A Half-yearly Peer Reviewed Journal of Bangladesh Forest Research Institute
Air drying characteristics of garjan Dipterocarpus spp. railway sleepers were investigated employing 1 x 5, 2 x 5, 1 x 7 and 2×7 piling methods. Although there was no significant difference among the drying periods in different methods, the 2×7 method appeared to be the most efficient one. This method exhibited a relatively shorter drying time irrespective of higher density and higher initial moisture content of sleepers as compared to those in other methods. The faster drying in the 2×7 method was attributed to better air circulation. Sleepers stacked in the month of April, dried down to 28% mosisture content in about eight months on
the average. It is recommended that garjan sleepers be air dried following the 2×7 method during the active drying season beginning November, instead of April, as was done in the present study, with a view to achieving further reduction in total drying time.
The moisture distribution inside the sleepers was highly variable ; the moisture gradient was steeper with increasing depth of the zone, but the steepness of the gradient decreased with increasing drying time.
Jam (Syzygium grandis), because of its availability and strength properties, was considered for substituting garjan ( Dipterocarpus spp. ) for making railway sleepers. Since treatment with creosote is normally the part of the manufacturing process for railway sleepers from nondurable wood, jam heartwood was treated with Lowry empty cell process using 40 ; 60 creosote-petroleum oil preservative in order to develop a treating schedule for jam sleeper. Treatments were performed with the various combinations of treating schedules with or without the pretreatment ot steaming-vacuum or incision. None of the treatments, however, could achieve penetration and retention recommended for the purpose of railway sleepers
Black pepper (Piper nigrum, Linn.) locally known as gid marich – is a highly prized spice with heavy demand in the western countries. Oldrecords indicate that limited vines of the species were in Jessore and Sylhet districts. Large scale use of black pepper as a condiment and scope of its introduction for multiple use of land made the authors to initiate studies for cultivation and field studies in Bangladesh.
Trials were given to raise the vines from stem cuttings on trellis as well as on living support of available fruit trees. Different methods of raising cuttings were also evaluated. Growth, flowering and fruiting behaviour were also observed.
Because of limited stock, work on pollination mechanism and ratio of male and female flowers could not be undertaken.
But as a whole it appears to be a promising crop for introduction in Bangladesh.
This paper clearly shows that propagating bamboos from material other than seed is possible. Propagation of bamboos from offsets is well known and practised in village groves. The development of planting material from branch cuttings is a two-stage operation. The first is the striking of roots and the other, the development of a rhizome. Getting vigorous rooted stock is not enough because this does not always develop rhizomes ; for this the biological condition of the buds is very important. In bamboos, successful planting material must have all the characters of growing clumps, the most important of which is the production of new culms. Though offsets are a good propagating material, these are not suitable for large scale plantations due to handling difficulties, long branch cuttings with swollen basal nodes and 2-3 branch nodes physiologically similar and can be made branch 18-20 inch are morphologically and to function like the offset in suitable conditions. Such cuttings develop into good planting material in 6-30 months, depending on the biological condition of the cutting and the period of the year when the cuttings were taken. The superiority of the branch cutting over the offset is in the fact that it is easy to raise, economic to produce, and convenient to transport. At the moment the percentage of success is low, and further research in the factors governing the production of planting material from branch cuttings is necessary.
The paper examines the profitability of teak ( tectona grandis, Lin. f) plantations under the existing system of management in Bangladesh. The Forest Department has fixed 69 years as the rotation length for teak on all sites. Land expectation values have been calculated on the basis of the Faustmann formula and preliminary yield tables for three site qualities. They have been calculated on the assumption that the sites would be used for teak plantations for an infinite number of 60 year rotations. The sensitivity of results to changes in the planting and overhead costs and in yields was also calculated. The result indicates positive net returns for sites of qualities I to III under all cost conditions at an eight percent rate of interest. At thirteen percent, sites of qualities I and II show a positive result but those of quality III indicate a net loss Land expectation values are not found to be a convenient index of profita
Studies at the Forest Research Institute show that only teak fruits of 14 mm or above in diameter should be used in nurseries. Smaller fruits produce so few seedlings that their use is not practical.
