Can I deduct the purchase price of land if it was bought and set up under forestry for the purpose of growing and selling timber? where do I put the cost of the land?

Did you sell the land in 2017?

No I bought it for forestry land in 2017.

Unfortunately, you receive no immediate deduction for purchasing land, even if you plan to use it for business. 

The cost of land purchased for investment becomes your basis in the property, which is a capital asset. Land is not depreciated, so you receive no depreciation or other deductions over the time you own the property. If you sell the land in the future, your basis will reduce the capital gain you might realize if the selling price is more than your purchase cost.

However, if you sell timber that was growing on the land when you purchased it, your basis in the investment will be reduced by the Fair Market Value of the timber at the time of the sale. Any timber you plant and grow would have a cost basis separate from the original land.

See also: National Timber Tax Website Determine Your Basis