Tree Risk and Premise Liability: Property Owners Beware!

Trees, Premise Liability and Risk Management

My appreciation for trees dates well back to my childhood days spent at summer camp and camping trips with my family. I still remember the distinct fragrance of the California Sycamore trees that provided shade during the summer camp months and wonderful Coast Live Oak trees encountered throughout California hillsides and campgrounds.

As a certified arborist, professional horticulturist, licensed landscape contractor and land development professional, my perspective on tree aesthetics and utility is now tempered by the business reality of liability and the risk trees create. An old specimen tree viewed from a liability perspective is a completely different experience than enjoying the historical or horticultural wonders the tree may present. In fact, when viewed from a risk management perspective, the same wonderful historical or landmark tree could pose a potentially serious safety threat or legal liability. Imagine the beautiful Coast Live Oak above in an urban setting with some of those branches hanging over a vehicle!

Premise Liability and the Property Owner

It is a property owner’s legal duty to maintain their premise in a safe, hazard free condition and that responsibility also applies to the trees on their property. Whether a homeowner, business, or homeowner association, an integrated inspection and maintenance program can reduce an owner’s exposure to expensive negligence lawsuits while improving the aesthetics and health of the overall landscape. Minimizing the potential harm or loss from a tree related accident is a proactive form of tree risk management.

There are two principle forms of risk associated with trees. Whether the tree is located in a public or private setting, there is potential risk for the tree to cause physical harm or property damage. Typically, it is the public at greatest risk for experiencing harm caused by a tree failure. There is also the financial risk borne by the Owner caused by the potential failure of the tree or tree part.

While many municipalities focus on the financial risk associated with tree failure, owners should focus on the risk of physical harm as the reason and foundation for developing an effective risk management program. Unfortunately, there are no existing inspection standards for tree hazard or risk management in the United States. Jurisdictions implement their own standards, trade associations such as the International Society of Arboriculture (ISA) and American Society of Consulting Arborists (ASCA) are working toward standardization of specifications, techniques, and risk evaluation, but it is still a matter for each property owner to monitor and care for their trees, preferably before they become a legal liability.

Tree Protection Plans During Construction and Development

In San Diego County there is a community that was developed in an existing and enhanced Eucalyptus tree forest. What appeared a great idea 30 or 40 years ago to create an urban Eucalytus forest surrounding a residential suburban community now appears to be a risk management nightmare as 100’ plus tall, 24”-36” diameter Eucalyptus trees drop limbs or suffer complete structural failure falling onto adjacent homes and unfortunately, killing and injuring the public.
In the past, when land was under mass development, existing trees were paid little attention other than objects to be removed during grading. In some instances, specimen trees may have been transplanted and relocated, trees retained in the landscape were usually neglected or had minimal devices installed to protect the tree during development. When a property is under development, the focus is on grading and infrastructure, utilities and street improvements, protecting existing trees is usually overlooked or a very low priority.

With time and recognition of the value and aesthetics trees create, development and politics have combined to create new incentives to preserves trees. The public clamors for “green” improvements in sustainability and now demands trees be retained and preserved. Unfortunately, in some cases the pendulum has now swung to the opposite extreme, whereby the public or property owner is insisting on preserving a potentially risky tree without realizing the potential consequences.

That is why it is imperative to protect and preserve existing trees in a construction zone to ensure their overall health and vigor during and after the construction process and to prevent the tree from becoming a future liability due to damage caused during construction. Most people might not notice symptoms of tree decline caused by construction activities. Without proper protection, tree roots may be damaged by soil compaction or grade change. Trees are often damaged by construction equipment striking limbs or scraping the trunk. Utility trenches cutting across or through root tree root systems seriously undermine the mechanical stability of the tree while compromising the trees ability to absorb water and minerals from the soil.

In instances where historic or specimen trees were retained in and around development, those trees eventually had to be removed due to declining health conditions and the increased risk these trees possessed. Had they been better protected during the development process, there would have been increased likelihood of successful retention of these valuable assets.

