Urban trees are under unprecedented pressure and competition worldwide with other land uses. Homestead windbreaks in urban areas are an important part of urban forests because of their proximity to settlements. To aid in the conservation of old-growth homestead trees in the urban setting on Ryukyu Archipelago, Japan, this article surveys the dimensions and spatial distribution of century-old trees planted as windbreaks along homestead borderlines on Ishigaki Island in the Ryukyu Archipelago and the historical change caused by urban sprawl. The homesteads studied in this article do not match the scale of a traditional Western context and usually consist of an area of less than 200 square meters on Okinawa. A combined approach consisting of field surveys and the study of aerial photos was applied to identify changes in spatial distribution of tree lines surrounding the houses in 1945, 1972 and the present. We measured the dimensions of 1659 Fukugi trees with a minimum diameter at breast height (DBH) of 5 cm. The mean tree height, mean DBH and mean estimated tree age were 7.3, 26.9 and 107.5 years, respectively. Homestead trees are not only useful as windbreaks, timber sources and musical instruments, but have also been historically resilient in the face of strong typhoons and catastrophic tsunamis in the of the region. Over 60% of the surveyed trees were planted on the east and north sides of homesteads as protection from typhoons and monsoonal winds in the winter. In addition to G. subelliptica, other tree species, namely Podocarpus macrophyllus and Diospyros egbert-walkeri, have been commonly used as homestead windbreaks. However, homestead windbreaks in highly urbanized regions are generally declining and have experienced fragmentation, lower tree density and shorter tree height than those in rural areas. Because of the small number of trees older than 200 years, we assume that high urbanization has jeopardized old-growth trees. The demand for settlement land dramatically increases as the population increases and household-size decreases, creating more households. Therefore, a conservation project involving multiple stakeholders must be developed to conserve old-growth trees in urban settings.

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私有化宅基地上的城市化与旧式防风林的衰落：以日本琉球群岛乡村为例

城市树木承受着前所未有的压力，并且在全球范围内与其他土地用途竞争。由于城市宅基地的防风林靠近居民点，因此是城市森林的重要组成部分。为了帮助保护日本琉球群岛上城市环境中的老式宅基地树木，本文调查了沿琉球群岛石垣岛沿宅基地边界线防风林种植的百年古树的尺寸和空间分布以及历史由城市扩张引起的变化。本文研究的宅基地与传统西方环境的规模不匹配，通常在冲绳岛上的面积不足200平方米。结合了实地调查和航拍照片研究的方法，确定了房屋周围树木的空间分布在1945年，1972年和现在的变化。我们测量了1659棵Fukugi树的尺寸，其最小胸径（DBH）为5厘米。平均树高，平均DBH和平均估计树龄分别为7.3年，26.9年和107.5年。宅基地树木不仅可用作防风林，木材来源和乐器，而且在该地区遭受强台风和灾难性海啸的影响下，在历史上也具有韧性。超过60％的被调查树木种植在房屋的东侧和北侧，以防冬季遭受台风和季风影响。此外 我们测量了1659棵Fukugi树的尺寸，其最小胸径（DBH）为5厘米。平均树高，平均DBH和平均估计树龄分别为7.3年，26.9年和107.5年。宅基地树木不仅可用作防风林，木材来源和乐器，而且在该地区遭受强台风和灾难性海啸的影响下，在历史上也具有韧性。超过60％的被调查树木种植在房屋的东侧和北侧，以防冬季遭受台风和季风影响。此外 我们测量了1659棵Fukugi树的尺寸，其最小胸径（DBH）为5厘米。平均树高，平均DBH和平均估计树龄分别为7.3年，26.9年和107.5年。宅基地树木不仅可用作防风林，木材来源和乐器，而且在该地区遭受强台风和灾难性海啸的影响下，在历史上也具有韧性。超过60％的被调查树木种植在房屋的东侧和北侧，以防冬季遭受台风和季风影响。此外 木材来源和乐器，但在面对该地区强烈的台风和灾难性海啸时，历史上也具有韧性。超过60％的被调查树木种植在房屋的东侧和北侧，以防冬季遭受台风和季风影响。此外 木材来源和乐器，但在面对该地区强烈的台风和灾难性海啸时，历史上也具有韧性。超过60％的被调查树木种植在房屋的东侧和北侧，以防冬季遭受台风和季风影响。此外G.subelliptica，其他树种，即罗汉松和Diospyros egbert-walkeri，通常被用作宅基地防风林。然而，与农村地区相比，高度城市化地区的宅基地防风林通常在减少，并且支离破碎，树木密度较低，树木高度较短。由于200年以上的树木数量很少，我们认为高城市化程度已经损害了老龄树木。随着人口的增加和家庭规模的减少，对定居土地的需求急剧增加，从而创造了更多的家庭。因此，必须开发一个涉及多个利益相关者的保护项目，以保护城市环境中的老树。