Assessment of natural regeneration status and diversity of tree species in the biodiversity conservation areas of Northeastern Bangladesh

A study was conducted at two-biodiversity conservation areas of Northeastern Bangladesh (a part of Sylhet Forest Division) to assess the species composition, diversity and density of natural regeneration of tree species both indigenous and exotic species. Data were collected by stratified random quadrate method during January 2010 to July 2010. Totally 200 circular plots of 2 m×2 m in size had 5 different habitat types of plants namely; forest, roadside, homestead (surrounding forest dwellers house), fallow land and others (canals, streams and tea gardens side), which included a total of 55 regenerating species belonging to 28 families. Meliaceae is the dominant family and shows the highest family importance value (26.3), having six species, followed by Moraceae (24.24). Among the five habitat types, forest (43 species) possess the highest number of species, followed by roadside (23 species). Total 15 exotic species among 9 families and 40 indigenous species with 24 families were recorded. For exotic species, Tectona grandis possess the highest relative density (11.7%) and relative frequency (10.5%); Senna siamea had highest relative abundance (7.83%). In case of indigenous species, Chickrassia tabularis possess the highest relative density (4.23%) and relative frequency (4%); Dipterocarpus turbinatus had the highest relative abundance (3.92%). Tectona grandis (29.66) and Chickrassia tabularis (10.8) had the highest IVI for exotic and indigenous species respectively. Different diversity indices such as Shanon-Winner diversity index, species diversity index, species richness index, species evenness index, Simpson index and species dominance index, etc. were applied to quantify definite diversity. The regeneration of species associated with low levels of disturbance was in the exotic species. Study suggests that proper protection from human disturbances and scientific management of natural regeneration of two-study forests may lead a rich biodiversity site in the country.     

Economic dependence of rural people on homestead forestry in Mymensingh, Bangladesh

Homestead forests contribute substantially to the rural economy of Bangladesh. Rural people depend on trees and plants for their energy usage, housing, food and other forms of subsistence livelihood. In order to identify the potential role of forests on homestead dwellers, an empirical field investigation was conducted in the four Upazilas of Mymensingh district of Bangladesh. It was found that land holdings of the respondents within the four sites are the highest in Mymensingh. The study made an important observation that among all homestead vegetation between 5–6 years old, tree species are generally preferred over plants. This is perhaps due to the efforts of the social forestry extension service to demonstrate that planting trees is an important long-term investment. In all four Upazilas, there was a significant correlation between household annual income and homestead forestry, agriculture and fisheries practice, suggesting that higher income families tend to have larger holdings of homesteads, farms and pond areas. Three Upazilas displayed a strong positive relationship (nearly 45%) between homestead forest areas and annual family income; however, the Fulbaria Upazila showed a very poor relationship (0.2%) in this regard. The results of this study suggest that homestead forests play a positive role in the rural economy, in addition to helping mitigate the increasing problem of deforestation in Bangladesh.     

乐昌市外来入侵植物调查研究

基于野外考察及相关文献查阅,调查分析了乐昌市现有外来入侵植物的种类组成、生长型、分布生境、入侵范围及危害程度.结果表明:乐昌市2013-2015年共有外来入侵植物104种,隶属于36科,81属.其中菊科(23种)、豆科(14种)、禾本科(8种)和苋科(8种)植物占乐昌市外来入侵植物总种数的50.96％.另外根据生物学与生态学特性、自然地理分布、入侵范围及其所产生的危害,将乐昌市外来入侵种划分为5级:即恶性入侵类(1级,14种)、严重入侵类(2级,13种)、局部入侵类(3级,38种)、一般入侵类(4级,18种)和有待观察类(5级,21种).与周边其他地区外来入侵植物相比发现,乐昌市与香港地区共有种数最多,为72种;广州市与乐昌市共有种数百分比最大,为69.86％.     

Homestead forest resources and their role in household economy: A case study in the villages of Gazipur Sadar Upazila of central Bangladesh

This study examines the species composition, diversity and economic importance of homestead forests in the household economy of central Bangladesh. The study documents 57 homestead forest species and their main usage in 90 households across three villages of Gazipur Sadar Upazila. Homestead forests in Bangladesh comprise a mixture of fruit, timber and bamboo species. While superficially homestead forestry appears unimportant in rural livelihoods, in reality the contribution is huge, both as a source of food security and for other necessary household materials. A clear understanding of the physical characteristics and economic role of homestead forests in rural livelihoods is vital for ensuring sustainable resource management. Income and production of homestead forestry on a per hectare basis are found to vary widely between landholding size classes. Significant relationships are identified between forest performance (production and income) and species richness and education level. Homestead forestry appears to be a potential subsistence income generating land-use practice in the study area. The economic scope of homestead forestry can be further enhanced provided the appropriate species composition of the forest is achieved and the education of forest owners is ensured through targeted management and policy interventions.     

