Economic dependence on mangrove forest resources for livelihoods in the Sundarbans,Bangladesh

This study examines the importance of mangrove resources to the livelihoods of people living beside the world's largest contiguous mangrove forest. Median annual household income was USD 1122, based on household survey data from 264 households in six villages adjacent to the Sundarbans, in Khulna, Bangladesh. Forest income represented 74% and 48% of the total household income for the lower and middle income households respectively, but just 23% for higher income households. Although higher income households derived a larger absolute income from forest resources than the lower income households, the addition of forest income to household income reduces measured income inequality by 27% suggesting that forests offer a more egalitarian source of income than most other sources at the study sites. Thus reducing forest income as a result of reduced access to forest resources would greatly affect the livelihood outcomes for the rural poor and increase wealth discrepancies among households near the forest margins.     

Timber species grouping in Bangladesh: linking wood properties

Timber species grouping (TSG) is essential for meaningful and cost-optimal use of wood. Bangladesh forests are exceedingly diverse and comprise many woody species which are potentially suitable for versatile uses including structural materials. Traditionally, widely known tree species are used for structural timber because technological properties of most of the species are poorly known. In this study, a hierarchical agglomerative cluster analysis based on three selected wood properties [i.e., wood density, modulus of elasticity (MOE) and modulus of rupture (MOR)] of seventy-nine timber species was done. The clustering process led to the formation of four distinct species groups [i.e., very low (TSG1), low (TSG2), medium (TSG3) and high (TSG4)]. However, the species grouping patterns also varied from trait to trait. This might be due to moderate relationship between density and MOE (r ² = 0.46) or MOR (r ² = 0.52). Species of the TSG1 group are mainly characterized by extremely low trait values, while the TSG4 group consists of species having exceedingly high trait values. The TSG2 and TSG3 groups are characterized by low and medium trait values. Hence, it is suggested to select suitable species from these groups, particularly the lesser known high-quality species in afforestation and reforestation programs to meet future timber demand in Bangladesh.     

Five heavy metals in propagules of ten mangrove species of China

Five heavy metals in the propagules of 10 mangrove species in China have been investigated. The results revealed that the levels of five heavy metals in most of the propagules were lower than the background levels of the soil. The levels of copper, manganese, zinc, cadmium, and lead in the propagules varied at about 2.1–7.8 g/g, 3.9–28.0 g/g, 5.7–60.0 g/g, 0.014–0.057 g/g, and 0.018–0.038 g/g, respectively. On average, the levels of five heavy metals were in the order Zn > Mn > Cu > Cd > Pb. The biological absorption coefficients were 0.02–1.30 for copper, manganese, zinc, and cadmium and about 0.0007–0.0020 for lead in propagules, showing the following order: Zn > Cd > Cu > Mn > Pb. The above results indicate that the five heavy metals have low accumulation in most of the propagules of 10 mangrove species and are at safe levels for the effective utilization of mangrove resources.     

Overlap in mangrove species zonal patterns: some methods of analysis

Considerable variety is to be found in zonal expression within the mangroves of riverine estuaries in tropical northeastern Australia. Detailed surveys have shown that this is partly due to differences in the sequencing order of taxa across the intertidal surface (Bunt, 1996). However, it is evident that the clarity and pattern of zonation may also be affected by overlap in species distributions. The need to consider the latter in detail arose in the course of ongoing surveys. For the latter purpose, procedures are here described that enable complex field data sets to be analysed in numeric and graphical terms. Data for a single transect from the Endeavour river have been used to explain the methods used and to illustrate results.     

Growth models for six Eucalyptus species in Angola

This study developed growth models for Eucalyptus saligna Sm., E. camaldulensis Dehnh., E. macarthurii H.Deane & Maiden, E. resinifera Sm., E. siderophloia Benth. and E. grandis Hill ex. Maiden, for the central highlands of Angola, and used these models to simulate the development of stand characteristics. The obtained model set included dominant height, diameter increment, tree height and self-thinning models. The study was based on 10 499 radial increment observations measured on cores taken from about 700 trees growing in 22 plots located in seven sites in the Angolan highlands. The model set makes it possible to simulate stand development on an individual tree basis. Comparison of simulated stand development and measurements indicated good performance of the models. A non-linear fixed-effects diameter increment model performed best for most species, but a non-calibrated linear mixed-effects model used with the Snowdon correction was better for E. saligna and E. macarthurii. This study showed a similar dominant height development of young stands as found in most previous studies done for southern Africa. Some differences emerged at older ages.     

