How do i put into this years return a timber sale net of forester agent costs

Assuming you are doing this as a temporary transaction, not associated with your job or profession, you would enter the sale of timber as an investment sale in TurboTax.

In the Income and Expenses section, look for Investment Income, then choose Stocks, Mutual Funds, Bonds, Other as the type of investment sold. Indicate in that section that you did not receive a form 1099-B, then enter the description, date sold, date acquired, sale proceeds and cost basis of the timber. The cost basis would be all of the money, including the forester agent cost, that you spent on the timber.

Depending on which year and version of TurboTax you are using, you may see a list of options detailing what you sold. If you see this, choose "Other" as the investment type as opposed to Stocks, Mutual Funds, etc...

If you are in the business of selling timber, then you need to enter the sale in the Business Income or Self-employed income and expenses section of TurboTax, depending on what year and version of TurboTax you are using.