Managing Tree Risk Through Policy and Action

Let’s define a policy as a line of argument used to rationalize a given course of action. From an ownership standpoint, having a documented tree risk policy is extremely important. The policy provides a clearly defined direction and course of action for managing the risks associated with tree resources or assets. If a tree failure results in a legal action, having a documented policy is the basis for a legal defense. By having a tree risk management policy, Ownership demonstrates their legal duty to maintain their trees to protect the public and the actions they took to address the risk. Obviously, having a tree risk management policy is better than having no policy at all.

While a policy and procedures are best management practices for larger businesses and homeowner associations, an individual property or homeowner can benefit from a simplified annual inspection and maintenance program without having to have a written tree risk management program. By having a certified arborist inspect the trees annually and implementing the recommendations made in the inspection report, a property owner is demonstrating their duty to protect the public and reduce the risk associated with trees on their property. In so doing, the owner is building a basis for a legal defense in the event of tree related litigation.

Whose Duty is it Anyway?

Owners who think a tree failure is considered an Act of God as a defense will find this to be untrue. Courts across the country have found property owners have the duty to inspect, maintain and correct hazardous tree conditions that inhibit line-of-sight. There has been a natural progression toward statutes that deal with premise liability and the duties owed to guests and the public regarding “foreseeable” problems from trees.

Over time, the legal industry has worked to extend this duty or responsibility to developers, builders, property managers and other property professionals, including those who act in a property owner’s stead. If you work as an agent for an owner, you could find yourself having inadvertently taken on the “duty to inspect” and increased your exposure to a liability lawsuit.

The legal duty for property owners or those acting in their stead to protect visitors, workers, guests, pedestrians or vehicles from hazardous conditions exists in many states. Acknowledgement of this duty is witnessed in the daily maintenance activities and repairs made to fences, sidewalks, walls, gates, building edifices and more. Obstructions are cleared in sight line corridors to insure traffic flow and safety. In many states, the same duty to protect the public has been extended to trees and their appropriate maintenance requirements.

A routine annual tree inspection can in theory, be performed by anyone. However, many tree problems are difficult to detect and require a trained professional to identify hidden deficiencies. A knowledgeable arborist should perform a visual tree assessment, including tree identification, growth characteristics, size, tree biology, and site specific environmental influences. Most importantly is the risk evaluation of a specific tree branch, limb or complete tree failure and risk of harm to any surrounding potential target(s).

Managing Tree Risk

The tree above was a 10-ton Erythrina (Coral tree) that fell and crushed the car below. The tree was noted to have lost a limb earlier but was not properly inspected, nor was the risk abated.

Trees pose a risk only when there is a target. A target can be a person, animal, property, vehicle; almost anything of value can be considered a potential target.
In the urban forest, trees are located in immediate proximity to people, buildings, vehicles, and countless moving and stationary targets. Sites requiring special attention due to increased risk include parks, schools and playgrounds, campuses, golf courses, athletic fields, and adjacent buildings. While the simplest means to reduce risk is to remove the target, that is not a practical reality in most urban settings. Therefore, an active risk management plan or policy will help reduce the risk of your trees causing a serious accident or injury resulting in a lawsuit.

  1. Schedule an annual visual tree inspection and hazard evaluation by a certified arborist.
  2. Implement the recommendations made in the inspection report.
  3. For larger properties, consider a risk management policy and program.
  4. For larger sites, implement a tree inventory log, noting identification, location, size, health and special characteristics of all site trees.
  5. Work with a certified arborist trained in visual tree assessment and tree hazard evaluation.
  6. Maintain written records, pictures and documents that support your efforts to maintain and protect the public from tree related hazardous conditions.


There are certain “red flags” used in visual tree assessment that you should be aware of. If you notice any of the following symptoms on your trees, contact a tree professional immediately:

  • Large holes, fissures and cracks in the tree trunk
  • Obvious areas of rot or decay including tree hollows
  • Presence of birds, insects, ants etc streaming into tree openings
  • Broken branches, dead and hanging limbs
  • Sucker or aberrant growth
  • Conks, mushrooms or fungi fruiting bodies at base of tree or on trunk
  • Any line of sight obstruction

Although a property owner may not want to know, thinking ignorance of a condition eliminates potential liability, our judicial system continues to find owners have a duty to inspect and maintain their properties and ignorance of a hazard is not an adequate defense.

