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We studied the latitudinal and altitudinal variations in composition and species richness of trees in 24 plots across temperate to subtropical regions from southern Kyushu to the northern Ryukyu Ar...

Aim Large trees (d.b.h. 70 cm) store large amounts of biomass. Several studies suggest that large trees may be vulnerable to changing climate, poten- tially leading to declining forest biomass storage. Here we determine the importance of large trees for tropical forest biomass storage and explore which intrinsic (species trait) and extrinsic (environment) variables are associated with the density of large trees and forest biomass at continental and pan-tropical scales. Location Pan-tropical.

The guild composition of a hill dipterocarp forest was examined using growth traits of 1566 trees comprising 422 species through field observation at a 6-ha plot for 6 years in Sumatra. Three parameters, intrinsic growth rate, attainable maximum stem diameter, and stem hardness, were used for guild determination. The intrinsic growth rate showed a significant correlation with stem hardness, which suggested a trade-off between volume growth and architectural strength under the restraint of photosynthetic products. Four major guilds were determined, characterized as Soft wood-Small size-Fast growth, Soft-Big-Fast, Hard-Big-Slow, and Hard-Small-Slow traits. Ecological niches of these guilds were related to the large variance of resources in time and space of a tropical rain forest. A secondary forest part in the 6-ha plot retained high species diversity, but species composition was largely different from that of the mature stand. Human activities biased guild composition to reinforce the Soft-Small-Fast guild, with a reduction in the Hard-Big-Slow guild that included many marketable timber trees. Logging impacts on dipterocarp and fagaceous trees were assessed with reference to their spatial distribution and attributes of guilds.

Spatial distribution patterns and habitat associations of Fagaceae species in a Fagaceae-codominated hill forest in Sumatra were investigated. Ten Fagaceae species believed to be zoochorous (animal-dispersed seed) and five codominant canopy and emergent anemochorous (wind-dispersed seed) species from Anacardiaceae and Dipterocarpaceae were studied. Five Fagaceae species and all codominant anemochorous species were significantly aggregated while the other five Fagaceae species showed a random distribution pattern. The median distance of small saplings from the nearest reproductively mature tree tended to be shorter for aggregated species than spatially random species. This implied that some Fagaceae species dispersed over longer distances than anemochorous species. Relationships between four habitat variables and distribution of the target species were examined with torus-translation tests. ThreeQuercusand oneLithocarpusspecies showed positive habitat associations. TwoQuercusspecies aggregated at the preferred habitat, but the others were randomly distributed. Thus tree species with specific habitat preference do not only aggregate at the preferred habitat. The three ridge-specialistQuercusspecies showed gradual changes in habitat association, which could reflect avoidance of competition among the species. Most of theLithocarpusspecies showed little correlation with habitat variables. Coexistence of the threeQuercusspecies partly reflected subtle differences in topographical preferences. Distribution of five of the sixLithocarpusspecies was unrelated to topography, so other mechanisms must be sought to account for the maintenance of coexistence in this species-rich genus.

The altitudinal distribution of Fagaceae in West Sumatra was studied on the basis of herbarium specimens and field tree censuses conducted at Gunung Gadut and Sipisang. Forty-two species were examined (Castanopsis: 8 spp., Quercus: 8 spp., Lithocarpus: 25 spp., and Trigonobalanus verticillata), and it was revealed that altitudinal distribution patterns vary among species and genera. The species richness of Fagaceae in West Sumatra was highest at 400-700 m, decreasing with increasing altitude above 700 m, while about half the total number of species occurred below 400 m. Though the altitudinal distribution patterns of some species were compressed toward a lower altitude in Gunung Gadut, species richness in Gunung Gadut and Sipisang regions were also highest at 400-700 m above sea level (76 % of 33 species were found growing in these regions), and more than half of the species were found at 150-400 m. Quercus showed gradual replacement/overlapping of higher/lower altitudinal species at a range of 700-1100 m, and Lithocarpus showed a remarkably high species richness at 400-700 m in both regions. The altitudinal diversity patterns of Fagaceae appeared to involve both species coexistence/concentration at particular altitudes and species replacement with changing altitudes. The high species richness of Fagaceae at 400-700 m was especially due to the coexistence and concentration of Lithocarpus species.

The altitudinal gradient of vegetation of the Barisan range in a coastal region near Padang, West Sumatra, was studied in 10 plots (0.1-6.55 ha) distributed from 600 to 1780 m. Trees with a diameter at breast height of more than 10 cm were employed for classification of the vegetation. Four vegetation zones, two types of montane and two types of lowland vegetation, were recognized based on cluster analysis, floristic information, and the physiognomy of these forest stands. An upper zone of montane vegetation (Lower montane Fago-Myrtaceous forest) was distinguishable from a lower zone (Sub-montane Fago-Myrtaceous forest) due to the remarkable dominance of several species of Fagaceae and Myrtaceae, and its lower canopy height. The two zones of lowland vegetation (Upper hill dipterocarp forest and Mid-hill dipterocarp forest) were distinguishable by their species composition of Dipterocarpaceae and stratification of the stand. The altitudinal zonation corresponded well with classic zonation patterns previously reported for West Malesia, but the critical threshold altitudes were lower in comparison with those in other regions. The borderline between the lowland and montane vegetation, corresponding to a Kira’s warmth index of WI = 180 °C · month, was around 200 m lower in Padang than in other regions of West Malesia, and the critical altitude between the two zones of lowland vegetation was also around 300 m lower in Padang than on Mt. Kinabalu. The characteristics of altitudinal zonation in Padang were discussed with reference to the climatic features of this region, namely, the low temperature and hyperhumidity.