Recruitment of three non-native invasive plants into a fragmented forest in southern Illinois

Plant invasions are a current threat to biodiversity conservation, second only to habitat loss and fragmentation. Density and heights of three invasive plants, Rosa multiflora, Lonicera japonica, and Elaeagnus umbellata, were examined between edges and adjacent interiors of forest sites in southern Illinois. Density (stems m⁻²) and heights (cm) of invasive plants were obtained in plots along transects at edge and interior sampling locations within forest sites. The effect of species, sampling location, and site shape index on invasive plant density was investigated, as well as differences in heights of invasive plants in edge vs. interior sampling locations.

Species, sampling location, and fragment shape index were significant factors influencing invasive plant density at study sites. Density for all three species ranged from 0 to 18 stems m⁻². All three species invaded interiors of sites, however, R. multiflora and L. japonica had significantly greater densities in edge as opposed to interior transects. These two species also had significant differences in density among site shape indices. Density of E. umbellata was not significantly different between edge and interior sampling locations or among site shape indices. Mean heights of all three invasive plants were higher in edge transects, however, this relationship was only significant for L. japonica.

These findings suggest that (1) preservation of tracts of forest with less edge can minimize invasion by these three plants in this area. Interiors of forest sites can be protected from invasion by having less edge habitat for invasive species to enter and become established; and (2) E. umbellata, unlike the other two species, is established in both interior and edges of study sites. Therefore, E. umbellata may pose the most ecological damage because it is well established throughout sites, and should be given a high priority when implementing management and control efforts in southern Illinois forest ecosystems.     

Seed and seedling survival of African mahogany (Entandrophragma spp.) in the Central African Republic: Implications for forest management

African mahoganies of the genus Entandrophragma are among the most valuable and important timber species harvested in Central Africa, representing more than 70% of total export volume from many areas. In spite of the importance of these species, relatively little is known about their regeneration ecology and little effort has gone into understanding the reasons for the consistently reported regeneration failures after logging. I assessed seed survival to germination (Entandrophragma angolense) and seedling survivorship (E. cylindricum) in three different forest types – monodominant Gilbertiodendron, mixed species, and fallow forest – under three different treatments – control, small mesh chicken wire, and large mesh chicken wire – to evaluate the relative importance of different causes of mortality. All seeds were eaten in controls and in both exclosure treatments within Gilbertiodendron forest in a matter of days. Seed survivorship to germination within exclosures in mixed species and fallow forest increased by approximately 10 and 25%, respectively, compared to Gilbertiodendron forest. Six-month seedling survivorship in controls was 37, 12, and 9% in Gilbertiodendron, mixed species and fallow forest, respectively. Seedling mortality was due to different causes in each forest type. In Gilbertiodendron forest controls, an equivalent percentage of seedlings died due to fungal and insect attack (27 and 28%, respectively), while in mixed species forest controls 28 and 55% of seedlings died of these causes, respectively. In fallow forest controls, 48% of seedlings died from predation and/or uprooting by small mammals, all in the first few weeks post-sowing; insect attack (26%) and drought (13%) were other important causes of seedling deaths. Protecting seedlings with exclosures had a dramatic effect on seedling survivorship within the fallow forest, increasing to over 50%.     

东莞常平旗岭森林公园植物景观规划和配置初探

以森林生态原则为基础,遵循现代林业理论,根据树种的生态特性,从森林美学的角度对广东东莞常平旗岭森林公园进行植物配置与植物景观规划。对坡度大、植物生长环境较差的区位进行封山育林,使其自然生长与更新;对裸露的废弃石场采取复绿措施;对面积较大和林相较单一的桉树林和相思林,选择生长快的乡土树种,并配置少量红叶树种进行改造,以改善林间生态环境,增添景观效果。根据植物花期不同选择开花树种进行改造,打造四季有花的森林公园。根据道路使用功能的不同配置树种,以追求森林公园生态和社会效益的最大化。     

福建东山岛外来入侵植物调查与控制对策

采取线路调查与随机样方调查相结合的方法对东山岛外来入侵植物进行了调查分析,结果表明:东山岛现有植物种类总计约1 055种,其中本土野生植物632种,外来和栽培植物423种。423种外来和栽培植物中有外来入侵植物22科59种,种组成类以菊科最多,有16种,占27.1%;起源地以美洲最多,有45种,占76.3%;引入途径以无意引入最多,有32种,占54.24%。在分析外来入侵植物的来源、生境特点、入侵途径、生活型和危害性的基础上,提出了加强对外来入侵植物管理和控制的对策。     

