Age-related trends in the growth performance of seedlings and cuttings of Chamaecyparis obtusa

For the success of forestry practices, it is important to understand the performance of cuttings and seedlings over time to properly understand the advantages and disadvantages of seedling and clonal forestry. In this study, we investigated the tree height, diameter growth, and trunk forms in Chamaecyparis obtusa (Sieb. et Zucc.) Endl. at four plantation stands, and compared the performances of seedlings and cuttings. The seedlings surpassed the cuttings in terms of tree height and diameter growth, while the cuttings exhibited better trunk forms. The superior growth of seedlings diminished when aging; i.e., seedlings grew more than cuttings at younger ages, while the seedlings to cuttings ratio in terms of growth in height and diameter stabilized as trees grew older. This superiority in growth exhibited by the seedlings especially at younger ages suggested that their use is suitable for fast-growing afforestation, while planting cuttings has advantages to produce high-quality logs with straighter trunks in clonal forestry. The present results provide useful basic information for the selection of clonal or seedling forestry practices of Chamaecyparis obtusa, and the need for improving the initial tree growth rates to reduce weeding labor would favor seedling forestry rather than clonal forestry.