The floristic composition of a tropical hill forest in Ulu Gadut, West Sumatra, Indonesia, was studied. High species diversity and differences in the floristic composition compared to other forests in West Malesia were observed. Based on the tree numbers of common species in 20 × 20m quadrats, habitat axes representing floristic composition were determined by detrended correspondence analysis. Axis 1 was significantly related to the slope convexity and stand height of a quadrat, indicating that the floristic composition is influenced not only by topography but also by growth stage and disturbance. The major disturbance in this forest prior to the study was local logging, the influence of which was found not only in the variation in floristic composition but also in vegetation development after disturbance. We concluded that the harvest of upper layer trees by local loggers enhanced the growth of lower layer tree species in this forest. The estimated original vegetation without logging differed from that of other forest stands in West Malesia because of its relatively low dominance of Dipterocarpaceae and high dominance of Fagaceae. This might have been caused by the lower temperature of the plot compared with other forests at similar altitudes in West Malesia regions. This climatic feature is also thought to contribute to the high diversity of the plot.

The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼40,000 and ∼53,000, i.e. at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼19,000-25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼4,500-6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa., 0, SCOPUS: ar.j, info:eu-repo/semantics/published

Decomposition processes of leaf litter were observed during one year with same kinds of substrates at a warm-temperate evergreen oak forest in Japan and a tropical rain forest in Sumatra simultaneously. A warm-temperate forest showed high rates of carbon-weight loss in summer. A tropical rain forest had high rates at the initial stages in particular and apparently low rates during the severe dry weather in early 1997. When time trends of carbon-weight loss could be approximated by a single exponential curve for each leaf litter, the average values of decomposition factor of five Japanese fagaceous leaf litter were 0.70±0.13 y-1 at a warm-temperate forest and 1.62±0.24 y-1 at a tropical rain forest, respectively. The C/N ratios of litter gradually decreased with the progress of decomposition at the initial stages, then tended to be constant at about C/N =20 at the last stages irrespective of kinds of leaf litter and study sites. Basing on these results we discussed characteristics of decomposition at these two forest ecosystems.

An equatorial rainforest in the coastal region of West Sumatra suffered a long period of dry and hazy weather in 1997. Canopy trees with higher growth rates before the event had reduced growth rates during the 8 months from June 1997 to an average of 23% of their 1996 growth rate. The size-dependency of growth depression in forest trees greater than 5 cm in stem diameter could be observed during this period. The weather induced defoliation, and high litterfall rates of leaves continued throughout the period. The impacts of the weather on growth rates were analyzed by using Saeki’s mathematical model for community production. This model suggested that the great reduction in growth-rates of active canopy trees would be caused mainly by the interacting effects of potential photosynthetic rate and leaf biomass because of their sensitive responses to drought. In the severe weather conditions, these variables were estimated to have decreased to more than 50% of their 1996 values.

Quercus miyagii is an endemic tree species in the Ryukyu Islands, Japan. We isolated and characterized 15 microsatellite loci in this species. The number of alleles ranged from 2 to 16 and expected heterozygosities from 0.07 to 0.92. This set of markers is potentially useful to investigate the genetic structure, gene flow, and the biogeographic history of Q. miyagii in the Ryukyu Islands, Japan.

Successive changes of stand structure and primary productivity of a ropical secondary forest from clear cutting were studied through long-term observation during 12 years from 4 years later after the event in a foothill rain forest area of West SumaEa, Indonesia. Species number of trees over 5 cm dbh at the initial observation ranged from 30 spp. to 40 spp. per a stand being under 1000 m2 in area, and this value was less than half of one in a matuled forest stands with same area. The secondary forest had some prominently dominant species derived from germination after the last logging. Growth rate of biomass was largely different among sites, and a sund on fertile soils conditions grew up to 300 metric ton ha-1 in aboveground biomass within 9 years. Many canopy trees in the forest, however, rapidly died at the latter phase of this observation, and Eees sprouted from logged stumps and species in a matured forest both increased their dominance relatively. Frequent logging would be to the advantage of species having coppice generation because ofpositive correlation between a stump size and growth rate of shoots. Hardness of stem wood of secondary species tended to be lower than one of matured forest species, and the property had a positive conelalion with relative growth rate of dbh (RGRD) for secondary species. A mathematical model based on this relation suggested that amount of photosynthetic product of a tree would not be largely different irrespective of stem hardness under similar external and internal conditions, and a tree would allocate the product to suitable positions for the growth ofvolume or bulk density based on is life srategy. A time rend of a primary net productivity had the maximum value within a few years after logging, and tended to be constant. The value at the stable stages was not sigrificantly different from one of a neighboring matured forest, and was estimated at26 - 30 metric ton ha-1 y-1 as total primary productivity including roots. The RGRD - dbh of a stand largely changed with time on regeneration process, and it produced the maximum productivity at the initial stages. Basing on this time rend of this relation, we analyzed successive changes of stand structure and primary productivity under consideration with effecs of stem hardness of a Eee as physical property.

