Thank you for your excellent question! The sale of standing timber or logs is a financial transaction that has federal, and likely state, tax considerations.
However, the milling of your own logs into lumber for personal use is not taxable. I personally do not consider the "one time" sale of several boards to be considered a wholesale or retail business, but if it does become that way in the future (i.e., business or hobby income) then you would want to contact a tax specialist to figure out the best strategies to account for those future lumber transactions! I suppose you can always report the income yielded from your lumber transaction as "hobby income" on your IRS tax return!
I'm not a tax specialist, nor am I a certified public accountant (CPA), therefore I cannot legally give you tax or accounting advise.
Best of luck!