CWUIC · California Wildland-Urban Interface Code

How must shrubs and trees be planted and maintained near structures?

Q: Can I plant a tall conifer within 30 feet of my house?

Tall conifers are typically nonfire‑smart . Under § 603.4.2.1 , a nonfire‑smart tree is only permitted if its mature drip line is 30 ft from the building, or it is planted 10 ft away and is kept very well pruned and maintained to prevent rapid fire transmission.

Q: Do these measurements use the plant’s mature size or its planting size?

They use the plant’s mature size (for example, the tree’s drip line at maturity), so plan and plant accordingly. See § 603.4.2(1) and § 603.3 (which requires expected mature dimensions on landscape plans).

Q: Where do I show these plant dimensions during permitting?

Provide them on the landscape plan as required by § 603.3.1 , which specifically asks for expected height and width at maturity and identification of irrigated areas.

Keep shrubs small and grouped no more than 10 ft across and at least 30 ft from buildings; plant trees so their mature drip line is at least 10 ft from combustibles (or follow the 30‑ft or strict‑maintenance options for nonfire‑smart species).

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Last reviewed: July 6, 2026

What the code requires — plain English

The California Wildland‑Urban Interface Code requires that new vegetation be “fire‑smart” and that shrubs and trees planted near buildings meet specific size and separation rules to reduce wildfire spread. Key requirements are in § 603.4, with the shrub rules in § 603.4.1 and the tree rules in § 603.4.2; special allowances for nonfire‑smart vegetation are in § 603.4.2.1.

Keep shrub groupings well away from buildings (minimum 30 feet), limit shrub size and grouping width, and place/maintain trees so their mature drip line is kept at least 10 feet from combustible parts of a structure — or farther if the tree is nonfire‑smart.

Requirements in detail

Scope / baseline

All new plantings in State Responsibility Areas and designated fire hazard zones must follow the vegetation plan provisions in § 603.2–§ 603.4.2.1; landscape plans must show the 30‑foot and 100‑foot fuel management zones and plant species/expected mature sizes per § 603.3.

Shrubs — what you may plant and how

First mention: § 603.4.1 (shrubs).
Principal points (paraphrased from the code):
- Maximum shrub height: 6 feet at maturity.
- Maximum grouping size: a shrub grouping may have an aggregate diameter up to 10 feet.
- Distance between shrub groupings: at least 15 feet from other shrub groupings.
- Distance from structures: any shrub grouping must be at least 30 feet from a structure.
- Under‑tree clearance: if shrubs sit under or within a tree’s drip line, the lowest tree branch must be at least three times the shrub height or 10 feet, whichever is greater.

Trees — planting and maintenance inside the 30‑foot zone

First mention: § 603.4.2 (trees).
Principal points:
- Drip line to structure (new trees): at maturity, a tree’s drip line must be at least 10 feet from any combustible structure.
- Horizontal crown separation (new trees): crowns of new trees must be at least 10 feet apart from crowns of adjacent trees.
- Chimney/stovepipe clearance (existing trees): existing trees must be trimmed so branches are at least 10 feet from chimney and stovepipe outlets (referenced to Title 14 §1299.03 in the code).

Nonfire‑smart vegetation (special rules)

First mention: § 603.4.2.1 (nonfire‑smart vegetation).
If a tree species is not classified fire‑smart (examples the code cites include many conifers, palms, pepper trees and eucalyptus), it may still be allowed only if one of two alternatives is met:
1. Plant so the tree’s drip line at maturity is 30 feet from an applicable building; or
2. Plant so the drip line is 10 feet from any combustible structure, and keep the tree well pruned and maintained so it will not rapidly transmit fire (i.e., not act as a ladder or direct ember transfer).

Decision matrix (quick reference)

Decision dimension	Value / requirement	Code Reference
New vegetation must be fire‑smart (baseline)	Yes (except where § 603.4.2.1 applies)	§ 603.4
Shrub max height (new plantings)	6 ft	§ 603.4.1(1)
Shrub grouping max aggregate diameter	10 ft	§ 603.4.1(2)
Separation between shrub groupings	15 ft	§ 603.4.1(3)
Separation of shrub groupings from structures	30 ft	§ 603.4.1(4)
Under‑tree shrub rule (lowest branch)	lowest branch ≥ 3× shrub height or 10 ft, whichever greater	§ 603.4.1(5)
Tree drip line to combustible structure (new trees)	10 ft minimum	§ 603.4.2(1)
Crown‑to‑crown horizontal distance (new trees)	10 ft minimum	§ 603.4.2(2)
Chimney/stovepipe branch clearance (existing trees)	10 ft minimum	§ 603.4.2(3)
Nonfire‑smart tree permitted options	drip line 30 ft from building OR 10 ft with strict pruning/maintenance	§ 603.4.2.1

Exceptions & special cases

The general rule requires fire‑smart vegetation for new plantings, but § 603.4 expressly allows trees classified as nonfire‑smart when they comply with § 603.4.2.1 (the two alternatives above).
Landscape plans (when required) must show fuel‑management zones and expected mature plant sizes so officials can check compliance; see § 603.3. This can affect whether a proposed planting is acceptable on plan review.
The code treats new plantings (design/plan) and existing vegetation differently in places — e.g., trimming requirements for existing trees near chimneys are addressed in § 603.4.2(3).