Role of homestead forests in household economy and factors affecting forest production: a case study in southwest Bangladesh

Empirical information regarding the role of homestead forests in household economy is essential in understanding the importance of these resources. Identification of the factors that affect homestead forest production and understanding forest owners' attitudes toward key forest management issues have great significance in making appropriate policy responses to manage these resources on a sustainable basis. In Bangladesh, homestead forests are claimed to play an important economic role in rural livelihoods, but no reliable quantitative information exists. This study was undertaken to investigate the role of homestead forests in the household economy, examine if forest production and income vary across landholding size classes, to explore the relationships of homestead forest production with species richness, education level, and household size, and to assess the attitude of homestead forest owners toward key forest management issues. Results show that homestead forests contribute 15.9% of the household income and generate 51.4 man-days of employment per household per year. Production of homestead forests significantly varies across landholding size classes. It was observed that forest production depends significantly on species richness of homestead forests and the education level of forest owners. However, no such relationship was found between forest production and household size. The study revealed that farming families depend more on forest income than nonfarming families. Attitudes of forest owners toward key forest management issues differ significantly across landholding size classes. For example, although the majority of the forest owners prefer fruit species to timber species, the percentage of respondents decreased as the landholding size class increased, while the opposite trend was observed for timber species. The findings of this study suggest that diversification of forests and extension of education amongst forest owners would improve forest production. Furthermore, forest policy should address the concerns of the forest owners in different landholding classes and focus on their specific requirements to enhance sustainable forest management.     

Harvesting and conservation: are both possible for the palm, Iriartea deltoidea?

We consider the mechanism of certification to encourage sustainable harvesting and best management practices of Iriartea deltoidea Ruíz and Pavón, in the context of current land use and agricultural management in Amazonian Ecuador. Interviews and observations with harvesters, storeowners, and furniture-makers provided information about current and potential markets for goods made from the palm. To understand the demographic variables that are critical for population stability, data from five plots in each of three different forest types (mature, secondary, and dissected) were collected. Matrix models were used to develop harvesting simulations through which biological constraints on sustainable harvesting were explored. These simulations suggest that sparing individuals 5–15 m tall when pastures are cleared and adding this palm to current agroforestry polycultures can improve the likelihood of sustainable harvesting for this species. Results showed that harvesting Iriartea could fit within current land use. Some forest colonists clear pastures to graze cattle, while others devote land to agriculture, including polycultures of annuals and perennials. In either case, palms can be left standing when forests are cleared. Swidden agriculture (slash and burn or slash and mulch) depends on a fallow period during which secondary forest may begin to regenerate. These secondary forests are ideal locations for extraction of forest products that fit within the cycle of fallow regeneration in areas near human settlements. Sparing Iriartea individuals 5–15 m tall could benefit agriculture, encourage the sustainability of future harvests, and help ensure the future of this palm as a part of the Amazonian landscape.

Interviews with staff of governmental and non-governmental conservation organizations investigated the policy context for certification as a mechanism for conservation. Establishing guidelines for harvesting requires input from all stakeholders in the decision, not simply an ecological analysis. Such guidelines for certifying good management practices, if they are developed, should include provisions for monitoring unanticipated consequences of harvesting or changes in future environmental conditions. Transportation issues and stem drying processes need to be addressed if efforts to expand markets are to succeed. More generally, guidelines for management of forest resources can be improved by combining ecological and social research perspectives; the potential for carrying out such guidelines can be improved by incorporating the knowledge of local forest dwellers and NGOs.     

Degrading uplands in the rainforest region of Madagascar: Fallow biomass,nutrient stocks,and soil nutrient availability

