Tree Protection, Removal & Relocation in Los Angeles Residential Construction

Los Angeles has among the most protective tree ordinances of any major city in the United States. The City of LA's Protected Tree and Shrub Regulations, codified in LAMC Sections 46.00 through 46.06, restrict the removal, relocation, and even the indirect damage of specified native species on both public and private property. For residential construction projects, this means trees are not simply a landscaping consideration. They are a regulatory, structural, and scheduling issue that can fundamentally reshape a project if not identified and addressed early.

Last updated: March 2026

WHY TREES MATTER ON LA CONSTRUCTION PROJECTS

On hillside lots throughout the Santa Monica Mountains, Pacific Palisades, Bel Air, and Malibu, mature coast live oaks and Western sycamores often sit exactly where the building pad, driveway, retaining walls, or utility trenches need to go. A single large oak with a 40-foot canopy diameter creates a tree protection zone that can consume a significant portion of a 50-foot-wide lot. That protection zone is not a suggestion. It is a regulated area where construction activity is restricted, heavy equipment cannot operate, and grade changes are prohibited without arborist supervision and city approval.

The intersection of trees with other site systems is what makes this topic consequential for project planning. Tree root zones conflict with foundation design. Canopy spread constrains crane swing and concrete pump placement. Tree protection zones limit grading operations and can force redesign of retaining wall alignments. Utility routing has to work around root zones rather than through them. And the permitting timeline for protected tree removal or relocation - typically 90 to 120 days from a complete application - adds months to the front end of a project if it was not anticipated during pre-construction.

LA'S PROTECTED TREE ORDINANCE - THE REGULATORY FRAMEWORK

The City of Los Angeles regulates protected trees and shrubs through Article 6 of Chapter IV of the Los Angeles Municipal Code (LAMC Sections 46.00 through 46.06), as amended most recently by Ordinance No. 186,873, effective February 4, 2021. Additional provisions governing protected trees in the context of subdivision and land development projects appear in LAMC Sections 12.21 and 17.02 through 17.06. Together, these provisions establish which species are protected, what actions require a permit, and what conditions the city imposes when removal or relocation is approved.

Protected Species

The following Southern California native tree species are protected under the City of LA ordinance when they measure four inches or more in cumulative trunk diameter at a height of four and one-half feet above the ground (referred to as Diameter at Standard Height, or DSH):

• Oak trees (Quercus spp.) - including California live oak (Quercus agrifolia), valley oak (Quercus lobata), and any other tree of the oak genus indigenous to California, excluding scrub oak (Quercus berberidifolia)
• Southern California black walnut (Juglans californica)
• Western sycamore (Platanus racemosa)
• California bay laurel (Umbellularia californica)

The 2021 amendment (Ordinance 186,873) expanded protections to include two native shrub species:

• Mexican elderberry (Sambucus mexicana)
• Toyon (Heteromeles arbutifolia)

These shrubs are subject to the same permitting requirements as protected trees when they meet the four-inch cumulative diameter threshold. Protected trees and shrubs grown or held for sale by a licensed nursery, or planted as part of a tree planting program, are excluded from the definition.

Coast live oaks are by far the most commonly encountered protected species on residential construction projects across the Westside and in the hillside communities of the Santa Monica Mountains. They are long-lived, they develop extensive root systems, and mature specimens can have canopy spreads exceeding 60 feet. Western sycamores are common along drainages and in canyon bottoms. Black walnuts appear on properties throughout the foothills and inland valleys. California bay is less common but appears on hillside lots with north-facing slopes and canyon microclimates.

What Counts as "Removal"

The ordinance defines "removal" broadly. It includes not only cutting a tree down but any act that will cause a protected tree or shrub to die. The specific language in LAMC Section 46.00 lists damage to the root system or other parts of the tree by fire, application of toxic substances, operation of equipment or machinery, or changing the natural grade by excavation or filling within the drip line area around the trunk. This definition is important because it means a protected tree can be "removed" under the ordinance without anyone ever taking a chainsaw to it. Grading that cuts through major roots, compaction from heavy equipment operating within the root zone, or raising the grade with fill soil that suffocates the root system can all cause a protected tree to die over the following months or years - and each of those actions constitutes removal under the code.

The Permitting Authority

Protected tree permits in the City of LA are issued by the Board of Public Works through the Bureau of Street Services, Urban Forestry Division (UFD). The Urban Forestry Division is located at 1149 S. Broadway, Suite 400, Los Angeles, CA 90015, and can be reached at (213) 847-3077. The UFD reviews protected tree reports, conducts site inspections, and issues permits for removal and relocation of protected trees on private property.

For projects that involve discretionary planning entitlements (conditional use permits, zone variances, tract maps), tree issues are also reviewed by the Department of City Planning, which may impose its own conditions related to tree preservation and replacement as part of the entitlement process. Los Angeles City Planning publishes a Tree Report Form (CP-4068) that provides a standardized format for the required tree inventory and impact analysis.

The Replacement Requirement

When the city approves the removal of a protected tree, the current Board of Public Works policy requires replacement at a 4:1 ratio - four replacement trees of a protected species for every one tree removed. Each replacement tree must be at least a 15-gallon specimen, measuring one inch or more in diameter at one foot above the base, and at least seven feet in height. Protected trees can only be replaced with other protected tree species, not with ornamental or non-native varieties. Similarly, protected shrubs must be replaced with other protected shrub varieties.

When the removal involves more than two protected trees or shrubs, the permit must be considered at a full public hearing before the Board of Public Works, which adds time and public notice requirements to the process.

