Comparisons of Early Growth between Seedlings and Sprouts, and Relationship between Original Tree Size and Vigor of Sprouts of Pusania edulis

Abstract

Early growth characteristics were compared between seedlings and sprouts of Pasania edulis developed after clear cutting of the forest stand, and a relationship between the original plant size before cutting and the vigor of sprouts was also investigated. The early growth of sprouts during the first growing season were far greater than those of seedlings on both individual and unit area basis. The sprouts showed unique growth characteristics. They developed non-photosynthetic parts earlier than photosynthetic parts to expand foliage at more advantageous position which might be supported by the abundant reserved substances and large water and mineral absorbing capacity of the original root system compared with those of seedlings. The vigor of sprouts was closely related to the original plant size used in this study as an index of the amount of reserved substances. However, even if the number of sprouts per unit reserved substances decreased, use efficiency of reserved substance did not increase. This result may suggest the possibility that all of the reserved substances are not utilized for regrowth by sprouts.