An equatorial rain forest in West Sumatra suffered defoliation and severe stem damages from two storms in early 199S, Intensity of litter production at a storm generated gap site was 225 ton ha-1, and big woody debris over 10 cm in diameter accounted for 78%. A mass of fine litter promptly lost its weight of dry matter in Ao layer directly after the event, and the Tate tended to have a positive correlation to the initial amount of accumulation. An impact of these mass litter production on a material cycling of an equatorial rain forest ecosystem was simulated basing on these field data and monitoring data of a forest since 1981. The simulation showed that fine litter would supply nutrients enough for revegetation at an initial stage in particular, and a great amount of woody debris would contribute to the process at later stages because of their low decomposition rate. The time needed for 95% loss of initial litter amount by decomposition at a gap site was estimated at 11 years in this forest i[respective of amount, when the composition of litter is same. This average decay rate overcomes a net primary productivity. From a carbon balance between both potential rates of decay and growth for initial 11 years after a damage, it shows that about 100(organic matter) ton ha-1 of litter production is a boundary value between its sink and source for this stand.

The coppice stands under the climatic conditions of Warmth Index (WI)≧85°C·month, and Coldness Index (CI)≦−10°C·month could be classified into aQuercus serrata type andCarpinus types at a heavy snowfall climate region of central Japan. The latter types tended to be more distributed on steeper slopes rather than the former. An analysis of tree forms and growth rates of species could reveal the characteristic of this habitat and vegetation type. The growth rates of stem diameter of dominant species on a gentle slope were higher than ones on a steep slope. However, the dominant species on the steeper slope had plasticity to basal bend with sustentacular roots, which is one form of tolerance of heavy snowfall on steep slopes. Average mortality during 14 years was 26%, irrespective of the gradient of a slope. More than one-third of dead shoots were induced by direct damage, while cracked or broken pieces of a stem were from heavy snowfall. The shoot density at smaller diameter classes tended to be higher at a stand having high horizontal variance of canopy surface caused by basal bend of big shoots. A frequency distribution function of individual tree weight (w), f(w)=pw−3/2, could be obtained at each coppice stand by statistical analysis. The value of a parameter p, a packing factor, tended to be higher at stands on steeper slopes consisting of largely bent shoots and was constant irrespective of the growth.

The marked biogeographic difference between western (Malay Peninsula and Sumatra) and eastern (Borneo) Sundaland is surprising given the long time that these areas have formed a single landmass. A dispersal barrier in the form of a dry savanna corridor during glacial maxima has been proposed to explain this disparity. However, the short duration of these dry savanna conditions make it an unlikely sole cause for the biogeographic pattern. An additional explanation might be related to the coarse sandy soils of central Sundaland. To test these two nonexclusive hypotheses, we performed a floristic cluster analysis based on 111 tree inventories from Peninsular Malaysia, Sumatra, and Borneo. We then identified the indicator genera for clusters that crossed the central Sundaland biogeographic boundary and those that did not cross and tested whether drought and coarse-soil tolerance of the indicator genera differed between them. We found 11 terminal floristic clusters, 10 occurring in Borneo, 5 in Sumatra, and 3 in Peninsular Malaysia. Indicator taxa of clusters that occurred across Sundaland had significantly higher coarse-soil tolerance than did those from clusters that occurred east or west of central Sundaland. For drought tolerance, no such pattern was detected. These results strongly suggest that exposed sandy sea-bed soils acted as a dispersal barrier in central Sundaland. However, we could not confirm the presence of a savanna corridor. This finding makes it clear that proposed biogeographic explanations for plant and animal distributions within Sundaland, including possible migration routes for early humans, need to be reevaluated.

Architecture of evergreen broadleaf trees in evergreen warm-temperate and tropical forests was analyzed with a ratio (U/Ac) of total surface area of aboveground woody organs to leaf area (one-sided surface area) of each felled tree. The ratio,U/Ac, tended to decrease with the increasing ofdbh. There was little difference in a range of the ratio at eachdbh class between a warmtemperate forest and a tropical rainforest. The ratios of larger trees correlated with their relative growth rates ofdbh among similar sized trees. Canopy trees tended to stop their growth at some value of a ratio, a threshold value being about 1.5, irrespective of forest types. The threshold value showed the critical condition that annual respiration of woody organs of a tree consumed nearly all surplus production. On the basis of the pipe model, an ideal maximum tree height was considered with the ratio, and was estimated at 110 m and 70 m in a tropical rainforest and a warm-temperate forest, respectively.