Tropical Tree Species

To conserve a rare plant, conservation programs must be guided by the biological attributes of the species. What constitutes the most critical biological information for plant conservation has been the issue of discussion for the last 30 years. Most scientists promote an approach that is either ecological or genetic in emphasis. Ecological and genetic processes will often interact synergistically to influence the population viability and to determine the persistence of populations in the long run. Consequently, conservation management of plant species, in addition to ecological information, requires a robust understanding of underlying genetic processes as well as the variation within and between populations. Conservation has a cost and the resources available for conservation programs are always limited. Therefore, conservation management strategies should not only be scientifically justified but also practical in terms of resource availability. Shorea lumutensis is a rare and endemic dipterocarp in Peninsular Malaysia. A comprehensive research activity was initiated to assess the population ecology and population genetics of S. lumutensis to elucidate specific ecological and genetic requirements and subsequently to set conservation strategies and priorities. This paper is apparently the first attempt at applying both the ecological and genetic approaches into conservation management of a rare dipterocarp. In addition, this paper also attempts to link the gaps between conservation research and conservation management in a realistic manner. It is our hope that this study will serve as a model for the study of other rare dipterocarps which should be given priority for conservation.

To investigate the ability of pioneer and late-successional species to adapt to a strong light environment in a reforestation area, we examined the activities of antioxidant enzymes in relation to photosystem II, chlorophyll a fluorescence and photosynthetic pigment concentration for eight tropical tree species grown under 100% (sun) and 10% (shade) sunlight irradiation. The pioneer (early-succession) species (PS) were Cecropia

Big Fukugi (Garcinia subelliptica) trees exist prevalently around residences in traditional villages in Okinawa Prefecture, Japan. It is thought that such a rural landscape with planting trees, in particular Fukugi trees, as windbreak, was ameliorated based on Feng Shui concept in the then Ryukyu Kingdom around 300 yrs. ago. In order to explore how far Fukugi trees have been utilized in traditional villages in Nansei Islands, the southernmost archipelago in Japan. This study was designed to continue our previous study on the distribution of big Fukugi trees in Okinawa Islands, located in the center of Naisei Islands. We visited all villages, in particular older villages on almost each inhabited islands of Yaeyama Islands and Amami Islands. The biggest Fukugi trees found in each village were measured. It was found that big Fukugi trees are widely distributed on Ryukyu Islands, on the islands north to Amami Islands and south to Yaeyama Islands. In Amami Islands, Okinoerabu and its further south islands have Fukugi trees prevalently existing, while, for its further north islands, the remaining Fukugi trees were sparsely distributed and only a few old Fukugi trees found in few villages. Fukugi trees in Amami Ōshima and Kikai Island were among the biggest trees measured, however, most of them were individual stands around the residence. Even in these few houses with Fukugi trees, it is thought to have the affiliation to Ryukyu Kingdom in the past, and to be strongly influenced by Ryukyu culture. Thus, Okinoerabu Island could be considered as the northern borderline in Ryukyu Islands of such traditional rural landscape with prevalent Fukugi planting, which was established under the influence of Ryukyu culture.

Big Fukugi (Garcinia subelliptica) trees exist prevalently around residences in traditional villages in Okinawa Prefecture, Japan. It is thought that such a rural landscape with planting trees, in particular Fukugi trees, as windbreak, was ameliorated based on Feng Shui concept in the then Ryukyu Kingdom around 300 yrs. ago. In order to explore how far Fukugi trees have been utilized in traditional villages in Nansei Islands, the southernmost archipelago in Japan. This study was designed to continue our previous study on the distribution of big Fukugi trees in Okinawa Islands, located in the center of Naisei Islands. We visited all villages, in particular older villages on almost each inhabited islands of Yaeyama Islands and Amami Islands. The biggest Fukugi trees found in each village were measured. It was found that big Fukugi trees are widely distributed on Ryukyu Islands, on the islands north to Amami Islands and south to Yaeyama Islands. In Amami Islands, Okinoerabu and its further south islands have Fukugi trees prevalently existing, while, for its further north islands, the remaining Fukugi trees were sparsely distributed and only a few old Fukugi trees found in few villages. Fukugi trees in Amami Ōshima and Kikai Island were among the biggest trees measured, however, most of them were individual stands around the residence. Even in these few houses with Fukugi trees, it is thought to have the affiliation to Ryukyu Kingdom in the past, and to be strongly influenced by Ryukyu culture. Thus, Okinoerabu Island could be considered as the northern borderline in Ryukyu Islands of such traditional rural landscape with prevalent Fukugi planting, which was established under the influence of Ryukyu culture.

