For several years, climate change and drought created conditions for uncontrolled California wildfires. These wildfires burned with such intensity, several Giant Sequoia, (Sequoiadendron giganteum), forests were heavily damaged. We have lost approximately 20% of the entire species, over 10,000 Giant Sequoias have been destroyed the past three years alone.
Although these magnificent trees are fire adapted, with an incredibly thick outer bark protecting the cambium within, the recent fires burned with such incredible intensity scores of trees were incinerated. Another fire adaptation are the Sequoia cones that normally open after a fire, distributing thousands of seeds that germinate and replenish the burned groves. Yet the fires were so hot, even the cones were destroyed, so the trees produced no new seedlings.
All of the groves are located in a relatively small band on the western slope of the southern Sierra range. Due to climate change, the southern Sierra range has become a dryer environment, very different than 2,000 years ago when these magnificent trees first germinated. As the forest regenerates, shrubs, fir, and cedar have replaced the Sequoias.
Sequoia seedlings require a lot of water to germinate and grow into juvenile trees. The hotter, drier climate and competition with other less favorable species, reduces Sequoia germination and ultimately, the survival of the species. Imagine Sequoia National Park without any Sequoia trees. Your kids and grandchildren might end up never being able to visit and enjoy these incredible trees. My father took me to the park when I was a child. My love for this species influenced my decision to study horticulture, eventually making my profession, first as a landscape contractor, later as a consultant and expert witness as certified and registered consulting arborist.
Fortunately, the Save the Redwoods League has teamed with the US Forest Service and National Park Service undertaking replanting thousands of redwood seedlings throughout several burned forest areas. The goal is to reestablish groves that can be managed to become fire resistant again. It is a massive undertaking, that has never been tried before. While the odds of any seedling becoming a massive, thousand year old monarch are depressingly low, (one in 10 billion), it is the morally right undertaking for mankind. Without restoration, the redwood groves will convert to shrub lands, a sad ending for the official state tree of California.
Whether an attorney represents a plaintiff or defendant, they hire an expert who will provide compelling testimony to support their client. Sometimes, multiple experts from a variety of disciplines may be required. When should an attorney consider hiring a certified or registered consulting arborist as an expert witness?
Living with trees implies accepting a certain amount of risk in exchange for the wonderful benefits trees provide. While the risk of a tree limb or whole tree failure resulting in a fatal injury is low, hazards caused by trees that result in personal injury or property damage lawsuits are not uncommon.
Tree species and proximity to infrastructure may be a factor in accidents with personal injury or property damage. Tree roots seek out moisture regardless of their location. Structural roots emanate from the trunk to the edge of the crown, also known as the drip line, then small moisture absorbing root grow far beyond. Tree root systems may grow 1.5 times the tree crown diameter.
In the urban environment, tree proximity to hardscape may result in roots growing beneath concrete sidewalks and paved streets while seeking moisture. Roots will grow into adjacent water meters and sewer laterals, especially older leaking, permeable infrastructure. Once established beneath a paved surface, a root continues growing, over time enlarging in diameter.
Over time, these surfaces may begin to lift along the crack or expansion joint. Adjacent sidewalk panels may lift several inches, resulting in a hazardous condition for pedestrians and bicyclists.
Eventually root enlargement lifts concrete infrastructure, including water meter boxes and sidewalks. Cracks may develop across a sidewalk panel, in my experience, most concrete sidewalk uplifts occur along an expansion joint.
In their pursuit of moisture, roots from neighboring trees ignore property lines. They can grow beneath garage slabs and foundations, especially in situations where there has been a water or sewer leak beneath the slab. Moisture discharged beneath slabs, footing and foundations create an attractive environment for root development.
Installing street trees within small concrete confined planters is an invitation for root damaging infra-structure. Leaking water meters, fittings and sewer connections increase soil moisture, an invitation for root growth.
A root penetrating a leaking sewer lateral or potable water meter pipe or fitting will quickly establish a mass of roots within and surrounding the pipe. Root growth may continue from the sewer lateral into the public sewer main. Over time, the root growth may block or cause a sewer back up to neighboring properties.