The benefits of implementing an annual tree inspection and maintenance:

1. Increase in tree aesthetic appearance, health and vigor.
2. Increase in tree and property value.
3. Reduction in tree hazard risk.
4. Foundation for a legal defense.

An ounce of prevention is worth a pound of cure. Using a certified arborist for an annual tree inspection and monitoring program is an effective means to reduce tree hazard risk while improving the health and vigor of your investment. Just as you maintain your home, vehicles and other physical possessions, trees grown in the urban environment must receive the proper care and maintenance to keep them in a healthy, vigorous and safe condition.

Article Acknowledgments:
Mr. Mark Duntemann, Natural Path Urban Forestry, Seminar on Tree Risk Management, August, 20, 2010.
Premise Liability and Your Trees, by Petger S. Beering, Esq. and Judson R. Scott, RCA #392, American Society of Consulting Arborists, #3, 2010

What Will be the Development Future for Balboa Park?

Like many citizens of the City of San Diego, I have been closely monitoring proposals for the redevelopment of Balboa Park.  For those who might not be aware of this  situation, the Plaza de Panama  committee plan proposed changes to Balboa Park including removing vehicles and free parking within the park where they are now allowed and replace that with paid parking structures.  Included in the plan is construction of a 400 foot bridge extension and freeway like transition road from the historic Laurel / Cabrillo bridge for visitors to access the new parking structures.  The idea was to finish construction in time for the centennial celebration of 1915 Panama-California Exhibition, the reason Balboa Park first came into existence.

SOHO, (Save Our Heritage Organization), filed suit two years ago to block the city from proceeding with the proposed design.  On February 4, 2013, SOHO claimed a great victory when Superior Court Judge Timothy Taylor ruled the City Council violated municipal code and utilized “faulty logic” in approving the Plaza de Panama Committee plan last July, 2012.  Judge Taylor ruled the City “abused its discretion” in approving the project and ruled to set aside the project’s required Site Development Permit.

Key to the ruling was according to municipal code for historic sites, the City was required to find that the project site would otherwise have “no reasonable beneficial use” in order to have the permit approved.  Obviously, Balboa Park has a great deal of “beneficial use” without the permit issuance, which the City seemed to ignore in their decision to proceed with the committees recommendation, perhaps the reason Judge Taylor deemed City Council had “abused it discretion”, used “faulty logic” and held that “the critical finding by the City Council is so lacking in evidentiary support as to render it unreasonable; it must therefore be set aside”.

Balboa Park is a rare and extraordinary site located in the urban center of San Diego.  This has been a free “peoples park” for locals and tourists for generations.  Supporters of the Plaza de Panama project contend it would reclaim the park from cars that currently drive through the park to reach parking lots.  Opponents to the plan claim while one small area of cars would be freed up, the remainder of the park would be dominated by traffic, new buildings and acres of concrete parking lots.  Tranquil Alcazar Gardens would become an automobile, bus and delivery zone.

With so much as stake for one of San Diego’s most important, historic and enduring landmarks, why has the City of San Diego failed to find an agreeable compromise?  Balboa Park is a historic resource that should be protected and sensibly improved to benefit  ALL the citizens of San Diego, not just special interest groups or donors such as Mr. Jacobs, who pledged to donate $30 million for improvements, but only using the Plaza de Panama plan, in other words, the philanthropic donation had political strings tied to it.  Not much of a philanthropic gesture in my opinion.  If Mr. Jacobs is truly interested in improving Balboa Park for ALL citizens, tourists and park visitors, he donation should not be tied to a specific design.

While I have spent a career working in land development, I am also a proud citizen of San Diego and I do not want to see the historic Cabrillo bridge turned into a freeway, and do not want to see the western historic architectural facade of the existing buildings destroyed because of a poorly conceived traffic circulation plan.  There are better alternatives available and the City Council needs to stop considering free donations with strings attached as the reason for choosing one alternative plan over another.

