Diversity and regeneration of woody species were investigated in two ecological niches viz. gap and intact vegetation in old-growth seasonally dry Shorea robusta （Gaertn. f.） forests in Nepal. We also related variet...Diversity and regeneration of woody species were investigated in two ecological niches viz. gap and intact vegetation in old-growth seasonally dry Shorea robusta （Gaertn. f.） forests in Nepal. We also related varieties of diversity measures and regeneration at- tributes to gap characteristics. Stem density of tree and shrub components is higher in the gap than in the intact vegetation. Seedling densities of S. robusta and Terminalia alata （B. Heyne ex Roth.） are higher in the gap than in the intact vegetation, while contrary result is observed for T. bellirica （Gaertn. ex Roxb.） and Syzigium cumini （L. Skeels） in term of seedling density. The complement of Simpson index, Evenness index, and species-individual ratio in the seedling layer are lower in the gap than the intact vegetation. Gap size can explain species richness and species establishment rate. Gaps created by multiple tree falls in different years have higher seedling density of S. robusta than gaps created by single and/or multiple tree falls in the same year. In conclusion, gaps maintain species diversity by increasing seedling density, and favor regeneration of Sal forests. In addition to gap size, other gap attributes also affect species diversity and regeneration.展开更多
Plantations of tropical species axe becoming an increasingly important source of wood. However, it is important that research trials focus not only on tree growth performance, but also on wood quality. The aims of thi...Plantations of tropical species axe becoming an increasingly important source of wood. However, it is important that research trials focus not only on tree growth performance, but also on wood quality. The aims of this study were to assess the growth performance of six commercially and ecologically important tree species from separate plantation trials in Indonesia and to determine the relationships between tree growth and wood quality in terms of the dynamic modulus of elasticity （MOE） and wood density. Forty-eight 7-year Maesopsis eminii Engl. and thirty-five 9-year specimens （7 each of 5 Shorea spp.） were selected from two trials. The MOE, based on acoustic velocity, was indirectly measured to evaluate wood stiffness. Tree-growth performance was evaluated, and correlations between growth traits and acoustic velocity as well as density and wood stiffness properties were estimated. The growth performance of M. eminii in terms of tree volume was significantly different in three different cate- gories of growth （i.e. fast, medium, slow）. Of the five Shorea spp. studied, Shorea leprosula Miq. had the highest growth rate, as expected since it is known to be a fastgrowing Shorea species. Indirect measurement of wood quality by means of non-destructive ultrasonic methods showed a weak negative correlation between tree volume and acoustic velocity and dynamic MOE. Although each fast-growing tree could reach a merchantable size faster than other varieties or species, wood traits of various species tested were not significantly different based on tree growth rate performance. The findings from this study could be used to improve selection criteria in future breeding trials; indirect measurements of the dynamic modulus of elasticity can be used in mass pre-selection of genetic materials, to choose the most-promising material for in-depth evaluation.展开更多
Background:No studies have documented long-term trends in aboveground biomass(AGB)for mixed-dipterocarp forests(MDF),the dominant rain forest type in tropical wet equatorial Asia.In our study,we sought to document suc...Background:No studies have documented long-term trends in aboveground biomass(AGB)for mixed-dipterocarp forests(MDF),the dominant rain forest type in tropical wet equatorial Asia.In our study,we sought to document such trends over forty years across three sites representing lowland to lower montane elevations.Methods:To do this,we established fifty 100 m×25 m plots in 1978 across three sites sampled along an elevation gradient,identified as mature old-growth forest.We measured trees for diameter at breast height that we identified to species and tagged.We took wood samples to calculate species wood-specific gravity.We re-measured plots in 1998 and again in 2018.Results:We show standing AGB for all sites combined to be 517.52 Mg·ha^(-1)in 1978,but this declined by 17%over 40 years to 430.11 Mg·ha^(-1).No differences exist among sites in AGB primarily because of considerable within site variation;but interactions of time with site show declines across sites were not uniform,one remained about the same.Relatively few species represented a high proportion of the AGB with the top five species comprising between 34%and 65%,depending upon site and year sampled.One species,Mesua nagassarium,represented a disproportionately large amount of AGB and decline over time,particularly at the low elevation site.Conclusions:Our results are directly relevant to estimating AGB and standing carbon sequestered in MDF.Our study is the first to demonstrate varying but overall,declining trends in amounts of AGB among forests making predictions of biomass and standing carbon in MDF difficult over wide regions.展开更多