Improperly designed, installed or maintained sprinkler systems may result in over-spraying paved pedestrian sidewalks. Regardless of cause, their is no reason to allow sprinklers to over-spray onto paved surfaces, it wastes a vital resource while creating an obvious slip and fall hazard.
Tree limb and whole tree failures may result in personal injury and property damage lawsuits. Whole tree failures may occur due to loss of load bearing structural roots, whether due to root rot disease, construction impacts, mechanical root damage, or soil failure. Limb drops may occur for a variety of known reasons, typically the failure occurs during a weather event. Sometimes, a tree will drop a limb for unknown reasons, referred to as sudden or summer limb drop. Stems may contain defects such as cankers, decay, and cracks that may be predisposed to failure when enough force exceeds the wood carrying capacity. Forensic tree risk assessment may determine why the tree failed and whether the defects were open and obvious.
California has suffered countless wildfires the past two decades, resulting in substantial property damage. Tree appraisal for loss due to fire may be an important aspect in legal cases, especially when several major utilities are under scrutiny for causing wildfires.
The same holds true for tree loss or diminution in value due to trespass and vandalism. You may love your tree, but your neighbor may not. Neighbors frequently engage in tree disputes, sometimes resulting in trespass and vandalized trees. You may love your tree, but your neighbor may not.
Tree service contractors may become involved in a lawsuit for failing to satisfy the industry standard of care. When a tree failure occurs, the landscape maintenance or tree care contractor may find themselves as defendants in a lawsuit. A plaintiff may contend the landscaper or tree care company should have known the tree had defects but was the contractor responsible for risk assessment?
A C-27 landscape contractor may not be a certified arborist or provide arboricultural tree care, certified arborist may not be a trained or knowledgeable of Tree Risk Assessor Qualified, (TRAQ).
In summary, personal experience, education and training are essential qualifications an attorney looks when selecting an arborist expert witness. Having expertise in multiple disciplines is an added benefit. My qualifications as a professional horticulturist, a C-27 landscape contractor, a certified arborist, registered consulting arborist and tree risk assessor qualified and land development manager enable me to opine on a broad array of landscape, tree, plant and land development issues.
Rarely have I seen a successful turf block driveway. Turf block, turf stone, turf pavers are systems installed as living turf driveway alternatives. The material provides structural support via plastic or concrete cells that are filled with a soil media for turf installation. The block is designed to support vehicular traffic on driveways while providing a green alternative to concrete or asphalt driveways.
Turf blocks have been used for decades, but rarely have I seen thriving turf grass within the block. Not because of the product, but usually due to turf establishment and failure issues. Due to reduced soil root area, soil compaction, irrigation infiltration and damaged soil structure result in poor turf establishment. Soil preparation, drainage and proper irrigation coverage and operation are required to grow turf inside of a turf block system.
Lastly, using vigorous, warm season turf grasses that spread by horizontal solons, rhizomes, and rooting improves the successful establishment of turf grass, such as the Tiff hybrid Bermuda grasses developed for sports fields. Cool season turfs including rye, bluegrass and turf type fescues are clumping turfs that do not spread horizontally, thereby limiting establishment and healthy growth. Cool season grasses are more susceptible to leaf and soil borne diseases, are easily stressed during hot summer months, nor are they tolerant of vehicular and pedestrian traffic and compaction conditions.
Tiff hybrid Bermuda is well established within the turf block
An automatic irrigation system achieving 100% head to head coverage.
Properly installed, high quality plant material.
Each of these functions may require a specific type component, installed at a specific height or location to reduce the potential of creating a site hazard that may result in an accident. In commercial applications, landscape plans usually include details and specifications dictating type of product and how it should be installed.
Many common landscape products may be improperly installed including:
Pop up heads may be incorrectly set to grade against a sidewalk.
Valve or drainage boxes set too high or low relative to finish grade.
Shrub head installed on a riser adjacent to concrete improvement.
Hidden, obscured depressions in grade due to substandard compaction, settlement and subsidence.
Drainage box set too low.
Improper product selection or substandard installation practices may appear obvious. A pop up sprinkler head set above the top of adjacent concrete sidewalk creates a trip hazard. A drainage structure set well below the turf grade creates a trip slip and fall hazard. Selecting and installing a spray head on a rigid riser next to a pedestrian sidewalk is a sub-standard industry practice that creates a trip and fall hazard.
