MoeM you got it in one! Natural and 'coffee' or carbonised it is . I do it that way on most limbs as I like the look. Beachbowhunter 'hairy oak' is a native aussie timber with a true name of allocasurina. There are quite a few in the species, like river oak, she oak, flame oak as well. It is not a readily available commercial timber, although some timber specialists do stock it at times. A firm called Lazarides at Banyo in Brisbane some times have it though it might be cost prohibitive to ship , and its very hard to get a large piece without flaws and borer holes.