In-Lieu Fees

When a project site cannot feasibly accommodate the required number of replacement trees - which is common on smaller lots or sites where the building footprint leaves insufficient planting area - the property owner can pay an in-lieu fee to the city's tree planting fund. The current in-lieu fee for private residential development projects is approximately $2,600 per tree. The fee for residential non-development removals (not associated with a larger construction project) is approximately $1,950 per tree. These fees are set by the Board of Public Works and are subject to periodic adjustment.

Penalties for Unpermitted Removal

The consequences for removing a protected tree without a permit are significant. Under LAMC Section 46.06, the Bureau of Street Services has the authority to request that the Superintendent of Building withhold issuance of building permits for the property for up to ten years and to revoke any building permit for which construction has not commenced. The city has exercised this authority, and the practical effect is that unpermitted removal of a protected tree is one of the most disruptive regulatory violations a residential project can trigger. The ordinance provides for notice, hearing, and a finding process before these penalties are imposed.

Other Jurisdictions

The City of LA ordinance is the baseline for most of the Westside market, but it is not the only set of rules in play. Many of the communities where complex residential projects are built have their own tree protection ordinances with different species lists, different size thresholds, and different permitting procedures.

WHEN TO IDENTIFY TREE ISSUES - THE SURVEY AND ASSESSMENT PHASE

The tree survey should be one of the first site investigations ordered on any residential project in Los Angeles where mature trees are present on the property. It belongs in the same initial round of work as the topographic survey, the geotechnical investigation, and the preliminary title review. Tree issues discovered after design is well advanced or after permits have been submitted can force significant and expensive redesign. Tree issues discovered during grading are worse.

The Tree Survey

A tree survey is a field inventory of every tree on the property above a specified size threshold, conducted by a qualified arborist. For properties within the City of LA, the survey should inventory all trees, not just those suspected to be protected species, because species identification in the field is not always straightforward and because even non-protected trees above eight inches in trunk diameter may trigger mitigation requirements under CEQA or as conditions of discretionary planning approvals.

A thorough tree survey includes species identification for every inventoried tree, trunk diameter measured at standard height (DSH, 4.5 feet above natural grade), canopy diameter and spread mapped relative to the property, health and structural condition assessment, root zone estimation, GPS coordinates or surveyed locations tied to the topographic survey, and photographs of each specimen. The survey data is then plotted on the site plan so that the architect, structural engineer, and construction manager can see exactly where protected trees are located relative to the proposed building footprint, grading limits, retaining walls, utility routes, driveways, and construction access.

Who Performs the Work

The City of LA requires the tree report to be prepared by a "Tree Expert" as defined in LAMC Section 17.02 and Ordinance 186,873. A Tree Expert is a person with at least four years of experience in transplanting, moving, caring for, and maintaining trees who holds one or more of the following credentials: a certified arborist with the International Society of Arboriculture (ISA) who also holds a valid California license as an agricultural pest control advisor, a landscape architect licensed in California, or a registered consulting arborist with the American Society of Consulting Arborists (ASCA).

In practice, most protected tree reports on residential construction projects in LA are prepared by ISA-certified arborists who specialize in construction-related tree work. The distinction between a general arborist who primarily does tree care and pruning and one who regularly prepares reports for construction projects and navigates the Urban Forestry Division permitting process is meaningful. An arborist experienced with construction projects will understand the engineering constraints, can communicate effectively with the structural engineer about root zone conflicts, and knows what the UFD reviewer expects to see in the report.

Arborist Report Contents

The Protected Tree Report (PTR) submitted to the Urban Forestry Division or City Planning must include a comprehensive tree inventory table with species, size (DSH), height, canopy spread, physical condition, and health rating for each tree. It must identify which trees are protected under the ordinance, which are proposed for removal, which are proposed for relocation, and which will be retained in place. For trees proposed for removal, the report must state the reason, such as location within the construction footprint or inability to feasibly redesign around the tree. For trees to be retained, the report must include a tree protection plan specifying the measures that will be taken during construction.

The report must also include a tree replacement plan identifying the species, size, and proposed locations of replacement plantings, and a calculation of any in-lieu fees if on-site planting cannot accommodate the required replacement ratio. Color photographs of each tree are required, with a minimum photo size of 5 by 7 inches. The survey must be plotted on an 11-by-17-inch topographic site plan with protected trees color-coded by species per UFD standards: oaks in yellow, Western sycamores in blue, California bay in green, black walnuts in orange, Mexican elderberry in pink, and toyon in brown. Trees proposed for removal are circled in red.

The tree report must be current. City Planning requires that the field visit be conducted within the last 12 months. An older report submitted with a permit application will need to be updated.

Health Assessment

The arborist evaluates each tree's health through visual assessment of canopy density, leaf color, presence of deadwood, fungal fruiting bodies on the trunk or root crown, trunk cavities, bark condition, lean and structural defects, and signs of pest infestation or disease. For trees where more detailed information is needed - particularly when the question is whether a tree is healthy enough to survive relocation or whether it is structurally sound enough to preserve near a structure - the arborist may recommend additional diagnostic methods. Resistograph testing uses a thin drill bit to measure wood density and detect internal decay that is not visible from the outside. Sonic tomography creates a cross-sectional image of the trunk to map the extent of decay. Aerial inspection by a climbing arborist allows close examination of upper canopy defects that cannot be assessed from the ground.

