A friend had a large oak that was well over four feet in diameter. Since there was no one locally who could saw it into lumber, he took a slice off the stump end and made a (very heavy) table of it. when it was finished as a table, he started counting the growth rings from the outside in and marking important family info (births, weddings, funerals, etc) on the appropriate ring. Makes a pretty impressive "family tree". Hope this helps, Stan.