Spray head on a riser next to a sidewalk creates a trip hazard.
Not all landscape hazards are visible. Turf areas may have grade depressions or holes that are hidden by overgrown turf grass. Depending on the cause and time period, turf grass may completely hide the depth, location and size of the depression or hole, creating a hidden hazard.
A depression, rut or hole may result from several factors. Repeated mowing on saturated turf may create ruts. Overwatering may cause irrigation or utility trench settlement. A dead tree removed from a turf area may result in a future depression if the grade is not properly backfilled and compacted.
A seven inch deep hole hidden by turf grass.
Bermuda grass is a fast horizontal spreading turf-grass used in parks and recreation facilities throughout the country. Unless regularly aerated and de-thatched, Bermuda grass in known to grow a thick layer of thatch. Over time, the thatch layer can increase the turf grade several inches above adjacent sidewalk and curbs.
The backfill in utility trenches installed across pre-existing turf may settle, creating a depression in the sub-grade. The photo depicts the edge of a trench cut across an asphalt driveway, across a turf area. The trench backfill eventually settled, creating a trench sub-grade depression hidden by the Bermuda grass.
Thatch, hidden depression and sanded turf.
The depression resulted in a trip and fall accident. After the accident, several hidden turf depressions were “sanded” to fill depressions to proper grade.
Not all landscape hazards are open and obvious. Even a perfectly installed landscape may develop hazardous conditions if not regularly inspected and maintained.
Irrigation systems should be monitored, inspected, tested and adjusted monthly. Turf should be trimmed around utility boxes and vaults regularly, aerated and de-thatched annually to maintain optimum performance and minimize grade changes. Drainage structures should be grade adjusted, repaired or replaced when damaged. Valve, electrical and junction boxes should be monitored for grade changes and adjusted as required. Bark mulch thickness should be monitored and supplemented annually to maintain proper coverage and grade.
In summary, a properly installed landscape is composed of several systems and components that require regular ongoing maintenance for optimum performance, efficiency and safety. Pro-active landscape maintenance may reduce potential hazards, resultant accidents and lawsuits. These actions demonstrates an Owner’s recognition of protecting the health and safety of the public, pedestrians, friends and family who may visit and use the site and may prove useful in a legal action.
I took my usual walk through local neighborhoods surrounding Balboa Park in San Diego. A glorious spring day, I couldn’t help but marvel at the beautiful ornamental landscape trees, shrubs and vines in bloom everywhere! Very uplifting, glad plants are not affected by the virus!
In a recent blog, I discussed using online media for a site online site inspection involving a Torrey pine tree root conflict with adjacent asphalt paving. That marked the first time I used an online media tool rather than being physically present at the site. My client and I used Facetime to conduct the real time inspection.
As the restrictions ease, I believe the use of online media such as Zoom, Hangouts, Facetime etc will increase. I have already presented this concept to a legal client in Northern California concerning an irrigation inspection. Do I really need to fly from San Diego to San Francisco, rent a car, drive to the site, observe irrigation defects, then reverse the process returning home or, can I watch the inspection over the web? The level of scrutiny required depends on the individual case.
A slide from Dr. Smiley’s presentation
Like so many other industries, the tree industry is rapidly adapting to the new Covid – 19 reality. Today, I attended an online Zoom seminar titled Sidewalks, Urban Plazas and Tree Roots. This seminar was presented through the ISA Southern Extension. I believe it was originally going to be part of a “normal” ISA Southern Association Annual meeting that was cancelled due to Covid.
The online presentation occurred through Zoom with over 1000 arborists throughout the U.S. and other countries attending. The topic concerned tree roots damaging sidewalks, presented by Dr. Thomas Smiley. Once a few technical glitches were adjusted, the presentation was almost identical to what I had experienced attending many seminars.
The slides presented alongside the audio streaming from Dr. Smiley was easy to view. I became immersed in the content and found myself taking pics of some of the slides. The topic provided test data results using different techniques designed to reduce root intrusion beneath sidewalks.
