It is reported about Sayyiduna Abu al-Darda' (may Allah be pleased with him) that a man passed by him while he was planting saplings in Damascus. The man said: "You are doing this, while you are a Companion of the Messenger of Allah?" He said: "Do not be hasty in judging me. I heard the Prophet (peace and blessings be upon him) say: 'Whoever plants a sapling (or tree), then whatever human or whatever creature from among the creatures of Allah eats anything from it, that is counted as charity for that person.'"
Imam Ahmad and al-Tabarani in al-Mu'jam al-Kabir recorded it; its narrators have been declared trustworthy, and there is some criticism of its narrators that does no harm.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب البيوع / 6267