of the Tongva
Though they, too, were almost gone
By the time your seed sprouted

We are grateful for your shade
Your outstretched arms
As children ran about under you
Shouting and playing
Feeling spirit spreading grace

We are grateful for the grace
All live oaks give
More than just precious oxygen
Something of an ancient time
When trees were sacred

Now we must now send you back
To the earth from which you came
With hope that the spirit of trees
Remains in your seed

* In 1910, a Los Angeles Times correspondent wrote about Sunland: In the center of town the oaks are so thick that the sun is baffled
** “Tujunga” in the native Tongva language means “the old woman”

 

Library Tree Celebration, 1/13/2020
Sunland-Tujunga Branch Library

 By Pamela Shea, 9th Poet Laureate of Sunland-Tujunga
Published by permission of the author

Fluttering leaves have bid welcome
To Sunland-Tujunga Library.
Our beloved Coast Live Oak
Has blessed us over a century.

An icon, a landmark,
A beacon, and our friend,
Will live on in memory
Its influence will never end.

Oh dear, beautiful tree,
The time for goodbyes has come.
You’ve adorned our community,
Protecting us from rain and sun.

A sentinel to learning,
You have bridged earth and sky.
Welcoming, inspiring,
Our host and our ally.

Precious one, so majestic,
Standing proudly all these years,
We must now bid you adieu
With our thanks and with our tears.

 

The Twohorned Gall Wasp Might Sound like a Threat, but Don’t Worry, it’s Part of Complex Native Oak Ecology

by Rebecca Latta

If you have evergreen live oaks Quercus agrifolia (coast live oak) or Quercus wislizeni (interior live oak), you might have noticed unusual leaf-drop this winter, along with thousands of small pellets that look like BB shot collecting on your driveway and patio. You might have stepped under your oak tree, and heard those pellets dropping like rain.

leaf galls from oak gall wasp

Leaf galls form on the back of live oak leaves in the second generation of the twohorned gall wasp’s lifecycle.

What you’re experiencing is an unusual population explosion of tiny wasps that specialize in oak trees: twohorned oak gall wasps, Dryocosmus dubiosus. The pellets are tiny leaf galls, formed by the tree in reaction to the wasp’s eggs laid in leaf veins. Magnified, these galls have two small protuberances. So it’s the galls, not the wasps, that earned the name “twohorned.”

An insect with an extraordinary lifecycle, this tiny wasp passes its life mostly unnoticed, high above in the tree canopy. These wasps undergo two generations per year. In the first generation, wasps lay eggs in oak flowers (catkins), causing small galls to form on the blooms and along the edges of new leaves. Larvae feed inside the galls. In the second generation, eggs are laid in midrib and lateral veins on the underside of leaves, causing the tree to form tiny galls. Larval wasps overwinter as pupae in these galls, which often drop from the leaf.

Gall wasp populations vary naturally from year to year, but unusually high populations sometimes occur, causing noticeable yellowing of leaves and premature leaf drop in evergreen oaks. Most infestations are not considered threatening to tree health since twohorned oak gall wasps often kill only parts of a leaf. Unaffected leaves will survive on the same twig, unlike damage caused by fungi that cause oak twig blight and twig girdling beetles, which cause the entire leaf to die.

The good news: Gall wasp numbers are controlled by a host of natural enemies. Fungi, parasites, predators, and competing insects (primarily moth larvae and other wasps) share the gall and kill the wasps and their larvae.

No control for oak gall wasps is known or recommended, however it’s wise to promote good tree health by protecting oaks from stress. Don’t over-prune or over-water. Allow natural leaf litter to remain in place, protecting roots from heat and providing natural fertilizer. Water oaks in times of drought. Although aesthetically undesirable, don’t worry about oak gall wasps: nature will take care of them.

Call your professional arborist if you have questions and for a refresher course on best practices to preserve your oak’s good health.

Rebecca Latta Speaks on Caring for Oaks – September 21 at 10 a.m.

California Native Plant Society’s Riverside-San Bernardino Chapter presents Rebecca Latta on Oak Stewardship

Oaks are the iconic tree of California, providing timeless beauty, shade and a sense of place. Each oak can support thousands of associated species. Now with the stresses of climate change and new pests, oaks need our attention more than ever. Rebecca Latta will discuss how and when to water, when and whether to prune, and all aspects of the care of oaks.