Balboa Park was conceived and developed as a free park for all citizens to enjoy.  That was the original intent, we should honor that objective in careful deliberation about the future of how to thoughtfully redevelop the park for future generations.  Lets not rush to a limited decision so we can have a park renovated in time for the centennial.

Click to read the full SOHO article, SOHO Wins! Balboa Park Saved!

RDCS certified small business

Rappoport Development Consulting Services received approval from the California Department of General Services as a certified small business (SB).  Each certified SB receives a five percent (5%) bid preference on applicable solicitations.  Master
consultants and general contractors bidding California public works projects may receive a 5% preference using a RDCS LLC as a certified arborist sub-consultant.

In related news, with the certification of RDCS LLC as a small business, RDCS LLC is an approved A&E Bench Consultant for SANDAG projects.  Master consultants choose to seek certified arborist sub-proposals from RDCS LLC for SANDAG public works projects throughout San Diego county.  This is a tremendous benefit for master environmental and engineering consulting firms to add RDCS LLC to list of qualified certified arborist sub-consultants.

Environmental and Engineering firms working on large transportation, utility, and infra-structure public works and private improvement projects often times experience issues related to existing trees located in the path of or adjacent to public and private improvement projects.  When this occurs, agencies may require using a certified arborist as a sub-consultant.

As a sub-consultant to environmental and engineering firms, as well as general contractors, RDCS LLC provides multiple consulting services including:

  • Tree Inventories
  • Tree risk and health assessment
  • Tree construction protection and preservation plans
  • Tree Best Management Practices (BMP’s)
  • Tree appraisals.
  • Tree risk and tree management plans.
  • Field monitoring, inspections, supervision

General Consultants and Contractors can now benefit by having a professional, certified arborist consultant and receive a 5% bid preference using a  California certified small business

Give Jeremy Rappoport a call at 858-205-4748

State of CA. SBE Certification03072012_00001

Construction Development Versus Oak Trees: Can the Two Co-Exist?

I had the good fortune to be selected as the project arborist for a portion of the San Diego Gas and Electric Sunrise Power Link Project. This is a high voltage energy transmission project bringing an additional source of electricity to the San Diego County area and supplementing the California energy grid. The transmission lines bring energy from the desert southwest into and through San Diego County backcountry.

The portion of the project I consulted on is known as the Suncrest Substation, located at the edge of the Cleveland National Forest just east of Alpine, California. Beta Engineering was the design/build general contractor awarded the contract for constructing the substation for SDG&E. Since the substation was located three miles from the nearest paved road, a three mile construction and operations access road needed to be developed.

In order to build the access road, SDG&E obtained road easements with private land owners to grade and build the access road. However, due to the presence of hundreds of existing Coast Live Oaks and Engelmann Oaks, the property owners required a certified arborist be present before and during construction to make recommendations and implement best management practices to preserve and protect the oak trees during road grading and construction.

Beta Engineering selected Rappoport Development Consulting Services LLC as their independent certified consulting arborist for the Suncrest Substation construction project.

The following article describes the project and how Jeremy Rappoport, an ISA certified consulting arborist designed and implemented best management practices for oak tree construction preservation.

Construction Development Versus Oak Trees:

Can the Two Co-Exist?

Rappoport Development Consulting Services LLC recently completed a project providing independent certified arborist consulting services for Beta Engineering, a design build general contractor awarded the construction contract for the Suncrest Substation, a portion of the San Diego Gas and Electric Sunrise Power link Project. The Suncrest Substation is located east of Alpine, California adjacent to the Cleveland National Forest, approximately 40 miles east of San Diego.

The substation project included developing a 2.5-mile access road for constructing the substation and for ongoing operations and maintenance once completed. The access road runs 2.5 miles through private land used for ranching and recreation. The rugged hills and mountains contain many native California plant species and areas of relatively undisturbed native habitat.

