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!
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).
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.
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!
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.
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
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.
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.
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:
As Californians scramble to find a way to reduce water consumption to meet a 25% water reduction mandate, turf removal has become the latest means to accomplish significant water savings. From Santa Barbara to San Diego, with Los Angeles and Orange county in between, turf is being ripped out at a frenzied pace.
Considering the rebates offered by the Metropolitan Water District in Los Angeles and other municipalities, homeowners and businesses are jumping at the opportunity to be reimbursed for turf and spray irrigation removal. Succulent gardens, Mediterranean, and California natives and other drought tolerant plant materials are being used to replace water guzzling turf.
The decades long love affair with our green turf lawns is coming to an end. Unless you can afford to pay extremely onerous penalties for excessive water use, the California drought, climate change and dwindling water resources will change the way we design, plant, irrigate and use our landscaped areas.
As turf and spray irrigation is removed, it is easy to forget about trees in the landscape. Trees planted in the landscape rarely receive irrigation dedicated to just the tree. Typically, the tree is located in an irrigated turf or planter area. Tree roots grow where there is moisture. Trees adjacent to an irrigated turf area will certainly root into the turf zone because that is where the water and nutrients are.
A common misconception is trees develop deep tap roots that grow deeply into the soil to locate water. In fact, almost all tree roots grow within the top three feet of the soil mass, almost 80% of the roots grow within 12-24 inches from the soil surface! Initially, a tap root growing downward will encounter rocks, hard pan or other physical impediments causing the tap root to split into a fibrous system growing horizontally through the soil profile.
As roots grow outward from the trunk, the tree crown grows in conjunction with the spreading root system. The outward edge of the tree crown is referred to as the drip line of the tree. The structural tree roots grow outward toward the drip line, however they don’t stop there! Outside of the drip line, the structural roots become increasingly smaller in diameter and that is where the fine absorbing root hairs are located, often well outside of the tree drip line. Many tree species grow roots up to twice the tree crown diameter!
Knowing how tree roots grow is vital to understanding how your trees will react to changes in irrigation caused by converting turf or high water use areas. If the edge of a tree crown or drip line is near an irrigated turf area, it most certainly will have rooted into the turf soil zone. When the turf is gone and water is turned off, the tree will have lost it’s primary source of water and nutrients and will begin to decline. If it does not have or develop other water resources to tap into, the tree will eventually die.
If you notice the crown of your trees declining, not leafing out or new buds dying back, these are symptoms that may be caused by the affects of drought or lack of water. Think back and consider what changes have occurred in the past one to two years? Has there been construction or renovation work nearby? What about changes in the landscape, was the turf removed and sprinklers turned off? Was there trenching, rototilling or soil preparation in an area nearby existing trees?
You can still remove your water consuming turf and use drip irrigation, just remember to plan for irrigating the trees. If using a drip system, consider using higher volume emitters, or other distribution systems that will provide an adequate water supply to the tree. Add a drip valve solely dedicated to tree irrigation separate from the other shrubs or ground covers. Proper planning, installation and maintenance is required to convert water consuming landscapes into sustainable, water efficient landscapes while preserving existing tree health and aesthetics.
With proper planning, trees can be grown and will flourish using drip or low volume irrigation systems but you must provide enough water distribution to encourage the tree to root into the surrounding site soil. Unlike spray irrigation, drip systems must be maintained and upgraded as trees grow larger root systems. Additional drippers or emitters are required as the tree crown increases in diameter. Drip and low volume distribution systems work great but are more labor intensive than spray systems and require a higher degree of maintenance.
So go ahead and get rid of that old ugly bermuda grass lawn, or grit your teeth and say goodbye to your green lush tall fescue or Kentucky bluegrass and say hello to water savings without sacrificing visual aesthetics. You can keep your trees alive and flourishing while still achieve water savings and a unique, beautiful landscape. Use a landscape and certified arborist tree professional to help you achieve your sustainable, affordable landscape!
I recently read an article in the Los Angeles Times Drought Trees 1 , Drought Trees that addressed the tremendous die-off of trees within California’s national forests. The aerial pictures in the article depict vast areas of red colored trees dominating the forest land. As the drought continues, the death toll on our national forest lands is approaching record numbers.
To date, scientists and U.S. Forest Service representatives estimate at least 12.5 million trees in California’s national forest have been killed due to drought. Unfortunately, scientists expect the die-off to continue as the state heads into the summer season, traditionally the driest months of the season and the months with the greatest fire threat. The last time researchers saw such a great die-off was during the drought period of 1975-1979, when an estimated 14 million trees died.
As a professional arborist, horticulturist and outdoor enthusiast, I find it incredibly sad and painful as we helplessly watch millions of trees die in our forest lands. Since childhood, I have loved camping throughout California, whether in the local San Diego mountains, the Sierras, or coastal California, the common denominator was the presence of trees, sometimes big trees. Oaks, pines, sycamores, redwoods, cedars, the list goes on, so many beautiful tree species whose survival is now being threatened by drought.
I first became aware of the effect of the drought on client trees two years ago and the problems have only increased in the urban forest and wild land trees. Oaks, pines and peppers on non-irrigated lands that survived for decades are now finally succumbing to the drought. The grinding, relentless drought has reached a point where water tables and soil moisture are too depleted for many trees to survive. Clients have called with questions why trees they have in the past ignored are now declining. Non-irrigated trees located in slopes or non-viewed areas that survived and flourished for decades are now in decline or dead. As turf irrigation is turned off trees decline and die.
