Brachylaena transvaalensis is an evergreen tree, although it can be deciduous at times depending on its location. It can grow to a height of between 10 and 25 metres. This tree produces a single straight trunk which at times is slightly fluted. Although the grey to pale brown bark is smooth initially, it becomes vertically striated and stringy with age. The grey twigs are ribbed and hairless.
Forest silver-oaks are found in different forest types ranging from evergreen and semi-deciduous to riverine. They also occur in wooded grassland along the escarpment.