Soil fertility restoration depends on natural fallows in the slash-and-burn system of eastern Madagascar. In the Beforona-Vohidrazana study zone, none of the fallow species are able to withstand the slashing, burning and cropping frequencies of 3–5 years. Eventually soils are abandoned for agriculture. Along the degradation sequence, this study quantifies fallow biomass, nutrient stocks and soil nutrient availability of four dominant fallow species Trema orientalis, Psiadia altissima, Rubus moluccanus, and Imperata cylindrica. At 3 years, the shrubs Psiadia and Rubus were more productive (11–14.4 t/ha aboveground biomass or AGB) than the tree species Trema (8.5 t/ha). Only after 5 years did tree productivity (24.7 t/ha) exceed that of shrubs (17–20 t/ha). Imperata’s biomass stagnated at 5.5 t/ha after 3 years. A sharp decline in fallow productivity was observed with advancing fallow cycles after deforestation. While Psiadia produced highest AGB in the second fallow cycle (C2) being 100%, C1 achieved 89% of that, C3 74%, and C4 only 29%. With the ability to propagate vegetatively and to accumulate important amounts of nutrients in roots, Rubus and Imperata, both exotic and invasive species, showed improved adaptation mechanisms towards frequent disturbances compared to the two indigenous species Trema and Psiadia. Available soil nutrients P, K, Mg were highest under forest and declined rapidly with increasing fallow cycles. Ca and pH rose momentarily in the first fallow cycle before declining with advanced soil use. Al concentrations increased steadily with time. As lengthened fallow periods are not practical, there is a need to intensify upland systems based on improved nutrient cycling, targeted inputs, fire-less land management, and land use diversification. Allowing regrading tree and bush fallows to accumulate biomass (above- and belowground carbon) will significantly improve Madagascar's greenhouse gas mitigation contribution.     

Effects of multiple factors on plant diversity of forest fragments in intensive farmland of Northern Portugal

The joint and independent effects of dominant tree species, forest patch spatial attributes, and forest structure and management as drivers of plant species richness and composition in small forest patches scattered within an intensive agricultural landscape were addressed.In a landscape with scattered urban and intensive dairy agricultural areas in north-west Portugal, within which small forest patches (dominated by pines, eucalypts, or both) represent semi-natural habitat islands, 50 small forest patches, with areas ranging between 0.3 and 3 ha, were selected and surveyed for vascular plant diversity, within dairy farming landscape mosaics dominated by annual forage crops. Explanatory variables were composed of three datasets derived either from GIS mapping or field observations: forest type (dominant tree species), forest patch spatial attributes (patch area and shape index), and measures of forest management and structure (diameter at breast height, tree density per hectare, and percentage cover of vegetation strata). Variations in these forest patch attributes were assessed across forest types, and related to measures of plant diversity (total, native, alien, woody, and herbaceous species richness). Redundancy analysis with variance partitioning was applied to evaluate the joint and independent effects of the three sets of variables on species assemblages. The recent shift in canopy dominance from pine to eucalypt observed in the region appears to be related to a (nonsignificant) tendency for the increase of patch area and to the decrease of patch complexity, as well as several changes in forest structure and management, expressed as a trend to denser tree canopies and lower cover of understory plants. Dominant tree species and attributes related to forest structure and management were the most important factors determining plant diversity. The joint effect of the dominant tree species and forest structure and management resulted in lower levels of plant species richness in eucalypt plantations. These were also more prone to invasion by alien species, probably due to decreased biotic resistance from unsaturated native plant assemblages. Our results draw attention to the importance of dominant tree species and management practices for the maintenance of plant diversity levels (species richness and composition) in dairy landscape mosaics, highlighting the importance of the remnants of semi-natural forests as refuges for plant diversity in the landscape context. Nonetheless, forest plant diversity could further be fostered by promoting naturalness of pine stands and the regeneration of native oak woodlands in some forest areas. This would also diversify the range of ecosystem services that could be provided by forest areas in these peri-urban farmlands.     

印江自治县林业有害生物种类、危害及治理对策

通过整理印江自治县林业有害生物历年普查资料及开展补充调查,分析了林业有害生物为害现状及发生危害原因。鉴定出林业有害生物115种,其中虫害共79种,蛛形纲1种,昆虫纲5目34科78种;病害共30种,真菌类23种,类菌质类2种,外寄生植物类2种,线虫类1种,非侵染类2种;外来入侵物种6种。新发现柔毛油杉是思茅松毛虫和马尾松毛虫寄主。提出加强生物多样性保护,促进生境适应性,改善林分结构,提高经济林科学管理水平,科学园林绿化设计,强化植物检疫,加强林业有害生物调查监测等治理对策。     

城市森林的成分及其类型

城市森林是城市范围内及与城市关系密切的、以树木为主体的生物群落。为便于分类型进行研究、规划设计和建设以及经营，将其按主要功能、所处的位置、经营管理的一致性及与城市规划和习惯接轨等因素，区分成防护林、公用林地、风景林、生产用森林和绿地、企事业单位林地、居民区林地、道路林地和其它林地、绿地等子系统。     

盾叶薯蓣高产栽培技术

系统分析了黄姜的生态生物学习性，介绍了裸地栽培，疏林内间作和灌木林带状栽培等不同类型的黄姜人工栽培技术要点。     

Characterisation of Afzelia africana Sm. habitat in the Lama forest reserve of Benin

