Joshua Tree Extinction by End of Century?

Posted on April 14, 2020 by landscapeexpert

I just read an article in the Los Angeles Times about a potential listing of the Joshua tree as an endangered species. The western Joshua tree, Yucca brevifolia, is one of two genetically distinct species that occur in California. It range extends from Joshua Tree national park westward along the northern slope of the San Bernardino and San Gabriel mountains, northward along the eastern flank of the Sierra Nevada and eastward to Death Valley.

Approximately 40% of the western tree range is on private land, the eastern range is centered in the Mojave National Preserve and eastward into Nevada.

After decades of climate change, development, drought and wildfires, the species is facing a rapidly increased the risk of extinction. State Department of Fish and Wildlife Commission will decide in June whether to accept the department’s recommendation to declare the tree an endangered.

As usual, there are two sides to the issue. Conservationists see this as a triumph of state environmental law while critics claim it as a misguided overreach because Joshua trees are already protected under many city and county ordinances and within the 800,000 acre national park.

Environmentalists argue existing state and local ordinances are largely inadequate at protecting species habitat loss, the endangered species listing will finally provide a statewide protection for the species, including requiring wildlife managers devise a recovery plant for the species, which could limit development in SoCal real estate.

The Joshua tree exists in high desert communities such as Yucca Valley or Hesperia, communities with lower average median household incomes. They are concerned the listing would impose additional burdens to real estate development, making it tougher to improve their property or curtail new development in their communities.

However, researchers warn time is running out. The tree’s range is contracting at lower elevations, its reproduction has come to a halt. Trees are failing to reproduce at lower, hotter elevations. They could become extinct in California by the end of the century!

This would be a terrible outcome for a truly incredible species. This remarkable species deserves protection. I believe this tree, in its own way is as majestic in its high desert setting as the coast redwood. These are species distinct to our California heritage. The Joshua tree deserves protection for our future generations to enjoy, marvel and be uplifted by this unique species.

Download a pdf of the article here: Los Angeles Times – eNewspaper

California Olive Trees Dying from Exotic Pest Infestation

Posted on April 10, 2020 by landscapeexpert

Olive tree displaying decline symptoms

With so many trees dying in natural and landscape settings, I’ve observed a disturbing trend throughout San Diego, and I assume most of the state. Property owners allowing dead and declining trees, palms and shrubs to remain in place. The problem with this practice, aside from aesthetics, is the dead plant may serve as a vector, whereby flying insects such as beetles, leaf hoppers, spittle bugs etc. may spread the disease to other uninfected trees.

Over the past decade, drought and climate change has taken a toll on millions of trees throughout California. Drought weakened trees succumb to secondary invaders such as wood boring bark beetles. There appears to be a continuous proliferation of new exotic pests resulting in diseases that are killing millions of trees in nature and within our urban forests and residential landscape settings.

Gold spotted oak borer

First collected and identified in 2004 was the gold spotted oak borer, (GSOB). This flathead borer is responsible for killing over 100,000 live and black oaks in San Diego County alone. There is no effective prevention or cure.

Reports of the disease known as citrus greening, previously confined to China, appeared in Florida, threatening the entire U.S. industry. The disease is a vector-transmitted pathogen by the

Citrus damaged by Asian citrus psyllid

Asian citrus psyllid. This disease ravaged Florida citrus growers. Once infected, there is no cure.

Another exotic pest first detected in Southern California in 2003 has been infesting hundreds of different species and is now established throughout the southland.

The Polyphagous shot hole borer is a small ambrosia beetle responsible for transmitting Fusarium disease to many tree species including avocado,

Sycamore bleeding from shot hole borer

box elder, coast live oak, maple, liquidambar, coral, sycamore and many other species. Fusarium is a vascular clogging disease for which there is no cure.

The list goes on and on. Climate change and an ever more connected world will continue the trend toward future invasive erotic pests.

In early 2000, olive trees, (Olea europea) became very popular as a landscape tree, heavily planted throughout southland landscapes. For the past decade, olive trees have been declining from a number of diseases. Two of the diseases are fatal, both display similar symptoms, making diagnosis difficult.

Foliage display tip and marginal burn symptoms

Symptoms appears as leaf marginal burning, tip dieback, leaf scorch, and loss of foliage color. Defoliation proceeds from the top down and outside in toward the trunk. Small twigs die back, eventually larger branches and entire limbs die. Depending on location and season, the decline may be rapid or slowly over the years.