The potential of base treated Shorea dasyphylla（BTSD） sawdust for Acid Blue 25（AB 25） adsorption was investigated in a batch adsorption process.Various physiochemical parameters such as pH,stirring rate,dosage,con...The potential of base treated Shorea dasyphylla（BTSD） sawdust for Acid Blue 25（AB 25） adsorption was investigated in a batch adsorption process.Various physiochemical parameters such as pH,stirring rate,dosage,concentration,contact time and temperature were studied.The adsorbent was characterized with Fourier transform infrared spectrophotometer,scanning electron microscope and Brunauer,Emmett and Teller analysis.The optimum conditions for AB 25 adsorption were pH 2,stirring rate 500 r/min,adsorbent dosage 0.10 g and contact time 60 min.The pseudo second-order model showed the best conformity to the kinetic data.The equilibrium adsorption of AB 25 was described by Freundlich and Langmuir,with the latter found to agree well with the isotherm model.The maximum monolayer adsorption capacity of BTSD was 24.39 mg/g at 300 K,estimated from the Langmuir model.Thermodynamic parameters such as Gibbs free energy,enthalpy and entropy were determined.It was found that AB 25 adsorption was spontaneous and exothermic.展开更多
Objective:To evaluate antioxidant and antimicrobial activities of stembark of Shorea kunstleri(S.kunstleri)together with analysis of phytochemical and total phenolic contents.Methods:Extraction was conducted with diff...Objective:To evaluate antioxidant and antimicrobial activities of stembark of Shorea kunstleri(S.kunstleri)together with analysis of phytochemical and total phenolic contents.Methods:Extraction was conducted with different solvent polarity of n-hexane,dichloromethane(DCM)and methanol by using Soxhlet extraction.Total phenolic content was determined using Folin-Ciocalteu method.Free radical scavenging activity and inhibition of lipid peroxidation were evaluated with DPPH radical scavenging and ferric thiocyanate assays,respectively.Antimicrobial activities were performed using disc diffusion method,minimum inhibition concentration(MIC),minimum bactericidal concentration(MBC),and minimum fungicidal concentration.Results:S.kunstleri stembark extracts revealed presence of steroids,terpenoids,saponins,flavonoids,and phenolic compounds.Methanol extract exhibited the highest total phenolic content and free radical scavenging activity resulting in phenolic content of(8.340±0.003)g GAE/100 g of extract and(95.90±1.07)%DPPH inhibition(IC_(50)value of 18.6μg/mL),respectively.Ferric thiocyanate assay of n-hexane,DCM,and methanol extracts indicated lipid peroxidation inhibitory activity of(74.20±0.35)%,(74.00±0.10)%,and(72.80±0.27)%,respectively.In antimicrobial and antifungal tests,methanol extract showed inhibition against Staphylococcus aureus(S.aureus),Candida albicans,and Candida tropicalis with inhibition zones of 10-12,18-22,and 18-19 mm,respectively.The MIC test of methanol extract showed highest inhibition against Candida albicans and S.aureus(0.04 and 0.08 mg/mL,respectively)while DCM extract exhibited the highest activity towards Candida tropicalis(MIC value of 0.63 mg/mL).Taken together,MBC test of methanol extract strongly demonstrated bactericidal effect against S.aureus with MBC value of 0.08 mg/mL.Conclusions:The study demonstrated that stembark extracts of S.kunstleri possessed antioxidant and antimicrobial properties.展开更多
基金supported by Swedish International Development Cooperation Agency (SIDA)
文摘Diversity and regeneration of woody species were investigated in two ecological niches viz. gap and intact vegetation in old-growth seasonally dry Shorea robusta （Gaertn. f.） forests in Nepal. We also related varieties of diversity measures and regeneration at- tributes to gap characteristics. Stem density of tree and shrub components is higher in the gap than in the intact vegetation. Seedling densities of S. robusta and Terminalia alata （B. Heyne ex Roth.） are higher in the gap than in the intact vegetation, while contrary result is observed for T. bellirica （Gaertn. ex Roxb.） and Syzigium cumini （L. Skeels） in term of seedling density. The complement of Simpson index, Evenness index, and species-individual ratio in the seedling layer are lower in the gap than the intact vegetation. Gap size can explain species richness and species establishment rate. Gaps created by multiple tree falls in different years have higher seedling density of S. robusta than gaps created by single and/or multiple tree falls in the same year. In conclusion, gaps maintain species diversity by increasing seedling density, and favor regeneration of Sal forests. In addition to gap size, other gap attributes also affect species diversity and regeneration.
文摘Plantations of tropical species axe becoming an increasingly important source of wood. However, it is important that research trials focus not only on tree growth performance, but also on wood quality. The aims of this study were to assess the growth performance of six commercially and ecologically important tree species from separate plantation trials in Indonesia and to determine the relationships between tree growth and wood quality in terms of the dynamic modulus of elasticity （MOE） and wood density. Forty-eight 7-year Maesopsis eminii Engl. and thirty-five 9-year specimens （7 each of 5 Shorea spp.） were selected from two trials. The MOE, based on acoustic velocity, was indirectly measured to evaluate wood stiffness. Tree-growth performance was evaluated, and correlations between growth traits and acoustic velocity as well as density and wood stiffness properties were estimated. The growth performance of M. eminii in terms of tree volume was significantly different in three different cate- gories of growth （i.e. fast, medium, slow）. Of the five Shorea spp. studied, Shorea leprosula Miq. had the highest growth rate, as expected since it is known to be a fastgrowing Shorea species. Indirect measurement of wood quality by means of non-destructive ultrasonic methods showed a weak negative correlation between tree volume and acoustic velocity and dynamic MOE. Although each fast-growing tree could reach a merchantable size faster than other varieties or species, wood traits of various species tested were not significantly different based on tree growth rate performance. The findings from this study could be used to improve selection criteria in future breeding trials; indirect measurements of the dynamic modulus of elasticity can be used in mass pre-selection of genetic materials, to choose the most-promising material for in-depth evaluation.
