Sideroxylon inerme bark

The bark of an old Sideroxylon inerme or white milkwood tree is thick, the upper surface covered in quite dissimilar, small patches of cracked upper bark. Usually described as rectangular, it is a tall order to find congruent pieces or any that are exactly rectangular. Wonderful how the flaws of language may sometimes serve in conveying comprehensible information, while technically inaccurate! Words and pictures in combination fortunately serve in overcoming some of these failings in today’s continual refinement of all technologies.

Most of the little blocks are separated by dark channels in variable patterns, more systematic in their vertical than horizontal arrangement. This means that the force of stem thickening is doing more in separating bark sections systematically in the longitudinal than transversal dimension. The somewhat rectangular blocks are thus also more arranged with their longer sides in the vertical plane, less cracking happening from lengthening than spreading, the height growth occurring in young branches higher up.

Surface irregularity in the bark, caused long ago by scarring or even loss of branches, plays havoc with bark patterns. And some older looking blocks are still greyer, while others have lost upper bark layer(s), exposing redder brown underbark surfaces, patches with a newer look. The more worn, grey ones are expected to let go of upper layers at some stage later.

On some of these trees the bark may be much nearer to black than on this one seen in Fernkloof near Hermanus. Sometimes fairly straight, white milkwood trees usually display curved, crooked or strongly contorted trunks. The main trunk may be over 60 cm in diameter, although this is not too often seen.

The tree has legal protection in South Africa these days. It was used as general timber, also for boat and bridge building in the past. The fine-grained, yellow-brown wood is hard and durable, even in damp conditions. So, the real old tree trunks may hopefully keep adding millimetres to their girths in peace, achieving greater thickness records in these days of global warming.

The powdered bark and roots of S. inerme have been used in traditional medicine (Bean and Johns, 2005; Coates Palgrave, 2002; Schmidt, et al, 2002; Van Wyk and Van Wyk, 1997; Pooley, 1993; iNaturalist).