Not all logs are created equally. Not every log is worth hiring a sawmill for. Some are better as firewood. Others are best left alone to look pretty or grow apples or hang a tire swing from. Read onward to find out how to spot the ones that are good saw logs.
Good boards come from good logs. Good logs come from good trees. Good trees stand up straight. Trees who lean, twist or slouch often have boards that refuse to dry straight and bind in your tablesaw later when you're just trying to make some nice cabinetry. Good trees never have any nails or metal in them, only very naughty trees play with nails, screws or bolts. We've noticed a disturbing trend of trees who play near the road on corner lots or stand along fence lines and trails are often the ones who end up trying nails. Just say no. Very naughty.
Speaking of naughty, knotty trees can make decent beams, posts and slabs but nice thin strong boards that hold their shape don't have branches or knotholes riddling them throughout. If you see old branch scars on tree that have healed up on the outside, inside the tree you will find the beginnings of that branch tracing back to the growth ring of the year when it was just a bud.
Good saw timbers (standing up trees) are big. They have more boards in them if they're big. There's less waste and less work in one big log than seven small logs.
Look at the grain of the bark. If it is straight and uniform throughout, the wood grain beneath is often the same. Twists and turns in the bark surface covers woodgrain that twists and turns beneath. A split at the base, even if healing back up, is usually a sign internal damage and rot. Trees who have experienced years of abuse, mistreatment or disease will often show it in their bark and their structure. Bulges, voids and irregularities are all clues of a tortured life of affliction this tree has endured.
Logs who have sat on the ground for months and years become a host for fungi. Fungi spread throughout the log and initially create a desirable effect called spalting. Too much of this spalting however, and the log is more mushroom than it is wood.
All this being said, I like some irregularity around me. Perfect is boring. When I look at wood grain I see it's story. I like my stories to have little twists and turns that make things interesting and fun. Variations in the weather, children on tree swings and the occasional lightning strike makes for an exciting tale when told by the right tree and found by the lucky woodworker. Now you know some clues to look for in trees that hint to the kind of secrets they keep and what will make a good saw log for you.
So, let's go mill up some logs and see what's inside of them so they can tell us their tales on the boards we get from them.