Xylella or Verticillium?

Disease Infection

Diseases known as quick decline, leaf scorch, or variegated chlorosis are caused by Xylella fastidiosa, the bacteria best known for causing Pierce’s disease on grapes, but also attacks citrus, peach, almonds, oleander, olives and many other species.
Verticillium wilt affects olive trees in commercial and landscape plantings and many other species. The disease is caused by soil-borne fungi, Verticillium albo-atrim and dahliae.

Both are vascular clogging diseases, where the fungus or bacteria spreads throughout the vascular system, restricting water movement within the xylem tissue. However, they have separate means of transmission. Unfortunately, neither disease has a cure, infected trees and shrubs decline over time, usually resulting in death.

Description and Spread

Xylella is transmitted by the glassy-winged sharpshooter, (Homalodisca vitripennis), leaf hoppers and spittle bugs. These vectors are xylem feeding insects.
The pathogen multiplies and spreads throughout the host tissue, restricting water movement through the xylem tissue.
Insect vectors feeding on infected trees (such as olive and oleander) may acquire the bacterium and carry it to new hosts.

Verticillium is a soil-borne fungus, it invades the root system of olives when the soil temperature is cool.

After penetrating through roots, the fungus multiplies within the xylem tissue, interrupting and reducing water movement from the roots to the leaves.
Each disease clogs the vascular system, interrupting water movement from the roots to the leaves.
Both diseases have similar symptoms making identification difficult.

Common Symptoms: (not all symptoms may be present)

Xylella:

Tip burn
Leaf scorch beginning at the tip toward the stem (petiole).
Marginal browning, scorch and yellowing.
Twigs and branches dieback beginning in the upper crown.
Desiccated leaf and fruit drop.
Production of suckers.
Crown dieback

Oleander infected with Xylella

Verticillium:

Symptoms appear in spring.
Newer leaves curl inward.
Dead fruit clusters remain attached.
Loss of leaf color and luster.
Leaf and fruit drop follow.
Inward leaf curl

Progressive decline

Dead fruit retained

Individual branches and or large portions of the tree may die within one season.
The tree may not die, growth may develop on unaffected portions of the tree and suckering from the crown.
The new growth continues until re-infected; the cycle repeats the following year.
Vascular staining
Vascular staining may be present.

Control

There is no cure for Xylella or Verticillium. Recommendations for both diseases include:

Remove suspected plants immediately to prevent vectoring disease to other susceptible host plants, i.e.: olive, oleander, sweetgum, grapes, etc.
Integrated pest management to control insect vectors may help slow disease spread but spraying to control leafhoppers is expensive and futile.
Control of nearby weeds and grasses to help limit insect vectors.
Pruning out infected limbs may improve the appearance, but it is impossible to prune “below” the infected wood, so pruning does not get rid of the disease.
Fungicide applications are not effective.
Remove declining and dead trees immediately.
Replant with disease resistant species.

Avoiding the disease is most effective but not always possible. Soils are easily contaminated with Verticillium from former planting and the pathogen may survive in the soil for several years, ready to infect newly planted susceptible species.

While greenhouse soils may be heat pasteurized to kill the fungus, that is impossible in the landscape. Solarizing landscape soils has some effect at reducing verticillium infected soils. Prior to planting, rototill and irrigate the soil as deeply as possible. Cover the area with six mil plastic, seal the edges with soils to secure for six to eight weeks.

Effective cultural practices such as fertilizer application, irrigation management, weed and insect control may assist in preventing infection and possibly reduce the effects of the disease. Most of these practices focus on improving plant vigor that help mask the disease, however these treatments are not curative.

It is important to note, many of the foliar symptoms described above may also be due to drought or poor irrigation practices. There are also foliar diseases that may produce similar symptoms but are only minor and may not pose a serious threat.

Diagnostic laboratory testing is the definitive method for a positive identification of the disease.

The important take away is this: Don’t ignore decline symptoms in olive and other susceptible species, as the plant may be infected with a fatal vascular disease. Declining and dead trees left in place may serve as a source for the disease to be vectored by beetles, sharpshooters and other pests to healthy nearby trees. Remove dead or dying trees to prevent disease spread.

The Benefits of the ANSI A300 Tree Care Standards for Tree Related Lawsuits

Posted on January 18, 2018 by landscapeexpert

Guy + Chainsaw – Tree = Potential Lawsuit vs
ANSI A300 Tree Care Performance Standards

Does he know what he is doing?

