DEVELOPMENT OF KILN-DRYING SCHEDULES AND WITHIN TREE VARIABILITY IN THE PHYSICAL PROPERTIES OF TWO LESSER-KNOWN TIMBER SPECIES IN GHANA
DEVELOPMENT OF KILN-DRYING SCHEDULES AND WITHIN TREE VARIABILITY IN THE PHYSICAL PROPERTIES OF TWO LESSER-KNOWN TIMBER SPECIES IN GHANA
No Thumbnail Available
Date
2012
Authors
Effah, Bernard
Journal Title
Journal ISSN
Volume Title
Publisher
College of Agriculture and Natural Resources
Abstract
Decreasing supply of most commercial wood as raw material inspires the forest products
industry to look for other wood species which have similar or greater commercial values
but are not currently utilized by the forest products industry. Wood is versatile and the
oldest building material used by man. But there is limited knowledge about the
properties of a large proportion of timber-grade wood species. Proper utilization of a
particular wood species must be based on both basic properties and processing
properties. Drying is one of the most important processing properties, because a proper
drying process will be the main key to utilize efficiently and ensure high quality wood
products. Cola nitida (Bese) and Funtumia elastica (Funtum) are two lesser- known
species in Ghana that are not used for commercial timber purposes. The overall
objective of this study was to develop kiln-drying schedules for Cola nitida (Bese) and
Funtumia elastica (Funtum), as well as assess the variability of the physical properties
as the basis for determining the potential uses that may encourage the utilization and
promotion of these lesser known species. The basic properties were determined based on
British Standard 373 (1957), whiles the drying schedules were determined using the
quick drying test method developed by Terazawa (1965). The main statistical tools used
were Descriptive Statistics and Analysis of Variance (ANOVA). Variation in physical
properties was analyzed within the trees of the two species. Three trees each per species
were used in the study. Results of the study showed that initial moisture content were
66.6% and 79.4% for Cola nitida and Funtumia elastica respectively. The basic density
of Cola nitida was 623.8 kg/m3
and 499.6 kg/m3
for Funtumia elastica. According to
TEDB (1994), Cola nitida is a Medium-Heavy species and Funtumia elastica a Medium
Weight species. Mean total tangential shrinkage from green to oven-dry was 7.25 and
6.78% for Cola nitida and Funtumia elastica, respectively. Mean partial tangential
shrinkage from green to 12% MC is very small (under 2.5%) for Cola nitida and
medium (4.0-5.5%) for Funtumia elastica. The corresponding mean partial radial
shrinkage values also showed that shrinkage was very small (under 1.0%) for Cola
nitida and medium (2.0–3.0%) for Funtumia elastica. The shrinkage values for the two
species compared favourably with those of some locally used species for timber
production (like Scottellia coriacea and Lannea welwitschii), and therefore could be
considered suitable for timber utilization. The drying schedules also comformed to those
of Sterculia rhinopetala and Alstonia boonei as proposed by Ofori and Brentuo (2010b).
Checks in the early stages of drying were less severe in both Cola nitida and Funtumia
elastica samples (Class 3). There were no honeycombing (Class 1) in both Cola nitida
and Funtumia elastica species. There was no deformation (Class 1) in both Cola nitida
and Funtumia elastica species. Experimental dry kiln schedules for lumber of thickness
up to 38 mm corresponding to two Madison schedules were proposed: Cola nitida (T10-
C4) and Funtumia elastica (T10 – D4). The results of the analysis of variance (ANOVA)
revealed that the three axial sections of the trees showed significant differences at 5%
probability level (p < 0.05). The technical values of the study results compared
favourably with technical values of some locally used species for timber production (like
Scottellia coriacea and Lannea welwitschii), and therefore could be considered suitable
for timber utilization.
Description
Keywords
Citation
Effah, B. (2012). Development of kiln-drying schedules and within tree variability in the physical properties of two lesser-known timber species in Ghana (Doctoral dissertation).