Qasim Rahimahullah narrates: A man passed by Abu Darda (RA) in Damascus when he was planting a tree and said to Abu Darda (RA): Are you also doing a (worldly) work, though you are a Sahabi (companion) of Rasulullah (peace and blessings be upon him)? He said: Don't hasten to blame me; I heard Rasulullah saying: Never did a man plant a sapling (a young tree), and then a man, or any other creation of Allah Glory to Him, ate (or benefited) from it, except that it becomes a Sadaqah (charity) for the planter.
Source: Sahih Muslim.
Islam considers the slightest acts of helping others as charity! Even smiling at others to make them happy is counted as charity. It is due to our selfishness that mankind suffers. Let us give more and take less.