Common mistakes

Assuming “planting size” = “mature size.” The CWUIC distances use the tree’s drip line at maturity, not the height at planting — always plan for full mature spread. § 603.4.2(1).
Planting shrub groupings closer than 30 ft to structures (or exceeding the 10 ft aggregate grouping diameter) — both are code violations under § 603.4.1.
Forgetting the understory rule: shrubs under tree canopies require the tree’s lower branches to be high enough (3× shrub height or 10 ft) to prevent ladder fuels (§ 603.4.1(5)).
Planting nonfire‑smart trees (e.g., eucalyptus) close to structures without meeting either the 30‑ft setback or the strict pruning/maintenance condition in § 603.4.2.1.

Worked example — applying the rule with numbers

Scenario: You plan to plant a small ornamental tree (expected mature crown radius 8 ft — so drip line ~8 ft from trunk) and two shrubs beneath it near your house.

Step‑by‑step application:

Shrubs: You choose shrubs that mature to 4 ft high. Under § 603.4.1(1) the shrubs are under the 6 ft limit. Two shrubs in a group have an aggregate diameter of 6 ft (under the 10 ft limit) and are more than 15 ft from any other shrub grouping — OK. But the group must be 30 ft from the structure to comply with § 603.4.1(4) — if your planting site is only 20 ft from the house, you must relocate the grouping or remove shrubs.
Under‑tree clearance: Because the shrubs are under the tree’s drip line, the tree’s lowest branch must be at least 3 × shrub height = 12 ft, or 10 ft, whichever is greater; so the lowest branch must be 12 ft above ground per § 603.4.1(5). If the tree’s lowest limb is lower, prune it up before accepting this design.
Tree placement: The tree’s mature drip line is 8 ft from the trunk. To meet § 603.4.2(1) (drip line ≥ 10 ft from combustible structure), the trunk must be at least 18 ft from the house face (8 ft drip line + 10 ft required clearance) — if the trunk is only 12 ft away, the tree fails the new‑tree setback and must be relocated, replaced with a smaller species, or classified as nonfire‑smart and meet the 30‑ft alternative in § 603.4.2.1.

Related provisions

§ 603.3 — Landscape plans: delineation of the 30‑ and 100‑foot zones and plant legends.
§ 603.2 — Application: which areas must comply with §§ 603.3–603.4.2.1.
§ 602.3.2 — Final fire protection plan (requires listing expected mature sizes and irrigated areas).
§ 604.1 — General maintenance of defensible space (ongoing management of hazardous vegetation).

Code references

Grounded in the retrieved California Wildland-Urban Interface Code — click a citation to read the verbatim passage:

CWUIC § 603.4.1 High relevance — show source text
603.4.1 Shrubs. All new plantings of shrubs shall comply with the following: 1. Shrubs shall not exceed 6 feet (1829 mm) in height. 2. Groupings of shrubs are limited to a maximum aggregate diameter of 10 feet (3048 mm). 3. Shrub groupings shall be separated from other groupings a minimum of 15 feet (4572 mm). 4. Shrub groupings shall be separated from structures a minimum of 30 feet (9144 mm). 5. Where shrubs are located below or within a tree’s drip line, the lowest tree branch shall be a minimum of three times the height of the understory shrubs or 10 feet (3048 mm), whichever is greater.

603.4.2 Trees. Trees shall be managed as follows within the 30-foot zone (9144 mm) of a structure: 1. New trees shall be planted and maintained so that the tree’s drip line at maturity is a minimum of 10 feet (3048 mm) from any combustible structure. 2. The horizontal distance between crowns of new trees and crowns of adjacent trees shall not be less than 10 feet (3048 mm). 3. Existing trees shall be trimmed to provide a minimum separation of 10 feet (3048 mm) away from chimney and stovepipe outlets per California Code of Regulations, Title 14, Section 1299.03.