1Water availability is the main determinant of species’ distribution in lowland tropical forests. Species’ occurrence along water availability gradients depends on their ability to tolerate drought.2To identify species’ traits underlying drought-tolerance we excavated first year seedlings of 62 dry and moist forest tree species at the onset of the dry season. We evaluate how morphological seedling traits differ between forests, and whether functional groups of species can be identified based on trait relations. We also compare seedling traits along independent axes of drought and shade-tolerance to assess a hypothesized trade-off.3Seedlings of dry forest species improve water foraging capacity in deep soil layers by an increased below-ground biomass allocation and by having deep roots. They minimize the risk of cavitation by making dense stems, and reduce transpiration by producing less leaf tissue. Moist forest seedlings have large leaf areas and a greater above-ground biomass, to maximize light interception, and long, cheap, branched root systems, to increase water and nutrient capture.4Associations among seedling traits reveal three major drought strategies: (i) evergreen drought-tolerant species have high biomass investment in enduring organs, minimize cavitation and minimize transpiration to persist under dry conditions; (ii) drought-avoiding species maximize resource capture during a limited growing season and then avoid stress with a deciduous leaf habit in the dry season; (iii) drought-intolerant species maximize both below- and above-ground resource capture to increase competitiveness for light, but are consequently precluded from dry habitats.5We found no direct trade-off between drought- and shade-tolerance, because they depend largely on different morphological adaptations. Drought-tolerance is supported by a high biomass investment to the root system, whereas shade-tolerance is mainly promoted by a low growth rate and low SLA.6Synthesis. We conclude that there are three general adaptation strategies of drought-tolerance, which seemingly hold true across biomes and for different life forms. Drought- and shade-tolerance are largely independent from one another, suggesting a high potential for niche differentiation, as species’ specialization can occur at different combinations of water and light availability.Water availability is the main determinant of species’ distribution in lowland tropical forests. Species’ occurrence along water availability gradients depends on their ability to tolerate drought.To identify species’ traits underlying drought-tolerance we excavated first year seedlings of 62 dry and moist forest tree species at the onset of the dry season. We evaluate how morphological seedling traits differ between forests, and whether functional groups of species can be identified based on trait relations. We also compare seedling traits along independent axes of drought and shade-tolerance to assess a hypothesized trade-off.Seedlings of dry forest species improve water foraging capacity in deep soil layers by an increased below-ground biomass allocation and by having deep roots. They minimize the risk of cavitation by making dense stems, and reduce transpiration by producing less leaf tissue. Moist forest seedlings have large leaf areas and a greater above-ground biomass, to maximize light interception, and long, cheap, branched root systems, to increase water and nutrient capture.Associations among seedling traits reveal three major drought strategies: (i) evergreen drought-tolerant species have high biomass investment in enduring organs, minimize cavitation and minimize transpiration to persist under dry conditions; (ii) drought-avoiding species maximize resource capture during a limited growing season and then avoid stress with a deciduous leaf habit in the dry season; (iii) drought-intolerant species maximize both below- and above-ground resource capture to increase competitiveness for light, but are consequently precluded from dry habitats.We found no direct trade-off between drought- and shade-tolerance, because they depend largely on different morphological adaptations. Drought-tolerance is supported by a high biomass investment to the root system, whereas shade-tolerance is mainly promoted by a low growth rate and low SLA.Synthesis. We conclude that there are three general adaptation strategies of drought-tolerance, which seemingly hold true across biomes and for different life forms. Drought- and shade-tolerance are largely independent from one another, suggesting a high potential for niche differentiation, as species’ specialization can occur at different combinations of water and light availability.

Wood density information for a large number of tropical tree species is presented in units of ovendry weight in grams per cubic centimeter of green volume. The data base includes 1,280 entries from tropical America (40 percent), tropical Asia (36 per-cent), and ...

Cedrela odorata L. is a valuable tropical tree widely appreciated for its wood. This species confronts serious problems due to both overexploitation of its natural populations and its susceptibility to the Meliaceae borer Hypsipyla grandella, which destroys the apical meristems and produces structural deformations. The rapid introduction of new varieties through clonal forestry has been demonstrated to be the most effective way to improve the production of perennial plantation species. In this work, we report both a protocol for the rejuvenation of elite mature trees of C. odorata and the optimization of an in vitro culture system to scale up micropropagation. Several media formulations and the use of temporary immersion culture in bioreactors were evaluated. The addition of 20% coconut water to TY17 medium increased the number of adventitious shoots from hypocotyl segments to an average number of 4.68 shoots per explant. To replace coconut water and to define the culture medium, several cytokinins were tested at various concentrations; however, none of them produced the effect of coconut water. Rejuvenation of elite mature individuals was investigated by ex vitro grafting of mature tree twigs onto 3-mo-old juvenile trees. Although the grafting had a positive effect on the micropropagation of mature material, the multiplication rate of 1.5 new shoots per explant did not compare to the organogenic capacity of younger materials. Shoot and root elongation as well as acclimatization to ex vitro conditions were carried out in a temporary immersion culture of juvenile material using BioMINT® bioreactors. A 3.5-fold increase in shoot elongation and a 4-fold increase in root elongation were achieved compared to material cultured on semisolid media. Furthermore, this culture system allowed for 98% effectiveness in the soil adaptation of the in vitro-grown plants. The scaled-up multiplication capacity over a period of 6 mo calculated for the system is above 16,000 plants per mother plant with young materials but is only 125 with mature materials.