Parece ser um dos livros da série Xanth, mas há muitos e eu poderia tê-los misturado. Existem árvores devoradoras de homens e mágicos.
Each human character in Xanth is born with a unique magical ability,
called a talent. With the exception of the curse fiends, the winged
centaurs, and the child Surprise Golem (Daughter of Rapunzel and
Grundy Golem), these abilities never repeat exactly in individuals
throughout the entire history of Xanth (although nearly identical
talents show up on occasion.) Though many talents are limited in scope
(called the "spot-on-a-wall" variety), the series focuses mainly on
individuals with "Magician" caliber abilities (one of the criteria for
serving as King of Xanth).
In addition to the human characters, Xanth is populated by centaurs,
demons, dragons, fauns, gargoyles, goblins, golems, harpies, merfolk,
naga, nymphs, ogres, zombies, curse fiends, and other fictional
beasts. Though initially introduced as obstacles to the human
characters, some individuals from those groups become main characters
in later books of the series.
Source: Wikipedia article for Xanth