What is the religious ruling on the personal use of school firewood that is not being used, and which the head of the institution, who benefits from it for his personal interests, offers?

It is not permissible to benefit from the wood unless with the permission of its owner or the authorized entity, because benefiting from it without permission falls under the category of unjustly consuming people's wealth. It is also an unlawful appropriation of Allah's property if it belongs to the state, and severe warnings have been issued regarding this. Therefore, it is not permissible for the institution's director to use the wood for his personal interests or to give you any of it, except with the permission of the owning authority.