Council considers whether residents can, should build tree houses in protected species

A treehouse built by John Womack spanning three oak trees in his backyard. He received a letter from the city informing him the treehouse he built for his children was illegal and had to come down. (Tim Berger / La Cañada Valley Sun)

By Sara Cardine
May 16, 2018
La Cañada Valley Sun

READ STORY HERE

City Council members contemplated Tuesday whether and to what extent residents should be allowed to construct tree houses on their properties, after a structure built among oaks at a Patagonia Drive home recently caught the eye of city code enforcement officers.

La Cañada homeowner John Womack first addressed the council at an April 3 meeting, after a wooden play platform he’d built for his children was declared a violation of the city’s zoning code regarding the treatment of protected trees on private property.

“Trees don’t heal like people — the tissue just grows over the damage,” Latta said.
“[So] when you have a tree that’s been damaged, the damage is permanent.”

Womack said he didn’t believe he harmed the oaks, as no limbs were cut or damaged, and asked the council to reconsider allowing residents to build play spaces for their children. On Tuesday, he said he read the code and found nothing that prohibited him from placing stainless steel screws into the trees.

“We intentionally made sure we did not violate the code,” he told the council. “We intentionally designed this to cause the least amount of stress to the tree, and we made a point not to cut off any branches.

Rebecca Latta, an arborist consultant who examined the structure, said screws, nails and staples can cause harm by puncturing the bark and providing entry points for insects, bacteria and fungus.

“Trees don’t heal like people — the tissue just grows over the damage,” Latta said. “[So] when you have a tree that’s been damaged, the damage is permanent.”

Council members weighed the merits of protecting trees against families’ rights to enjoy their homes, but unanimously agreed protected species such as oaks and sycamores should never be built upon.

As for building in unprotected tree species, the council said homeowners should have some rights to install structures if they were willing to assume the risk.

Community Development Director Susan Koleda said while the city’s zoning code does not specifically address residential tree houses its building code, it was adopted from that of L.A. County, which does exempt tree houses of 64 square feet or smaller and do not exceed 8 feet in height from requiring a building permit.

Councilman Greg Brown said he’d like those specifications included in the city’s zoning code, to give homeowners some guidance.

“I would not allow this sort of damage to protected trees, but I would like to see our code provide an exception for … something small that’s reasonable. Then we wouldn’t have this issue in the future where we’ve just got a silent code people have to try and figure out.”

City Manager Mark Alexander suggested the council put the matter before the Planning Commission, for input and further consideration about placement, size and possible setbacks. The council voted 3-1 to follow that suggestion. Mayor Pro Tem Len Pieroni, leading the meeting while Mayor Terry Walker was out of town, cast the dissenting vote to avoid over-regulation.

“If you own a house you should be able to enjoy it,” Pieroni said.

Council members were not asked to rule on Womack’s situation, which will continue to be handled as a code enforcement issue.

 

Tree trimming guidelines in Edison wildfire plan may go too far, arborist says

La Canada Valley Sun News
By Sara Cardine
Feb 28, 2019

READ ARTICLE HERE

A tree was carved out to create a 12-foot clearance for the top power lines on Oakwood Avenue on Monday The trees are being trimmed by Southern California Edison tree trimming crews to protect power lines, but arborists are citing examples of how the trimming could be harmful.
(Tim Berger / La Cañada Valley Sun)

Southern California Edison is making big plans to reduce the chances of fire ignition in high-risk areas like La Cañada Flintridge, proposing to spend more than $118 million throughout its service area on enhanced vegetation management between now and 2020.

As part of a 119-page Wildfire Mitigation Plan, required by state law and submitted to the California Public Utilities Commission Feb. 6, the utility aims to reduce threats posed by falling trees and hanging limbs near power lines by removing at least 7,500 trees (with funding being sought for the removal of up to 15,000) in 2019 and maintaining a 12-foot clearance around all electrical wires.

Contracted work crews have been busy on the streets of La Cañada and neighboring Altadena in recent months, trimming or topping trees to accommodate the new radial requirement, far greater than the 4 feet standard previously imposed.

The results of their labor — visible on several La Cañada residential streets north of Foothill Boulevard — is causing concern among residents and at least one arborist who fear such extreme pruning could imperil the health of certain tree species.

