I recently commented about the abundant spring rain and numerous sunny summer days causing a profusion of orange American mountain ash tree berries here this September. Well, I discovered, about half a mile from the tree that I photographed then, this mountain ash that had a profusion of bright red (not orange) berries.
A little research indicates that this color variation apparently is fairly common for the American mountain ash (Sorbus americana, aka American rowan tree). Some of these trees have a genetic tendency to produce more red pigments (anthocyanins), while others produce more orange pigments (carotenoids). The amount of sun received, and age of the trees also apparently can affect their berry coloration.
(Images here taken in Brooklin, Maine, on September 22, 2025.)