We investigated the environmental factors and tree species characteristics that are important for colonization of an interior-exterior gradient across the forest edge, for application to the restoration of abandoned shifting-cultivation areas in tropical montane forests in the Umphang Wildlife Sanctuary, northwest Thailand. The relative importance of physical environment and recruit limitation was evaluated in relation to the regeneration traits of tree species. Three belt transect plots (150 m x 20 m) were established at the transition from secondary forest (edge interior) to open areas (edge exterior) of different ages (1, 3, and 5 years) after abandonment of shifting cultivation. We also set three belts (20 m x 50 m each) in a primary forest remnant. The species composition of canopy trees, regenerated seedlings, and saplings was studied, together with aspects of the physical environment. We found that it was difficult for primary forest species to effectively colonize the forest edge exterior, mostly due to recruitment limitations rather than the physical environment. Many of secondary forest species and generalists were also affected by recruitment limitation (significant negative correlation with the distance from forest edge), though they were also affected by factors related to the physical environment and forest structure and more abundant in open area. Only a few species, like Choerospondias axillaris (primary forest species), Wendlandia tinctoria (secondary forest species), Colona elobata, and Ficus hispida (generalist species) did not suggest recruitment limitation. These results suggested that natural regeneration of secondary forest and generalist species could be utilized as a first step in restoration expecting their facilitation effects for primary forest species.

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The coastal plant Pandanus odoratissimus L.f. is distributed from the tropics to the subtropics. We studied this species to clarify the differences in its population dynamics and growth strategies between populations at a tropical plot at Cipatujah, West Java, Indonesia (7°46´S, 108°04´E) and at subtropical plot at Tokuno-shima Island, Japan (27°53´N, 128°57´E). We measured plant morphological characteristics and estimated plant growth from stem elongation during a one year period. We analysed genetic differentiation using five inter-simple sequence repeat (ISSR) primers. Based on a sample of 60 individuals, we found 87 polymorphic ISSR loci in the tropical plot, versus 76 in the subtropical plot, suggesting higher genetic diversity in the tropical plot. The plants in the tropical plot had a taller, less-branched stem and larger leaves. The average stem elongation was 18 cm yr^-1 in the tropical plot and 7 cm yr^-1 in the subtropical plot. This difference probably caused the difference in maximum plant height between the tropical plot (9 m) and the subtropical plot (4.6 m). The stem diameters were similar in the two populations. The fruits were bigger in the tropical plot. Climate differences strongly affected plant height and fruit size, but had little effect on stem diameter.

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The Pangandaran Nature Reserve (PNR) is a 530-ha peninsula on the southeastern coast of West Java. It was designated as game reserve for ungulates in 1934 and as a nature reserve in 1961. Four grasslands (49 ha in total) were established as grazing sites in 1921, but some were abandoned (Batu Meja for 55 years and Badeto for 30 years), and the others were irregularly managed (Nanggorak) or frequently managed (Cikamal) by cutting and burning. We compared these different management histories to describe secondary succession at these sites where we set plots to measure the diameter at breast height of all woody species taller than 130 cm and the canopy cover of all shorter individuals. At three sites except Batu Meja we recorded the maximum height and coverage of each species in transects crossing the sites. The area of open grassland decreased from 41 ha around 1977 to 4 ha in 2011. The dominant grasses in Cikamal and Nanggorak changed from tall Imperata cylindrica to low creeping grasses, Ischaemum rugosum and Eleusine indica. Melastoma malabathricum invaded these grasslands from surrounding areas. Tectona grandis (teak) has been planted in the reserve’s public-use zone since 1932 and widely invaded the grasslands. Badeto became a young secondary forest dominated by Psychotria cf. robusta and Guioa pubescens. Batu Meja has been occupied by lowland tree species such as Buchanania arborescens and Diospyros hermaphroditica. These changes suggest that management will be essential in the remaining grasslands to preserve their ability to support ungulate populations.

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