A tree that appears healthy from grade level may have significant internal decay that makes it a poor candidate for relocation. Conversely, a tree that looks rough - sparse canopy, some deadwood, visible trunk wounds - may actually be structurally sound with years of life ahead. The arborist's professional assessment, not the tree's visual appearance, is what drives the project decisions and what the city relies on for permitting.

TREE PROTECTION DURING CONSTRUCTION

When protected trees are being preserved in place rather than removed or relocated, the project must implement and maintain a tree protection plan for the duration of construction. The tree protection plan is part of the arborist report and becomes a condition of the permit. Compliance is not optional, and the city can inspect the site at any time to verify that the plan is being followed.

Tree Protection Zone

The Tree Protection Zone (TPZ) is the defined area around a protected tree where construction activity is restricted. How the TPZ is established varies by jurisdiction and by the arborist's professional judgment for the specific tree, but the most common methods are based on either the drip line (the outer edge of the canopy projected to the ground) or a calculated radius from the trunk.

A common rule of thumb is one foot of radius per one inch of trunk diameter. A coast live oak with a 24-inch trunk diameter would have a TPZ extending 24 feet from the trunk in all directions, creating a circular restricted area 48 feet in diameter. For reference, on a typical 50-foot-wide lot in the hillside areas of the Westside, that single tree's TPZ would span nearly the entire lot width. The arborist may adjust the TPZ larger or smaller depending on species, root distribution, soil conditions, and the specific construction activities proposed. Some species, particularly oaks, have root systems that extend well beyond the canopy drip line, and the TPZ may need to be expanded accordingly.

The fundamental rule is that within the TPZ, no construction activity occurs without the arborist's written approval and on-site supervision. No grading. No excavation. No equipment operation. No material or soil storage. No vehicle parking. No foot traffic beyond what is necessary for arborist access. No changes to the existing grade, either by adding fill or by cutting. The TPZ is treated as an exclusion zone for the duration of the project.

Protective Fencing

The TPZ perimeter is marked with protective fencing before any site work begins. The City of LA requires rigid fencing for this purpose - typically six-foot chain-link on steel posts - not the orange plastic mesh fencing that is commonly used for general construction perimeters. Plastic mesh does not prevent equipment from accidentally encroaching into the TPZ, and it is not accepted as adequate tree protection by the Urban Forestry Division.

The fencing is posted with signage identifying it as a tree protection zone. It remains in place for the entire duration of construction and is not moved or modified without arborist approval. On sites where the TPZ boundary runs close to active construction areas, the fencing takes a beating from equipment maneuvering, material deliveries, and general site activity. Maintaining the integrity of the fencing throughout the project is a day-to-day site management responsibility. Inspectors from the city or the arborist conducting monitoring visits will check the fencing, and documented violations can trigger enforcement action.

Root Protection

On constrained sites, it is common for the construction footprint to encroach into the TPZ. A retaining wall footing, a utility trench, or a driveway subgrade may need to pass through the outer portion of the root zone. When this happens, root protection measures are implemented under the arborist's direct supervision.

Root pruning is performed by hand or with an air spade rather than with excavation equipment. An air spade is a high-pressure compressed air tool that blows soil away from around the roots without cutting or damaging them. It is one of the most important tools in construction-phase tree preservation. The air spade allows the arborist to expose the root structure, visually assess root health and size, determine which roots can be cleanly pruned and which are critical structural or feeder roots that must be preserved, and identify whether roots can be redirected around a foundation or utility line rather than severed.

Once roots are exposed, the arborist makes clean pruning cuts with sharp tools on the roots that must be removed. Clean cuts heal far more effectively than the ragged tears that result when an excavator bucket rips through roots. The arborist then determines whether the remaining root structure is sufficient to support the tree's long-term health and stability. For large trees where significant root pruning is required, the arborist may recommend supplemental watering, soil amendments, or temporary canopy reduction pruning to reduce the tree's water demand while the root system recovers.

Where construction must bridge over a root zone - for example, a driveway or pathway crossing the outer TPZ - steel plates or timber mats can be placed on the existing grade to distribute loads and prevent soil compaction over the roots. Compacted soil reduces the oxygen and water exchange that roots need to survive, and even a few weeks of heavy equipment operating on unprotected soil within the root zone can cause long-term decline in a mature tree.

Grade changes within the TPZ are particularly damaging. Filling over the root zone, even by a few inches, can suffocate roots by reducing oxygen exchange and altering drainage patterns. Cutting below the existing grade exposes and severs roots. Both actions can trigger a slow decline that may not become visible for a year or more after construction is complete, long after the project team has moved on. This is one reason the tree bond and guarantee period exist - they provide a financial mechanism to ensure accountability for tree health well beyond the construction period.

Canopy Protection

On sites where cranes, concrete pumps, or excavators with extended booms must operate near a protected tree, the canopy is at risk from equipment contact. Branches broken by a crane boom or concrete pump arm during a pour are not just aesthetic damage. For a protected tree, canopy damage above the one-third threshold (the ordinance prohibits excessive pruning, typically defined as removing more than one-third of the live canopy) can constitute removal under the code.

Canopy protection measures include wrapping exposed lower branches with protective material, temporary pruning of specific branches under arborist supervision to create equipment clearance (within the allowable pruning limits), and establishing swing restrictions and height limits for equipment operating near the tree. These operational constraints need to be communicated clearly to crane operators, pump operators, and equipment operators on site. The construction manager is responsible for ensuring that site personnel understand the tree protection requirements and that the operational restrictions are enforced.