Allometric relationship for estimating above-ground biomass of Aegialitis rotundifolia Roxb. of Sundarbans mangrove forest, in Bangladesh

Tree biomass plays a key role in sustainable management by providing different aspects of ecosystem. Estimation of above ground biomass by non-destructive means requires the development of allometric equations. Most researchers used DBH (diameter at breast height) and TH (total height) to develop allometric equation for a tree. Very few species-specific allometric equations are currently available for shrubs to estimate of biomass from measured plant attributes. Therefore, we used some of readily measurable variables to develop allometric equations such as girth at collar-height (GCH) and height of girth measuring point (GMH) with total height (TH) for A. rotundifolia, a mangrove species of Sundarbans of Bangladesh, as it is too dwarf to take DBH and too irregular in base to take Girth at a fixed height. Linear, non-linear and logarithmic regression techniques were tried to determine the best regression model to estimate the above-ground biomass of stem, branch and leaf. A total of 186 regression equations were generated from the combination of independent variables. Best fit regression equations were determined by examining co-efficient of determination (R2), co-efficient of variation (CV), mean-square of the error (MSerror), residual mean error (Rsme), and F-value. Multiple linear regression models showed more efficient over other types of regression equation. The performance of regression equations was increased by inclusion of GMH as an independent variable along with total height and GCH.     

6种宿根花卉植物的光合特性研究

目前,我国北方地区园林应用中宿根花卉的种类相对较少、品种单一。为了进行宿根花卉的引种栽培进而有效丰富园林宿根花卉的种类,以黑心菊、芙蓉葵、蜀葵、赛菊芋、紫茉莉、醉鱼草等6种宿根花卉为试验材料,利用CIRAS-3光合仪,研究其光合有效辐射、二氧化碳的响应以及光合速率日变化。结果表明,黑心菊、赛菊芋和醉鱼草净光合速率日变化表现为单峰曲线,未出现"午休"现象;芙蓉葵、蜀葵和紫茉莉为明显的双峰曲线,有明显的"午休"现象,且第2峰值均出现在14:00,其中黑心菊的光补偿点最低、光饱和点也较低,分别为18.69μmol/(m~2·s)和1 506.49μmol/(m~2·s),可以在遮阴环境下生长,而赛菊芋的光补偿点最高、光饱和点也较高,分别为32.45μmol/(m~2·s)和1 616.41μmol/(m~2·s),表现出较强的喜阳性。     

Planting six tree species on soda-saline-alkali soil

IntroductionThereareabout2,ooo,ooohm2Ofsoda-saline-alkaIisoilinSonglunpIaininHeiIongjiang(Shen1998).ltisdistributedmainlyinZhaodong,Zhaozhou,Zhaoyuan,Anda,Daqing,Duerbuteandothercountiesandcities.FormerIy,therewerenotreesonsoda-saline-alkaIisoil.CropscannotgrowonsuchsoiIs.PIantingtreesonthesesoilsmightimproveonitsquaIity(LingetaI1982).TostudypIantingonsoda-saline-aIkalisoiIhassignificanceforestablishingprotectivepIantationsystemofgrasslandandestabIishingperfectprotec-tivepIantations…     

Dynamic variation in sapwood specific conductivity in six woody species

Our goals were to quantify how non-embolism-inducing pressure gradients influence trunk sapwood specific conductivity (k(s)) and to compare the impacts of constant and varying pressure gradients on k(s) with KCl and H2O as the perfusion solutions. We studied six woody species (three conifers and three angiosperms) which varied in pit membrane structure, pit size and frequency of axial water transport across pits (long versus short conduits). Both stepwise ("steady") and nonlinear continuous ("non-steady") decreases in the pressure gradient led to decreased k(s) in all species but white oak (Quercus garryana Dougl. ex Hook), a ring-porous and long-vesseled angiosperm. In one diffuse-porous angiosperm (red alder, Alnus rubra Bong.) and two conifers (western red cedar, Thuja plicata Donn. ex D. Don, and Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco), k(s) was 10-30% higher under steady pressure gradients than under non-steady pressure gradients, and a decrease in the pressure gradient from 0.15 to 0.01 MPa m(-1) caused a 20-42% decrease in k(s). In another diffuse-porous angiosperm (maple, Acer macrophyllum Pursh) and in a third coniferous species (western hemlock, Tsuga heterophylla (Raf.) Sarg), there was no difference between k(s) measured under steady and non-steady pressure gradients. With the exception of western red cedar, a conifer with simple pit membranes, the differences in k(s) between low and high pressure gradients tended to be lower in the conifers than in the diffuse-porous angiosperms. In Douglas-fir, western red cedar and the diffuse-porous angiosperms, k(s) was higher when measured with KCl than with H2O. In white oak, there were no differences in k(s) whether measured under steady or non-steady pressure gradients, or when xylem was perfused with KCl or H2O. The species differences in the behavior of k(s) suggest that elasticity of the pit membrane was the main factor causing k(s) to be disproportionate to the pressure gradient and to the different pressure regimes. The results imply that, if nonlinearities in pressure-flux relationships are ignored when modeling tree water relations in vivo, large errors will result in the predictions of tree water status and its impact on stomatal control of transpiration and photosynthesis.     