“They’re topping trees, which are going to go into a permanent state of decline,” said Rebecca Latta, a longtime arborist who has clients in La Cañada. “They need to do a better job of explaining to us why they need to go to 12 feet.”

Vegetation poses a threat

In a Wildfire Town Hall forum held last week at Pasadena High School officials from Edison International and the CPUC explained maintaining vegetation was a chief concern.

“We collect statistics on ignitions,” said Elizaveta Malashenko, deputy executive director for CPUC’s Office of Safety and Enforcement. “At 25%, the top No. 1 cause is vegetation contact with power lines.”

Local arborist Rebecca Latta on Hook Tree Road with a topped off deodar cedar behind her. ““They’re topping trees, which are going to go into a permanent state of decline,” she says.
(Tim Berger / La Cañada Valley Sun)

Between 2015 and 2017, 132 ignitions occurred in the distribution voltage infrastructure that carries power from substations to customers in Edison’s high risk fire areas, the utility’s mitigation plan indicates. Of those, contact from vegetation accounted for 22 fires, or 17%.

Vegetation-related ignitions in higher voltage transmission infrastructure, which carries power from power plants to substations, was lower with only one instance during the same two-year period, accounting for 5% of fires.

Pedro Pizarro, president and chief executive of Edison International, told the town hall audience his utility inspects and trims more than 400,000 trees in high risk fire areas each year.

“We know that homeowners care deeply for their surrounding environment and foliage, and we want to respect that,” he said. “However, we will prioritize safety of your home and our communities first and foremost, so we will trim trees when needed.”

Crews on the march

Following orders to maintain adequate clearance, some 400 contractor work crews consisting of at least one groundsman and one foreman are inspecting private trees on residential streets throughout Edison’s territory and notifying customers when work is needed.

La Cañada is an area of high concern, according to David Guzman, who oversees Edison’s vegetation management program.

“There are a lot of trees in that area, it has a dense population, and it’s at an interface with the [Angeles National] Forest, so it’s definitely something we look at closely,” he said.

In the past, branches were trimmed back to a 4-foot radius around trees, with fast-growing species receiving at least 6 more feet of pruning, Guzman said. But since the CPUC passed a new regulation in December 2017 recommending a 12-foot clearance for all vegetation in high-fire-risk areas — even when lines are covered or insulated — the particular species of a tree no longer factors into the pruning.

“We have a basic, across-the-board trim area of 12 feet,” Guzman said, adding arborists pre-inspect trees and perform quality control work of about 30% of grid work to ensure clearance.

Latta worries over-trimmed trees may suffer and become even greater fire hazards.

“If you top the tree you expose the whole upper canopy to sunburn. And if you have any other issues going on, root rot or other health problems, the tree doesn’t have enough resources to defend itself,” she said, naming deodar cedars and some pines as particularly vulnerable.

The arborist also claimed some homeowners were not receiving proper notice before trim work was done on their property.

Guzman said customers receive door hanger notifications from inspectors at least 30 days in advance and a second notice days before trimming is scheduled. If people cannot reach the number provided, Guzman recommended calling Edison at 1 (800) 655-4555 and asking for a vegetation management manager who can look up properties and report details.

Despite the established notification process, Pizarro warned residents at the Feb. 21 Wildfire Town Hall public safety trumps standard operating procedures.

“Of course we want to give advance notice, but if we see something we think is a hazard we’ll take it on the spot,” he said.

Locals want more input

Edison’s enhanced vegetation management plan just doesn’t sit right with La Cañada resident Taylor Carbonetti, who had a crew perform some trimming at her Hill Street home but was shocked to see what she considers over-pruning in several other parts of town.

“It looks like if you were making paper trees and you just took scissors and took all the tops off — it’s intense,” said Carbonetti, who went on Facebook to inform neighbors. “You’re walking around and start noticing all these trees are chopped. And we’re seeing the trucks everywhere.”

Meanwhile, Latta said she appreciates Edison’s efforts to keep at-risk foothills communities safe, but wishes they would have developed a more collaborative approach with input from stakeholders. She’s currently trying to raise awareness in local arborist circles.

“It’s not my intention to do anything other than get their attention and get them to develop some options,” she said. “Why is it we’re not being allowed to be part of the conversation?”