De la moisson humaine : botanique et perfectibilit dans les Lumires mdicales

Longitudinal and geographic variations in the green moisture content and basic density of bamboo culm were evaluated by using linear mixed-effect models for three bamboo species (Bambusa vulgaris Schrad. ex J.C., Bambusa maculata Widjaja, and Gigantochloa atter (Hassk) Kurz ex Munro) naturally grown in four locations in Lombok Island, Indonesia. The mean green moisture contents and basic densities were 74.2 % and 0.69 g cm－3 for B. vulgaris, 78.5 % and 0.65 g cm－3 for B. maculata, and 80.3 % and 0.65 g cm－3 for G. atter, respectively. No significant differences in green moisture content and basic density were found among the species. A significant negative correlation between basic density and green moisture content was found in all three species. Based on the results of model selections for longitudinal variations, the green moisture content decreased with an increase in the culm height in all three species, and basic density tended to increase from the base to the top of the culm. Relatively large geographical variation was found in the green moisture content and basic density of G. atter, although the main reasons for variation of these properties were individual culm in three species.

Colony composition and behavioral characteristics of the myrmicine ant, Aphaenogaster rugulosa, a species endemic to Yonagunijima Island, were investigated. Colonies nested in rotten woods fallen on the forest floor. All queenright colonies (N=42) were monogynous with one dealate queen. The average colony size in worker number was 140.5±SD 94.9. Under laboratory conditions, workers and larvae fed on both fresh and dried insect preys. The workers used a kind of tool to transport diluted sugar water to the nest chamber. They dropped pine needles and trashes into the diluted sugar water and then transported the food-soaked materials back into the nest chamber, where nest members then sucked on the materials inside the nest chamber. Trophic eggs were laid by the workers, the majority of which were given to the larvae. The queens also fed on trophic eggs as well as insect preys. The workers under an orphan condition laid reproductive eggs that grew up to be males.

Mangrove forests are the most carbon-rich ecosystems in the world however, baseline information on its pheno-logy is poor. Information on seasonal changes in canopy greenness, which reflects the level of photosynthetic activity, is helpful for understanding seasonal patterns of carbon uptake by mangrove forests. To elucidate the periodicity, timing, and length of the active photosynthetic season, we examined temporal patterns in enhanced vegetation index (EVI) and normalized difference vegetation index (NDVI) derived from 18-year (2001-2018) Moderate Resolution Imaging Spectroradiometer images for four major forest types in the Sundarbans, Bangladesh. We identified a dominant cycle for the time-series of EVI and NDVI after Fourier transformation. We also estimated four phenological dates among the forest types: the start of the season (SOS), time of maximum greenness (MaxGreen), end of the season (EOS), and length of the season (LOS). Fourier analysis revealed that both the NDVI and EVI exhibited distinct cycles per year for all forest types, suggesting that there are annual cycles of canopy greenness. The SOS as estimated using the EVI and NDVI was consistently from late May to mid-June across forest types. However, the MaxGreen, EOS and LOS estimated varied between the two indices. Because EVI-based phenological dates match better with phenological information at the ground level than do NDVI-based dates, the EVI would be better than the NDVI for depicting changes in canopy greenness. The results of this study provide baseline information for future phenological changes in the Sundarbans.

Tropical forest trees take up silicon (Si) and return it to the forest floor via leaf litterfall. Our objective was to explore to what extent litter Si flux and Si availability from the soil are spatially coupled. We examined these relationships within a 4-ha area of lowland mixed dipterocarp forest of Lambir Hills National Park in Borneo. Using leaf litter samples collected with litter traps, we found that Si concentration and flux of leaf litter ranged 2-23mgSig－1 and 0.8-13.1gSim－2 yr－1, respectively, whereas water-extractable Si from 0-10cm deep soil ranged from 5.9 to 24.5mg kg－1 (0.7 to 3.0gSim－2) at 80 litter trap locations. There was no significant correlation among these three aspects of Si cycling via trees. Water-extractable soil Si from three 95cm deep cores showed no significant change with depth, whereas in-situ measurements with six tension lysimeters showed higher soil-water Si concentration in the upper soil layer (0-5cm depth). These results suggest that spatial variations of Si concentration and flux in leaf litter do not reflect those of soil Si availability, but are modulated by distribution of tree species that differ in Si uptake. Si returned to the soil via leaf litter did not show strong spatial signals probably because solubility of Si from dead leaves differs among species. At the stand level, our results are consistent with the perspective that litter Si input enriches plant-available Si pool in the upper soil horizons in tropical forests.

This paper aims at clarifying how immigrants from rural areas use the outskirts of Bintulu City in Sarawak, Malaysia and form places of residence there. The area under tropical rain forest climate conditions in Southeast Asia generally has a sparse population. In recent decades, urban areas have started to grow rapidly. In the state of Sarawak, urban areas have developed, and the formation of squatter areas by immigrants from rural areas has been reported. Until a few decades ago, after leaving urban areas, the landscape immediately changed from an urban landscape into a rural one consisting mainly of forests, dotted with swidden farms and longhouses. Recently, however, in areas such as those after leaving the urban area (urban outskirts) of Bintulu City, in addition to shops and offices managed by the Chinese, longhouse communities (LHCs) formed by immigrants from rural areas are densely dotted. In such LHCs, dwellings and ways of living are observed to have different characteristics from those in rural LHCs and squatter areas in urban areas. Characteristics of LHCs in urban outskirts are shown below. Regarding land acquisition, the land was in most cases purchased from former occupants. Regarding members of the LHCs, in LHCs formed before the 1960s, many males married in and households moved in around the 1970s and 1980s. On the other hand, in newly formed LHCs, in many cases no kinship links or very weak kinship links between households are observed. Regarding livelihoods, many members of LHCs work in the urban area, while some who own land cultivate cash crops such as oil palm. Suburban formation has begun as a mix of such LHCs, Chinese shops and offices, and forests in the study area.