Background

Tree care professionals contracting for services are frequently members of the Tree Care Industry Association, (TCIA). The International Society of Arboriculture, (ISA), administers various types of arborist certification programs, including certified arborist or certified tree worker climber. The American Society of Consulting Arborist offers arborists training and testing to become a registered consulting arborist, (RCA). These associations provide industry standards and best management practices for members to adopt into in their own practice.

Personal protective clothing, ropes, saddle etc.

In California, C-27 landscape contractors and D-49 tree service contractors are licensed by the state, both can legally perform tree care service. Prior to 1991, various industry associations, contractors and practitioners followed their own standards for tree care.

The industry recognized the need for a standardized, scientific approach and agreed to develop an official American National Standard, resulting in the American National Standards Institute (ANSI) A300 Tree Shrub, and Other Woody Plant Management Operations – Standard Practices.

They are voluntary industry consensus standards developed by TCIA and written by the Accredited Standards Committee (ASC) A300, whose mission is to develop consensus performance standards based on current research and sound practices for writing specifications to manage trees, shrubs, and other woody plants.

The ISA and ASCA are members of the ASC and their member practices should conform to the ANSI A300 tree care performance standards. The standards “apply to professionals who provide for, or supervise the management of trees, shrubs, and other woodsy landscape plants. Intended users include businesses, government agencies, property owners, property managers and utilities.” Many municipalities have adopted the ANSI A300 performance standards as part of their tree and landscape maintenance ordinance. The A300 standards are separated into 10 parts based on the tree care practice.

ANSI A300 Performance Standards for Legal Conflict Support

Arboriculture professionals adhere to the ANSI A300 performance standards for developing specifications for tree care. Gardeners, landscapers, designers, and handy men are not certified arborists and rarely have knowledge of industry standards. Even licensed landscape architects, civil engineers, general and landscape contractors may not be familiar with or have knowledge of the A300 standards. Ignorance of the standards is not a legal excuse for violating or ingnoring the standards.

The standards are separated into ten different parts. Through case experience, I have found three of the ANSI A300 standards applicable for plaintiff or defendant tree related legal actions. In conflicts I’ve been involved with, the civil engineer, landscape architects, general contractor, landscape and sub-contractors and even licensed tree care companies were not aware of the A300 standards. In some instances, industry professionals were aware of the standards but failed to adhere to the them.

Without proper planning and management, construction and development projects adjacent to existing trees commonly damage tree roots, trunks and limbs, increasing the risk of a potential tree failure and resultant lawsuit. ANSI A300 (Part 5) Standard Practices (Management of Trees and Shrubs During Site Planning, Site Development, and Construction) is the recognized industry standard for managing trees during construction and is the focus of this discussion.

The A300 Part 5 Performance Standard is intended for use for industry professionals, including all levels of government agencies, private entities including commercial, industrial and residential property owners and managers, engineers, architects and utilities for developing written specifications. The standards apply to any person or entity engaged in the management of trees, shrubs or other woody plants.

ANSI A300 Part 5 standard

Without specifications for tree protection during construction and development, tree injuries occur. Depending on the severity of the injury, the defect may degrade the structural integrity of the tree. Over time, the injury may continue to decay, increasing the risk of failure and resultant damage to people and or property. The reason for the standard is to assess the level of risk and to provide information for risk mitigation.

Civil engineers, landscape architects and other professionals responsible for developing plans and specifications should be aware of the A300 standards. These professionals may not have the tree knowledge expertise, which is why the standard refers professionals to use a certified arborist qualified in tree management during site planning, development and construction.

The standard discusses implementation procedures that should be designed by a professional arborist including:
• Tree management plans in compliance with applicable ordinances and standards.
• Decision making should be based on the knowledge of health and safety of the tree resources present.
• Prime consultant and contractor should involve the arborist in the initial planning phases.
• Arborist site monitoring during construction should be specified to ensure compliance with plan requirement.
• Monitoring specifications should address demolition, grading, vertical construction, walks and pathways, playgrounds, excavations, trenching, drainage systems, and landscape.