Arborist Monitoring

Most tree protection plans require periodic arborist monitoring visits throughout construction. The frequency depends on the intensity of construction activity near the protected trees and the conditions of the permit, but weekly or biweekly visits are typical during active phases. The arborist inspects the TPZ fencing, checks for signs of tree stress or damage, verifies that the protection plan is being followed, and documents compliance. These monitoring reports are submitted to the city and become part of the project's compliance record.

The arborist monitoring program is a real cost carried through the duration of construction, which on complex residential projects can span 18 to 30 months or longer. It is also a real benefit, because an experienced construction arborist can identify early signs of tree stress - drought stress, root damage, canopy dieback - and recommend corrective action before the damage becomes irreversible.

Watering and Maintenance

Protected trees may need supplemental watering during construction, particularly after root pruning, during extended dry periods, or when grading and construction activity has altered the drainage patterns that the tree previously relied on. Drought stress during construction is one of the most common causes of delayed tree mortality on residential projects. The tree may look fine at the final inspection, appear healthy through the first year, and then go into decline in the second or third year when the accumulated stress from root loss and reduced water uptake catches up.

TREE REMOVAL - PROCESS, PERMITS, AND REPLACEMENT REQUIREMENTS

When a protected tree must be removed because it cannot feasibly be preserved or relocated given the project scope, the removal requires a permit from the Board of Public Works through the Urban Forestry Division. This is not a fast process, and it is not an automatic approval.

When Removal Is Approved

The city does not grant protected tree removal permits on request. The applicant must demonstrate that alternatives were explored and that removal is the only feasible option. Removal is typically approved under specific circumstances: the tree is dead, dying, or in a hazardous structural condition as determined by a certified arborist; the tree cannot be preserved in place or relocated given site constraints and the proposed development; or the proposed construction cannot be feasibly redesigned to avoid the tree.

The burden of proof is on the applicant, and the review process includes a site inspection by a city arborist from the Urban Forestry Division. The city arborist evaluates the tree's condition independently and reviews the applicant's arborist report and the proposed project plans to determine whether the requested removal is justified. If the city arborist disagrees with the applicant's assessment, the permit can be denied or conditioned on additional preservation measures.

Application and Review Timeline

The application for a protected tree removal permit must be submitted in person at the Urban Forestry Division public counter with all required documentation. Applications are not accepted by email, mail, or fax. The required documentation includes the Protected Tree Report (PTR) with all elements described in the survey and assessment section above, plot plans with trees to be removed highlighted and distances from improvements indicated, clear color photographs of each tree (not satellite or street-view images), and supporting documentation such as approved geotechnical reports, CEQA documents, and planning case information for projects with discretionary entitlements.

The average processing time from the date a complete application is received is 90 to 120 days. That timeline assumes the application is complete at submittal, that the site inspection proceeds without complications, and that the removal does not trigger a public hearing. Incomplete applications are returned and the clock resets.

When the removal involves three or more protected trees, the trees must be posted on site for 30 days prior to removal to allow for public comment. This public notification period is in addition to the review and processing time and must be factored into the project schedule. Neighbor opposition to tree removal can also trigger appeals, which adds further time. For projects with discretionary planning entitlements, the tree removal conditions may be processed as part of the planning case rather than as a standalone Urban Forestry permit, which introduces the planning department's own timeline and hearing schedule.

The 4:1 Replacement Ratio in Practice

The practical implications of the 4:1 replacement ratio are worth walking through with a real scenario. If a residential project requires the removal of two protected coast live oaks, the permit will condition replacement planting of eight new protected-species trees on the property, each a minimum of 15-gallon size. Eight trees at 15-gallon size are each roughly 7 to 8 feet tall at planting, with a root ball approximately 15 inches in diameter. They need adequate spacing for long-term canopy development, access to sunlight and water, and planting locations that are compatible with the site's irrigation, hardscape, and utility layout.

On a 10,000-square-foot hillside lot where the house, pool, driveway, retaining walls, and required setbacks already consume most of the buildable area, finding suitable planting locations for eight new trees is a genuine design challenge. The landscape architect must coordinate the replacement planting plan with the architect's site plan, the civil engineer's grading and drainage plan, and the arborist's recommendations for appropriate species and locations. If the site truly cannot accommodate the required number of replacement trees, the property owner pays the in-lieu fee - currently approximately $2,600 per tree - for each tree that cannot be planted on site. For two oaks removed at 4:1, with only four of the eight replacements fitting on site, the in-lieu fee for the remaining four trees would be approximately $10,400.

The replacement trees, whether planted on site or funded through in-lieu fees, must be protected-species varieties. The city determines the appropriate replacement species, and the species and size are specified on the permit.

Tree Bonds

When the city approves removal or relocation of protected trees, it typically requires the property owner to post a tree bond - a cash deposit or surety bond guaranteeing that the replacement trees will be planted and maintained, or that a relocated tree will survive, for a specified guarantee period. The standard guarantee period is a minimum of three years from the date the bond is posted or the date the trees are planted or relocated, whichever is later. The bond amount varies based on the number and size of the replacement trees and the appraised value of any relocated trees.

The bond is not released until the Urban Forestry Division inspects the property and confirms that the replacement or relocated trees are alive, healthy, and meeting the conditions of the permit. If a replacement tree dies during the guarantee period, the property owner must replant at their own expense. If a relocated tree fails to survive, the bond may be forfeited in whole or in part.