603.4.2.1 Nonfire-smart vegetation. New trees not classified as fire-smart vegetation, such as conifers, palms, pepper trees and eucalyptus species, shall be permitted provided the tree is planted and maintained in accordance with one of the following: 1. The tree is planted so that the tree’s drip line at maturity is a minimum of 30 feet (9144 mm) from an applicable building. 2. The tree is planted so that the tree’s drip line at maturity is a minimum of 10 feet (3048 mm) from any combustible struc- ture, and is well pruned and maintained so as not to form a means of rapidly transmitting fire from other nearby vegetation to the structure or from the structure to nearby vegetation or to interrupt the advance of embers toward a

structure.

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FIRE PROTECTION REQUIREMENTS

SECTION 604—MAINTENANCE OF DEFENSIBLE SPACE

604.1 General. Hazardous vegetation and fuels shall be managed to reduce the severity of potential exterior wildfire exposure to build- ings and to reduce the risk of fire spreading to buildings as required by applicable laws and regulations.

Defensible space shall be managed around all buildings and structures in State Responsibility Areas (SRA) as required in Public Resources Code 4291.

604.2 Application. Buildings and structures located in the following areas shall maintain the required hazardous vegetation and fuel management: 1. All unincorporated lands designated as a State Responsibility Area (SRA). 2. Land designated as a Very High Fire Hazard Severity Zone by a city or local agency. 3. Land designated in a city or local agency ordinance as a wildland-urban interface (WUI) area.
CWUIC § 603.2 High relevance — show source text
603.2 Application. All new plantings of vegetation in State Responsibility Area (SRA) and Local Responsibility Areas (LRA) designated as a Fire Hazard Severity Zone shall comply with Sections 603.3 through 603.4.2.1.

603.3 Landscape plans. Landscape plans shall be provided when required by the code official. The landscape plan shall include devel- opment and maintenance requirements for the vegetation management zone adjacent to structures and roadways, and provide significant fire hazard reduction benefits for public and firefighting safety.

603.3.1 Contents. Landscape plans shall contain the following: 1. Delineation of the 30-foot (9144 mm) and 100-foot (30 480 mm) fuel management zones from all structures. 2. Identification of existing vegetation to remain and proposed new vegetation. 3. Identification of irrigated areas. 4. A plant legend with both botanical and common names, and identification of all plant material symbols. 5. Identification of ground coverings within the 30-foot (9144 mm) zone.

603.4 Vegetation. All new vegetation shall be fire-smart vegetation in accordance with this section.

Exception: Trees classified as nonfire-smart vegetation complying with Section 603.4.2.1.

To be considered fire-smart vegetation, vegetation must meet at least one of the following: 1. Be identified as fire-smart vegetation in an approved book, journal or listing from an approved organization. 2. Be identified as fire-smart vegetation by a licensed landscape architect with supporting justification. 3. Plants considered fire-smart vegetation and approved by the local enforcing agency.

603.4.1 Shrubs. All new plantings of shrubs shall comply with the following: 1. Shrubs shall not exceed 6 feet (1829 mm) in height. 2. Groupings of shrubs are limited to a maximum aggregate diameter of 10 feet (3048 mm). 3. Shrub groupings shall be separated from other groupings a minimum of 15 feet (4572 mm). 4. Shrub groupings shall be separated from structures a minimum of 30 feet (9144 mm). 5. Where shrubs are located below or within a tree’s drip line, the lowest tree branch shall be a minimum of three times the height of the understory shrubs or 10 feet (3048 mm), whichever is greater.

603.4.2 Trees. Trees shall be managed as follows within the 30-foot zone (9144 mm) of a structure: 1. New trees shall be planted and maintained so that the tree’s drip line at maturity is a minimum of 10 feet (3048 mm) from any combustible structure. 2. The horizontal distance between crowns of new trees and crowns of adjacent trees shall not be less than 10 feet (3048 mm). 3. Existing trees shall be trimmed to provide a minimum separation of 10 feet (3048 mm) away from chimney and stovepipe outlets per California Code of Regulations, Title 14, Section 1299.03.

CWUIC § 1.11. High relevance — show source text

Additionally, make sure you have 10 feet (3048 mm) of clearance_ around your wood piles. 9. Fences—remove or relocate all vegetation, combustibles and combustible debris adjacent to and underneath fences. 10. Replace wood mulch products within five feet (1524 mm) of all structures with noncombustible products such as dirt, stone, or gravel. 11. Remove all dead or dying grass, plants, shrubs, trees, branches, leaves, weeds, and pine needles within 30 feet (9144 mm) of all structures or to the property line. 12. Be sure to store combustible outdoor furnishings away from your home when not in use. 13. Remember to properly store retractable awnings and umbrellas when not in use so they do not collect leaves and embers.

