Freshwater swamp forests are wetland ecosystems with poorly understood ecology. With increasing degradation across the Niger basin (where it is the most extensive across West Africa), it is deemed important to underst...Freshwater swamp forests are wetland ecosystems with poorly understood ecology. With increasing degradation across the Niger basin (where it is the most extensive across West Africa), it is deemed important to understand its distribution, patterns and composition. This is aimed at both increasing botanical inventories in the ecosystem and also elucidate vital steps that could guide its effective conservation. This study assessed the floristic composition and diversity across 16 one hectare forest plots and sought to show how varied the sites were in terms of diversity, stem density and basal area. The survey showed that the area had 116 species within 82 genera and 36 families. The number of species found in each of the disturbed sites was generally higher than the intact forest sites, which was not diverse but comprised many trees with higher basal area. While the stem density which ranged from 94 - 409 stems·ha-1 is comparable with that of other tropical forests, species richness was low (ranging from 8.65 - 0.52). Diversity ranged from 3.38 - 0.98 and was higher in disturbed sites than in intact locations. Species richness was generally low and implies that loss of species in the ecosystem could threaten species’ existence and conservation in the ecosystem. Disturbed locations had more species than the intact zones and as such show the importance of targeted conservation not only in the undisturbed locations but also in the disturbed locations with a higher species value and potential for species stability of the ecosystem.展开更多
The objective of this study was to compare the wood properties related to wood pulp quality of two widely planted Acacia species viz.Acacia mangium Willd.and Acacia auriculiformis A.Cunn.Ex Benth.and their hybrid.Acid...The objective of this study was to compare the wood properties related to wood pulp quality of two widely planted Acacia species viz.Acacia mangium Willd.and Acacia auriculiformis A.Cunn.Ex Benth.and their hybrid.Acid insoluble lignin content(Klason),mean stem density and fibre length differed considerably among the species and hybrids.A.mangium possessed a high percent of lignin content compared to A.auriculiformis and the Acacia hybrid.However,mean stem density of A.auriculiformis was higher than A.mangium and the hybrid.Fibre length of heartwood tissues was generally shorter than that of sapwood tissues.The hybrid had longer fibres than the parent species.Lignin was negatively correlated with mean stem density.Generally,the wood properties of the hybrid were superior to its parent species.The significant intraspecific variation observed for wood properties of Acacia species could be used in breeding superior hybrids combining desirable traits of the two species.Considering thedifficulty involved in accurately measuring the lignin content compared to mean stem density,selection for plants with low lignin content can be achieved by indirect selection of high mean stem density.展开更多
Growth and wood and bark properties of Abies faxoniana seedlings after one year＇s exposure to elevated CO2 concentration （ambient ＋ 350 （± 25） μmol/mol） under two planting densities （28 or 84 plants/m^2）...Growth and wood and bark properties of Abies faxoniana seedlings after one year＇s exposure to elevated CO2 concentration （ambient ＋ 350 （± 25） μmol/mol） under two planting densities （28 or 84 plants/m^2） were investigated in closed-top chambers. Tree height, stem diameter and cross-sectional area, and total biomass were enhanced under elevated CO2 concentration, and reduced under high planting density. Most traits of stem bark were improved under elevated CO2 concentration and reduced under high planting density. Stem wood production was significantly increased in volume under elevated CO2 concentration under both densities, and the stem wood density decreased under elevated CO2 concentration and increased under high planting density. These results suggest that the response of stem wood and bark to elevated CO2 concentration is density dependent. This may be of great importance in a future CO2 enriched world in natural forests where plant density varies considerably. The results also show that the bark/wood ratio in diameter, stem cross-sectional area and dry weight are not proportionally affected by elevated CO2 concentration under the two contrasting planting densities. This indicates that the response magnitude of stem bark and stem wood to elevated CO2 concentration are different but their response directions are the same.展开更多
文摘Freshwater swamp forests are wetland ecosystems with poorly understood ecology. With increasing degradation across the Niger basin (where it is the most extensive across West Africa), it is deemed important to understand its distribution, patterns and composition. This is aimed at both increasing botanical inventories in the ecosystem and also elucidate vital steps that could guide its effective conservation. This study assessed the floristic composition and diversity across 16 one hectare forest plots and sought to show how varied the sites were in terms of diversity, stem density and basal area. The survey showed that the area had 116 species within 82 genera and 36 families. The number of species found in each of the disturbed sites was generally higher than the intact forest sites, which was not diverse but comprised many trees with higher basal area. While the stem density which ranged from 94 - 409 stems·ha-1 is comparable with that of other tropical forests, species richness was low (ranging from 8.65 - 0.52). Diversity ranged from 3.38 - 0.98 and was higher in disturbed sites than in intact locations. Species richness was generally low and implies that loss of species in the ecosystem could threaten species’ existence and conservation in the ecosystem. Disturbed locations had more species than the intact zones and as such show the importance of targeted conservation not only in the undisturbed locations but also in the disturbed locations with a higher species value and potential for species stability of the ecosystem.
基金funded by e-Science 02-01-02-SF0403 from the Ministry of Science,Technology and Innovation,Malaysia
文摘The objective of this study was to compare the wood properties related to wood pulp quality of two widely planted Acacia species viz.Acacia mangium Willd.and Acacia auriculiformis A.Cunn.Ex Benth.and their hybrid.Acid insoluble lignin content(Klason),mean stem density and fibre length differed considerably among the species and hybrids.A.mangium possessed a high percent of lignin content compared to A.auriculiformis and the Acacia hybrid.However,mean stem density of A.auriculiformis was higher than A.mangium and the hybrid.Fibre length of heartwood tissues was generally shorter than that of sapwood tissues.The hybrid had longer fibres than the parent species.Lignin was negatively correlated with mean stem density.Generally,the wood properties of the hybrid were superior to its parent species.The significant intraspecific variation observed for wood properties of Acacia species could be used in breeding superior hybrids combining desirable traits of the two species.Considering thedifficulty involved in accurately measuring the lignin content compared to mean stem density,selection for plants with low lignin content can be achieved by indirect selection of high mean stem density.
基金the Key Project of the National Natural Science Foundationof China (90511008, 90202010)the Sino-Finland International CooperativeProject (30211130504)the Program of 100 Distinguished Young Scien-tists of the Chinese Academy of Sciences (01200108C).
文摘Growth and wood and bark properties of Abies faxoniana seedlings after one year＇s exposure to elevated CO2 concentration （ambient ＋ 350 （± 25） μmol/mol） under two planting densities （28 or 84 plants/m^2） were investigated in closed-top chambers. Tree height, stem diameter and cross-sectional area, and total biomass were enhanced under elevated CO2 concentration, and reduced under high planting density. Most traits of stem bark were improved under elevated CO2 concentration and reduced under high planting density. Stem wood production was significantly increased in volume under elevated CO2 concentration under both densities, and the stem wood density decreased under elevated CO2 concentration and increased under high planting density. These results suggest that the response of stem wood and bark to elevated CO2 concentration is density dependent. This may be of great importance in a future CO2 enriched world in natural forests where plant density varies considerably. The results also show that the bark/wood ratio in diameter, stem cross-sectional area and dry weight are not proportionally affected by elevated CO2 concentration under the two contrasting planting densities. This indicates that the response magnitude of stem bark and stem wood to elevated CO2 concentration are different but their response directions are the same.
