The price of logs depends on stem straightness, but generally tree stems have more or less curvature. Although foresters prefer trees with straight stems to curved trees, it is difficult to measure the stem straightness of standing trees.
This investigation was aimed to obtain pertinent method for measuring the stem straightness of the standing trees. Fifty trees are measured by the newly devised method. Even in well cultured Cryptomena japonica stand studied, some trees have severely curved stems. This is derived from either genetical origin or snow damage.