He broke a branch off his neighbour’s tree when he was small; what must he do now?
Question

Is breaking a branch from the side of someone’s property prohibited? Please note that I broke it when I was small, many years ago, and I happened to pass by that house and I remembered that incident.
Praise be to Allah.Prohibition on transgressing against a Muslim’s property
It is prohibited to transgress against a Muslim’s property, no matter how small the transgression. This is indicated by a great deal of evidence in the Holy Qur’an and Prophet’s Sunnah.
Allah, may He be exalted, says (interpretation of the meaning):
{O you who have believed, do not consume one another’s wealth unjustly but only [in lawful] business by mutual consent}
[an-Nisa’ 4:29].
The Prophet (blessings and peace of Allah be upon him) said: “It is not permissible to take the property of a Muslim except with his consent.” Narrated by Ahmad, 20172; classed as authentic by al-Albani in Irwa’ al-Ghalil, 1459.
And the Prophet (blessings and peace of Allah be upon him) said: “Your blood, your wealth and your honour are sacred to all of you.” Narrated by al-Bukhari, 1739; Muslim, 1679.
All of this evidence – and much more – indicates that it is prohibited to transgress against the wealth of a Muslim, whether that transgression means destroying, usurping, stealing or anything else.
Secondly:
Whoever destroys something is liable for it
Whoever destroys the property of a Muslim is liable for it, so if the property can be replaced, then he must replace it for its owner; if it cannot be replaced, he must give him its value.
It is the same whether the one who destroyed it is a child or an adult. When it comes to liability, it is not stipulated that the one who destroyed the property should be an accountable person [i.e., an adult of sound mind]; rather having the age of accountability is required for the sin to be recorded as such.
Ibn al-Qayyim (may Allah have mercy on him) said:
With regard to liability, it is not stipulated that a person should be accountable in order to be liable. So a minor, an insane person and one who was asleep are all liable for whatever property they destroy. This is one of the general rulings without which the interests of the ummah cannot be attained. If they were not liable for damage that they cause, they would destroy one another’s property and claim that it was a mistake and was not deliberate. This is different from the rulings on sin and punishment, because it is connected to going against the rules and to a person’s action and his committing of sin.
End quote from I`lam al-Muwaqqi`in, 2/502.
So if we suppose that this branch had some value, what you must do is give that value to its owner, but it is not stipulated that you must inform him of that; rather you should make sure it reaches him by any means. This has been discussed previously in the answer to question no. 220949.
But what appears to be the case is that the branches that children are able to break do not usually have any value. In such a case, it is sufficient for you to apologize to the owner if you meet him and ask him to forgive you for that, and usually people overlook and pardon such things.
And Allah knows best.