Dinis of Portugal’s “Ai flores, ai flores do verde pino” (Oh flowers, oh flowers of the green pine) is the medieval monarch’s most famous cantiga de amigo and one of the best-known songs of the Galician-Portuguese tradition. Many have read Dinis’s “pine song” as an allusion to the Pinhal de Leiria, the pine forest that he planted—or so the story went. Though Portuguese historians and paleobotanists have debunked the Leiria forest’s origin story, a preponderance of documentary evidence from Dinis’s reign suggests that the monarch recognized the forest as a poetically generative site of political and social tension. In this article, I chart ecocritical and new materialist paths through the “pine songs” of Dom Dinis and other Galician-Portuguese troubadours. Examining the medieval forest in its cultural, commercial, and poetic dimensions, I argue that Dom Dinis understood the pine and his poems as affectively and acoustically co-constituted—and that the Galician-Portuguese troubadour tradition, particularly in its woman’s-voice compositions, encodes important ecological knowledge.