Photosynthetic properties of the Amazonian forest tree species, Cedrela odorata, Swietenia macrophylla, and Aniba rosaeodora, were studied in a nursery and in an open field to assess their potential success for planting purposes. These species were compared with nursery grown Ochroma lagopus Sw. and Dipteryx odorata. In the nursery, light-saturated net photosynthetic rate (A_max) and maximum stomatal conductance (g_smax) were highest in O. lagopus, a fast growing and light demanding plant, and lowest in D. odorata, a slowgrowing and shade tolerant species. A_max and g_smax were relatively high in C. odorata, which is medium to fast growing and has intermediate light requirements. Low A_max of A. rosaeodora suggests that this species may be classified as a slow growing species. In the open field, Amax and gsmax were highest in C. odorata, followed by S. macrophylla, and lowest in A. rosaeodora. Water use efficiency of A. rosaeodora was lower than that of C. odorata and S. macrophylla. Stomatal closure of C. odorata and S. macrophylla under high leaf-to-air vapor pressure difference (VPDL) enabled these species to avoid excessive water loss, but A. rosaeodora appeared not to avoid excessive water loss. These inferior photosynthetic properties of A. rosaeodora may explain it’s high mortality and slow growth in the open and, thus, this species is not suitable for open planting. Both A_max and g_smax of the open planted seedlings were higher than those of the nursery seedlings, while specific leaf area (SLA, leaf area per unit leaf dry weight) was smaller in the open planted seedlings than in the nursery seedlings, suggesting that the leaves of the nursery seedlings were shade-adapted while the open planted seedlings developed sun-adapted leaves. In order to enhance acclimation to exposed conditions, we recommend hardening the seedlings by exposing them to full sunlight before planting them in the open.

抄録全体を表示

Phenological characteristics during the reproductive processes of flower budding, flowering, fruiting and seed formation were investigated in a Durio zibethinus Murray tree growing in an experimental field of Universiti Putra Malaysia (UPM) in Selangor, Peninsular Malaysia. The survival curve showed that the relative fall rate of reproductive organs was lower at the mixed stages of flower budding, flowering and fruiting than at the early fruiting stage. The fall of flower buds commenced after the flower budding was completed. However, the falls of flowers and fruits occurred within a few days after the formation of flowering and fruiting. The periods of flower budding, flowering and fruiting were 34, 19 and 28 days, respectively. The fruit weight growth was approximated by a logistic equation, where the intrinsic growth rate varied from 0.419 to 0.794 week^-1. The forming seeds germinated or possessed germination ability at the fruit growth stage where the fruit weight reached the asymptote of the logistic growth curve. Total numbers of emerged flower buds, flowers and fruits over the whole reproductive period were 1629, 1467 and 1412 per tree, respectively. The percentage of fruits with germination ability was estimated to be 1.2% of the number of fruiting ones.

抄録全体を表示

Phytosociological classification of the coastal vegetation according to the concept and method of the Zürich-Montpellier School was done for the natural terrestrial vegetation that remains as isolated patches on sandbars parallel to the seashore of Narathiwat, Thailand. Twelve study sites were marked and the vegetation types were discussed. The results show that the plant communities in the study areas can be classified into 3 categories: 1) foredune and dune grassland communities; 2) dune scrub communities; 3) dune woodland communities. This report is the first description of such communities on peninsular Thailand. Profiles of the natural vegetation gradient across the sandbars are proposed.

抄録全体を表示

The relationship between species composition and environmental factors, including human activities, such as beach cleaning, mowing and trampling, in Southern Thailand’s maritime strand forests and sand dunes, -, was studied in order to assist in the development of a plan for the conservation of coastal plant species. Species composition at the study sites was studied using the phytosociological method (full-floristic inventory and total cover estimate of each species in quadrats). Quadrats are homogeneous representative samples of vegetation, varying from 9 to 100m². The following environmental data were collected at the site: width of sand dune, beach type, beach management type (beach cleaning), seawater salinity, slope, aspect, micro-topography and the amount of discarded garbage. Based on these data, two results were found: 1. The species composition of the sites was shown to be similar by the Bray-Curtis method, based on phytosociological relevé samplings; and 2. The main factors determining species composition were wind speed, rainfall, soil texture, salinity and especially beach management practices, based on the CCA method. Most of the general coastal species use thalassochory (seed dispersal by sea currents) and are distributed from tropical to subtropical regions, including the Okinawa Islands of Japan. The diversity of coastal plants was sustained by beach management practices on abandoned beaches, such as garbage cleaning and mowing. There were many shrubs (microphanerophytes) and sub-canopy trees (mesophytes) as a result of burning and cutting. Regeneration of maritime strand-forest species could be seen in open areas that resulted from burning and cutting. The spectra of life forms (dormancy types) varied from site to site, due to varying environmental conditions and human activities.

