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Ohio State University Extension


Tax Treatment of Timber Damaged by Insects

Sunday, June 23rd, 2013

Larry Gearhardt, Asst. Professor, OSU Extension

Much of Ohio’s forestland has been plagued by, first, the emerald ash borer, and more recently, the Asian longhorn beetle. Can you deduct the loss on your tax form when a major portion of your forest land is destroyed by these insects? You can if the timber or forest land is held to produce income. If the timber is held merely for personal use, the loss is not deductible. A tax deduction is available to owners who hold timber or forest land to produce income, as opposed to personal use.  

Casualty Versus Non-Casualty Loss

Where to deduct a loss on your tax forms depends upon whether the loss is a casualty loss or a non-casualty loss. A “casualty” is defined as the damage, destruction, or loss of property from an identifiable event that is sudden, unexpected, and unusual. Disease, insect infestation, drought, or combinations of factors seldom qualify as a casualty because these types of damage tend to be gradual or progressive rather than sudden. However, Revenue Ruling 79-174 provides that a massive southern pine beetle infestation that killed residential shade trees in 5 to 10 days did qualify as a casualty. Whether or not it is a casualty depends upon the facts of the situation.  

A “non-casualty” loss is defined as the damage, destruction beyond use, or loss of property from an identifiable event. Like a casualty, the precipitating event for a non-casualty loss must be unusual and unexpected, but unlike a casualty, it does not have to be sudden. For example, insect attacks have resulted in deductible non-casualty losses of timber according to Revenue Ruling 87-59.  

Deduction of a Non-Casualty Loss

A non-casualty loss is a business deduction. With one exception, owners who hold their timber as an investment, as opposed to managing timber as a business, cannot deduct a non-casualty loss. The exception is unusual and unexpected drought.  

To calculate the amount of a non-casualty loss, the owner must first calculate the basis of the timber lost as you would for a sale. You then divide the adjusted basis in the affected block of timber by the basis of the total volume of timber in the block, updated to immediately before the loss. The result is multiplied by the volume of timber lost.  

As an example, assume that the fair market value of the timber lost was $9,000. The basis of the timber lost was $3,500. If you held the timber as part of a trade or business, you could deduct $3,500 allowable basis in the timber lost on IRS Form 4797. Start on IRS Form 4797, Part II, for timber held one year or less, or Part I for timber held more than one year. The loss will be netted with other gains and losses from the disposal of other business property. If you are holding the timber as an investment, you cannot deduct a non-casualty loss unless it was from drought.  

In contrast with casualty losses, which are deducted first from ordinary income, non-casualty losses are first deducted from capital gains. This treatment of non-casualty loss is a disadvantage, since capital gains receive more favorable tax treatment.  


A loss frequently gives rise to related expenses, such as the cost of a cruise or appraisal to determine the extent of the loss, that cannot be included as part of the loss. Such expenses are often deductible, but where you take the deduction differs according to the type of loss.

If you hold your timber or forest land as part of a trade or business, these expenses are deducted on IRS Form 1040, Schedule C, or Schedule F if you qualify as a farmer.   If you hold your timber or forest land as an investment, an owner can deduct expenses related to a non-casualty loss to the extent that they qualify as “ordinary and necessary” expenses, even if you cannot deduct the loss itself. However, an owner holding timber as an investment will report expenses on IRS Form 1040, Schedule A, in the “Miscellaneous deductions” section. This deduction will be subject to the 2% of adjusted gross income floor.  

What If There Is a Gain?

If timber or forest land is damaged or destroyed and the owner receives payment in the form of a damage claim, salvage proceeds, insurance recovery, or other compensation, the transaction is called an involuntary conversion or involuntary exchange. If the payment that the owner receives is greater than the basis of the timber lost, there will be a gain rather than a deductible loss. Unless the owner elects to defer the gain by replacing the property within specified time limits, the gain must be reported.

For more information, see the USDA Forest Landowners' Guide to the Federal Income Tax here.  

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