Success of clonal tree plantations depends on genotype as well as phenotypic plasticity, which determines acclimation potential of individual trees to different environmental conditions. Short-term acclimation of genotypes to local growing conditions can be tested using clonal trials, but stand productivity and yield depends on the ability of the genotype to acclimate to long-term environmental variation. In Japan, clonal plantations of Cryptomeria japonica (Thunb. ex L. f.) D. Don are common and many elite clones have been developed. We evaluated growth of clonal C. japonica plantations in 45-year-old clonal trials taking into account effects of both genotype, environment and their interaction (i.e., phenotypic plasticity). In all five sites, tree sizes were larger for clonal cultivars evaluated initially as “early-growth type” than for the “late-growth type” cultivars. All cultivars showed decrease in tree height from lower to upper slope. The differences in tree growth among cultivars were more marked in sites where trees grew well, suggesting poor site conditions prevented the early-growth cultivars from fully exploiting their growth potential. Phenotypic plasticity of each cultivar was evaluated as growth variation among sites (regional variation) and along slope within sites (topographic variation). Plasticity was observed at both regional and topographic scales and cultivars with higher plasticity generally grew larger. The result of our study suggested that genotypes with greater phenotypic plasticity may possess greater acclimation potential, enabling them to grow well under a wide range of environmental conditions.

无性树人工林的成功取决于基因型和表型可塑性，这决定了单个树木对不同环境条件的适应潜力。可以使用克隆试验测试基因型对当地生长条件的短期适应性，但是林分生产力和产量取决于基因型适应长期环境变化的能力。在日本，日本柳杉（Chunderia japonica）（Thunb。ex L. f。）D. Don的无性繁殖林很普遍，并且已经开发了许多优良的无性系。我们评估了无性C.japonica的生长在45年的克隆试验中，人工林考虑了基因型，环境及其相互作用（即表型可塑性）的影响。在所有五个地点中，最初被评估为“早期生长型”的克隆品种的树木大小均大于“晚期生长型”的品种。所有品种的树高都从低到高倾斜。树木生长良好的地区之间树种生长的差异更为明显，这表明场地条件恶劣阻止了早生品种充分利用其生长潜力。将每个品种的表型可塑性评估为位点之间的生长变化（区域变化）和位点内的坡度（地形变化）。在区域和地形尺度都观察到可塑性，具有较高可塑性的品种通常会变大。我们的研究结果表明，具有更高表型可塑性的基因型可能具有更大的适应潜力，从而使其在各种环境条件下都能良好生长。