建立造林樹種健康林苗生產專區(1/4)

本研究調查臺南市新化林場以及嘉義縣澐水工作站小葉桃花心木母樹生長資料，結果發現新化林場小葉桃花心木生長較好，平均DBH 94.5 cm，平均樹高23 m。於小葉桃花心木育苗中發現，其種子苗有大葉、中葉及小葉三種不同形態差異，苗齡約30個月的苗木，平均苗高大葉型態苗木(85.6±17.6 cm)及小葉型態苗木(86.9±15.6 cm)相差不多，但平均地徑大葉型態苗木(14.5±0.1 mm)則明顯高於小葉型態苗木(10.5±3.2 mm)。桃花心木每年4~5月開花，翌年3~4月果實成熟種子可直接播種在容器中，如需儲藏，應將種子含水率降至5%左右，並儲藏在0℃以下低溫環境。一般桃花心木苗木最適合出栽為苗齡22個月，苗高在50-88 cm，地徑在8.2-11.8 mm，纖弱指數<7.5範圍內。桃花心木新植造林木易受風害作用，因此出栽造林之苗木應選擇纖弱指數較小，根系健全者為佳，如此便可提高造林木成活率。 This study investigated the growth of Swietennia mahagoni mother trees in Shinhua National Forest Arboretum and Taiwan Forestry Research Institute Yunshui Workstation. The result shows that the average DBH was 94.5 cm, and average height of tree was 23 m in Shinhua National Forest Arboretum, it was better than that in Yunshui Workstation. We found that Swietennia mahagoni seedlings were big leaves, medium leaves and small leaves three different appearance types. It was not significant differences of average height of 30 month age in big leaves seedling (85.6±17.6 cm) and small leaves seedling (10.5±3.2 mm), but the ground diameter, big leaves seedling (14.5±0.1 mm) was significant bigger than the small leaves seedling (10.5±3.2 mm). Mahogany flowering during April to May, and the fruit ripening during March to April next year. Mahogany seeds could direct be sown in vessels, and should be stored in moisture content 5% and temperature under 0℃. Mahogany seedlings at 22 month age, seedling height between 50-88 cm, ground diameter between 8.2-11.8 mm, and Sturdiness Quotient under <7.5 were fit to be planted. Because Mahogany new planting trees easy being damage by wind, so we should choose the seedlings that Sturdiness Quotient smaller and roots were health and complete to plant. It could raising the survival probability of planting.本研究针对台南市新化林场及嘉义县澐水工作站的小叶桃花心木（Swietenia mahagoni）母树生长资料展开调查。结果显示，新化林场的小叶桃花心木生长表现更优，其平均胸径（DBH）达94.5 cm，平均树高为23 m。在小叶桃花心木育苗过程中发现其实生苗存在大叶、中叶、小叶三种不同的形态类型；对苗龄约30个月的苗木而言，大叶型苗木（85.6±17.6 cm）与小叶型苗木（86.9±15.6 cm）的平均苗高相差不大，但大叶型苗木的平均地径显著高于小叶型苗木，分别为14.5±0.1 mm与10.5±3.2 mm。桃花心木每年4~5月开花，翌年3~4月果实成熟，其种子可直接播种于容器中；若需储藏，则应将种子含水率降至5%左右，并置于0℃以下的低温环境中保存。一般而言，小叶桃花心木苗木的最佳出圃造林苗龄为22个月，此时苗木需满足苗高50~88 cm、地径8.2~11.8 mm、纤弱指数（Sturdiness Quotient）小于7.5的标准。由于新栽植的桃花心木林木易遭受风害，因此出圃造林的苗木应优先选择纤弱指数较低、根系发育健全完整的个体，此举可有效提升造林成活率。