Trees weakened by drought are being infested and killed by wood boring beetles.There has been an uptick in the beetle populations due to the dry drought conditions. A healthy tree exerts internal pressure and pushes sap out of the tree surface, in effect forcing intruders out of the tree. But when a tree is dried up, it cannot develop the sap flow and other natural defenses to ward off the wood boring insects. Trees weakened by drought become susceptible to invasion and colonization by beetles, killing the host then spreading to other weakened or even healthy trees.
As trees die-off from drought or killed off by beetles, millions of dead trees increase the likelihood of devastating summer wildfires. San Diego county has suffered some of largest wildfires in the state. Decades ago, I used to take my family to campgrounds in the Cuyumaca and Laguna mountains that were later destroyed in the Cedar and Witch fires back in 2003-2005. Even now, the standing dead, blackened, trees are a reminder of the terrible results of wild land fires.
In the past, “normal” spring weather resulted in green hillsides and mountains, with wildflowers and snowcapped peaks. That has not been reality for the past several years. Anyone can easily see the already brown, grey hillsides, it looks like the middle of the summer yet it is only May. The small amount of rain this past weekend, while a wonderful event, two days later you would never know it rained at all.
I have no recollection of the drought in the late seventies. I was a college student back then and drought was not something that registered on my horizon at the time. Now, after decades working in the landscape, arboriculture, horticulture and land development industries, this drought is frighteningly real and showing no signs of relenting. Mandatory water restrictions are affecting the lives of all Californians.
The real scary question for me, is this our new climate? I don’t want to see a California devoid of redwoods, oaks, sycamores and so many species I have grown up with and grown to love. Regardless of how much water we conserve, the trees in our forest lands are at the mercy of mother nature. The drought of the seventies killed millions of trees but that drought ended and millions of trees recovered and flourished. Lets hope for a similar scenario with the current drought and tree die back.
When I tell people I’m a consulting arborist they often ask what is that? Everyone is familiar with tree care companies, but not so much what the role of a consulting arborist. The common conception is when there is a tree problem, call up a tree contractor and have them do the work.
Yet, there are many tree problems that require expertise beyond a tree care company. When a tree has a change in condition or conflicts with infrastructure, such as tree roots lifting up a sidewalk, a consulting arborist is required to assess the situation and make recommendations.
Consulting arborists have one or more certifications. The primary designation is a certified arborist. This designation is administered through the International Society of Arboriculture (ISA). The second and more difficult designation to obtain is that of Registered Consulting Arborist (RCA), administered through the American Society of Consulting Arborists (ASCA). Consulting arborists with the RCA designation are the preeminent authorities on tree related matters.
To receive the RCA designation, an individual must already be a certified arborist. Once they meet the experience and education requirements, an applicant must enroll in the Consulting Academy. This rigorous training focuses on technical and report writing. Applicants who receive their RCA designation are trained to produce the highest quality written reports and work product, a terrific benefit for attorneys, insurers and professional consultants.
To learn more about registered consulting arborists, please click on the link below.
If you are a landscape or tree care contractor, you should be aware of the potential liability you face by an unhappy client. This awareness begins when you understand your “duty of care” as a landscape or tree care professional.
What is “duty of care”? It is a very important legal concept that simply stated means a person or organization has the legal obligation to avoid acts or omissions that could harm others. The duty of care extends to your actions or lack of action that would cause harm to your client or their property, perhaps even extending to adjacent properties and utilities.
Licensed contractors should understand their client hired them for their expertise and professionalism. The client is reliant upon the contractor to provide a product and service that conforms to industry standards. It is incumbent upon the contractor to satisfy all contractual obligations and satisfy the industry standard of care, or face a possible lawsuit.
If you are a landscape, maintenance or tree contractor interested in learning how to minimize you legal exposure and reduce your liability, please read the full article at:
Through a business acquaintance, I had the good fortune to meet with Mr. Christian Rodriguez, a company representative from Blue Drop, Inc. We met at a downtown San Diego street intersection where Blue Drop, Inc. had a contract with the City of San Diego to replace old cast iron tree grates with their new product called Safe Path.
Tree planters within pedestrian sidewalks are typically small confined spaces surrounded by concrete with lots of pedestrian traffic. Tree grates were installed around the planter pit primarily to protect people from tripping over tree roots. The grate also allowed watering to occur beneath the grate and afforded the tree a degree of root protection from pedestrian traffic.
When first installed surrounding a young tree, there is plenty of room for the tree trunk and root collar to grow and expand. Tree grate openings typically are up to 12″ in diameter.
A young tree with a two inch diameter trunk will add one inch of trunk diameter per year. The tree will outgrow the tree grate opening within a decade. Just as the tree reaches maturity and is starting to provide the maximum intended benefits, the trunk begins to lift the tree grate. Either the tree or tree grate must be replaced.
When I met Mr. Rodriguez, he showed me a downtown site where Blue Drop had installed their new Safe Path product. The product is a poured in place permeable rubberized material that levels the planter surface with the adjacent sidewalk. Water quickly infiltrates the permeable product which allows for both water and gas exchange. The tree trunk, root collar and any surface roots are safely protected by the product. As the trunk and roots enlarge, the products cracks, allowing for easy product removal and mending.
Because Safe Path is poured in place, it appears to be an ideal product to retrofit existing planter systems and especially for irregular shaped planter areas. The product provides a smooth, yet permeable surface, creating a safe environment for pedestrians while protecting tree roots and enhancing street scene aesthetics
I have no financial of special interest in Blue Drop Inc or any of their products. As a certified arborist who has provided expert witness testimony in trip and fall cases involving trees, I was interested in discovering new technologies that improve public safety around trees.
Click the link to read the full article reviewing the product. A Better Way to Protect Trees and Pedestrians