Eucalyptus Species Selection for Superior Adaptability to Indoor-Outdoor Environments in South Korea

This study was initiated to examine suitable Eucalyptus species with high survival and acclimation rates among E. pulverulenta, E. cinerea, E. globulus, E. websteriana, E. parvula, E. kruseana, E. cordata, E. polyanthemos, E. gunnii, and E. crebra, in South Korea where have not been conducted under both greenhouse and field conditions during the early tree growth stage. Germination at 70 days after sowing (DAS) was highest in E. crebra at 86.1%, followed by E. cordata (76.4%), E. globulus (68.1%), and E. pulverulenta (66.7%). E. cinerea and E. polyanthemos maintained seedling survival of 100.0% at 70 DAS, with the lowest survival observed for E. websteriana and E. kruseana (approximately 84‒85%). The tallest trees were observed in E. globulus at 141.7 cm, followed by E. polyanthemos and E. crebra at 150 days after transplanting (DAT); the smallest trees were detected in E. kruseana (33.7 cm) and E. parvula (38.6 cm), with conditions affecting the thickness of their trunks. The number of shoots was significantly higher in E. globulus and E. cordata at 150 DAT with highest number of leaves in E. parvula, followed by E. globulus, E. cordata, and E. crebra. Foliar SPAD was highest for E. gunnii at 150 DAT but lower for E. cinerea, E. globulus, and E. polyanthemos with light bluish and whitish green foliage. Leaf browning was negligible for all Eucalyptus spp. at 30 DAT but occurred considerably at 150 DAT during early winter, with E. kruseana at approximately 45%, E. polyanthemos at 21%, and E. parvula at 20%. The dry mass of the leaves, shoots, and roots of each species was highest for E. globulus at 107.7 g, followd by E. polyanthemos and E. crebra, and was lowest for E. cinerea and E. websteriana. A thicker trunk significantly increased the tree height (r2 = 0.7779), total dry weight (r2 = 0.7987), root dry weight (r2 = 0.7194), and number of leaves (r2 = 0.1963).