Elevating street trees to infrastructure status: A comparison of street tree spacing guidelines in Los Angeles with U.S. peer cities

While researchers recognize the health and ecological benefits of green infrastructure , at the level of city governance trees are relegated to second class status compared to other infrastructure with which they compete for space in the public right-of-way. The result is an unwelcoming environment for walking, cycling, and socializing, particularly in disadvantaged neighborhoods, at a time when city governments are also pursuing ambitious plans for Complete Streets and green infrastructure to address compound challenges related to health, equity, and the environment. This article contributes a thorough review of municipal street tree spacing guidelines through a comparison of guidelines in eight California and nine large U.S. cities, consideration of their change over time, an in-depth examination of laws applying to tree placement in Los Angeles , and interviews with City of Los Angeles staff. Results demonstrate that guidelines in many of the municipalities studied are more restrictive than legally required, vary greatly between cities even while evidence does not support the efficacy of one approach over another, and have not changed substantially over time to align with shifting priorities. Centralized control of the right-of-way could help align guidelines and practice with municipal goals and facilitate consideration of competing priorities. • Tree spacing guidelines vary tremendously without clear differences in performance. • Guidelines have not changed to align with Complete Streets and GI ideals. • Legal changes would often not be necessary to enact less restrictive guidelines. • Street tree standards need additional nuance to better adapt to different contexts. • Centralized right-of-way management should prioritize large tree wells.