The mature ftuits are 2 g in fresh weight, having five wings 6Xl cm in size and one seed inside. In contrast with the distribution of seedlings and small trees, many fruits dropped under the crowns of mother trees. The number of fruits decreased exponentially with distance from a mother tree, and ftuits dispersed further than 50 m were rare.

All individuals of Calophyllum cf. soulattri Burm. (Guttiferae) were surveyed in two plots set in a tropical rain forest, Padang, West Sumatra. In Pin plot (1.0 ha) covered mostly by mature patch of 50-60 m in height, we found four mother trees of C. cf. soulattri (27-39 m in height), and 2,722 juveniles (0-9 m). Instead of the seedling abundance, the mother trees made fruits only in 1981 during the survey period from 1981 to 1989. They seemed to disperse fruits in the whole area of plot. The seedlings and saplings in a subplot of 14 m2 adjacent to a mother tree, 30-38% of them survived from 1981 to 1989 and grew 2.5 cm/yr in height. Bigger juveniles (4-9 m) occurred more often in area apart from mother trees. In Gaja plot (0.86 ha) having more gaps than Pin Plot, only 31 C. cf. soulattri existed, which were 0.7-17 m in height.The following regeneration characteristics are supposed for this species. 1) Only old and big tree can reproduce, and the dispersal area of propagule is wide; 2) the dispersed propagule can survive around the mother trees; 3) the residual life span after maturation is short, and die before offsprings start reproduction. These characteristics will make a mosaic of two types of patches: one composed of mother tree, seedlings and saplings, and the other of young poles. The patch size will be related to dispersal area. Thus the plant population exists continuously in the same area, while sporadic reproduction events create the mosaic pattern.

The spatial distribution, survival and growth of Elateriospermum tapos Bfume (Euphorbiaceae) were studied from the data of a L-ha permanent plot at Gunung Berui, West Kalimantan.In the plot, number of species and individuals of Euphorbiaceae were 35 and254, respectively and the most abundant and dominant was E. tapos. Forty four percent of seeds produced in a mast fruiting season could be escaped from predators and germinated into seedlings. The number ofthe established siedlings was drastically dropped in the next year of the mast fruiting and slightly increased in the second year, The species has classical inverse J-shaped frequency size distribution, suggesting its continuous regeneration. The species was contagiously distributed in the plot. Mortality of shorier seedlings was higher than that oftaller seedlings, and the mortality ofseedlings in the gap was slightly higher than that of in closed forest. The mortality rate of seedlings was not related to the density oflohort seedlings and variables representing stand structure. The relationships among measured tree dimensions drew a simple linear; suggesting the growth pattern of tree dimensions in each individual plant was closely dependint one to another. The RGR-height tended to decrease in hyperbolic manner by increasing the hiight of seedlings and saplings, and the RGR-height in the gap were consistently higher than that in the closed forest. The RGR of height on seedlings and saplings or the RGR of diameter on trees in the sub-plots was not significantly related to the variables representing stand structure and relative light intensity ambient the individuals.Key words: E/ateriospermum tapos / Kalimantan / mast fruiting / distribution / tree dimension and growth Euphorbiaceae is among the most important and successful family in a mixed dipterocarp forest (MDF) of West Kalimantan. Number of species and individuals of Euphorbiaceae trees in an area was often found more than those ofDipterocarpaceae were. The non-pioneer species ofEuphorbiaceae are often associated with other species in sub-canopy layer of MDF community at climax stage. Some species of Euphorbiaceae have also been reported to be resistant to a long dry season period, and some species were able to recover after forest burning in East Kalimantan.