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.
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.
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
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.
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.
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.
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.
A preliminary study on veneer cutting and gluing properties of Albizzia
moluccana Miq., an exotic species, showed that the species is suitable for making good
quality veneer and plywood and can be used for making tea boxes and crates. It
is also suitable for making corestock.
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A brief review is given of investigations into the cause of agaru, a valuable
aromatic oleoresinous deposit found in the stems of Aquilaria agallocha in
Bangladesh, East India and other parts of South East Asia.
In previous investigations various fungi have been identified in association
with agaru deposits but their casusal role in this context has not been fully
established.
The present investigation includes microscopic examinations and identification
of fungal isolates from four samples of agaru collected in the Sylhct region
of Bangladesh. From this evidence it is concluded that it is unlikely that there
is a specific fungal cause for agaru. Suggestions are made for further research.
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