Arlington | Trees, Airport and Historic Rules

Arlington Tree, Airport and Historic Rules: Cross Timbers Oaks, Noise Zones and Landmark Review

Three Arlington rules can change a project even on a lot where zoning allows the homes. The tree preservation rule makes every subdivision of one acre or more keep a share of its trees, with extra credit for native oaks. The Airport Overlay bars new houses in the noisier zones around Arlington Municipal Airport. And the Landmark Preservation and Conservation District overlays add design review in historic areas. All three are in the Unified Development Code (UDC). The Arlington overview gives the short version.

Why Arlington Counts Trees

Section 5.2.3 opens with the reason: "A large area of the eastern branch of the Cross Timbers ecosystem lies within the City of Arlington." The Cross Timbers is a band of native oak woodland, and the code defines "Cross Timbers oaks" as "post oaks, Texas oaks, and blackjack oaks." The section applies "to all types of development, including non-structural improvements such as parking lots," and the applicant submits a preservation plan "at the time of application for a planned development, plat, site plan, or building permit, whichever is the first to occur."

The rule was last rewritten by Ordinance No. 25-014 on February 25, 2025, which the ordinance history describes as "updating tree preservation credits, increasing penalties for the removal of protected tree, and providing development incentives for preserving additional trees." The City's UDC page links its "Protected and Prohibited Tree Species" list, which says which species count.

How the Tree Count Works

The code counts in tree points. "One tree point shall be equal to one caliper inch," and caliper is the width of a trunk. The steps are:

• Minimum inventory. List every tree with a number, species, caliper and type, then add up "the total caliper inches of all protected trees." For non-residential projects, small trees inside the building footprint are taken out first.
• Preservation plan. Start from the inventory. "Add one-half additional point per caliper inch for the proposed preservation of Cross Timbers oaks" and one-quarter point for "Bonus Trees." Subtract the inches of every protected tree "at least six caliper inches or greater in size that are to be removed," and subtract one more point per inch for any heritage tree removed.
• Compare. The preservation plan, as a percentage of the minimum inventory, must meet the target in the table below.

Source: Arlington UDC, Section 5.2.3, subsections B, D, E and I, PDF amended by Ordinance No. 25-059.

For homes, the code says "residential development" means "single-family, two-family, or cottage community development," and that "all residential developments, including small-lot residential developments, shall achieve a minimum of 35 percent preservation." The same subsection "shall not apply to residential development under one acre in size," so a single infill lot is outside it. That share "may not be reduced by mitigation," so planting new trees cannot make up for cutting too many. Trees "shall be preserved in contiguous stands," meaning groups that touch, except that on lots of 10,000 square feet or more trees may be kept lot by lot "inside a landscape easement." Credit for a kept tree requires that "a minimum of 75 percent of the critical root zone shall be preserved at natural grade," the soil around the roots left at its original level.

Removing Trees Outside a Development

Section 5.2.3.I covers trees removed when no project is under review. A tree removal permit is required, but "neither a tree removal permit nor mitigation shall be required for the removal of trees on a parcel, tract, or lot under one acre in size with an occupied residential structure." On other land, removing "trees six caliper inches or greater or Cross Timbers oaks three caliper inches or greater" requires payment into the Reforestation Fund for each inch at the tree replacement fee. The fee schedule effective October 1, 2026 lists:

• Tree removal permit, not with a building permit: $10.00 per tree, minimum $30.00, maximum $150.00.
• Tree replacement fee: $200.00 per caliper inch.
• Unauthorized tree removal fee, effective April 1, 2025: $600.00 per caliper inch.
• Tree preservation plan review: $400.00.

Clearing land before a project is approved is barred: "the removal of trees is prohibited prior to recordation of a plat associated with site development," unless, on written request, the Zoning Administrator allows it under the approved preservation plan. An owner who clears land without approval faces the $600 per inch fee, a stop work order, and the City "withholding any future permits associated with the responsible party or the subject property until such time as all fees assessed are paid in full."

Trees as a Trade for Lot Size and Parking

Section 5.2.3.G rewards projects that keep more. It applies when "the Minimum Inventory meets or exceeds 300 caliper inches of protected trees." A residential project that preserves more than 35 percent may reduce lot area, lot dimensions or home size by "one percent for each one percent increment" above 35, up to 15 percent, except small-lot projects. A multi-family project may cut garage parking by one percent per percent above its target, up to "50 percent of the garage parking requirements," while "the overall parking requirements for the development shall not be reduced." Separately, Section 5.2.3.H lets the Zoning Administrator approve "a reduction of not more than ten percent of the number of required parking spaces" to save Cross Timbers oaks. The lot size page shows the lot rules this reduces.