To reach the future substation site, the access road had to be constructed on land containing many native oak trees, including Quercus engelmannii andQuercus agrifolia. The Engelmann oak and Coast Live Oak, both native to California, thrive in the hills, canyons and mountains in eastern San Diego County.

The Engelmann and Coast Live Oaks ranged from 50 to 250 years old, with some magnificent Engelmann specimens displaying 42-inch diameter trunks.

While the Engelmann oaks appeared in relatively good health, the Coast Live Oaks (Quercus agrifolia) showed symptoms of Gold Spotted Oak Borer (GSOB), infestation including crown thinning and dieback, with major trunk and vascular system damage. Fortunately, the Engelmann oaks did not display any signs of bark beetle infestation.

In an effort to minimize tree loss due to construction impacts, the road was surveyed and redesigned several times. Even with the best efforts of the design team, many oak trees had to be removed for construction. Additionally, there were several hundred oak trees adjacent to the construction zone and road easement that would be impacted by construction activities.

Since Beta Engineering was the GC responsible for grading and improving the access road, they were also responsible for protecting and preserving oak trees immediately adjacent to the construction zone. Beta Engineering was required to provide an experienced, certified consulting arborist to implement an oak tree construction preservation plan and provide monitoring and recommendations throughout the access road construction time period of approximately one-year.

Beta Engineering selected Rappoport Development Consulting Services LLC as the certified consulting project arborist. The first site visit revealed beautiful, relatively undisturbed natural terrain. Since the access road was built within an easement on private land, much of the area has been protected by development, resulting in large oak trees and other native species including Ceanothus, Manzanita, Rhus and Malosma.

Pre-Construction Panning

Pre-construction tree protection planning is mandatory to achieve success in the design and implementation of a protection plan. The scope of the assignment was:

  • Review and amend the existing tree inventory with current site data.
  • Analyze grading, improvement and tree survey exhibits, determine and rate the extent of adjacent construction impact to the trees.
  • Design best management practices (BMP’s) and specifications to minimize construction impacts.
  • Provide field inspections and observations prior to and throughout the construction period. Make job site recommendations as required.
  • Develop a final report summarizing the results of the project.

Using an existing tree inventory and survey maps identifying tree locations, pre-construction field inspections compared this information with the survey stakes located in the field. Current field status was updated in the tree inventory, including digital photographs and the tree condition.

The importance of pre-construction planning is crucial for a successful tree protection plan. Tree protection best management practices generally work far better when implemented before heavy equipment and grading operations begin.

With a complete understanding of the field and tree conditions and upcoming construction schedule, RDCS LLC developed best management practices for the general contractor to implement and distribute to their sub-contractors and consultants.

General pre-construction recommendations included erecting barriers and fencing to define the workspace from the tree protection zone. A primary concern was protecting the root zone from mechanical damage and soil compaction. Warning signs were specified at regular intervals. Crown and canopy pruning specifications were designed and implemented to achieve vertical and horizontal clearance for large trucks and equipment while avoiding mechanical damage to oak tree limbs and branches.

Best management practices to minimize impacts to the oak trees during construction included placing mulch layers to reduce soil compaction, adjustments to changes in grade to minimize root disturbance and root pruning to reduce mechanical damage to roots caused by grading equipment. During the summer months, the trees canopies were rinsed by water truck to remove accumulated dust from construction activities.

Grading Impacts:

Due to site topography, the access road was constructed along slope side contours. To achieve a level roadbed through a hillside contour, one side of the road was a cut resulting in a 2:1 upslope from the edge of road to the top of slope. A concrete lined brow ditch was constructed at the top of the slope.

The other side of the road required a fill slope that resulted in a down-slope from the edge of the road to the bottom of the slope.

There were several storm drain crossing that conveyed water under the road in storm drain culverts to the downhill side of the road where the water “day-lighted” out of the toe of slope and ran in free flowing creeks. Therefore, construction impacts were anticipated where storm drain inlets and outlets were constructed.

Due to slope cuts and fills, the existing oak trees were threatened with several impacts. The trees on the cut slope side of the road would suffer from mechanical damage to their roots from grading and brow ditch cuts into the slope. Many trees contained low scaffold branches that would be damaged by grading equipment. Tree impacts on the fill slope side of the road included root disturbance and suffocation by placing fills soils over the existing surface grade.