This means the project carries a financial obligation that extends years beyond the completion of construction. The bond cannot be released at the certificate of occupancy. It remains in effect until the guarantee period expires and the city confirms compliance. For owners who plan to sell the property after construction, the outstanding tree bond is a condition that transfers with the property and must be disclosed. For owners who are building their own home, it means budgeting for ongoing tree maintenance and the administrative process of bond release several years after move-in.

TREE RELOCATION - BOXING, MOVING, AND REPLANTING

Tree relocation is the process of physically moving a protected tree from one location to another, either elsewhere on the same property or to a temporary nursery facility for storage until the site is ready for replanting. It is a specialized construction operation that involves months of preparation, heavy equipment, and a coordinated team of arborists, crane operators, and rigging crews. When it works, it preserves a mature tree that would take decades to replace. When the conditions are not right, it can be an expensive operation with a poor outcome.

When Relocation Makes Sense

Relocation is typically considered when several conditions align. The tree must be healthy enough to survive the process - a tree with significant internal decay, a compromised root system, or active disease is a poor candidate. The tree must be of a size that is practically movable; there are limits to what can be boxed and lifted. The project site or a nearby location must have a suitable replanting spot with appropriate sun exposure, drainage, and soil conditions. And the cost of relocation must be justified relative to the penalties and replacement requirements of removal.

For a healthy coast live oak with a 12-inch trunk diameter in a location that conflicts with a proposed retaining wall, relocation to another part of the same property may be straightforward and cost-effective. For a 30-inch oak with a massive canopy and a root system that has been growing undisturbed for 80 years, the feasibility question is far more complex. The root ball required for a tree of that size may be enormous, the crane capacity required to lift it may be beyond what can be positioned on a hillside street, and the survival rate drops as the tree size increases.

The arborist evaluates each tree individually and provides a professional opinion on relocation feasibility and projected survival rate. That assessment, combined with the construction manager's evaluation of site access, crane positioning, and logistics, determines whether relocation is a viable option.

Size and Feasibility Limits

There is no absolute maximum size for tree relocation - Senna Tree Company, one of the well-known tree relocation specialists in the Los Angeles market, holds a Guinness World Record for relocating a 916,000-pound valley oak with an 84-inch trunk diameter and a 100-foot canopy spread. That tree, moved in 2002, still thrives. But operations of that scale are extraordinary. For typical residential projects, the practical upper limit depends on species, site access, and budget.

Trees in the 48-inch to 72-inch box range (roughly 6 to 12 inches in trunk diameter, depending on species) are routinely relocated on residential projects in LA with high success rates. Trees in the 84-inch to 96-inch box range (larger trunk diameters, heavier root balls) are feasible but require significant crane capacity and clear site access. Beyond 96-inch box, the weight of the root ball and the crane requirements become the limiting factors, particularly on hillside lots with narrow streets where large crane setup is constrained.

The Boxing and Relocation Process

Tree relocation follows a defined sequence that typically spans several months from start to finish.

1. Root pruning (3 to 6 months before the move). The arborist root-prunes the tree well in advance of the actual relocation, often in two phases several months apart. Root pruning is performed at the planned perimeter of the box - the arborist cuts the roots cleanly at the line where the box walls will be constructed, stimulating the tree to generate new feeder roots within the planned root ball volume. This step is critical to the tree's survival after transplanting. The new feeder roots that grow in response to the root pruning are what will sustain the tree in its new location. Skipping or compressing the root pruning timeline significantly reduces survival rates.

Root pruning is typically done by hand excavation or air spade to expose roots before making clean cuts. The timing of root pruning depends on the species and the season. Dormant season pruning (late fall through early spring in Southern California) generally produces better outcomes because the tree is not under active transpiration demand.

2. Box construction. A wooden box, typically constructed from plywood and dimensional lumber, is built around the root ball in place. The box dimensions correspond to the tree size - a 60-inch box is nominally 60 inches on each side. The box must be structurally rigid enough to support the weight of the root ball during lifting, transport, and replanting without cracking or shifting. The bottom of the box is undercut after the sides and top are secured, using a combination of equipment excavation outside the box perimeter and hand work or air spade inside the root zone. The bottom boards are slid or driven under the root ball to close the box.

3. Crane lift and transport. Once the box is closed and secured, a crane lifts the boxed tree out of the ground. Rigging a boxed tree requires experience - there are no engineered lift points on a tree, and the rigging must be threaded through the canopy and secured around the box without damaging branches or shifting the root ball. Senna Tree Company operates its own fleet of hydraulic truck cranes with NCCCO-certified operators and rigging crews who do this work full-time. The experience of the rigging crew directly affects both the safety of the operation and the tree's chance of surviving the move without significant canopy damage.

If the tree is being moved to another location on the same site, the crane may be able to swing it directly from the old location to the new one. If the tree is leaving the property - either going to a temporary nursery or to a different site - it is loaded onto a flatbed trailer for transport. Oversize load permits may be required for large boxed trees being moved on public roads.

4. Replanting. At the new location, a hole is pre-excavated to receive the boxed tree. The hole must be sized to allow the box to be removed (or left to decompose, depending on the method) and must be prepared with appropriate drainage and soil conditions. The tree is set by crane, the box is removed or scored, the tree is backfilled, staked for wind stability, and placed on a watering program.

5. Temporary nursery storage. When the final planting location is not ready at the time the tree needs to be moved - which is common on construction projects where the tree must be relocated before grading begins but the landscape will not be installed for a year or more - the boxed tree is transported to a nursery facility for storage. Senna Tree Company operates nursery facilities in Los Angeles and Orange County for this purpose. Storage involves ongoing maintenance, watering, and arborist monitoring. When the site is ready, the tree is transported back and planted, which means two crane operations and two transport operations instead of one, adding to the total cost.

