Black Birch Tree An essential oil is obtained from the bark and twigs, it is distilled in quantity and is an item of commerce. It can be used medicinally, as a food flavouring, as an ingredient in cosmetic shampoos and also to make a wholesome tea. The oil, when decolourized, is similar to 'Oil of Wintergreen' (obtained from Gaultheria procumbens) and is considered to be of superior quality.