Lehigh County, PA Landscaping Rules: Tree Removal & Heritage Trees (2026)

Section 492.42, Existing Vegetation, opens with a design mandate: all subdivisions and land developments shall be laid out to preserve the healthy trees on the site. Section 492.422 then sets the operative removal-and-replacement standard: if a tree greater than eight inches in caliper is removed, it must be replaced with a tree at least three and one-half inches in minimum caliper drawn from the ordinance's recommended plant list. During construction, Section 492.423 separately requires trees and shrubs to be protected by fencing so their dripline is not encroached by grade changes, trenching, material or topsoil stockpiling, or vehicle compaction, unless the developer meets the limited encroachment allowance in Section 492.4231, capped at one-third of the dripline area if an equivalent share of canopy is removed by a trained arborist through pruning.

Grade within a protected dripline cannot be raised more than six inches without tree wells and aeration piping under Section 492.4232. Separately, Section 492.425 requires that diseased or dead trees be promptly removed from the site, which is a removal mandate rather than a restriction. None of this reaches Allentown or any other Lehigh Valley municipality with its own subdivision ordinance: Section 121.1 confines the county SALDO to municipalities that have not adopted one, and most local zoning and shade tree ordinances, not this county chapter, control tree removal and permitting on private property in the rest of the county.