I encountered the expression "fiestas de árboles" in a song by a Chilean singer whose lyrics are:
Tus ojos son fiestas de árboles, son mi ventantaventana.
Son estrellas que guían mi caravana.
Google translates itthe expression as "holiday tree" and my search shows it is about trees used in ceremonies. Now, shouldn't it be "árboles de fiestas", that is "trees of holiday"? "Fiestas de árboles" sounds like holidays fulls of trees, if that makes sense.