基金the National Science Foundation of Sri Lanka(RG/2016/EB/02)Uva Wellassa University(UWU/RG/2016/10)。
文摘Background:No studies have documented long-term trends in aboveground biomass(AGB)for mixed-dipterocarp forests(MDF),the dominant rain forest type in tropical wet equatorial Asia.In our study,we sought to document such trends over forty years across three sites representing lowland to lower montane elevations.Methods:To do this,we established fifty 100 m×25 m plots in 1978 across three sites sampled along an elevation gradient,identified as mature old-growth forest.We measured trees for diameter at breast height that we identified to species and tagged.We took wood samples to calculate species wood-specific gravity.We re-measured plots in 1998 and again in 2018.Results:We show standing AGB for all sites combined to be 517.52 Mg·ha^(-1)in 1978,but this declined by 17%over 40 years to 430.11 Mg·ha^(-1).No differences exist among sites in AGB primarily because of considerable within site variation;but interactions of time with site show declines across sites were not uniform,one remained about the same.Relatively few species represented a high proportion of the AGB with the top five species comprising between 34%and 65%,depending upon site and year sampled.One species,Mesua nagassarium,represented a disproportionately large amount of AGB and decline over time,particularly at the low elevation site.Conclusions:Our results are directly relevant to estimating AGB and standing carbon sequestered in MDF.Our study is the first to demonstrate varying but overall,declining trends in amounts of AGB among forests making predictions of biomass and standing carbon in MDF difficult over wide regions.
基金the Universiti Sains Malaysia for the financial support (No. 304/PKIMIA/638056)
文摘The potential of base treated Shorea dasyphylla（BTSD） sawdust for Acid Blue 25（AB 25） adsorption was investigated in a batch adsorption process.Various physiochemical parameters such as pH,stirring rate,dosage,concentration,contact time and temperature were studied.The adsorbent was characterized with Fourier transform infrared spectrophotometer,scanning electron microscope and Brunauer,Emmett and Teller analysis.The optimum conditions for AB 25 adsorption were pH 2,stirring rate 500 r/min,adsorbent dosage 0.10 g and contact time 60 min.The pseudo second-order model showed the best conformity to the kinetic data.The equilibrium adsorption of AB 25 was described by Freundlich and Langmuir,with the latter found to agree well with the isotherm model.The maximum monolayer adsorption capacity of BTSD was 24.39 mg/g at 300 K,estimated from the Langmuir model.Thermodynamic parameters such as Gibbs free energy,enthalpy and entropy were determined.It was found that AB 25 adsorption was spontaneous and exothermic.
基金Supported by International Islamic University Malaysia(Grant No.EDWB11-018-04960).
文摘Objective:To evaluate antioxidant and antimicrobial activities of stembark of Shorea kunstleri(S.kunstleri)together with analysis of phytochemical and total phenolic contents.Methods:Extraction was conducted with different solvent polarity of n-hexane,dichloromethane(DCM)and methanol by using Soxhlet extraction.Total phenolic content was determined using Folin-Ciocalteu method.Free radical scavenging activity and inhibition of lipid peroxidation were evaluated with DPPH radical scavenging and ferric thiocyanate assays,respectively.Antimicrobial activities were performed using disc diffusion method,minimum inhibition concentration(MIC),minimum bactericidal concentration(MBC),and minimum fungicidal concentration.Results:S.kunstleri stembark extracts revealed presence of steroids,terpenoids,saponins,flavonoids,and phenolic compounds.Methanol extract exhibited the highest total phenolic content and free radical scavenging activity resulting in phenolic content of(8.340±0.003)g GAE/100 g of extract and(95.90±1.07)%DPPH inhibition(IC_(50)value of 18.6μg/mL),respectively.Ferric thiocyanate assay of n-hexane,DCM,and methanol extracts indicated lipid peroxidation inhibitory activity of(74.20±0.35)%,(74.00±0.10)%,and(72.80±0.27)%,respectively.In antimicrobial and antifungal tests,methanol extract showed inhibition against Staphylococcus aureus(S.aureus),Candida albicans,and Candida tropicalis with inhibition zones of 10-12,18-22,and 18-19 mm,respectively.The MIC test of methanol extract showed highest inhibition against Candida albicans and S.aureus(0.04 and 0.08 mg/mL,respectively)while DCM extract exhibited the highest activity towards Candida tropicalis(MIC value of 0.63 mg/mL).Taken together,MBC test of methanol extract strongly demonstrated bactericidal effect against S.aureus with MBC value of 0.08 mg/mL.Conclusions:The study demonstrated that stembark extracts of S.kunstleri possessed antioxidant and antimicrobial properties.