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CALIFORNIA WILDLAND-URBAN INTERFACE CODE – MATRIX ADOPTION TABLE

APPENDIX H – REFERENCED CALIFORNIA DOCUMENTS

(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)

(Not adopted by the State Fire Marshal)

Adopting Agency	BSC	BSC- CG	SFM	Col5	HCD	Col7	Col8	DSA	Col10	OSHPD	Col12	Col13	Col14	Col15	Col16	BSCC	DPH	AGR	DWR	CEC	CA	SL	SLC
Adopting Agency	BSC	BSC- CG	T-24	T-19*	1	2	1/AC	AC	SS	1	1R	2	3	4	5	5	5	5	5	5	5	5	5
Adopt Entire Chapter
Adopt Entire Chapter as amended (amended sections listed below)
Adopt only those sections that are listed below
[California Code of Regulations, Title 19, Division 1]
Chapter / Section

The California Code of Regulations (CCR), Title 19, Division 1 provisions that are found in the California Wildland-Urban Interface Code are a reprint from the current CCR, Title 19, Division 1 text for the code user’s convenience only. The scope, applicability and appeals procedures of CCR, Title 19, Division I remain the same. The state agency does not adopt sections identified by the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.

CWUIC § 1299.02 High relevance — show source text
1299.02 Definitions. The following definitions apply to this article: (a) Defensible space. The buffer that landowners are required to create on their property between a “Building or Structure” and the plants, brush and trees or other items surrounding the “Building or Structure” that could ignite in the event of a fire.

APPENDIX H-16 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE

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APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS

(b) Building or Structure. Anything constructed that is designed or intended for support, enclosure, shelter, or protection of persons, animals, or property, having a permanent roof that is supported by walls or posts that connect to, or rest on the ground. (c) Outbuilding. Buildings or structures that are less than one hundred-twenty (120) square feet in size and not used for human habitation. For purposes of this Section, an “Outbuilding” is not a “Building or Structure” as defined in subsection (b) above.

1299.03 Requirements. Defensible space is required to be maintained at all times, whenever flammable vegetative conditions exist. One hundred feet (100 ft.) of defensible space clearance shall be maintained in two distinct “Zones” as follows: “Zone 1” extends thirty feet (30 ft.) out from each “Building or Structure,” or to the property line, whichever comes first; “Zone 2” extends from thirty feet (30 ft.) to one hundred feet (100 ft.) from each “Building or Structure,” but not beyond the property line. The vegetation treatment requirements for Zone 1 are more restrictive than for Zone 2, as provided in (a) and (b) below. The Department of Forestry and Fire Protection's “Prop- erty Inspection Guide, 2000 version, April 2000,” provides additional guidance on vegetation treatment within Zone 1 and Zone 2, but is not mandatory and is not intended as a substitute for these regulations. (a) Zone 1 Requirements: (1) Remove all dead or dying grass, plants, shrubs, trees, branches, leaves, weeds, and pine needles from the Zone whether such vegetation occurs in yard areas around the “Building or Structure,” on the roof or rain gutters of the “Building or Structure,” or any other location within the Zone. (2) Remove dead tree or shrub branches that overhang roofs, below or adjacent to windows, or which are adjacent to wall surfaces, and keep all branches a minimum of ten feet (10 ft.) away from chimney and stovepipe outlets. (3) Relocate exposed firewood piles outside of Zone 1 unless they are completely covered in a fire resistant material. (4) Remove flammable vegetation and items that could catch fire which are adjacent to or under combustible decks, balco- nies and stairs.
CWUIC § 6-3 Medium relevance — show source text
2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 6-3

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FIRE PROTECTION REQUIREMENTS

602.3.2 Final fire protection plan. Final fire protection plan shall include items listed in Section 602.3.1 and the following: 1. A map identifying all proposed plants in the fuel modification zones with a legend that includes a symbol for each proposed plant species. The plan shall include specific information on each species proposed, including but not limited to: 1.1. The plant life-form;

1.2. The scientific and common name; and

1.3. The expected height and width for mature growth. 2. Identification of irrigated and nonirrigated zones. 3. Requirements for vegetation reduction around emergency access and evacuation routes. 4. Identification of points of access for equipment and personnel to maintain vegetation in common areas. 5. Legally binding statements regarding community responsibility for maintenance of fuel modification zones. 6. Legally binding statements to be included in covenants, conditions and restrictions regarding property owner responsibili- ties for vegetation maintenance.

SECTION 603— VEGETATION PLAN

603.1 General. Planting of vegetation for new landscaping shall be selected to reduce vegetation in proximity to a structure and to maintain vegetation as it matures.

603.2 Application. All new plantings of vegetation in State Responsibility Area (SRA) and Local Responsibility Areas (LRA) designated as a Fire Hazard Severity Zone shall comply with Sections 603.3 through 603.4.2.1.

