| MadSci Network: Botany |
To tell you the truth I have no idea how much cat urine or at what frequency will kill a tree.
Cat urine, as well as other types (?) of urine, are high in soluble salts content. When soluble salts accumulate in the soil plant roots may be damaged. I think that is probably what is happening to your neighbors tree. Being relatively freshly planted the tree is producing alot of new roots and if they are being damaged the tree may not be getting enough water, nutrient, etc.
In my opinion if you know that your cat pees on the neighbors tree then you need to control your cat. Contact your vet about remedies or materials that would deter kitty from relieving itself over at the neighbors.
Good luck
Gary