Survival Rates

Relocation is not guaranteed to succeed. Survival rates depend on species (some tolerate transplanting better than others - oaks generally do well, sycamores can be more variable), the tree's health before the move, the ratio of root ball size to canopy size, time of year (dormant season moves produce better outcomes), post-transplant care, and how well the new location matches the tree's requirements for sun, soil, and water.

Younger, smaller trees survive transplanting at substantially higher rates than large mature specimens. A healthy 48-inch box oak relocated with adequate root preparation and proper post-transplant care can have survival rates above 90 percent. A large, mature specimen with a 96-inch box under good conditions may still have acceptable survival rates, but the margin for error is smaller and the cost of failure is higher. The arborist provides a professional estimate of the survival probability for each specific tree, and that estimate should be part of the project team's decision-making when weighing relocation against removal and replacement.

TAGGING, CATALOGUING, AND SPECIES IDENTIFICATION

The field work of tree assessment follows a systematic process that produces the data underlying every decision about tree protection, removal, or relocation on the project.

Tagging

During the tree survey, the arborist physically tags each inventoried tree with a numbered metal or plastic tag attached to the trunk. The tag number corresponds to the tree inventory table in the arborist report and to the plotted tree locations on the site plan. Every tree on the property above the survey threshold is tagged - not just the trees suspected of being protected species. This creates a complete, numbered inventory that the architect, engineer, construction manager, and city reviewer can all reference by the same identification system.

The tags remain on the trees through the permitting process and into construction. When the arborist, the contractor, or a city inspector refers to "Tree #7," everyone is looking at the same tree. On properties with dozens of trees, including both protected and non-protected specimens, this tagging system prevents the confusion that arises when trees are described only by location or species.

Off-site trees - protected trees on adjacent properties or in the public right-of-way that may be affected by the project - are also tagged and catalogued, typically with a separate coding system (e.g., OS#1 for off-site tree number one). Construction activity near the property line that could damage a neighbor's protected tree carries the same regulatory exposure as damaging a tree on the project site.

Species Identification

Identifying the protected species in the field is usually straightforward for an experienced arborist, but there are situations where species identification becomes a point of contention. The most common is the distinction between coast live oak (Quercus agrifolia, a protected native) and interior live oak (Quercus wislizeni, which can appear similar but is not indigenous to the LA basin). London plane trees (Platanus x hispanica, a non-native hybrid commonly used as a street tree) can be confused at a glance with Western sycamore (Platanus racemosa, which is protected). For multi-species properties where the presence or absence of protection turns on species identification, the arborist's determination governs the permitting process.

The City of LA's Urban Forestry Division publishes a Protected Trees Photo Guide (last updated September 2024) to assist with species identification. The guide includes photographs of each protected species with identification notes on leaf shape, bark characteristics, and growth habit. Owners and architects can refer to this guide for preliminary assessment, but the arborist's field determination is what matters for regulatory purposes.

Canopy Diameter and Root Zone Math

Understanding the spatial implications of tree protection requires some basic math. A coast live oak with a 40-foot canopy diameter has a drip line that extends 20 feet from the trunk in every direction. That drip line defines the minimum tree protection zone - a circle 40 feet in diameter. On a 50-foot-wide lot, that single tree's TPZ spans 80 percent of the lot width. Any grading, excavation, or construction activity within that 40-foot circle is restricted.

The root zone typically extends even further than the canopy. A general guideline is that roots extend 1.5 to 3 times the radius of the canopy, depending on species, soil conditions, and available water. That 40-foot-canopy oak may have significant roots extending 30 to 60 feet from the trunk. Not all of those roots are critical - the structural and primary transport roots are concentrated closer to the trunk - but the extent of the root system means that construction activity well outside the visible canopy can still affect the tree if major roots are severed.

Multi-Trunk Trees and Cumulative Caliper

The four-inch diameter threshold that triggers protection under the City of LA ordinance is measured as cumulative diameter for multi-trunk specimens. A tree with four trunks each measuring 2 inches in diameter has a cumulative diameter of 8 inches and qualifies as protected, even though no single trunk reaches the 4-inch threshold independently. This measurement method is specified in the ordinance and catches multi-trunk specimens that might otherwise appear to be below the protection threshold.

ENVIRONMENTAL OVERLAPS AND BIOLOGICAL SURVEYS

Trees on LA construction sites are not solely a tree ordinance issue. They also intersect with state and federal wildlife protections that operate independently of the municipal tree regulations and can impose their own constraints on project scheduling and operations.

Wildlife Protections and Construction Activity

The federal Migratory Bird Treaty Act (MBTA) and California Fish and Game Code Sections 3503, 3503.5, and 3513 protect native birds, their occupied nests, and their eggs. It is unlawful to destroy an active bird nest - a nest containing eggs, young birds, or being actively used by nesting adults - regardless of whether the nest is in a protected tree, a non-protected tree, a shrub, or a building structure. These protections apply to virtually all native bird species, not just rare or threatened ones. Common species like red-tailed hawks, mourning doves, and house finches are all protected.

For construction projects involving tree removal, significant pruning, or demolition of structures where birds may nest, this means that work performed during nesting season requires a pre-construction nesting bird survey by a qualified biologist. If active nests are found, a buffer zone must be established around each nest and maintained until the young have fledged and the nest is no longer active. For songbirds, a typical buffer is 100 to 300 feet. For raptors (hawks, owls, eagles), the buffer may extend to 500 feet or more depending on the species and the biologist's assessment.