603.3 Landscape plans. Landscape plans shall be provided when required by the code official. The landscape plan shall include devel- opment and maintenance requirements for the vegetation management zone adjacent to structures and roadways, and provide significant fire hazard reduction benefits for public and firefighting safety.

603.3.1 Contents. Landscape plans shall contain the following: 1. Delineation of the 30-foot (9144 mm) and 100-foot (30 480 mm) fuel management zones from all structures. 2. Identification of existing vegetation to remain and proposed new vegetation. 3. Identification of irrigated areas. 4. A plant legend with both botanical and common names, and identification of all plant material symbols. 5. Identification of ground coverings within the 30-foot (9144 mm) zone.

603.4 Vegetation. All new vegetation shall be fire-smart vegetation in accordance with this section.

Exception: Trees classified as nonfire-smart vegetation complying with Section 603.4.2.1.

To be considered fire-smart vegetation, vegetation must meet at least one of the following: 1. Be identified as fire-smart vegetation in an approved book, journal or listing from an approved organization. 2. Be identified as fire-smart vegetation by a licensed landscape architect with supporting justification. 3. Plants considered fire-smart vegetation and approved by the local enforcing agency.

California Wildland-Urban Interface Code Medium relevance — show source text

Appendix B: Electric and Gas Service Documents

Tree Planting Matrix Table s

Applicants should not plant trees either under or adjacent to power lines. IF applicants decide to plant trees or shrubs on their properties, attached is a list of low-growing, fire-resistant vegetation to consider for ground cover near facilities.

Table B-1 through Table B-6 list trees that are suitable for planting near ( not adjacent to or under ) power lines. The trees are listed by genus and species in each table. The list is limited and does not include all suitable trees; however, applicants can use this information as a guideline for choosing an appropriate tree for planting near power lines. The basic rule of thumb is to choose plants that grow to be 25 feet or less at maturity. For additional suggestions about appropriate trees, consult with nurseries, certified arborists, gardening books, and websites like SelecTree at http://ecologycenter.org/directory/directory−entries/selectree/ (maintained by the Urban Forest Ecosystems Institute at Cal Poly State University, San Luis Obispo).

PG&E urges applicants to consider planting shrubs, grasses, and flowers near and under power lines. By selecting low-growing vegetation, applicants ensure that trimming back intrusive growth is not an issue.

2022 – 2023 B−6

Appendix B: Electric and Gas Service Documents

Table B-1 Plant Matrix for Stockton, Yosemite, Fresno, and Kern Divisions [1]

Botanical Name Genus and Species	Common Name	Evergreen vs. Deciduous	Height and Spread (in feet)	Drought Tolerant	Special Considerations	Climate Zones 2
Acer buergeranum	Trident Maple	D	25 s	No	Low spreading growth, red to yellow fall color.	4‐9, 14‐16, 20, 21
Acer palmatum	Japanese Maple	D	25 h	No	Green leaf varieties tolerate sun best, fire resistance favorable.	1‐9, 14‐24
Cercis canadensis	Eastern Redbud	D	25‐40 h 3	No	Small rosy pink flowers in early spring, is easily killed by over‐watering.	1‐3, 7‐20
Cotinus coggygria `prupurea'	Smoke Tree	D	25 h	—	Branches droop but resist breakage, full sun, dramatic puffs of purple to lavender from fading flowers.	1‐24
Crataegus laevigata	English Hawthorn	D	25 h 15 s	—	Thorny branches, need pruning to thin out excess twiggy growth, bright rose to red flowers.	1‐11, 14‐17
Koelreuteria paniculata `Kew' or` Fastigiata'	Golden Rain Tree	D	25 h	No	Branches susceptible to breakage,

California Wildland-Urban Interface Code Medium relevance — show source text
***** This document is not in the printed manual and is available only in the online version of

the Greenbook on www.pge.com/greenbook.

Applicants should access PG&E’s Internet website at www.pge.com/greenbook to find the latest versions of, and updates to, these documents. Also, applicants may contact their local PG&E service planning offices to ensure their documents are current.

N OTE : See Table FM-1, “Service Planning Office and Inspection Desk Contact

Information,” at the front of this manual starting on Page iv, for specific contact numbers listed by area.

Applicants should refer to PG&E’s Community Wildfire Safety Program Guide to Landscaping in High Fire-Threat Areas (included on the following two pages) for updated guidance on extending the defensible space around your property, specifically around power lines. Following this guidance could help save both real estate and lives.

B−1 2022 – 2023

Appendix B: Electric and Gas Service Documents

2022 – 2023 B−2

Appendix B: Electric and Gas Service Documents

B−3 2022 – 2023

Appendix B: Electric and Gas Service Documents

2022 – 2023 B−4

Appendix B: Electric and Gas Service Documents

B−5 2022 – 2023

Appendix B: Electric and Gas Service Documents

Tree Planting Matrix Table s

Applicants should not plant trees either under or adjacent to power lines. IF applicants decide to plant trees or shrubs on their properties, attached is a list of low-growing, fire-resistant vegetation to consider for ground cover near facilities.

