News | USC Dornsife News | March 2025

How changing L.A.’s tree rules could cool more neighborhoods

A new USC Dornsife study finds that outdated guidelines are limiting tree growth — especially in lower-income neighborhoods — and offers a path forward.

Key points:

• Los Angeles has some of the strictest tree planting rules in the nation. These policies limit tree growth, worsen shade disparities and don’t improve safety, researchers found.
• When USC Dornsife researchers modeled looser planting restrictions in a lower-income neighborhood, potential tree space increased by nearly 26%. But narrow sidewalks and dense infrastructure still limited where larger, shade trees could thrive.
• Many of L.A.’s strict tree-spacing rules are internal guidelines — not laws — meaning they could be updated more easily to allow for more trees.
• Closing L.A.’s shade gap, however, will require more than policy tweaks; infrastructure investments are also needed.