Is a person considered sinful and liable to guarantee if they accidentally cause the leaves of a tree owned by their relatives to fall while playing?

If what fell from you was by mistake, then there is no sin upon you, as Allah Almighty says: "And there is no blame upon you for that in which you have erred, but [only for] what your hearts intended," and as the Prophet, peace and blessings be upon him, said: "Indeed, Allah has overlooked for my Ummah errors, forgetfulness, and what they are forced to do."

However, if what fell from the tree leads to its damage or has value, then you must compensate the owners of the tree unless they forgive you, because intentional and unintentional acts regarding people's property are equal.