Table B-1 through Table B-6 list trees that are suitable for planting near ( not adjacent to or under ) power lines. The trees are listed by genus and species in each table. The list is limited and does not include all suitable trees; however, applicants can use this information as a guideline for choosing an appropriate tree for planting near power lines. The basic rule of thumb is to choose plants that grow to be 25 feet or less at maturity. For additional suggestions about appropriate trees, consult with nurseries, certified arborists, gardening books, and websites like SelecTree at http://ecologycenter.org/directory/directory−entries/selectree/ (maintained by the Urban Forest Ecosystems Institute at Cal Poly State University, San Luis Obispo).

PG&E urges applicants to consider planting shrubs, grasses, and flowers near and under power lines. By selecting low-growing vegetation, applicants ensure that trimming back intrusive growth is not an issue.

2022 – 2023 B−6

Appendix B: Electric and Gas Service Documents

Table B-1 Plant Matrix for Stockton, Yosemite, Fresno, and Kern Divisions [1]

California Wildland-Urban Interface Code Medium relevance — show source text

needs full sun, it is quite frost
sensitive.|14‐24| |Myoporum insulare|Myoporum|E|30 h 3
20 s|—|Fire resistant, takes full sun, tough,
fast growing, it is quite frost sensitive.|8, 9, 15‐17,
19‐24| |Styrax japonica|Japanese Snowdrop
Tree, Japanese
Snowbell|D|30 h 3|No|Needs well‐drained soil, full sun or
part shade, plenty of water, prune to
control shape, tends to be shrubby if
lower branches left.|3‐10, 14‐21|

1 Plant Matrix for North Coast (counties Humboldt, Mendocino, Lake, Sonoma) (Zones 1, 2, 14, 15, 17) and North Bay Division (counties Napa, Marin) (Zones 7, 14, 15, 16, 17). 2 Refer to the climate zone map in Sunset Western Garden Book for the climate zone in your area. 3 Trees referenced as growing to 30 feet (or more) at maturity generally do not reach their maximum height except under optimum growing conditions.

PG&E-Prohibited Trees

Applicants must not plant the trees listed in Table B-7, “Do Not Plant These Trees Under or Within 15 Feet of Overhead Power Lines,” under or within 15 feet of overhead power lines. When mature, these trees affect PG&E’s ability to provide and maintain safe and reliable service. Many species of trees are not appropriate for confined spaces under electric lines, although they may be appropriate for other locations within a development or building site. The list is limited and does not include all varieties of unsuitable trees; however, applicants can use this information as a guideline when choosing an appropriate tree for planting near power lines. Applicants should plant trees that grow higher than 25 feet at maturity at least 15 feet to the side of overhead power lines .

2022 – 2023 B−12

Appendix B: Electric and Gas Service Documents

Under the botanical names of the trees, occasionally only the genus is listed. Applicants should not plant any types of trees within these genera under or within 15 feet of overhead power lines.

Table B-7 Do Not Plant These Trees Under or Within 15 Feet of Overhead Power Lines

Botanical Name (Genus and species)	Common Name	Evergreen vs Deciduous	Height and Spread (in feet)	Special Considerations	Climate Zones 1
Acacia baileyana	Bailey Acacia	—	30 h	Most commonly planted. Fast growing, short lived.	7‐9, 13‐24
Acacia mellanoxylon	Blackwood Acacia	—	40 h 20 s	Fast dense upright growth. Roots aggressive, lifts sidewalks, splits easily and suckers (grows from the roots).	8, 9, 13‐24
Acer macrophyllum	Bigleaf Maple	D	30‐95 h	Native to California foothills, too big for small gardens and streets.

CWUIC § 1.11. Medium relevance — show source text
- The California Code of Regulations (CCR), Title 19, Division 1 provisions that are found in the California Wildland-Urban Interface Code are a reprint from the current CCR, Title 19, Division 1 text for the code user’s convenience only. The scope, applicability and appeals procedures of CCR, Title 19, Division I remain the same. The state agency does not adopt sections identified by the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.
The California Code of Regulations (CCR), Title 14, Division 1.5 provisions that are found in the California Wildland-Urban Interface Code are not listed in the Matrix Adoption Tables as they are not within the State Fire Marshal’s authority to adopt. These provisions are a reprint from the current CCR, Title 14, Division 1.5 text for the code user’s convenience only and are identified in the body of the code by square brackets containing references to applicable Title 14 sections.

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APPENDIX F-2 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE

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F CHARACTERISTICS OF FIRE-SMART VEGETATION

This appendix is for informational purposes and is not intended for adoption.