For safety, the standard requires only arborists familiar with the standards, practices and hazards of arboriculture shall perform tree management. One of the objectives of the standard it to avoid damaging trees during construction; including damage caused by physical contact, grade changes and soil compaction. To achieve the defined objectives on any project, the arborist should be involved in the management of trees during all five phases of development including:
• Planning
• Design
• Pre-construction
• Construction
• Post-construction

Development and construction projects are complex, requiring planning and coordination among project shareholders. The prime consultant and or contractor should maintain arborist involvement throughout the various phases of the project in conjunction with the arborist developing specifications, resource assessment, conservation plans, monitoring and recommendations. The TCIA website has an exhibit of a Tree management plan flow chart defining what should occur during the development phases, arborist responsibility and development activity.

How the A300 Standard Applies in a Legal Context

The standard applies to all design and planning professionals such as civil engineers and landscape architects. These firms usually work as prime consultants and are responsible for producing the plans and specifications for development projects. They are responsible for knowing and adhering to the A300 performance standards. The same applies to prime contractors and their sub-contractors, and other project stakeholders.

Failing adherence to the A300 standards renders prime consultant(s), general and sub-consultants potentially liable if a tree related accident occurs. I used the A300 standard in a case involving a tree limb that fell from a tree onto an adjacent tot-lot.

A city decided to build a park within a former old growth forest. A civil engineer and landscape architect developed plans and specifications, including a grading plan with notes and a detail for tree protection. The general contractor, grading, and recreation equipment sub-contractors constructed the park. The design included a tot-lot with children play equipment built where trees were removed, with old, construction damaged trees remaining left intact at the edge of the tot-lot.

A few days after the park opened, a tree limb dropped onto the tot-lot, striking and killing a young child seated on a piece of play equipment. The parents sued the city, the design consultants and all the contractors because the defendants did not observe the city tree ordinance. The city ordinance adopted the A300 tree care standards as part of their tree ordinance, which the defendants ignored, arguing the standard did not apply to their trade(s). After extensive deposition testimony, using the standards in support of the Plaintiffs (parents of the deceased child), all the defendants settled rather than proceeding with a trial.

In another case, a property owner agreed to allow a guy to prune a tree. The guy claimed to have forestry experience. He had a rope tied around a limb that he cut just as a neighbor walked out of their house. The limb dropped, rebounded at the end of the rope causing it to swing and strike the neighbor in the face. In the resulting lawsuit, the A300 standards were used to support the plaintiff complaint with a resultant settlement from the insurer.

The A300 standards apply to tree care companies, certified and consulting arborists. Different standards may apply depending on the case. For example, A300 (Part 9), Tree Risk Assessment A. Tree Failure, provides performance standards for tree risk assessment and guidelines for establishing written specification and best management practices, (BMP).

As a certified and registered consulting arborist, tree risk assessment inspections and reports are consulting services I provide, I’ve incorporated this and other standards into my practice. Tree care contractors might find other standards, such A300 (Part 1) Pruning, Part 5 (previously discussed) and Part 9 particularly applicable to their business.

In conclusion, the ANSI A300 Tree, Shrub, and Other Woody Plant Management Performance Standards are a powerful tool that may benefit a plaintiff or defendant involved in a tree related accident. The standards are broad reaching in scope and application to a wide variety of construction and development professionals. Attorneys and insures should consider the potential application of A300 performance standards in tree related cases.

Spring Madness

Posted on April 3, 2017 by landscapeexpert

The beauty of spring is all around us, take a moment to enjoy it. Take a walk through any of our coastal canyons, parks and open spaces. You’ll be rewarded!

Not a field of poppies but still…

Wow

Get out there!

One of the Best Flowering Trees!

Posted on March 30, 2017 by landscapeexpert

Back in my college days at Cal Poly Pomona, I took several plant identification courses as part of the educational requirements for Ornamental Horticulture. Two trees from the same genus always stood out for their outstanding floral display and landscape use. Back then, the genus was called Tabebuia, since changed to Handroanthus. The two useful landscape species are Handroanthus impetiginosa,(Pink trumpet tree) and H. chrysotrichus, (Golden trumpet tree).

The Pink trumpet tree in full bloom

While taking a walk, I came across a beautiful pink trumpet tree in full bloom. I then started noticing a few other trumpet trees scattered about the neighborhoods in North Park. I’m not to sure why, but in my view, this species is an under utilized ornamental landscape tree. Perhaps due to a slow growth rate, medium appetite for water or its deciduous nature, the species is not heavily promoted by the nursery industry. But it has many beneficial characteristics making it a useful ornamental landscape tree.

