But such fence shall not be removed, if it was made of timber or other material taken from the land on which it is built, until the party pays to the owner of the land the value of the timber or other material, to be ascertained by the fence viewers; nor shall a fence be removed at a time when the removal will throw open or expose the crop of the other party, but it shall be removed within a reasonable time after the crop is secured, although the six months above specified have passed.