User notes:

About this appendix: Appendix F is an informational appendix provided for the convenience of the code user. It is simply a compilation of the eight characteristics of fire-smart vegetation that can be used effectively within wildland-urban interface areas to reduce the likelihood of fire spread through vegetation.

SECTION F101—GENERAL

F101.1 Characteristics of fire-smart vegetation. All plants will burn under extreme fire weather conditions, such as drought. However, plants burn at different intensities and rates of consumption. Fire-smart plants burn at a relatively low intensity, slow rates of spread and with short flame lengths. The following are characteristics of fire-smart vegetation:
1. Growth with little or no accumulation of dead vegetation (either on the ground or standing upright).
2. Nonresinous plants (willow, poplar or tulip trees).
3. Low volume of total vegetation (for example, a grass area as opposed to a forest or shrub-covered land).
4. Plants with high live fuel moisture (plants that contain a large amount of water in comparison to their dry weight).
5. Drought-tolerant plants (deeply rooted plants with thick, heavy leaves).
6. Stands without ladder fuels (plants without small, fine branches and limbs between the ground and the canopy of overtopping shrubs and trees).
7. Plants requiring little maintenance (slow-growing plants that, when maintained, require little care).
8. Plants with woody stems and branches that require prolonged heating to ignite.
2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE APPENDIX F-3

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APPENDIX F-4 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE
CWUIC § 4.1 Medium relevance — show source text
2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE APPENDIX A-5

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

APPENDIX A—GENERAL REQUIREMENTS

A105.3 Explosives. Explosives shall not be possessed, kept, stored, sold, offered for sale, given away, used, discharged, transported or disposed of within wildland-urban interface areas, except by permit from the code official.

A105.4 Combustible materials. Outside storage of combustible materials such as, but not limited to, wood, rubber tires, building materials or paper products shall comply with the other applicable sections of this code and this section. A105.4.1 Individual piles. Individual piles shall not exceed 5,000 square feet (465 m [2] ) of contiguous area. Piles shall not exceed 50,000 cubic feet (1416 m [3] ) in volume or 10 feet (3048 mm) in height.

A105.4.2 Separation. A clear space of not less than 40 feet (12 192 mm) shall be provided between piles. The clear space shall not contain combustible material or nonfire-smart vegetation.

SECTION A106—DUMPING

A106.1 Waste material. Waste material shall not be placed, deposited or dumped in wildland-urban interface areas or in, on or along trails, roadways or highways or against structures in wildland-urban interface areas .

Exception: Approved public and approved private dumping areas.

A106.2 Ashes and coals. Ashes and coals shall not be placed, deposited or dumped in or on wildland-urban interface areas.

Exceptions:
1. In the hearth of an established fire pit, camp stove or fireplace.
2. In a noncombustible container with a tightfitting lid, which is kept or maintained in a safe location not less than 10 feet (3048 mm) from nonfire-smart vegetation or structures.
3. Where such ashes or coals are buried and covered with 1 foot (305 mm) of mineral earth not less than 25 feet (7620 mm) from nonfire-smart vegetation or structures.
SECTION A107—PROTECTION OF PUMPS AND WATER STORAGE FACILITIES

A107.1 General. The reliability of the water supply shall be in accordance with Sections A107.2 through A107.5.

A107.2 Objective. The intent of this section is to increase the reliability of water storage and pumping facilities and to protect such systems against loss from intrusion by fire.

A107.3 Fuel modification area. Water storage and pumping facilities shall be provided with a defensible space of not less than 30 feet (9144 mm) clear of nonfire-resistive vegetation or growth around and adjacent to such facilities.

Persons owning, controlling, operating or maintaining water storage and pumping systems requiring this defensible space are responsible for clearing and removing nonfire-smart vegetation and maintaining the defensible space on the property owned, leased or controlled by said person.

A107.4 Trees. Portions of trees that extend to within 30 feet (9144 mm) of combustible portions of water storage and pumping facilities shall be removed.

California Wildland-Urban Interface Code Medium relevance — show source text

The list is limited and does not include all varieties of unsuitable trees; however, applicants can use this information as a guideline when choosing an appropriate tree for planting near power lines. Applicants should plant trees that grow higher than 25 feet at maturity at least 15 feet to the side of overhead power lines .

