It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Its thorny trees are not to be cut, its game is not to be startled, its grass is not to be uprooted, and its lost property is lawful only for one who announces it." Sayyiduna Abbas (may Allah be pleased with him) said: Except the idhkhir? He (peace and blessings be upon him) said: "Except the idhkhir."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11583