House Bill 1153 amends chapter 76.15 RCW (including RCW 76.15.010 and 76.15.110) and adds new sections to direct the Department of Natural Resources to develop voluntary model urban forestry ordinances that incorporate "tree bank" programs and development incentives. The bill creates and updates statutory definitions (including "tree bank" and "highly impacted community"), expresses legislative findings about encouraging tree preservation while allowing needed housing, and makes programmatic changes to how urban and community forestry is supported and regulated. The measure is primarily procedural and programmatic: it requires the department to use best available science to set appropriate tree-planting ratios, species selection, and criteria for critical trees; to provide tools such as a tree selection and siting tool, best practices and maintenance cost estimates, and optional model ordinances; and to strive to make tools compatible with urban forest carbon market reporting. The bill prohibits local jurisdictions from requiring retention of noncritical trees where retention would reduce allowed density, lots, or floor area ratio, or would preclude middle housing, accessory dwelling units, or required access or utility connections. The department must also offer incentives jurisdictions can adopt to encourage on-site tree retention (for example increasing allowed density or height, reducing lot size or landscaping requirements), provide technical assistance and capacity building, encourage community participation including vulnerable populations, and may consult with the Department of Commerce. The bill creates a grant program, subject to appropriation, to fund jurisdictions that substantially adopt the model ordinance related to tree banks (with additional eligibility rules for jurisdictions over 75,000 population and discretionary awards for prior adopters). It also includes a funding nullification clause: if specific funding for the act is not provided in the omnibus appropriations act by June 30, 2025, the act is null and void. The text available is incomplete on some specifics: the criteria for designating tree bank areas and certain model ordinance provisions are truncated or not shown, appropriation amounts, grant application processes, timelines, enforcement mechanisms, and the effective date referenced for prior adoptions are not provided in the extracted facts.

If enacted, the Department of Natural Resources would produce voluntary model rules and practical tools to let cities, counties, tribes, and community groups set up "tree banks" where trees planted in designated areas can offset trees removed elsewhere, and jurisdictions could allow developers to pay a fee instead of planting. The department would also issue science-based guidance on how many trees are needed in those banks, which species to use, maintenance best practices with cost estimates, and incentives local governments can offer developers to keep large or significant trees (for example allowing more height or density or smaller lots). The state would offer grants to jurisdictions that substantially adopt the model ordinance and allow tree bank options, but those grants and the whole program depend on specific appropriations and will be void if no funding is provided by June 30, 2025. The people most affected are local governments (who will get new tools and optional incentives but face choices about adopting the models), developers (who gain options to satisfy tree requirements via tree banks or fees and are protected from tree-retention rules that would block required housing or access), urban forest managers and tribes (who get technical support and potential access to carbon market–compatible tools), and the Department of Natural Resources (which must produce the guidance and administer grants if funded). Important details are missing from the facts available—such as exact tree-to-tree ratios, fee amounts, grant sizes and timelines, and the full criteria for designating tree bank areas—so the program’s cost implications and how aggressively jurisdictions will adopt the models remain uncertain.