The behavior Al's cat is displaying is TERRITORIALITY.
The cat is marking his territory so that whatever animal comes in Al's yard, they will know that a cat lives there because they can smell his urine and identify his scratches.
Animals who arrives in the cat's territory will be aware of possible danger that the cat may inflict on them for tresspassing his territory. Urine and tree scratches are used as deterrent for other animals from venturing farther in the yard.