The pink trumpet tree requires full sunlight to part shade and grows to approximately 25-feet in height in Southern California. The non-aggressive rooting system makes it a good choice for use in smaller confined planter areas such as a parkway strip. It performs well in the urban environment. Like most trees, it prefers well drained fertile soils however I see this tree flourishing under less than ideal conditions. No noted pests or disease, hardy to 24º F, damaged below 18º F. After spring flowering, it grows a green to brown colored pod.

A close relative to the pink trumpet tree but faster growing. By M.Ritter, W. Mark, J. Reimer, C. Stubler

Unlike the pink trumpet tree, the closely relate golden trumpet tree is a more rapid, larger growing tree. It too is deciduous, and like the pink trumpet, it flowers in the spring with an impressive display of brilliant, fragrant yellow trumpet flowers.

This tree grows to a larger size than the pink trumpet, up to 50-feet tall and similar width. It has a spreading, low canopy that matures into a broad, round-headed or vase shaped crown. It prefers full sun to part shade.

Branch strength is rated as medium to somewhat weak and root growth is more aggressive than the pink trumpet. Unlike the pink trumpet, the golden trumpet tree should not be used in a confined planter are.

Both these trees perform well in our mediterranean climate and their different growth characteristics allow for varied use, one in more confined areas, the other requires more room to grow. Once established, both are relatively drought tolerant.

Hope you find this helpful, let me know if you have any questions!

Worried About Your Tree?

Posted on March 23, 2017 by landscapeexpert

We have gone from record drought to record amounts of snow and rain throughout California. While the winter storms have wreaked havoc on our infra-structure (Oroville dam spillway, flooding in San Jose, etc, they have been a blessing for drought starved trees throughout the west. Years of inadequate rainfall reduced soil moisture leading to an incredible dieback of trees numbering over tens of millions within the state.

The urban environment creates stresses not normally encountered in the wild. In cities and suburbs, trees contend with confined planter area, compacted soils, improper or inadequate irrigation, poor maintenance practices, improper pruning, shading by homes or buildings. Stresses created by the urban environment reduce tree life expectancy, sometimes by as much as 50%.

During the drought, I have seen an increase in tree failure, whether a limb drop or whole tree failure. In most instances, crown, limbs, branch and twig dieback were the obvious symptoms of the drought. Many times, clients mistakenly thought the dieback was caused by disease or insect, however root dieback from minimal soil moisture was the cause of crown dieback.

Now, with the heavy rainfall and wind, tree failure due to saturated soils are on the increase. Trees remain upright due to their root system. Structural and buttress roots grow outward from the trunk at the (root crown), out to the edge of the crown (known as the dripline). At the dripline, the structural roots are 1-2″ in diameter. They continue to grow outward, branching into the small, fine feeder roots that absorb moisture and nutrients. Depending on local conditions, tree roots may extend 1.5 times the tree crown diameter. Based on San Diego soil conditions, most roots grow within the upper three feet, typically 80% of the roots are within the top 18-24″ of the soil.

Roots in dry soil are held in place by friction. However, when rain saturates the ground, it acts as a lubricant, lessening the soil friction holding roots in place. When wind combines with excess weight from rain or snow, the energy is transmitted down the trunk to the roots. Soil root friction reduced by saturation causes roots to loose anchorage, resulting in a failure. When roots fail to support the tree, it is assessed as a root failure. When the entire root ball rotates up from the soil, it is a soil failure.

Homeowners with large trees in close proximity to their property should examine their trees for any change in condition as a warning sign of a potential problem. Changes to be aware of include:

Is the tree leaning?
Are there soil cracks at the base of the tree?
Is the soil lifting, tilting or rippling at the tree base?
Are there dead limbs or branches in the crown?
Is there a progression of twig, branch and limb dieback?
Did the tree drop it’s leaves abnormally early?
Did the tree not leaf out as in the past?
Any obvious open cavities, cracks or splits?
Any animals or insects nesting within a hollow, cavity or crack?
Any fluids, abnormal sap flow or other discharges from the tree?
Has irrigation been reduced or eliminated to the tree?
Has there been construction activity near the tree?
Have the roots been disturbed by any nearby utility or sidewalk work?
Is the tree sitting in water, is there proper drainage?
Has there been a change in grade near the tree?