2022 – 2023 B−12

Appendix B: Electric and Gas Service Documents

Table B-7 Do Not Plant These Trees Under or Within 15 Feet of Overhead Power Lines

Botanical Name (Genus and species)	Common Name	Evergreen vs Deciduous	Height and Spread (in feet)	Special Considerations	Climate Zones 1
Acacia baileyana	Bailey Acacia	—	30 h	Most commonly planted. Fast growing, short lived.	7‐9, 13‐24
Acacia mellanoxylon	Blackwood Acacia	—	40 h 20 s	Fast dense upright growth. Roots aggressive, lifts sidewalks, splits easily and suckers (grows from the roots).	8, 9, 13‐24
Acer macrophyllum	Bigleaf Maple	D	30‐95 h	Native to California foothills, too big for small gardens and streets.	4‐17
Acer negundo	Box Elder	D	60 h	Fast growing, seeds readily, subject to breakage.	1‐10, 12‐24
Acer rubrum	Red Maple	D	40+ h 20+ s	Fast growing, red twigs, branchlets and buds.	1‐9, 14‐17
Acer saccharinum	Silver Maple	D	40‐100 h equal spread	Fast growth, weak wood.	1‐9, 12, 14‐24
Ailanthus altissima	Tree of Heaven	D	50 h	Fast growing, suckers and self seeds.	All zones
Alnus spp.	Alder Trees	D	40‐90 h	Relatively fast growing, invasive roots, several native California species.	Various
Eucalyptus	Eucalyptus	E	30‐200 h	Fast growing, invasive roots, many species.	8‐24
Fraxinus	Ash Trees	D	35‐80 h	Relatively fast growing.
Carya illinoensis	Pecan Trees	D	70 h 70 s	Long tap root and leathery mature leaves.	8‐9, 12‐14, 18‐20
Catalpa spp.	Catalpa	D	up to 70 h	Some litter from fallen flowers in summer and seed capsules in fall.

CWUIC § 302.1 Medium relevance — show source text

2|Purpose|Y|||||||51176|4201| |302|Wildland-Urban
Interface Area
Designations|Y||||||||| |302.1|Mapping|Y|||4904.2||||51178|4202
4203(a)
4204| |302.2|Review of wildland-
urban interface areas|Y|||||||51181|4204| |Chapter 4|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements| |401|General|Y||||||||| |401.1|Scope|Y||||||||| |401.2|Objective|Y||||1273.00||||| |401.3|General safety
precautions|Y||||||||| |402|Applicability|Y|||||||||

APPENDIX H-26 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS

2025 CWUIC—continued	Col2	Adopted Yes/No	IWUIC Section	CBC Section	CFC Section	Title 14, Division 1.5 Section	Title 19, Division 1 Section	Gov Code Section	PRC Section	HSC Section
Section	Title	Title	Title	Title	Title	Title	Title	Title	Title	Title
Chapter 4	Wildland-urban interface area requirements	Wildland-urban interface area requirements	Wildland-urban interface area requirements	Wildland-urban interface area requirements	Wildland-urban interface area requirements	Wildland-urban interface area requirements	Wildland-urban interface area requirements	Wildland-urban interface area requirements	Wildland-urban interface area requirements	Wildland-urban interface area requirements
402.1	Subdivisions	Y
402.1.1	Access	Y			503
402.1.2	Water supply	Y			507
402.1.2.1	Parcel map approval	Y						1275.01
402.2	Individual structures	Y			503 507
402.2.1	Access	Y			503
402.2.2	Water supply	Y			507
402.3	Existing conditions	N			505.1
403	Access	Y				1273
403.1	General	Y				1273.00
403.1.1	Section 403 definitions	Y				1270.01(f)
403.1.2	Width	Y				1273.01(a) 1273.

Frequently asked questions

What is “drip line” as used in these rules?

The CWUIC uses the term but the code excerpts retrieved do not include a formal definition of drip line; the rules reference the tree’s drip line at maturity when setting clearances (see § 603.4.2(1)). Use the common arboricultural meaning — the outermost edge of the tree crown where water drips off leaves — when measuring setbacks.

Can I plant a tall conifer within 30 feet of my house?

Tall conifers are typically nonfire‑smart. Under § 603.4.2.1, a nonfire‑smart tree is only permitted if its mature drip line is 30 ft from the building, or it is planted 10 ft away and is kept very well pruned and maintained to prevent rapid fire transmission.

Do these measurements use the plant’s mature size or its planting size?

They use the plant’s mature size (for example, the tree’s drip line at maturity), so plan and plant accordingly. See § 603.4.2(1) and § 603.3 (which requires expected mature dimensions on landscape plans).

If my tree is already planted and too close at maturity, what then?

Existing trees have trimming requirements: for example, branches must be kept 10 ft from chimney and stovepipe outlets per § 603.4.2(3); other corrective actions (pruning, removal, or relocation when possible) will be enforced per local authority and defensible space rules (see related §§).

Where do I show these plant dimensions during permitting?

Provide them on the landscape plan as required by § 603.3.1, which specifically asks for expected height and width at maturity and identification of irrigated areas.

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