Sahih Muslim 1553a

This Hadīth means that any Muslim who plants a tree or sows a field, then any living being eats from it, he will receive reward for it, even after his death, for the reward of his action will continue as long as the his plants stay beneficial. This Hadīth encourages the planting trees and sowing fields for what they entail of abundance goodness, for they have religious benefits as well as worldly benefits.

If anything is eaten of such trees or plants, it will be counted as charity, even something is stolen of it, i.e. when someone steals dates from his date palm, yet he will receive the reward, keeping in mind that if the owner recognizes the thief, he will sue him in the court, even though, Allah, the Almighty, counts it as charity for its owner until the Day of Judgment.

Also if some animals or insects eat form it, the owner will still receive the reward of charity. The Hadīth specifies the Muslim because he is the one who benefits from this charity in this world and the Hereafter.