Trees in Bangladesh paddy fields. 2. Survival of trees planted in crop fields

The design and methods are described of farmer-managed action-research to test the survival and performance of trees planted in paddy fields of private farms in Bangladesh. Farmers received seedlings of indigenous and exotic trees with extension advice on planting methods and care. Planting was done in systematically designed randomized modules involving twelve thousand trees up to the end of 1990. Survival and condition of individual seedlings were monitored twice annually, and mortality was replanted for up to three years after which little further mortality occurred.Stocking rate, including original survivors and replanted seedlings, tended towards 55% after six years. The main factors conductive to survival were the presence of a nurse crop in the field at the time of tree planting, and the quality and size of planting stock. Cause of death could not be attributed in about 8% of mortality. Main recorded causes of tree mortality, in order of frequency, were livestock browsing, physical damage during cultivation or harvesting operations, pests or diseases, drought, and flooding.About 15% of tree mortality was due to losses of complete modules owing to catastrophic flooding, land disputes, and public works such as roads or pipelines. It is suspected that some of this mortality may be unacknowledged changes of mind and deliberate removal by the participating farmers.     

Biological screening of Bangladeshi mango mistletoe bark extracts

The ethyl acetate extract of the Bangladeshi mango mistletoe (Loranthus globosus) bark was found to be most effective against both Gram (+) and Gram (-) bacteria and it also showed good cytotoxicity with a LC50 10.83 microg/ml.     

Antimicrobial activity and cytotoxicity of Zanthoxylum budrunga

The petroleum ether, chloroform and methanol extracts of the leaves and barks of Zanthoxylum budrunga have been evaluated for their antibacterial, antifungal and cytotoxic properties.     

Comparison of structural diversity of tree-crop associations in Peripheral and Buffer zones of Gachabari Sal forest area, Bangladesh

The original version of this article unfortunately contained three mistakes.
（1） The spelling of the [A. Nishad＇] name was incorrect. The corrected spelling is given below.     

Ethnobotany of medicinal plants from Dibru-Saikhowa Biosphere Reserve of Northeast India

A survey of medicinal plants used by the ethnic communities of Dibru-Saikhowa Biosphere Reserve in Northeast India has been reported. Fifty-five plant species belonging to 34 families and 52 different genera were included. For each plant species, botanical name, vernacular name, part(s) used, popular medicinal use, forms of preparation and applications of the herbal remedies are provided.     

Constituents and cytotoxicity of Zanthoxylum rhesta stem bark

3,5-Dimethoxy-4-geranyloxycinnamyl alcohol (1), 8-methoxy-N-methylflindersine (2), xanthyletin and sesamin have been isolated from petroleum ether extract of the stem bark of Zanthoxylum rhesta. The petroleum ether extract and 8-methoxy-N-methylflindersine showed cytotoxicity on brine shrimp nauplii.     

Modeling spatiotemporal distribution of Dipterocarpus turbinatus Gaertn. F in Bangladesh under climate change scenarios

ABSTRACT

Climate change affects plant phenology, spatial distribution, and even extinction of vulnerable species. Dipterocarpus turbinatus, locally known as garjan, is a valuable but vulnerable native tree species of Bangladesh whose spatial distribution under future climate change scenarios is not fully understood. The aim of this study was to examine the effects of present and future climatic scenarios on spatiotemporal distribution of D. turbinatus. We used maximum entropy species distribution modeling to perform the present and future habitat suitability of garjan under different climate scenarios. The representative concentration pathways (RCP) 2.6 and 8.5 were considered for bioclimatic variables from the Global Climate Model – Hadley Global Environment Model 2 Atmosphere-Ocean. The predictive accuracy of the model was more than 97% in both the training and test data. The prediction results suggest that compared to present areas (7624 km²) under moderate habitat class it will be 2755 km² and 1239 km², respectively, in 2050 and 2070 under RCP2.6 scenario and decreases more rapidly under RCP8.5 scenario. Besides, the prediction also indicates that the habitat of the species will shift toward the high altitudinal south-eastern corner of the country whereas local extinction might occur in the north-eastern part during 2070.     

Analgesic and anti-inflammatory activity of Leonurus sibiricus

The methanolic extract of Leonurus sibiricus aerial parts injected intraperitoneally at dose of 250 and 500 mg/kg showed a significant analgesic effect in acetic acid-induced writhing in mice. Moreover, when given orally to rats at dose of 200 and 400 mg/kg, it showed a significant anti-inflammatory activity against carrageenin induced rat paw edema in rats.     

Interception of photosynthetic photon flux density in a mangrove stand of <Emphasis Type="Italic">Kandelia candel</Emphasis> (L.) Druce

The canopy structure and interception of photosynthetic photon flux density (PPFD) in a 10-year-old Kandelia candel (L.) Druce stand were investigated before and after artificial defoliation. Leaf and wood areas for different layers were measured through area–weight relationships of subsamples. PPFD was measured at specified heights before and after leaf clipping. The leaf area index (LAI) and wood area index (WAI) were 4.501m²m^–2 and 1.412m²m^–2, respectively. There was a strong linear relationship between the cumulative wood area © and leaf area (F) densities from the top down to a given depth of the canopy, C = aF (r ² = 0.950), with a proportional constant a of 0.096 ± 0.008 (mean ± SE). The PPFD relative to that above the canopy (relative PPFD; I _R) at a given depth of the canopy was assumed to be given by the equation I _R = e^–(KCC+KFF ) = e^–KF , where the apparent light extinction coefficient K (= K _F + aK _C , where K _F and K _C are respectively the light extinction coefficient of leaves and woody organs) was calculated to be 0.502 ± 0.041 (mean ± SE) m^–2m² before leaf clipping. After leaf clipping, I _RC = e^–KCC is satisfied. As a result, the value of K _C was estimated to be 0.785 ± 0.046 (mean ± SE) m^–2m². The light extinction coefficient of leaves K _F was calculated to be 0.427m^–2m² using the indirect method, K _F = K – aK _C, and 0.432 ± 0.026 (mean ± SE) m^–2m² using the direct method, I _R/I _RC = e^–KFF . Of the total PPFD intercepted by the canopy, the fraction K _F/K due to leaves alone was estimated to be 85.0%–86.1% and the rest was contributed by woody organs.     

A water balance model to estimate groundwater recharge in Rechna doab,Pakistan

The main objective of this study was to develop a procedure to evaluate various recharge components of a groundwater reservoir to estimate the long term average seasonal groundwater recharge in Rechna doab in the Punjab province of Pakistan. A regional lumped water balance model for the Rechna doab was developed and applied to estimate the long term a seasonal recharge to groundwater reservoir. For comparison, recharge was also estimated by a specific yield method from observed groundwater levels. A water balance study was conducted on seasonal basis (6 months) for a period of 31 years (1960–1990). Recharge estimated by the two methods was found to be in good agreement. The average value of net groundwater recharge during Kharif (April–September) season was found to be some 60 mm. No recharge occurred during Rabi (October–March), rather there was a depletion of the groundwater reservoir during the winter months. Long term average annual depletion of a groundwater reservoir was found to be greater than corresponding value of annual recharge. It was concluded that on a regional basis the groundwater reservoir was being depleted resulting in an average groundwater table of Rechna doab about 2.3 m fall over the 1960–1990 period.