Chemical components of Fraxinus species

A wide range of chemical components including coumarins, secoiridoids, phenylethanoids, flavonoids, and lignans has been isolated from Fraxinus species. Extracts and metabolites have been found to possess antiinflammatory, immunomodulatory, antimicrobial, antioxidative, skin regenerating, photodynamic damage prevention, liverprotecting, diuretic and antiallergic activities. Some species find application in contemporary medicine. In the present review the literature data on the phytochemical and biological investigations on the genus Fraxinus are summarized up to the middle of 2004.     

Comparison of antioxidant activity in enzyme-independent system of six Stachys species

The antioxidant activity of six Stachys species native to Hungary in an enzyme-independent lipid-peroxidation system was examined. The methanolic extracts were found to be more effective than the controls alpha-tocopherol succinate and ascorbic acid. The following components were determined by spectrophotometric analysis: hydroxycinnamic acid derivatives, phenols content and flavonoids.     

木荷等6种阔叶树种光合生理特性比较

在东江中上游,对6年生木荷、红锥、火力楠、藜蒴、灰木莲和枫香的净光合速率（Pn）、蒸腾速率（Tr）、水分利用效率（WUE）等生理生态指标开展观测研究,结果表明：8月,6种树种均表现较强的生活力,保持了较高的净光合速率与蒸腾速率;10月,6树种均通过降低光合、蒸腾和提高水分利用效率来适应逆境。8月平均Pn和Tr要比10月均值分别高71.86%和129.22%,10月WUE却要比8月均值高25.78%。6树种Pn、WUE的平均值高低排序,均表现为木荷〉红锥、藜蒴和火力楠〉枫香和灰木莲,说明木荷有较强的环境适应能力和抗旱能力,其次为红锥、火力楠和藜蒴,而灰木莲和枫香较低。     

Leaf gas exchange characteristics of three neotropical mangrove species in response to varying hydroperiod

We determined how different hydroperiods affected leaf gas exchange characteristics of greenhouse-grown seedlings (2002) and saplings (2003) of the mangrove species Avicennia germinans (L.) Stearn., Laguncularia racemosa (L.) Gaertn. f., and Rhizophora mangle L. Hydroperiod treatments included no flooding (unflooded), intermittent flooding (intermittent), and permanent flooding (flooded). Plants in the intermittent treatment were measured under both flooded and drained states and compared separately. In the greenhouse study, plants of all species maintained different leaf areas in the contrasting hydroperiods during both years. Assimilation-light response curves indicated that the different hydroperiods had little effect on leaf gas exchange characteristics in either seedlings or saplings. However, short-term intermittent flooding for between 6 and 22 days caused a 20% reduction in maximum leaf-level carbon assimilation rate, a 51% lower light requirement to attain 50% of maximum assimilation, and a 38% higher demand from dark respiration. Although interspecific differences were evident for nearly all measured parameters in both years, there was little consistency in ranking of the interspecific responses. Species by hydroperiod interactions were significant only for sapling leaf area. In a field study, R. mangle saplings along the Shark River in the Everglades National Park either demonstrated no significant effect or slight enhancement of carbon assimilation and water-use efficiency while flooded. We obtained little evidence that contrasting hydroperiods affect leaf gas exchange characteristics of mangrove seedlings or saplings over long time intervals; however, intermittent flooding may cause short-term depressions in leaf gas exchange. The resilience of mangrove systems to flooding, as demonstrated in the permanently flooded treatments, will likely promote photosynthetic and morphological adjustment to slight hydroperiod shifts in many settings.     

Arbuscular mycorrhizal associations in different forest tree species of Hazarikhil forest of Chittagong, Bangladesh

