March 11, 2026
Court of Appeal, Second Appellate District, Division Five
The Rule of Yan v. City of Diamond Bar is that evidence of prior branch failures from the same tree species in the same vicinity is admissible to prove a public entity's actual or constructive notice of a dangerous condition, under circumstances where the trees share common characteristics (same species, maintenance schedule, and environmental factors) and the evidence demonstrates a pattern of recurring problems that should attract the entity's attention to a condition requiring correction.