I've done the same thing when I built my house, I setup a wood mill and cut my own timber from the trees on my own property then I got hit with a 5% yield tax from the timbers I cut down. When I purchased my land the land was considered 'forested land' then meaning the trees were considered crops (lesson learned) I should have purchased my lumber and saved a year of cutting and milling the timber, at the time it would have been cheaper to purchase pre-cut, though I take comfort in knowing I have TRUE 2x6, 2x4, 4x4 and 4x12s!