Biodiversity of arbuscular mycorrhizal (AM) colonization and AM fungal spores were studied in the roots and rhizosphere soils of Acacia catechu (L.f). Wild., A. mangium Willd, Anthocephala cadamba Miq., Artocarpus chaplasha Roxb., Chickrassia tabularis A. Juss., Swietenia macrophylla King., Tectona grandis L. from plantations; Albizia procera (Roxb.) Benth., A. falcataria L., Alstonia scholaris (L.) R. Br., Aphanamixis polystachya (Wall.) Parker., Hydnocarpus kurzii (King.) Warb., Heynea trijuga Roxb., Lagerstroemia speciosa (L.) Pers., Messua ferrea Linn., Podocarpus nerifolia Don., Swintonia floribunda Griff., Syzygium fruticosum (Roxb.) DC., S. grandis (Wt.) Wal. from forest and nursery seedlings of A. polystachya, A. chaplasha, Gmelina arborea Roxb. and S. cuminii (L.) Skeels from Hazarikhil forest, Chittagong of Bangladesh. Roots were stained in aniline blue and rhizosphere soils were assessed by wet sieving and decanting methods. The range of AM colonization varied significantly from 10%-73% in the plantations samples. Maximum colonization was observed in A. mangium (73%) and minimum colonization was observed in C. tabularis (10%). Vesicular colonization was recorded 15%-67% in five plantation tree species. The highest was in A. cadamba (67%) and the lowest was in T. grandis; A. chaplasha and C. tabularis showed no vesicular colonization. Arbuscular colonization was recorded 12%-60% in four plantation tree species. The highest was in A. mangium (60%) and the lowest was in A. cadamba. Roots of Artocarpus chaplasha, C. tabularis and T. grandis showed no arbuscular colonization. Among 12 forest tree species, nine tree species showed AM colonization. The highest was in A. falcataria (62%) and the lowest was in S. fruticosum (10%). Significant variation in vesicular colonization was recorded in seven forest tree species. The highest was in H. trijuga (52%) and the lowest was in L. speciosa (18%). Hydnocarpus kurzii, M. ferrea, P. nerifolia S. fruticosum and S. grandis showed no vesicular colonization. Arbuscular colonization was recorded in seven forest tree species. The highest was in A. falcataria (60%) and the lowest was in A. procera (10%). All the nursery seedlings showed AM colonization and the range was 10%-73%. Vesicules were recorded in G. arborea (40%) and S. cumini (40%). Arbuscular colonization was recorded in G. arborea (100%) and S. cumini (100%). Spore population was recorded 77-432/100 g dry soils, 80-276/100 g dry soils, and 75-153/100g dry soils in plantation, forest and nursery, respectively. Glomus and Acaulospora were dominant genera among the six AM fungi recorded. Significantly positive correlation was observed between AM colonization and AM fungal spore population in Hazarikhil plantation tree species, forest tree species and nursery tree seedlings. The present study showed the biodiversity of root colonization and AM fungi are active in nutrient cycling, survivals and seedling establishment of the plants in the Hazarikhil forest, plantation and nursery.     

木兰科6个树种的引进与栽培技术

介绍了木兰科6个树种的形态特征、生物学特性、主要特点和用途，并通过栽培试验得出了木兰科6个树种在四川的生长表现，且从播种、育苗、栽植、修枝整形、施肥、病虫害防治等方面介绍了木兰科6个树种的栽培管理技术。     

蜡彩袋蛾取食不同红树植物后纤维素酶活力的测定

通过对蜡彩袋蛾喂饲7种红树植物叶片,观察取食情况,测定对不同红树植物叶片的取食量及取食后其体内纤维素酶活力变化,探讨蜡彩袋蛾(Chalia larminati Heylaerts)对不同红树植物叶片的消化吸收能力。结果表明,取食无瓣海桑、木榄、红海榄和秋茄的幼虫体内纤维素酶含量较高,而取食白骨壤和海漆之后纤维素酶含量较低,差异显著。根据林间调查结果显示,秋茄上的蜡彩袋蛾虫口密度最高,木榄最低,而在无瓣海桑、白骨壤和海漆没有发现蜡彩袋蛾危害。     

Chemical constituents of Tolpis species

Phytochemical research of two Tolpis species, T. webbii and T. sp., led to the isolation of three new compounds: 2,4′-dihydroxy-4-methoxybenzophenone (1) and the triterpenes 21α, 22α-epoxy-20α-hydroxy-20(30)-dihydrotaraxasterol (2) and 3β-hydroxytaraxaster-20-en-30-oic acid (3) together with 16 known compounds. The structures of the new compounds were elucidated by means of extensive IR, NMR, MS and X-ray analysis and by comparison of data reported in the literature.     

Seed germination of six mature neotropical rain forest species in response to dehydration

We studied effects of dehydration and rehydration on germination of seeds of six mature tropical rain forest species-Cupania glabra Swartz, Cymbopetalum baillonii Fries, Poulsenia armata (Miq.) Standl., Stemmadenia donnell-smithii (Rose) Woodson, Rheedia edulis Triana & Planch. and an understory palm Chamaedorea alternans H. Wendl.-from Veracruz, México. Before the seeds were sown, their water content was reduced by 0 (control), 30, 54 and 72% of their original water content. Dehydration affects the ability of seeds to rehydrate, as well as the rate and final percentage of germination when seeds are subsequently rehydrated. Seed survival and germination behavior showed three patterns: (1) C. baillonii, P. armata and S. donnell-smithii had greater tolerance to seed dehydration than C. glabra, C. alternans and R. edulis; (2) partial dehydration enhanced germinability of C. glabra and C. baillonii seeds; and (3) partial dehydration of C. alternans and R. edulis seeds resulted in delayed or sporadic germination. A relationship was found between the effects of dehydration on germination and the seasonality of seed production.