A study was carried out in the Lama forest reserve of Benin to characterize the habitat of Afzelia africana Sm., an endangered multipurpose tree species (found in African humid, dry forests and woodlands), in order to define a sustainable management strategy for its conservation. An estimation of species density was done on 100 square plots of 1 ha each, while tree height and dbh of all the species were measured on subplots of 50 m × 30 m within the 1 ha plots. The regenerations of A. africana (dbh < 10 cm) were counted in the diagonal quadrats of the principal plots. Presence–absence data of the species was subjected to multidimensional scaling and results showed four vegetation communities including: young fallow, old fallow, typical dense forest and degraded dense forest. Significant differences were noted between the four communities with respect to dendrometric parameters of the species. High values of these parameters were noted for the species in typical dense forest (5.2 stems/ha, 66.7 cm, 17.9 m, 7.9 m²/ha and 38.8% for the tree-density, the mean diameter, the mean height, basal area and basal area contribution of the species, respectively) whereas the lowest values were obtained for the old preforest fallow as far as the mean diameter (59.7 cm), the mean height (15.7 m) and the basal area contribution (27.7%) of the species were concerned. In general, the basal area of A. africana in the over vegetation types was less than 3 m²/ha. No A. africana tree was found in the young preforest fallow while more than 80% of A. africana trees were found in the typical dense forest community. Stem diameter and height structures of the species in all the four communities showed a left dissymmetric Gaussian shape and were well adjusted to Weibull distribution.     

冶金企业道路防护绿地种植设计

文章阐述了道路防护绿地种植设计的影响因素,提出了道路防护绿地建设的原则,归纳了适合污染区域道路防护绿地建设的树种及种植模式。       

Species Composition,Diversity and Productivity of Homesteads in Southeastern Bangladesh

A homestead is an integrated production system where trees, crops, livestock and poultry are found in and around the household residence in Bangladesh. It is a potential production unit that provides various product, service and ecological functions. Almost all people in Bangladesh including landless households have homesteads in which they grow trees and crops even in a small piece of land. This study characterizes the species composition, diversity and productivity of the homestead production system in the Teknaf peninsula, southeastern Bangladesh. Survey data collection was from a total of 180 homesteads covering five household categories: large, medium, small, marginal and landless. Vegetable, fruit, timber, and livestock and poultry were common components in the homestead production system. Various types of plants were mainly concentrated in back yards, front yards, boundaries and corners of homesteads. The mean number of tree species per homestead was about 15. In total, 189 tree and shrub species were recorded, and were distinctly high and low in the large (363.7) and landless (55.7) household categories. Species composition, diversity and productivity of homesteads were found to be related to household categories. Richness and diversity of tree and shrub species increased with household size. Betel nut was the dominant tree species followed by mango, jackfruit and coconut. Annual income from homesteads also varied among the household categories, with a mean contribution of the homestead to annual income of about 25 %. A large portion of homestead income came from betel nut trees. There is scope to increase species diversity and income by designing homesteads with the engagement of women and other family members.     

胶东半岛乡村人居林建设类型及发展思路

针对胶东半岛新农村绿化现状及存在问题,提出了胶东半岛新农村绿化的总体思路,对胶东半岛现有的乡村人居林进行了分类,并形成了不同类型乡村人居林的发展思路,可为山东及同类地区的新农村绿色家园建设提供借鉴与参考。     

Exotic plant species in the southern boreal forest of Saskatchewan

Exotic species possess abilities to harm the ecosystems they invade. This study assesses the density, frequency and cover of exotic plants in roadside right-of-ways, logged areas and wildfire sites within mixedwood sections of the southern boreal forest of Saskatchewan. A total of 23 exotic species were observed including nine species of Gramineae, seven species of Leguminosae and five species of Compositae. Average density of exotic species in areas recently disturbed by timber harvesting or wildfire was 0.2 stems m⁻² with a frequency of 72%. Exotic species adapted for wind dispersal were best represented including common dandelion (Taraxacum officinale), perennial sow thistle (Sonchus arvensis) and annual hawksbeard (Crepis tectorum). Only two exotic species, T. officinale and Canada bluegrass (Poa compressa), were observed in mature forest; both occurred with a frequency of 13% and an average density of 0.002 stems m⁻². A total of 22 exotic species was found in the right-of-ways quadrats with an average density of 117 stems m⁻² and a frequency of 94%. The most frequently observed exotic species in the roadside right-of-way areas were T. officinale, alsike clover (Trifolium hybridum), S. arvensis, creeping red fescue (Festuca rubra) and smooth brome grass (Bromus inermis). These species are either common agricultural weeds or were part of the original seed mixture used to establish a plant cover in the roadside right-of-ways.