Growth behavior of sago palm (Metroxylon sagu Rottb.) from transplantation to trunk formation

Because of the large amounts of starch accumulated in its trunk, the sago palm (Metroxylon sagu Rottb.) growing in tropical areas of Southeast Asia has received much attention as a starch crop mainly for use as an industrial raw material. Sago palm propagates generally by transplantation of suckers, but little agronomical knowledge is available for transplanted sucker growth. Our objectives are to clarify sago palm growth after transplantation and to assess the transition of stem growth from horizontal to vertical. The transplanted sucker stems elongate horizontally, creeping along the ground surface in the early growth stage. Subsequently, the stem elongation shifts gradually from horizontal to vertical. The creeping stem stands up, drawing a large arc and elongating vertically. The horizontal stem elongation stops at around 6.5 years after transplantation and the stem growth curve shows a sigmoidal curve. The stem growth stage of a transplanted sucker is divisible into three stages based on its elongation direction: the creeping growth stage, the trunk formation stage, and the trunk elongation stage. The creeping growth stage, which is the early growth stage after transplantation, is an important period because the standing positions of trunks are determined in the plant and in the sago palm garden. In the area we investigated, the transplanted suckers remained in the creeping growth stage for 4-5 years. They remained in the trunk formation stage for around 1.5 years. These suckers will probably be in a trunk elongation stage for 6-7-years.