抄録全体を表示

We investigated the abundance of arboreal arthropods in pure Acacia mangium and Paraserianthes falcataria plantations in South Sumatra, Indonesia, to evaluate the function of fast-growing tree plantations as wildlife habitats in the tropics. Two plots were established on each tree species,&lsduo;plantation and insecticide fogging was conducted to sample arboreal arthropods. The mean number of arthropods collected was higher in the A. mangium plantation (230.9-268.0 ⁄ m²) than in the P. falcataria plantation (13.9-21.0 ⁄ m²). In all plots, Collembola was the most abundant order, comprising more than 50.4-56.2% and 82.5-89.2% of the total number of arthropods in the P. falcataria and A. mangium plantations, respectively. The predominance of Collembola in the A. mangium plantation resulted in lower diversity indices (Shannon-Wiener H’ and Simpson 1 ⁄ λ) than in the P. falcataria plantation. Compared to data in the literature, the abundance of arboreal arthropods in the A. mangium plantation was comparable to that of natural forests, although the low H’ in the A. mangium plantation and the low abundance in the P. falcataria plantation were extreme.

抄録全体を表示

Fire is still the best tool for land preparation for shifting cultivation, because it is quick, cheap and easy. Unfortunately, it is not clear whether or not shifting cultivation is sustainable in terms of quality and duration. To elucidate this, research was conducted on shifting cultivation land in the village of Pelalawan, Pelalawan district, Riau Province, Indonesia. The research was conducted during dry season in the year 2001. The main objective was to determine changes in the soil's chemical and physical properties three and six months after burning.
Results of research show that the fuel load in the site varied from 39.5-51.8 ton ha^-1 and consisted of litter and branches, the fuel bed depth varied from 71.8 to 108.4 cm and the rate of fire spread varied from 1.1 to 2.5 m minute^-1 and resulted in high flame temperatures that varied from 900 to 1100 °C. The high flame temperatures were accompanied by high fire intensities that varied from 2552.3 to 5050.9 kW m^-1 caused peat destruction that ranged from 6.0 to 7.2 cm depth. At three months after burning there was only base saturation in hemic 2 increased significantly, while at six months there was only base saturation in both hemic 2 and 3. As for soil physical properties, it was found that only the water holding capacity increased at three and six months after burning.

抄録全体を表示

A pollen and charcoal record of a core from the Rawa Danau peat swamp in Central West Java provides a picture of environmental change and fire history from ca. 7400 yr BP. This record also verifies the results of a previous study on the causes of change in lignin-phenols along the core. Woody peat has been accumulating at the site along the core. The record demonstrates that vegetation change occurred in the area as a response to climatic and environmental changes, as well as human disturbances. In addition, charcoal particles in peat indicate that fire occurred in this area throughout the period. Initially, the site was a swamp forest with numerous open areas from ca. 7400-6500 yrs BP. Vegetation in the Rawa Danau appears to have been stable during the period from ca. 6500 to 3800 years BP. Subsequently, open herbaceous swamp developed in the area from ca. 3800 to 2300 years BP as indicated by the preponderance of Gramineae. Dry climatic conditions with lower effective precipitation than that of the previous period prevailed during this period. This is correlative with regional climatic conditions at this time. The dry climatic conditions facilitated intensive fire, as indicated by the high C ⁄ P value in the pollen record. From ca. 2200 yr BP, the vegetation of the Rawa Danau swamp might have been more or less similar with the present vegetation. During the last 200 years, the vegetation in the Rawa Danau area became more open as a consequence of the significant increase in human disturbances. In addition, changes in lignin phenols (LPVI values) of the Rawa Danau core have been caused by changes in the proportion of Gramineae rather than that of the gymnosperms.

抄録全体を表示

The insecurity of farmers’ land tenure rights are thought to bring about resource degradation and low crop productivity in tropical areas. Private property rights are therefore expected to optimize farmers’ land use by allowing the usage of perennial crops that will increase land privatization for longer growing periods. This article discusses the effects of community property regimes on land use by examining a case study from West Sumatra, Indonesia.
Farmers of the study area grow rice, non-rice food crops, and tree crops on community, lineage, family, and private land. Family and private land are dominant nowadays, while community or lineage land control is declining. Despite their preference for new, private land in forested areas, however, local Minangkabau farmers maintain joint ownership of their ancestral land through matrilineal inheritance as is the custom instead of privatizing it. Community leaders allow farmers who have familial inheritance rights to plant trees and other crops on every tenure type of land, because there is a separation of crop tenure and cultivation rights from land ownership rights. Crop productivity is similar between private land and common land in rice fields and dry-land farms, given similar biophysical and socio-economic conditions. Tree crops and idle bushy land occur on both land tenure types.
Private land ownership rights do not always lead to more investment in sustainable and efficient resource utilization in the study area. Local institutions also manage common resource pools to sustain the whole kinship group, including the poor. The principle problem is the continued degradation of natural resources caused by the decline in local institutional capability and the lack of technical innovation. Institutional restructuring of common forest resource management and technical interventions for agricultural intensification, not the privatization of the indigenous common property which will weaken communities’ control of land and resources, are crucial for the improvement of farmers’ land use.

抄録全体を表示