Nesting Season and Construction Scheduling

In Southern California, the California Department of Fish and Wildlife defines the general nesting season as February 1 through August 31. Some agencies and permit conditions extend the window through September 15 for certain species. Raptors and hummingbirds may begin nesting as early as January.

If the project schedule requires tree work during nesting season, the biologist conducts a survey within a specified window before work begins - typically within three to seven calendar days of the planned activity, depending on the permit conditions. If active nests are found, the biologist establishes buffer zones and monitors them until the young fledge. Fledging can take anywhere from two weeks to several months depending on the species. A red-tailed hawk nest discovered in a tree scheduled for removal in April could delay that tree's removal until July or later.

This is a scheduling constraint that should be identified during pre-construction. When the project requires removal or relocation of trees, coordinating that work with the nesting season window is part of the construction timeline planning. If the tree work cannot happen before February, the project team needs to build the potential for nesting bird delays into the schedule rather than treating it as a surprise.

Sensitive Habitat

On properties adjacent to natural areas - hillside lots backing onto parkland, canyon properties, and lots bordering undeveloped slopes - additional biological review may be required. Some properties in Los Angeles County fall within designated Significant Ecological Areas (SEAs), which trigger supplemental environmental review under the county's General Plan policies. Properties within or adjacent to SEAs may require a biological assessment beyond the standard tree report, particularly if the project involves grading or vegetation removal near sensitive habitat.

For projects requiring CEQA review (typically those with discretionary planning entitlements), biological resources are evaluated as part of the environmental analysis. The CEQA review may impose mitigation measures related to tree replacement, habitat restoration, and construction-phase biological monitoring that exceed the baseline requirements of the tree ordinance.

Biologist vs. Arborist

These are different professionals with different credentials addressing different issues. The arborist handles tree health, species identification, tree protection plans, root pruning supervision, and relocation operations. The biologist handles wildlife issues - nesting bird surveys, sensitive species assessments, habitat evaluation, and buffer zone monitoring. A project with protected trees and construction activity during nesting season needs both. The arborist manages the tree work; the biologist clears the tree for wildlife before the arborist's work can begin. The construction manager coordinates the sequencing between the two.

HOW TREES AFFECT PROJECT DESIGN AND SEQUENCING

Trees do not exist in isolation on a construction project. Their protection zones, root systems, and canopy envelopes intersect with foundation design, grading plans, retaining wall alignments, utility routing, and construction sequencing in ways that can reshape the project if addressed late.

Design Implications

A protected tree near the proposed building footprint may require the architect to adjust the floor plan, shift the building pad, redesign a retaining wall alignment, or reroute a driveway. A tree protection zone that overlaps with a proposed swimming pool location may force the pool to another part of the site or eliminate it from the program entirely. These design changes are significantly less costly when identified during schematic design than after construction documents are complete and permits are in review.

This is why the tree survey should be overlaid on the site plan at the earliest stage of design. The architect and the construction manager can evaluate the spatial conflicts between protected trees and the proposed building program while there is still flexibility to adjust. By the time the project is in construction documents, the cost of accommodating a tree that was not accounted for in the design is measured in redesign fees, resubmittal delays, and potentially major changes to structural systems that were already engineered.

The feasibility report and lot due diligence process should flag protected tree issues as one of the site constraints that shapes the project's viability and budget. On properties where protected trees occupy significant portions of the buildable area, the tree constraints may be as influential on the final design as the zoning envelope or the geotechnical conditions.

Foundation and Retaining Wall Conflicts

When a protected tree's root zone overlaps with a planned foundation or retaining wall, the structural engineer and arborist must collaborate on a solution. The options depend on the extent of the overlap, the size and health of the tree, and the structural loads involved.

Pier and grade beam foundations can be designed to span over root zones, with the piers drilled outside the TPZ and the grade beams bridging across the root area without excavating through it. This approach requires coordination between the structural engineer, who sizes the spans and pier depths, and the arborist, who identifies which root zones must be avoided and where pier locations are acceptable. Retaining wall alignments can be adjusted to curve around tree protection zones rather than running through them, though this adds complexity to the structural design and the formwork. Root barriers - physical barriers installed in the ground to redirect root growth away from structures - can provide long-term protection for foundations and utilities but must be designed in consultation with the arborist to avoid creating conditions that damage the tree.

The foundation systems and retaining walls pages cover these structural systems in detail.

Grading Impacts

Protected trees constrain grading operations in several ways. Heavy equipment cannot operate within the TPZ, which may require hand grading or alternative methods near protected trees. Grade changes within the root zone - whether cutting below existing grade or filling above it - can damage or kill the tree over time. The grading plan must account for access routes that avoid TPZs, which on constrained hillside lots may limit where the grading contractor can position equipment and where export or import soil can be staged. The haul route for soil export may need to be redesigned if the most direct path passes through a tree protection zone.

On hillside sites where grading is extensive and protected trees are present at multiple locations, the grading plan becomes a negotiation between the volume of earth that needs to move and the areas where that movement is restricted. The grading contractor, the arborist, and the construction manager work through this during pre-construction to develop a grading sequence that accomplishes the site work without violating the tree protection plan.

Construction Sequencing

Tree work often needs to happen in a specific sequence relative to other construction activities, and several of those sequences have long lead times that affect the overall project schedule.

