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

M. M. Rahman  H. Vacik  F. Begum  A. Nishad  K. K. Islam 《林业研究》2007,18(1):23-26

The structural diversity of different tree-crop associations were studied at Gachabari Sal forest area of Madhupur Garh on Buffer and Peripheral Zone during 2006. The total density, basal area of trees in the Buffer and Peripheral Zone were 155.5 trees·hm^-2, 795.4 trees·hm^-2 and 3.9 m^2·hm^-2, 5.8 m^2·hm^-2, respectively. No regeneration and natural trees were found in Peripheral Zone and the Zone is totally occupied by exotic species where the Buffer Zone comprised of both natural and exotic trees. The Peripheral Zone belonged to younger and smaller trees whereas the Buffer Zone belonged to mixture of smaller, taller, younger and mature trees simultaneously. For the practicing of different agroforestry systems both Zones have lost their original characters of Sal forest.  相似文献   

Quantification and Understanding of Above and Belowground Biomass in Medium Saline Zone of the Sundarbans,Bangladesh: The Relationships with Forest Attributes     

Md. Salim Azad  Md. Kamruzzaman  Akira Osawa 《Journal of Sustainable Forestry》2020,39(4):331-345

ABSTRACT

The relationship between stand attributes and biomass accumulation pattern in a mangrove forest has been intensively studied in this study. We assessed above (AGM) and belowground mass (BGM) and examined the relationship between forest attributes and aboveground mass in the Sundarbans, Bangladesh. The study was conducted with 18 plots having total area of 1.08 ha. The mean AGM and BGM of the study sites were 234.08 and 132.85 Mg ha^?1 respectively. H. fomes contributed the highest amount (82.9% of total AGM and 80.53% of total BGM) of above (193.56 Mg ha^?1) and belowground mass (107.09 Mg ha^?1) at the study site. Our study revealed structural attributes (tree diameter, height, and basal area) positively correlated with AGM. In contrast, species richness and species diversity negatively correlated with AGM. Our study indicated that lack of positive relationship between species diversity and AGM which may be attributable to high AGM of the dominant species (H. fomes) and may have a considerable consequence in AGM of the study area. Thus, maintaining large trees (DBH and height) rather than species diversity in the Sundarbans mangrove forest might be an effective approach for increasing aboveground mass.  相似文献   

Antimicrobial and cytotoxic constituents from the seeds of Annona squamosa   总被引：1，自引：0，他引：1  

Mukhlesur Rahman M  Parvin S  Ekramul Haque M  Ekramul Islam M  Mosaddik MA 《Fitoterapia》2005,76(5):484-489

Annotemoyin-1, Annotemoyin-2, squamocin and cholesteryl glucopyranoside were isolated from the seeds of Annona squamosa. These compounds and plant extracts showed remarkable antimicrobial and cytotoxic activities.  相似文献   

Effect of intermittent heat treatment on crystallinity in wood cellulose     

Md. Tariqur Rabbani Bhuiyan  Nobuyuki Hirai  Nobuo Sobue 《Journal of Wood Science》2001,47(5):336-341

The effect of intermittent heat treatment on cellulose crystallites in wood was studied to evaluate quantitatively the changes of crystallinity induced by intermittent and continuous heating. The changes in crystallinity were found to be strongly affected by the intermittent heat treatment. The increased crystallinity, the width of the crystals, and the piezoelectric properties were the same for the first intermittent heating as for continuous heating. Further intermittent heating for the same time duration and temperature had no effect on the above properties, probably due to the stopping of the thermal reaction during the interval. Our results suggested that intermittent heat treatment has certain critical cooling temperatures that stop the thermal reaction and are closely related to the duration of the interval. Samples once exposed to a certain duration of heat treatment and then cooled need more time, about twice that of the first duration of intermittent heating compared with continuous heating, to reach maximum crystallinity in wood cellulose.  相似文献   

Compressive deformation of wood impregnated with low molecular weight phenol formaldehyde (PF) resin II: effects of processing parameters   总被引：1，自引：0，他引：1  

Md Iftekhar?ShamsEmail author  Hiroyuki?Yano 《Journal of Wood Science》2004,50(4):343-350

To obtain high-strength phenol formaldehyde (PF) resin-impregnated compressed wood at low pressing pressure, the effects of resin content, preheating temperature, pressing temperature, and pressing speed on the compressive deformation of oven-dried low molecular weight PF resin-impregnated wood was investigated. With an increase of PF resin content, the Youngs modulus of the cell wall perpendicular to the fiber direction decreases, and collapse-initiating pressure decreases linearly with the Youngs modulus. This indicates that the occurrence of cell wall collapse is strain-dependent. By increasing preheating temperatures, the collapse-initiating pressure increases due to the increment of the Youngs modulus of the cell wall. An increase in pressing temperature results in the thermal softening of the cell wall and causes collapse at a lower pressure. The wood is compressed effectively despite accelerated resin curing. The pressing speed significantly affects the viscoelastic deformation of the cell wall and the wood is well deformed with decreasing pressing speed, although the differences in density and mechanical properties are relatively small after a pressure-holding period of 30min. In all the parameters examined in this study, the Youngs modulus and bending strength increase with increasing density.  相似文献   

