Unfortunately, unless the area that was sprayed is also your rental property, that cost would not be deductible on Schedule E.
If you report the timberland on Schedule F (farming/agriculture) or Schedule C (business), you would be able to deduct the cost of the spraying as a Farm/Business Expense.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
