As time passes, some trees develop bald or barkless places on their trunks as a result of harsh weather conditions. The barkless portion usually begins at the place where the roots emerge from the ground, and grows increasingly thinner as it continues up the trunk. Intense sunlight will bleach these parts, forming a very characteristic portion of the tree. With Bonsai the bark is removed with a very sharp knife and the barkless spot is treated with calcium sulfate in order to speed up the bleaching process.
