L35等杨树新品种造林当年年生长节律研究

利用Logistic方程对4个黑杨派杨树无性系的1a生林木的树高、胸径的年生长节律进行拟合。结果表明：利用Logistic方程拟合效果显著，相关系数皆在0．90以上。并以此将各无性系的年生长过程分为成活期、生长前期、速生期和生长后期4个时期，年生长量在后3个时期表现出明显的“慢—快—慢”的节律，其中速生期内的树高生长量占总生长量的比率平均为66．4％，胸径生长量占总生长量的比率平均为64．0％。树高比胸径进入速生期早且结束晚，速生期持续时间长。对各个生长时期林木的生长特点进行了分析，探讨了林木的年生长规律，为加强林木生产管理、提高林地的生产力，提供了理论依据。

GROWTH RHYTHM OF NEW POPLAR CLONES AT JUVENILE STAGE

Logistic equation is applied to fit annual growth increment of new poplar clones at juvenile stage. The results show that correlation of the modeling is significant and the correlation coefficients are higher than 0.90. Based on the equation, annual growth process can be divided into four stages, namely survival stage, pre-growth stage, fast-growth stage and post-growth stage. Average height and ground diameter in fast-growth period is 66.4% and 64.0% respectively of the total annual growth.Fast-growth period of height begins earlier and last longer than diameter. Growth performance of each period is also described and discussed. This paper has provided theoretical basis for intensive management of poplar plantation at juvenile stage and enhancement of forest land productivity.