Physico - chemical properties and natural durability within Two varieties of Borassus aethiopum
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Date
DECEMBER, 2014
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Abstract
Many commercial Ghanaian timber species are over-exploited and threatened with extinction due to current pressure on traditional timbers. The need to investigate the potential utilization for Non-Timber Forest Products (NTFPs) to ascertain their possible utilization is important. Some physical and chemical properties, and the natural durability within two varieties of Borassus aethiopum harvested from Kobreso were investigated. Moisture content at green state ranged between 59.03 % (for periphery of the base) and 129.42 % (at core of the crown) for the male, and 56.38 % and 137.98 % respectively for the female. At the dry state, the male respectively recorded 12.19 % and 12. 94 % and also 12.29 % for the female and 12.85 % at the same sites. The density also ranged from 450.00kg/m3 (at the core of crown) and 960.50 kg/m3 (at periphery of base) for the male, and 423.50 kg/m3 and 1026.50 kg/m3 respectively for the female at green state. The male, at dry state, respectively recorded 264.00kg/m3 and 827kg/m3 and also 219.50kg/m3 for the female and 754.50kg/m3 at the same sites. Longitudinal swelling and shrinkage ranged from 0.22-0.48 % and 1.11-3.69 % respectively along the male and 0.22-0.52 % and 1.32-3.94 % for female. Tangential swelling and shrinkage similarly was 0.62-2.23 % and 1.75-4.04 % respectively for male and 0.69-2.21 % and 2.24-3.13 % for female. Radial swelling and shrinkage increased from 2.54-4.76 % and 2.41-3.54 % respectively for male while 2.14-4.66 % and 2.34-3.40 % along the female. Generally, volumetric swelling and shrinkage had a range of 2.88-6.99 % and 5.88-10.68 % respectively along the male with the female having 4.01-6.23 % and 6.82- 9.22 %. The male and female peripheries at base obtained greater total extractive (4.41 % and 3.25 % respectively), lignin (36.88 % and 39.53 %), alpha-cellulose (40.09 % and 37.01 %) and holocellulose (74.44 % and 75.23 %). Contrary, the core of crown had lowest total extractive (1.81 % and 1.83 % for male and female respectively), lignin (29.31 % and 28.60 %) and alpha-cellulose (28.02 % and 24.40 %) while the core of middle recorded least holocellulose (62.64 % and 62.62 %). Hemi-cellulose ranged from 32.59-41.93 % and 31.61-46.09 % for male and female respectively. The core of base for male gained lowest (31.61%) with core of crown for female having greatest (46.09%). The ash and mass loss for the male also ranged from 0.65-3.39 % and 4.17-100 % respectively likewise 0.85-5.64 % and 4.07-100 % for female. The core of crown for female recorded greater ash (5.64 %) with the periphery of base having least (0.65 %). For mass loss, both the core of crown for male and female obtained greatest (100 %) whilst periphery of the female recorded the least (4.07 %). The lignin, alpha-cellulose and holocellulose correlated strongly with the mass loss. Generally, the peripheries at the base and middle within the two varieties were durable and could be utilized for structural and exterior works. The cores of the base and middle could be also very useful for minor artifacts. The usage of B. aethiopum in the timber industry could reduce pressure on primary wood species and forest degradation as a result of excessive logging for the traditional timber species.
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Thesis submitted to The Department of Wood Science and Technology, Kwame Nkrumah University of Science and Technology in partial fulfilment of the requirements of MSc. Wood Science and Technology