Smaller fruits usually produce very few seedlings because most them are empty, i. c., they contain no seeds. The presence of empty fruit varies from 15 to 41 percent among the five different localities of Bangladesh. Emptiness explained 78 percent of the variation in germination rates among five diameter classes of fruits.
Low germination rates of the fruits haye been widely reported to be a problem in work with teak reproduction.
This paper deals with the effect of two growth hormones, IAA and IBA in the rooting response of stem cuttings, rooting of branches by air layering through the application of Seradix B-3, and bud and cleft graftings of six species in different months. It was found that rooting occurred in four species with hormone applications to stem cuttings ; of these, three species rooted throughout the year. In air layering, four species roofed only in August-September. Bud grafting were successful in all the species. Bud propagation in April-May was the most successful. Fair results
were also obtained from budding in November-December. Cleft grafting did not show much response in any of these species.
Immature gamar (Ginelina arborea, Linn.) plants at about the age of 10 to 12 years become infested with loranthus, a parasitic plant, and ultimately die if a heavy infestation occurs. Gamar of 8,12,16 and 20 years age groups, having little timber value, have been studied for the manufacture of exterior grade hardboards. Fibre analysis and solvent extractibility show that the wood will be suitable for the purpose. Fibre length, flexibility coefficient, fibre diameter, relative fibre length and other related factors arc better than those of many other tropical wood and grass species. The presence of high percentages of waxes, fats and resins makes the fibres naturally moisture resistant.
Pulps have been made by Cold Soda and Steaming processes. Both soaking and pressure impregnation methods have been tried in the Soda process. Steaming for one hour at 140 psi steam pressure has been found to be the optimum in the other process.
Additive chemicals have been used in the slurry for imparting water resistance to the boards. Fire retardant and insect repellent chemicals have been sprayed on the damp-dry mat or on the formed boards. Heat treatment and oil wax tempering were followed by applying protective coating with urea-formaldehyde glue and enamel paint.
Accelerated aging tests have been conducted according to ASTM procedures. Board specimens have been tested for physical strength, water resistance and fire rctardance. For charring tests, a device has been developed at the Forest Research Institute. Modulus of rupture values, as high as 7000 psi, have been obtained. Tempered boards absored as low as 4% by weight and 1% by volume of moisture. Even after aging tests the boards were quite water resistant, though moderate in strength.
The numerous islands constituting the littoral forests of the Sundarbans have been formed by river-borne silts of the Ganges and the Brahmaputra, the two main rivers of Bangladesh. The forests lie between latitudes 21°30’N and 22°31’N and between longitudes 89°E and 90°E.
The productive forest lands of 939820 acres of the Sundarbans produce only 15 million cubic feet of wood per annum at the present (1971)-one acre produces only 16 eft of timber per acre per annum. This poor yield is perhaps due to the inclusion of varied crops under one management plan, an improper management system, ill supervision and the complete reliance on nature for regeneration. The present (1971) poor yield of 16 eft of timber per acre per annum may still go down if proper attention is not given to restocking the forests under an efficient system of management instead of the current selection system.
At least two of the main littoral species, sundri and gewa can be managed in even-aged stands.
The Bangladesh Energy Study, sponsored by the Planning Commission and published a year ago, reviewed the estimates and surveys made of fuelwood consumption and requirements in the country. It concluded that the consumption of domestic firewood and other forms of vege.tativc fuels is unknown.
Since the use of wood as fuel far exceeds other uses in volume importance a proper study is now considered necessary.
The paper describes the main physical, economic and statistical determinants of fuelwood consumption in Bangladesh. It proceeds to describe survey methods and strategy for determining this statistic. Supply estimates are then briefly described.
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