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|Title: ||Seasoning characteristics of the wood of celtis mildbraedii|
|Authors: ||E. K. B., Obese-Jecty|
|Issue Date: ||7-Jun-1996|
|Series/Report no.: ||2276;|
|Abstract: ||This is a study of the physical and seasoning properties of the wood of Celtis mildbradii. Engl. locally called “Esa fufuo” which is perishable and exhibits strong tendencies to degrade during seasoning.
This work used samples from five trees of the Bobiri Forest Reserve and determined the basic density, moisture content distribution, shrinkage characteristics (including the effect of under water storage) and proposes two kilning schedules based on Terazawa’s (1985) oven sample method.
The basic density determination based on the green volume and oven-dry weight using a water displacement method was found to average 664 kg/m3 in the “heartwood” and 638 kg/m3 in the “sapwood”. The difference between the “heartwood” and sapwood” densities were only significant at the 80% level.
The moisture content distribution patterns obtained by oven-drying 2cm cubes at 100°C did not exhibit wide variations and no consistent pattern emerged, either radially or vertically. The average radial moisture content was 54% with standard deviation 5.7% with 255 degrees of freedom.
The variation, of shrinkage with height was erratic, alternately rising and falling between 10.4% at the base and 6.9% at the top of the tree. Radially, the “sapwood” shrunk less than the “heartwood” (7.9% against 9.2%). This was accompanied by abnormal shrinkage (13.3%) in the region of the “sap-heart” interface. Shrinkage values from the pith were similarly high (10.4%).
Generally samples that had undergone water storage shrunk more than those that had not. Strangely, those that had undergone long periods of water storage shrunk less than those that had shorter storage periods. These differences were more apparent at higher moisture content: by the oven-dry stage all plots converged on the same final average.
Samples measuring 2cm x 10cm x 20cm dried at 100°C exhibited strong tendency to honeycomb, collapse and end-check. Twisting and cupping was observed in a third of the samples. Some exudation and peculiar cracking was observed.
Two Kiln schedules are proposed. The first is based on the majority classification (schedule 1 initial temperature 45°C, wet bulb depression 1.8°C and final temperature 79°C) and a conservative schedule 2 with initial temperature 45°C, wet bulb depression. 1.8°C, and final temperature 77°C.|
|Description: ||A thesis submitted to the Board of Postgraduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirement for the award of the Degree of Master of Science in Wood Technology and Industrial Management, 1996|
|Appears in Collections:||College of Agric and Natural Resources|
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