During grading construction, very heavy grading equipment would result in soil compaction in the adjacent tree root zone.

Construction Monitoring and Supervision

In addition to developing and implementing best management practices for oak tree preservation, another project assignment included supervising the grading sub-contractor responsible for oak tree crown and root pruning activities. The grading contractor sub-contracted the tree pruning work to a professional tree service. The grading contractor utilized in house employees for root pruning laborers.

Rappoport Development Consulting Services LLC supervised both above grade crown and canopy pruning and well as below grade root pruning. With the advent of the raptor-mating season, all tree crown pruning had to be completed no later than December 31, 2010. Gaining vertical vehicular access road clearance was the main objective and reason for crown pruning. Therefore, crown pruning included skirting up low lying limbs to achieve seventeen feet vertical clearance from the future finish road surface. Horizontal clearance required pruning back any growth to prevent encroachment into the right of way. Crown reduction and selective limb removal were the main crown pruning techniques used to satisfy access specifications. One had to be experienced in reading survey stakes to understand where the finished road surface would be in relation to the existing tree limbs.

Due to the age and maturity of the oaks, many trees had very large scaffold branches ranging up to sixteen inches in diameter. Unfortunately, several large limbs had to be removed to achieve the required clearances. In those instances, cuts were carefully selected and made well outside the branch collar to provide as much protection for the tree to compartmentalize the wound. Dead wood was removed as required.

The root pruning work included both mechanical and hand trench excavation starting from the outside edge (drip line) of an individual tree crown or a stand of oak tree canopies. The trench was located between the outside edges of the grading work adjacent to the trees. Most of the tree rooting occurs in the upper twenty-four inches of the soil profile. Therefore, the trench specifications were approximately eighteen inches wide (wide enough to accommodate a laborer and shovel) with an average depth of thirty inches. In some cases the trench excavation extended to thirty-six inches. Approximately 80% of the roots were encountered above twenty-four inch depth.

The goal with root pruning is to avoid construction and mechanical damage to the root system by trenching and cutting roots prior to heavy equipment making grading cuts that would severely damage adjacent tree roots. Once the root pruning is employed, grading equipment can then excavate and pull the cut roots out without mechanically tearing the roots, thereby minimizing root disturbance and tree shock.

The objective was to expose roots, cut and remove roots crossing through (perpendicular) to the trench. As the trench deepened, roots up to six and eight inches in diameter were cut throughout the entire trench profile. Large diameter roots were cut with a sharp chainsaw, smaller size roots were cut with sharp tree loppers. Once all of the roots were cut, the trench was backfilled and grading proceeded up to the trench cut.

Monitoring and Data Collection

The tree crown pruning started in December of 2010 with grading operations beginning in February of 2011. Root pruning began with grading and was completed by March of 2011. Oak tree monitoring began prior to construction in November of 2010 and the final monitoring occurred prior to paving in September of 2011.

During the access road design, the consultant team rated potential damage to the tree based on the percentage system below:

Status of the Tree:

% Damage to the Tree:

Preservation Category:

1. Save the treeNo damageTree is considered preserved
2. Save the tree, minor pruning requiredUp to 25% damageTree is considered preserved but affected
3. Save the tree, major pruning requiredOver 25% damageTree is not considered preserved
4. Remove the tree100% damageTree is considered a loss

The consultant team defined tree damage as any physical alteration of the tree caused by proposed construction, including branch and root pruning, grading within the root zone, removal of one or more multiple trunks. The determination of the percent damage is a judgment made by the arborist at the site during construction and the amount of disturbance to the individual trees and considers roots, trunks, branches, and crown.

Tree monitoring was implemented based on seasonality and for job specific construction events. All of the monitoring utilized visual observation and digital photographic record keeping. While monitoring, many types of data were collected. Much of the data was relative, comparing the tree health and condition from the original tree inventory to the current monitoring event.