Incorporating root growth inhibitor practices
The presentation lasted an hour, same amount of time I’m accustomed to when attending a seminar. Although I already knew a great deal about the topic, I still came away with new information for use in my practice, including a great specification detail incorporating multiple root growth inhibitor practices that may reduce sidewalk damage due to roots.
In the past month, I’ve been able to continue my consulting practice from my home office. I’ll continue to utilize more online media tools, whether for learning, conducting site inspection work, and client meetings. I believe these new opportunities are one of the (few) beneficial results from the Covid-19 virus.
I recently provided a client with a proposal to develop landscape maintenance specifications for commercial properties located in several different climatic regions. The proposal did not include any site visits. All data collection would occur online through various means. Using online data collection versus conducting multiple site visits saved the client thousands of dollars.
I’m looking forward to these new opportunities utilizing online media sources as potential replacement for physical presence. Hopefully it will prove an efficient, effective, cost saving technique without sacrificing product accuracy.
The corona virus and resulting stay at home order has prevented me from scheduling or attending site inspections. I require site inspection for most forms of consulting work, including as a consulting arborist or expert witness.
Tree failures, health and risk assessment
Tree and nursery appraisals
Tree roots and infrastructure damage.
Landscape appurtenances creating trip and fall hazard.
Obscured landscape hazards, grade changes
Irrigation operation, maintenance issues
A client wanted me to attend and observe asphalt paving taking place adjacent to an 80 year old Torrey Pine. I had previously consulted on preserving this tree during construction on an adjacent property. The client was repaving his driveway on the alley, the pine is right on the edge of the paving.
Due to California stay at home orders, I informed the client I could not be present to observe the paving to make recommendations, so we used the Facetime app and did an online site observation whereby I watched in real time as the work was being performed. I was able to give the client recommendations in real time.
Moistened towel protect surface roots
He was concerned about root damage, and rightly so. Some of large buttress roots would be impacted by the paving. Instead of cutting, I recommended covering the roots with wet towels, fabric etc, then placing moistened sand base, then pave over the roots.
Moistened sand placed over protected roots
As terrible as it is, the corona virus has created many new ways for industries to re-invent how they do their business. This was the first time I have attempted on online site inspection and it worked! This may not be applicable for the types of investigations I perform, but there is a great new tool I can use for certain types of investigations during stay at home and even beyond.
Asphalt paving over protected roots
The financial savings for the client are obvious. Travel costs for me to travel to Los Angeles, Orange or Inland Empire typically range from $500 to $1000 or more if hotel stay is required.
Not all inspections can be performed remotely. Forensic investigations that require measurements, excavations, sampling, testing etc may not be applicable.
Since this is new to me, it will take some real time client cases for me to determine how and when I can utilize this new tool.
This is not the first time tree activists have climbed hundreds of feet up old growth redwoods to prevent logging the tree and surrounding trees. It reminded me of a remarkable novel I read called “The Overstory” by Richard Powers. The novel is about people and their interaction with and the affect specific trees and forests.
It primarily focuses on loss of old growth redwoods and firs in the pacific northwest and activists actions to prevent tree and habitat loss. However, the novel was historical, taking place several decades ago. Yet it appears old growth logging in Humboldt county continues to in present.
I recently visited, camped and explored the Jedediah Smith State and National Redwood park, not far from where present day logging takes place. For me, the thought of logging off trees that are hundreds to over a thousand year old is difficult to accept.
We have commercial redwood farms for harvesting lumber. Of course, it does not possess the grain, size, color and characteristics of true old growth redwood trees. If we want future generations to be able to view and experience the incredible creation of a true, old growth tree, we MUST stop logging and preserve this resource.
To was the San Diego Walk to End Alzheimer Disease and it was a moving event. Thousands showed up to support this worthy cause. The walk exceeded the goal of raising over $150,000. Through so many donations, WE managed to raise almost $600, and we were rewarded with a medallion for achieving “Champion Club” status.
It seemed everyone their had a friend of family member affected in some way. The feeling of community and support was very emotional for me. I thought about my mom a lot today, at the end of the walk, I felt really good contributing to the effort. There were great speakers, including the Mayor, and I met and spoke with wonderful people. A shout out to Delores, great talking to you today, good luck on starting your new job Monday!
Well, I have posted pictures of the event, thanks again!