If you can say yes to any of the above, your tree may have acquired defects that increase the risk of failure. The increased risk of failure may result in property damage or personal injury to your family, friends, or any pedestrian near the tree. A tree with a history of previous failures possesses an increased risk of failing. Trees may not present any obvious signs or symptoms of a defect. Unseen decay may exist within a limb or trunk, or as a root rot.

Whether commercial or residential property, if you are concerned about the health and safety of your trees, you should contact an arborist certified by the International Society of Arboriculture, (ISA). Once certified, the ISA allows arborists to enroll in specialized training to earn the credential of a Tree Risk Assessor Qualified. While anyone may attempt to assess the health and structural integrity of a tree, certified arborists who are qualified in tree risk assessment represent the industry standard and best management practice for tree risk assessment.

Tree risk assessment is the current best management practice to determine tree risk of failure associated with defects. The assessment utilizes a level two basic visual assessment and a two page ISA format for the assessment protocol. The assessor may determine more advanced assessment techniques are required, however usually a basic visual assessment will suffice.

If you have noticed a change in the health or condition of your tree, take proactive measures before a catastrophic accident, call a certified arborist knowledgeable in tree risk assessment.

Click here to read an article published in the LA Times Risk Assessment article.

Cactus and Succulent Blooming at Balboa Park

Posted on March 20, 2017 by landscapeexpert

A blooming hidden garden at Balboa Park

Blooming agave in a less visited area of the park

Such a gorgeous spring day, had to go for a walk through Morley Field and Balboa Park. I knew it would be a busy day with lots of people seeking the beauty and sunshine at the park, so I decided to walk through some of the less visited areas of the park in search of plants.

When your a horticulturist, arborist, landscape contractor and avid gardener, it is kind of a curse and a blessing. I cannot help but be drawn to looking at trees, shrubs, landscape design and contrasting plant foliage and flower colors.

I took a bunch of pictures, some might seem more obscure or leave you wondering what the heck that plant is! Take a moment and enjoy!
Cactus, succulents and natives at Balboa Park

Trees Damaging Los Angeles Infrastructure, Who Is Responsible for Liability and Repairs?

Posted on August 17, 2015 by landscapeexpert

In May and June of 2015, The Los Angeles Times published articles addressing the problem of crumbling sidewalk infrastructure within the City of Los Angeles. The articles focused on the challenges pedestrians face in this car-dominated city. After years of mounting complaints and lawsuits caused by defective, dangerous sidewalks, city officials are finally beginning to address the problems caused by trees that were planted within city parkways, medians and right of ways.

Roots have damaged the sidewalk creating a trip and fall hazard

After decades of deferred maintenance, the City Council, the Mayor, and public work officials are finally turning their attention toward addressing the problem, and trying to figure out how to juggle spending requirements resulting from legal settlements and sort out who is responsible for future sidewalk maintenance, as well as liability for future injuries caused by damaged sidewalks.

The first question, who is responsible for sidewalk repair and replacement caused by trees growing within city parkways and right of ways? California state law placed the burden of sidewalk repairs on adjacent property owners. A majority of California cities adhere to the state policy, however not the City of Los Angeles, which forty years ago opted for a policy that made the City responsible for repairing sidewalks damaged by tree roots in city parkways. Back in the 1970’s, when federal funding was available for the work, Los Angeles opted to pay for tree-damaged sidewalks. When the federal funding was depleted, voters declined to support tax increases for the repair work, leading to the current massive backlog of damaged sidewalks.

Instead of removing invasive, surface rooting tree species and replacing damaged sidewalks, the city embarked on a less expensive program of temporary asphalt patches in an attempt to smooth over displaced, uneven sidewalks. The problems continue to mount, with over 19,000 sidewalk complaints within the past five years alone. Over 40% of the complaints have been ignored, with no repairs having been made, mainly due to inspections never being made or the sidewalks so severely damaged they require complete rebuilding.

The City is now proposing a policy to address the situation. Under the proposed policy, neighborhood sidewalks damaged by city parkway trees would be replaced at the city’s expense. However, after repairs are completed, responsibility for repair, maintenance and liability would be shifted upon the adjacent property owner.

The proposal has received mixed comments from residential and commercial property owners. Businesses already pay taxes they assume local government should be using for infrastructure repairs. Additionally, requiring businesses to pay for repairs would harm retailers, especially in districts lined with problematics trees. Many commercial property owners would be forced to pass on the expense to the small business owners that rent the property.