The Airport Overlay

Section 5.8.2 regulates land near Arlington Municipal Airport. The "controlled area" is the land "within an area measured no farther than one and one-half statute miles from the centerline of the Arlington Municipal Airport runway and lines no farther than five statute miles from each end of the paved surface of the runway," the area state law lets a city regulate for airport compatibility. Inside it, four overlay zones are drawn on the zoning map by noise. The code labels each zone with its "Average Sound Level (DNL)" in decibels; a higher number means more aircraft noise.

Source: Arlington UDC, Section 5.8.2.C and Table 5.9-1. Y means permitted, N means prohibited, and 25 means permitted with noise reduction of 25 decibels built into the structure under the City's Construction Chapter.

When a parcel lies in more than one zone, "the provisions of the most restrictive overlay are applicable to the entire parcel," unless the Zoning Administrator finds the building itself sits in one zone or outside the overlay. The overlay also sets height surfaces for aircraft approaches, but "nothing in this Code shall be construed as prohibiting the growth, construction, or maintenance of any tree or structure to a height up to 50 feet above the surface of the land."

The airport also limits the 2025 state-law routes. SB 15 small lots are barred on tracts "within 3,000 feet of an airport" (Section 3.2.1.A.3), and apartments on commercial land are barred "within 3,000 feet of the Arlington Municipal Airport" (Section 3.2.1.A.2). Two small errors in Section 5.8.2: the table is numbered "Table 5.9-1" though it sits in Section 5.8.2, and its header labels APO-4 "70 - above" while subsection C defines APO-4 as the area "inside the 75 DNL noise contours." Subsection C draws the zone boundaries, so read APO-4 as the area inside the 75 DNL contour.

Landmark Preservation Overlay

The Landmark Preservation Overlay (LPO) protects "buildings, structures, sites, and areas of architectural, historical, archaeological, or cultural importance or value" (Section 2.4.6). Under Section 10.4.9, "no person or entity shall construct, reconstruct, alter, change, restore, remove, or demolish any exterior architectural feature" in an LPO district without a certificate of appropriateness, a design approval from the Landmark Preservation Commission. Exempt are "ordinary repairs and maintenance that do not involve changes" in style, design, materials, primary color or texture, and "accessory buildings less than 320 square feet."

• Timing. The commission holds a public hearing "within 30 days of the receipt of a completed application," or within 45 days for removal or demolition, joined with the demolition permit hearing. Notice runs in a newspaper "at least seven days prior."
• No action means approval. "If the Landmark Preservation Commission takes no action within 60 days of receipt of the completed application, a certificate of appropriateness shall be deemed issued."
• Additions. The guidelines in Section 5.8.3 recommend additions at the rear or an inconspicuous side, set back "a minimum of 10 feet from the primary façade," and no more than "50 percent of the square footage of the existing footprint."
• Parking relief. Minimum parking need not apply to a new use in an existing LPO building that expands by no more than 30 percent, if the Zoning Administrator finds no harm.

The general house design rules in Section 5.5.3, including the masonry rule, do not apply in the LPO district. The fee schedule effective October 1, 2026 charges $100 for a "Request for 'LPO' Overlay only."

Conservation Districts

A conservation district overlay (CDO) is a less strict overlay for neighborhoods with a clear character that "may lack sufficient historical, architectural, or cultural significance at the present time to be designated as a historic district" (Section 2.4.2). Its purposes include "to promote and retain affordable housing and stabilize property values." Section 5.8.4 sets four tests: the area must be covered by a neighborhood plan adopted by the City Council that "recommends a conservation district overlay," contain "a minimum of one blockface," have "at least 75 percent of the structures" improved "at least 25 years ago," and show distinctive features such as scale, lot layouts or street layouts.

Under Section 10.4.2.B, a CDO zone change may be started only by owners of "60 percent of the land area," by "60 percent of the property owners," or by the planning director under an adopted plan. It then follows the normal zone change path, and the fee is $1,200. A CDO with its own residential design standards replaces the general design rules of Section 5.5.3. Before buying in an older area, check the zoning map for an LPO or CDO label.

Where to Go Next

Related on VanPlex: the Arlington overview, insurance and flood rules in Texas, and how Texas zoning works.

Frequently Asked Questions

Official sources (checked October 2026)