Does actor power impede outcomes in participatory agroforestry approach? Evidence from Sal forests area,Bangladesh     

K. K. Islam  S. Jose  Masakazu Tani  Kimihiko Hyakumura  Max Krott  Noriko Sato 《Agroforestry Systems》2015,89(5):885-899

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Heterotrophic and autotrophic nitrification in two acid pasture soils   总被引：1，自引：0，他引：1  

A. Islam  R.E. White 《Soil biology & biochemistry》2007,39(4):972-975

Laboratory incubation experiments, using ¹⁵N-labeling techniques and simple analytical models, were conducted to measure heterotrophic and autotrophic nitrification rates in two acid soils (pH 4.8-5.3; 1/5 in H₂O) with high organic carbon contents (6.2-6.8% in top 5 cm soil). The soils were from pastures located near Maindample and Ruffy in the Northeast Victoria, Australia. Gross rates of N mineralization, nitrification and immobilization were measured. The gross rates of autotrophic nitrification were 0.157 and 0.119 μg N g⁻¹ h⁻¹ and heterotrophic nitrification rates were 0.036 and 0.009 μg N g⁻¹ h⁻¹ for the Maindample and Ruffy soils, respectively. Heterotrophic nitrification accounted for 19% and 7% of the total nitrification in the Maindample and Ruffy soils, respectively. The heterotrophic nitrifiers used organic N compounds and no as the substrate for nitrification.  相似文献   

Intra-specific patterns of δ13C,growth and wood density variation at sites of contrasting precipitation with implications for modelling carbon sequestration of tropical tree species     

Halder  Nirmol Kumar  Chowdhury  Md. Qumruzzaman  Fuentes  David  Possell  Malcolm  Merchant  Andrew 《Agroforestry Systems》2021,95(8):1429-1443

Agroforestry Systems - Tropical agroforestry practices play a crucial role in mitigating global climate change by absorbing CO2 from the atmosphere through photosynthesis and storing carbon in...  相似文献   

CO2 elevation and soil warming reduce cold hardiness of jack pine under photoperiods of seed origin and latitudes of potential migration     

Newaz  Shah Md.  Dang  Qing-Lai  Man  Rongzhou 《New Forests》2021,52(5):777-790

New Forests - Climate change is predicted to cause northward migration of boreal tree species. However, the success of such a migration will be determined by trees’ ability to acclimate to...  相似文献   

Application of Biofloc Technology for the culture of Heteropneustes fossilis (Bloch) in Bangladesh: stocking density,floc volume,growth performance,and profitability     

Shamsuddin  Md  Hossain  M. Belal  Rahman  Moshiur  Kawla  Mst. Salamun  Shufol  Md. Badiul Alam  Rashid  Muhammad Mamunur  Md. Asadujjaman  Rakib  Md. Refat Jahan 《Aquaculture International》2022,30(2):1047-1070

Though Biofloc Technology is a new concept in Bangladesh, it provides advantages for improving aquaculture production in many countries, leading to achieve sustainable development goals. The objectives of this study were to determine the effects of stocking densities on the growth performance of stinging catfish (Heteropneustes fossilis) under Biofloc Technology and assess the economic prospects and business feasibilities. Fingerlings were stocked in unique 5000-L tanks with three stocking densities, i.e., 3500 fish/tank (Treatment-I), 4000 fish/tank (Treatment-II), 4500 fish/tank (Treatment-III). The treatments showed significant differences (P?<?0.05) considering the species-specific growth rate, feed conversion ratio, and protein efficiency ratio. Treatment-I had significantly ((P?<?0.05) higher final biomass (29.51 ± 0.04 kg/m³) than the other treatments. The present findings revealed that using a lower stocking density, the Biofloc Technology reduced ammonia (NH₃), nitrite (NO₂), nitrate (NO₃), TDS, and floc volume but significantly increased the dissolved oxygen. As a result, Treatment-I had generated significantly higher net income (BANGLADESHI TAKA—BDT 86,278.90) over the other treatments. Moreover, the NPV, net BCR, and RoR with 4% and 9% opportunity cost were also significantly higher in Treatment-I than other treatments. The internal rate of return (IRR) and SWOT analysis index indicates that investing in Biofloc Technology is far superior, and a stocking density of 3500 fish/tank (Treatment-I) resulted in a faster investment return.

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