2020 年 53 巻 2 号 p. 87-88
In the Tokachi plain of eastern Hokkaido, Japanese larch, Larix kaempferi, is often planted in arable land windbreaks to prevent wind damage to sugar beets,potatoes, and beans during the spring cultivation season. Japanese larch is fast-growing and very effective in reducing wind damage in the early spring cultivation season, even if its buds are not open or its leaves are not fully extended. However, many farmers dislike Japanese larch arable land windbreaks because they shed a lot of branches and branchlets to cultivation fields every year, which may cause damage to agricultural tractors. Therefore, it is necessary to suggest a model of arable land windbreaks with less amount of fallen branches and branchlets of larches entering the cultivation field. It is recommended to plant three rows of trees: Japanese larch in the most windward and middle rows, and Japanese white birch, Betula platyphyllavar. japonica, in the most leeward row. Japanese larch in the most windward and middle rows reduces wind speed, whereas Japanese white birch in the most leeward row reduces branches and branchlets of Japanese larch entering cultivation fields.