Ficus roots creating a sidewalk hazard

Under the “fix and release” program, repairs would be made by the city, and then future responsibility for the sidewalks transferred to the homeowner. Some homeowners feel this would be an equitable solution to the current problem, other disagree, stating they would be saddled with big bills down the road, particularly if the city does not fix the “root” cause of the problem, that being tree roots or leaking utilities.

The city must grapple with both sides of a delicate issue, trying to preserve the benefits of large, picturesque trees providing neighborhood character while having to remove the same trees whose invasive roots have damaged infrastructure and would continue to do so if left in place. To begin the process, the city acknowledged they do not really know how extensive the problem is. The city has no existing tree inventory of the tree and sidewalk condition. Without this information, it would be difficult for the city to measure progress as they attempt to implement any new sidewalk management policy.

Certified and registered consulting arborists consult with Southern California municipalities and private property owners involved in trip and fall litigation caused by tree root lifted and damaged sidewalks. Typically lifted and damaged sidewalks caused by tree roots are due to inappropriate tree selection. Species such as Sycamore, Ficus, Eucalyptus and Ash trees planted decades ago in restricted parkway planters were most often associated with damaged infrastructure.

Sidewalk repair or replacement without addressing the existing tree species ignores the problem. Passing on responsibility for future repairs and liability to adjacent property owners would be an unjust situation for taxpayers. Large, surface rooting, invasive species should be closely examined for mitigation in conjunction with infrastructure replacement. Perhaps root pruning and root barriers might be an appropriate remediation that would protect future infrastructure while retaining large pre-existing species.

However, many species planted decades ago were and will always be inappropriate for confined parkways. Root pruning a large Ficus or Sycamore could easily de-stabilize the tree, resulting in a catastrophic failure. Who would be liable for a tree failure and resultant property damage, or worse, personal injury or death? Citizens might have to accept they cannot have the best of both worlds, where large, invasive trees are retained for neighborhood character, sidewalks are repaired and the city remains responsible.

Over the decades, many newer street tree species have been developed that provide desirable growth characteristics while minimizing damaging invasive root systems and towering canopies that conflict with traffic and overhead utilities. Reasonable compromises can and should be made toward replacing older, inappropriate tree species with newer species that will provide community benefits while minimizing maintenance costs and damaged infrastructure.

Hopefully, the City of Los Angeles and other municipalities facing this problem elect to use certified and registered consulting arborist and horticulturists as they consider how to address their urban forest and infrastructure issues.

To read the full Los Angeles Times Article, click the link:

L.A. Considers Shifting Responsibility to Property Owners

Reducing Irrigation During the Drought? Don’t Forget Your Trees!

Posted on March 31, 2015 by landscapeexpert

I have been getting an increased number of calls from people concerned about their tree(s) starting to dieback. They want a certified or registered consulting arborist to evaluate the tree health condition, determine the cause of the tree decline, and recommend treatment options or removal.

For the past two to three years, I have noticed the increasing number of declining trees throughout San Diego. Especially noticeable is the tree dieback in the backcountry as well as local canyons and open spaces. Even drought tolerant Eucalyptus, Oak and Pines trees are struggling to survive.

The cause of our tree decline and dieback is the ongoing California drought. With yet another year of little winter rain, soils throughout San Diego county have little moisture reserve remaining. The drought is affecting native as well as ornamental trees used in the landscape.

Indeed, certain trees in our area are struggling due to insect infestation. The gold spotted oak borer attacking Coast Live Oak, as well as a host of ornamentals including Olive and Liquidambar trees have been infected with fusarium vascular disease introduced from borer and insect infestations. Therefore, it is not uncommon for most people to assume their tree must be declining due to some kind of insect or disease.

I have observed people rarely consider the effect of the drought as being the primary cause for tree decline. The tree living in the back yard or slope area for the past several decades may be dying simply because there is no more water in the soil profile! Even the deepest rooted trees cannot survive accumulated years of consecutive drought.

I recently received a call from a gentleman complaining his fifty year old Jacaranda tree was dying. The new foliage had germinated then died back, now small twigs and branches were dropping. The bark on the trunk was exhibiting uncharacteristic roughening. The tree was located at the bottom of a slope near a turf area. Months ago, the turf sprinklers had been turned off, now the tree was struggling to survive.