Root pruning for a tree that will be relocated must begin three to six months before the actual move. That means root pruning may need to start while the project is still in design development or permitting, well before general construction begins. If the tree relocation is on the critical path for grading - because the tree sits where the building pad will be cut - then the root pruning timeline effectively sets the earliest possible start date for site work.

Nesting bird surveys must be completed before any tree disturbance during nesting season, and the results can impose buffer zones that delay tree removal by weeks or months. Scheduling tree removal during the October-through-January non-nesting window avoids this constraint, but that window is only four months long, and the tree removal permit must be in hand before the work can proceed.

TPZ fencing must be installed before any equipment mobilization on the site. Arborist monitoring begins when construction begins and continues through the duration of the project. Replacement tree planting and tree bond posting must be completed before the city will issue a certificate of occupancy.

The sequencing has to be coordinated with the overall project timeline. On projects with significant tree work, the tree-related schedule becomes one of the governing sequences that the construction manager tracks alongside permitting, structural steel lead times, and other long-lead items. Missing the nesting season window or failing to start root pruning on time can delay the entire project by months, and those delays are difficult to recover because they are tied to biological cycles and regulatory timelines that do not compress.

COSTS

Tree-related costs on residential construction projects in Los Angeles vary widely depending on the number of protected trees, the size of the specimens, whether removal or relocation is required, site access conditions, and the duration of construction. The following ranges reflect the LA market for complex residential projects. All figures are approximate and should be verified with current quotes for project-specific conditions.

Several factors drive costs toward the higher end of these ranges. Large tree size increases relocation costs significantly because of the crane capacity required and the weight of the root ball. Poor site access - narrow hillside streets, limited staging area, no room for a large crane to set up - adds logistics cost to every operation that requires heavy equipment. Trees requiring temporary nursery storage incur ongoing monthly costs plus a second transport and crane operation when the tree returns to the site. Projects with multiple protected trees compound all of these costs across the inventory.

The total tree-related cost on a residential project with two or three protected trees requiring a combination of preservation, relocation, and removal can readily reach $50,000 to $150,000 when arborist fees, permit costs, relocation operations, replacement planting, monitoring, and bond requirements are fully accounted for. On projects with extensive tree work - multiple large trees, hillside access constraints, nursery storage - the total can exceed $200,000. These costs belong in the project budget from the feasibility stage, not as a contingency line item discovered during permitting.

WORKING WITH YOUR PROJECT TEAM ON TREE ISSUES

Tree issues on a residential construction project involve multiple professionals, each responsible for a different aspect of the work. Understanding who does what prevents gaps in coordination and ensures that tree requirements are addressed by the right specialist at the right time.

Owner. The property owner is ultimately responsible for regulatory compliance, pays all costs associated with tree work (surveys, permits, relocation, replacement, bonds, monitoring), and posts the tree bond. The bond obligation remains with the property for the duration of the guarantee period regardless of whether the original owner retains ownership.

Architect. The architect incorporates tree constraints into the site design. This means adjusting the building footprint, grading plan, driveway alignment, and hardscape layout as needed to preserve protected trees or accommodate tree protection zones. The tree survey overlay on the site plan is one of the first pieces of information the architect needs to begin design.

Construction Manager / General Contractor. The construction manager coordinates the arborist, crane company, biologist, and grading contractor with the construction schedule. On-site, the CM ensures TPZ fencing is maintained, operational restrictions near protected trees are communicated to all trades and equipment operators, and the tree protection plan is followed throughout construction. The CM also manages the sequencing of tree work relative to grading, foundation, and utility operations. This coordination role is described in our deliverables framework and is a core function of the CMAR delivery method.

Arborist (Tree Expert). The certified arborist prepares the tree report, develops the tree protection plan, supervises all root pruning and tree relocation operations, monitors compliance during construction, and certifies the condition of replacement and relocated trees for bond release. The arborist is the professional of record for all tree-related regulatory submittals.

Tree Relocation Specialist. Companies that specialize in tree boxing, rigging, transport, and replanting handle the physical relocation operation. Senna Tree Company, based in Sun Valley, is one of the established firms in the LA market for this work. They operate their own crane fleet, rigging crews, and nursery storage facilities. The relocation specialist works under the arborist's direction on root ball sizing, timing, and post-transplant care.

Biologist. A qualified biologist conducts nesting bird surveys and any required habitat assessments. The biologist is a separate professional from the arborist, with different credentials and a different scope. Projects with tree work during nesting season or on properties adjacent to sensitive habitat need both.

Geotechnical Engineer. On hillside sites, the geotechnical engineer evaluates how tree removal or root disturbance affects soil stability. Removing a large tree from a slope changes the moisture regime and root reinforcement that the soil previously relied on, and the geotech may require additional drainage or slope stabilization measures as a result.

Landscape Architect. The landscape architect designs the replacement planting plan, selects replacement species and box sizes, coordinates planting locations with the site plan and grading plan, and works with the arborist to ensure the replacement trees have appropriate conditions for long-term survival.

FREQUENTLY ASKED QUESTIONS

The information on this page is provided for educational purposes and reflects the professional experience and perspective of Benson Construction Group. Regulatory references, cost ranges, timelines, and permitting procedures reflect current conditions for the greater Los Angeles area and may vary based on project-specific conditions, jurisdiction, site complexity, and regulatory changes. Tree protection ordinances vary by municipality, and the information presented here focuses primarily on the City of Los Angeles. Consult a certified arborist and qualified legal counsel for project-specific guidance on tree protection compliance.