The duration of trunk growth stage (after the completion of rosette stage until the initiation of flowering), and starch accumulation in different trunk age and different trunk height of sago palm were investigated in Sepik basin, Papua New Guinea, in 1992.
 The major findings are as follows.
 1) Based on the observation of seedlings tarnsplanted in 1981, it was ascertained that the duration of trunk growth stage was 10 years in the earliest variety and 16 years in the latest variety.
 2) In two and half or three years after the initiation of trunking, starch accumulation initiated from the basement of trunk, and succeeded its accumulation to the upper part for the following aproximately 5 years. After then, the starch content ratio reached almost a plateau inside the trunk except the uppermost part.

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 The leaves of sago palm, nipa palm and coconut palm are widely used as covering material for housing and shade shelter in the tropics because of their three to five years’ durability. According to lamina anatomic observation for the durability mechanisms of the leaves of these three species and two other palm species as reference, the followings were observed. The epidermis of nipa palm has durable structure, and fibers in sago palm leaves have thick mass, which makes them strong enough to be used as roof and wall materials for several years. On the other hand, the leaves of coconut palm are less durable than the other two due to the lack of dense distribution of fiber in the leaf body. These palmleaves with different durability can be effectively utilized, taking their characteristicsinto consideration.

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 Entomophagy of Papua New Guinea, especially on sago weevils, was investigated. The weevil was identified as Rhynchophorus ferrugineus. People in the study villages of East Sepik Province collect the weevil larvae from the pith of sago palms which are left for several months after cutting down. The people, especially children, like to swallow the living larvae. A popular local cuisine is a stew made by cooking the larvae with coconut milk, salt, sodium glutamate, onion, aibika (a kind of vegetable), and mushroom. The chemical composition of the larva was 73.4% of water, 6.9% of protein, 8.5% of carbohydrate, 11.3% of fat and 0.7% of ash. Amino acid analyses revealed that tryptophan was deficient in free and protein-constituting amino acids. Biological characteristics of the sago weevils their utilization are discussed.

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 About 20 thousand ha of land are devoted to sago cultivation in Sarawak. Sixty percent of sago palm in Sarawak is grown on peat soils, and 33% is grown on alluvial soils. Copper (Cu) deficiency has been recognized and is thought to cause many severe disorders of plants on tropical peat soils, but it has not appeared in sago palms, so the sago palm is expected to be a potential food and industrial export crop utilizing the marginal land resource of deep peat soil. The abundance and distribution of Cu and zinc (Zn) in tropical peatlands, the relationship between sago palm growth and Cu and Zn content in the sago palm, and the evaluation of sago palm plantation as sustainable land use for tropical peat soil are discussed.
 Copper and Zn concentrations distributed in soil and aquatic environments in tropical peatland were low, ranging from nd to 25.1 µg/gCu and from 6.83 µg/L to 32.4 µg/gZn. Despite low Cu and Zn contents in peat soils and water, Cu and Zn deficiency did not appear in sago palm tissue, although Cu content was low in tissue taken from sago palms growing on deep peat soil. The sago palms on deep peat soils grew more slowly than those on shallow peat soils and alluvial soils. The preliminary input and output study of Cu and Zn showed that Zn tended to be lost from tropical peatland under sago palm cultivation. Sago palm cultivation without appropriate planning would not qualify for sustainable land use in tropical peatland.

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