牛樟扦插苗與實生苗之生長性狀及根系錨定力

GROWTH CHARACTERISTICS AND ROOT ANCHORAGE FORCE OF CUTTINGS AND SEEDLINGS OF CINNAMOMUM KANEHIRAI

詹明勳(Ming-Hsun Chan)；李嶸泰(Jung-Tai Lee)；周齊(Qi Zhou)；劉致廷(Jhih-Ting Liou)

牛樟 ； 扦插苗 ； 實生苗 ； 生長性狀 ； 根系錨定力 ； Cinnamomum kanehirai Hayata ； cutting ； seedling ； growth characteristics ； root anchorage ability ； root tensile strength

中華林學季刊

56卷2期（2023 / 06 / 30）

59 - 76

繁體中文;英文

牛樟為臺灣固有珍貴樹種。牛樟之人工造林常使用扦插苗作為造林材料。實生苗與扦插苗之品質會影響造林成效。所以，本研究之目的乃在探討牛樟實生苗與扦插苗生長、根系性狀及根系力學性質之差異性，以作為造林時選擇苗木種類之參考。本研究利用全根挖掘法調查苗木之根系性狀與結構型態，並應用WinRHIZO軟體分析根系性狀，以垂直拉拔試驗機測定根系之錨定力，並以拉伸試驗儀測定單根抗拉強度。研究結果顯示，實生苗與扦插苗之根系結構均屬垂直水平型，然而實生苗具主根。實生苗之苗高、基徑、根數量、莖生物量及根生物量等生長表現均顯著高於扦插苗者。根系生物力學分析結果證實，牛樟實生苗之根系錨定力顯著高於扦插苗者，而且牛樟實生苗之單根抗拉強度亦顯著高於扦插苗者。因此，建議在牛樟人工造林時以選擇實生苗作為造林材料為佳。

Cinnamomum kanehirai Hayata (Stout camphor) is an important endemic tree species for reforestation. Cuttings are used quite frequently as planting materials in artificial reforestation of Cinnamomum kanehira. During typhoon season, the forest plantations regenerated from cuttings are prone to serious toppling. On the other hand, the plantations regenerated from seedlings are relatively resistant to strong winds. However, the effects of growth characteristics and root anchorage ability of cuttings and seedlings of Cinnamomum kanehira have not been explored. In the present study, the growth traits of cuttings and seedlings of Cinnamomum kanehira were investigated with hand excavation method and analyzed utilizing WinRHIZO Image Analysis System. Root anchorage ability of 2-year-old cuttings and seedlings were estimated using vertical uprooting testing. The results show that the root systems for cutting and seedling were categorized as vertical horizontal type, while the root system for seedling had tap root. Nevertheless, relative to cuttings, the seedlings had significantly higher plant height, larger root collar diameter, higher stem biomass, higher root biomass and larger root volume. Moreover, the uprooting resistance force and root tensile strength of seedlings were significantly higher than those of cuttings. This research demonstrates that seedlings of Cinnamomum kanehira are superior to cuttings, considering growth characteristics, root anchorage ability and root tensile strength. Altogether, our results suggest that seedling of Cinnamomum kanehira is favorable for artificial reforestation. These results, together with seedling culturing technology, provide important information for silvicultural operation strategies of Cinnamomum kanehira plantations.