What is the ruling on one who mortgaged a farm and then refused to return it to its owner unless the owner destroyed what he had added to it of trees and plants, knowing that he exploited it, sold its fruits, and gave nothing to the original owner?

The mortgagee is not permitted to benefit from the mortgaged property unless the mortgage is part of a sale transaction and the manner and duration of the benefit are specified. If the mortgagee wishes to leave the land, he does not have the right to uproot its trees; rather, the choice belongs to the owner of the land.