Effects of year-round warming on the growth of Pinus densiflora SIEB. et ZUCC

Growth of Pinus densiflora SIEB. et ZUCC. seedlings were investigated grown under several controlled temperature conditions of outdoor temperatures altered by +4.5°C, +3.0°C, +1.5°C, 0.0°C and -1.5°C. As a result, growth initiation timing became the same among treatments. Dormancy of winter buds were not released much because of shortage of winter chilling in the high temperature treatments. Shoot length and the number of needle leaves became to be smaller under +4.5°C treatment caused by inhibition of leaf primordia formation and elongation of lammas shoot under warmer condition in the previous year.