The main categories in the tree-monitoring log examined items such as:

  • Tree category designation
  • Whether crown pruning occurred
  • Whether root pruning occurred
  • Trunk or root damage occurred
  • Spring defoliation and flush
  • Crown and leaf appearance
  • Comments on edge condition, wound response, presence of Gold Spotted Oak Borer (gsob) and general appearance
  • Photographic identification number

Comparisons between monitoring events examined:

  • Reaction to crown and root pruning
  • Signs of crown decline or dieback
  • Signs of new buds and growth
  • Spring flush, color and density
  • Leans or stability issues from root pruning
  • Overall tree health, vigor or decline
  • Current construction impacts
  • Punch list and corrective actions

The oak tree preservation and monitoring program was designed to minimize construction impacts to the trees and monitor the tree response over a period of time. The program did not include tree risk assessment for structural integrity, risk to the construction workers, the public or property, nor did the program address recommendations for the tree Owners to correct noted existing deficiencies.

The project construction timing may have benefitted the trees. The crown and root pruning occurred during the winter months, a time of slow metabolic activity for the oak trees. The grading disturbance began in early spring, approximately the same time many of the Engelmann oaks dropped their old leaves from the previous season and began their spring flush of new growth. The weather also cooperated in that San Diego county experienced above normal rainfall for the year, resulting in elevated water tables for the trees, keeping soil moisture conditions relatively high, even throughout the hot, dry summer months.


Of the 369 trees inventoried and monitored during the program, no trees were lost. However, at least three to five trees exhibited signs of crown decline and foliage discoloration. Symptoms of tree decline from construction impacts may take up to three to five years to fully manifest. Therefore, full knowledge of successful survivorship will not be known for another two to three years.

That being said, it was very encouraging to see these ancient oaks survive at least during the heavy construction phase. Pruning cuts on limbs from four to twelve inches in diameter showed signs of healing and minimal evidence of decay. The trees dropped their foliage in the spring and displayed a nice spring flush of growth by the June monitoring. Yellowing and discolored foliage with browning of tips and margins was a typical foliage symptom. The fact the trees put out a healthy spring flush following crown, root pruning and grading operations, followed by a successful growing season was a positive sign.

Trees that appeared stressed in March re-foliated and displayed improved general health in June. More importantly, the trees survived throughout the hot summer months and did not defoliate as of observations made in September of 2011.

The ultimate success of the oak tree preservation program cannot be fully assessed until a sufficient time period has elapsed whereby the trees exhibit typical healthy growth patterns without signs of increasing or ongoing decline. The minimum elapsed time period for a final health assessment would be three years from date of construction impacts or March of 2014. This would provide three full years of “non disturbed” growth and allow trees to either fully recover or decline. Trees that continue to decline after three years most likely have entered the “tree death spiral”, a condition whereby the tree is unable to recover from injuries incurred during construction and are a total loss.

Unfortunately, the contract with Beta Engineering expired and the continuing status of the oak trees is no longer available to RDCS. Based on current survivorship and tree health, upwards of 369 Quercus engelmannii and Quercus agrifolia were persevered due to protection and preservation best management practices.

While final results will not be known for another year or so, the oak tree preservation program was determined to be a major success by both the general contractor and the client, San Diego Gas and Electric.

It was very gratifying to see the various project stakeholders acknowledge the importance and value in preserving as many native oak trees as possible balanced with the project transmission and sub-station objectives. While a certain percentage of the oaks may fail from the construction impacts over a period of time, a great majority of the trees were saved through careful preservation and protection best management practices.Therefore, the answer to the question, can development and oak tree preservation co-exist, I believe the answer is yes.

The importance and value in preserving and protecting trees has gained awareness with the “green movement” and creating sustainable environments. Tree benefits and their inherent value figure prominently in construction and development projects. Hopefully, public, owner and agency awareness about the positive value of saving, preserving and protecting native and heritage trees will continue to grow.

We all need to be responsible stewards of our planets diminishing resources. Knowing these oak trees survived during construction of a major electrical transmission and substation construction project and will be seen by future generations is a very rewarding experience.