Regeneration Process of a Climax Species Calophyllum cf. soulattri in Tropical Rain Forest of West Sumatra.

Abstract

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.

Spatial Distribution Pattern of Representative Tree Species in a Foothill Rain Forest in West Sumatra.

“…Suzuki & Kohyama,l99l Table 3. Number of individuals and m*/m index (Iwao, 1977) (Mukhtar et al,1992). We found that the emergent dominant Swintonia schwenkii showed a clear negative correlation between adult rees and seedlings (Suzuki & Kohyama, 1991).…”

“…590-635 m) in the Ulu Gadut area, the basin of Sungei (River) Gadut Gadang, 18 km east from Padang, West Sumatra; for detailed description of the sites see Kohyama et al (1986), Suzuki & Kohyama (1991) and Mukhtar et al (1992). The The census for seedlings and saplings was carried out by tagging numbered tapes, measuring of top height and dbh (when taller than 1.3 m), and mapping the position of the stem base.…”

Population Dynamics of a Cohort from Mast Fruiting in 1981: Regeneration process of a climax species Calophyllum cf. soulattri in a tropical rain forest of West Sumatra.

“…Four mother trees in this plot would be aggregated in distribution, when we considered that no other mother trees of this species had been found around this a l-ha plot (Mukhtar et at., 1992 L989, under the assumption of the rate being constant irespective of age. The spatial distribution pattern and the estimated age structure for the four mother trees suggest that they would be regenerated from one grandmother and three motler trees having similar age would belong to one cohort.…”

“…Density ( p ) of seedlings and saplings in L989, as a cohort from mast fruiting L981, decreased steeply with increase of D within L0 m distance from the nearest mother tree and rather gradually at further distance (Mukhtar et al, 1992). We approximated these p -D relations by two straight lines on log-log coordinates.…”

“…Spatial distribution patterns of major species in this forest have been revealed and their regeneration mechanisms were discussed with demographic data (Suzuki & Kohyama, 1991; Mukhtar et aZ., 1992; Kohyama et aZ., 1994). This study follows the previous paper (Mukhtar et al, 1992) this cohort population in terms of rates of growth, recruitment and mortality. Based on these data, this paper reveals regeneration mechanisms of this climax species in the matured tropical rain forest.…”