Tree roots seeking moisture grow well beyond the drip line of the tree crown. Under drought conditions, soil moisture is not being recharged from winter rains. Unless a tree is receiving supplemental irrigation, it is reliant upon finding soil moisture by growing into irrigated turf and planter areas.

With increased water restrictions and rates, people are reducing or eliminating irrigation to their lawns and shrub beds without considering the effect on nearby trees. Trees that adapted their root systems to getting water from nearby irrigated areas that no longer get watered will begin to decline as the remaining soil moisture is exhausted.

A tree weakened by drought becomes increasingly susceptible to secondary pest or disease infestations. Many beetles can detect stressed trees from miles away. However, attempts to eradicate secondary insect infestations will not resolve the underlying cause of the tree decline.

So, if you notice your tree starting to decline, here is a brief check list of considerations:

-Is the tree irrigated or non-irrigated?
-If non-irrigated, does the tree get water from a nearby irrigated source?
-Has there been recent re-programming or turning off the irrigation?
-Any recent construction or trenching nearby the tree?
-Any grade change such as fill soils placed over the tree roots or cuts?

A well maintained, mature street tree in the front yard of a property may add an additional 7% to the assessed value of a property, a dead or declining tree obviously reduces street appeal and real estate value. Trees can be retained and successfully survive the ongoing drought, contact a certified or registered consulting arborist to provide a tree health evaluation and recommendations on how to protect your tree investment value.

“Arborgeddon” – PTCA Hosts Another Great Seminar and Field Day

Posted on August 25, 2014 by landscapeexpert

Ficus tree roots engulf a curb, seen during Field day at Balboa Park

The Professional Tree Care Association (PTCA) of San Diego hosted their annual seminar and field day, a two day event on Friday, August 22 and Saturday August 23, 2014. This was the 25th annual event and like many of the previous seminars, this was another informative, educational experience bringing together a wide diversity of speakers and audience!

The seminar was on Friday and this years theme centered on the ongoing California drought and ramifications to trees. There were a number of great speakers, starting with Mr. Ron Matranga who provided an overview about trees in times of drought, current and future water restrictions . Dr. Roger Kjelgren, Professor from Utah State University, provided a simplified method for landscape irrigation demand estimation. Dr. Linda Chalker-Scott, the Urban Horticulture Extension Specialist from Washington State University discussed how to treat and avoid drought stress in landscape trees and Ms. JoEllen Jacoby, the Water Conservation Landscape Architect for the City of San Diego enlightened us about planning for current and future water restrictions (gulp, better get some rain this winter)!

Ms. Mary Matav, Agronomist from Agri-Serve presented information on how to combat pests and drought, followed by Dr. Tracy Ellis, Entomologist with the San Diego County Department of Agriculture, scaring all of us about tree insect interceptions and quarantines in San Diego County.

A great roster of speakers who delivered relevant information in a beautiful setting at Balboa Park in San Diego. On Saturday, the event transferred to the field, where information discussed at the seminar was applied and viewed in the field, an aspect of the field day I find very beneficial.

As usual, Dr. John Kabashima, the Environmental Horticulture Advisor with the UC Cooperative Extension, presented new, current information on the latest insect threat to our ornamental and agronomic trees in California, that being the Polyphagous Shot Hole Borer, (PSHB). As many of us already know, this destructive ambrosia beetle is now active throughout the Southern California.

The PSHB is an invasive ambrosia beetle that carries the fungus Fusarium euwallaceae. The female tunnels through the bark and lays galleries of pre-fertilized eggs and grows the fungus, which becomes food the newly hatched beetles. The fungi infects the tree with a disease called Fusarium Dieback (FD), which interrupts the transport of water and nutrients through the vascular system of the tree. In essence, this is a vascular clogging disease resulting in dieback and death of a large host of trees. Unfortunately, there is no cure at the present time and beware of PSHB/FD look-alikes. Here is very informative attachment Dr. Kabashima provided that really provides current information about this insect. Handout is published from the University of California and the UC division of Agriculture and Natural Resources. PSHB Information

Many thanks to all of the hardworking voluntary staff of the PTCA. What a great local association, I am very proud to be a member of. The PTCA is an active association promoting the best in tree care and tree knowledge. An association composted of tree care companies, certified and consulting arborists and tree care professionals, the PTCA continues to provide current and relevant topics for it’s membership and community at large. Thanks again PTCA, looking forward to next years Seminar and Field Day!