Sahih Bukhari Volume 5, Book 59, Hadith Number 365.

Narrated By Ibn Umar: Allah’s Apostle had the date-palm trees of Bani Al-Nadir burnt and cut down at a place called Al-Buwaira. Allah then revealed: “What you cut down of the date-palm trees (of the enemy) Or you left them standing on their stems. It was by Allah’s Permission.” (59.5)