Anatomical and related properties of wood carving species in Kenya

Abstract

The macroscopic, microscopic, physical (density) and mechanical (hardness) characteristics for 52 wood carving species from Kenya were studied. This was a study done for WWF/UNESCO/KEW Plants and People Initiative. It aimed at generating information on wood properties of these species and producing two dichotomous keys based on physical, macroscopic and microscopic features of these species. Wood samples were obtained from Coast, Eastern and Nairobi Provinces in close collaboration with Forest Officers in the field and local communities in the Wood carving industry. The samples were prepared and analysed at KEFRI Forest Products laboratories in Nairobi using standard procedures. The macroscopic and physical features used in the description of the wood specimen were mainly density, colour of heartwood and sapwood, odour, pore size, ray size, growth rings, wood grains and texture. In the description of microscopic structures, IAWA list of microscopic features for hardwood identifications was used (Wheeler E. A. et al, 1989). Some of the salient macroscopic features important for wood carving species were found to be: heartwood darker than sapwood, non irritating odour, minute pores and rays, fine to medium wood texture, straight grains and distinct growth rings. High wood density was also found to be an important feature and about 80% of the species had densities ranging between 0.60 g/cm3 to 1.23 g/cm3. Wood hardness is also important and most of the wood carving species are moderately hard to very hard (4 to 20KN). The important microscopic features were found to be minute rays (1-3 cells wide), pores solitary or in radial multiples of 2 or more, vessels with simple perforations, very thick walled fibres and few parenchyma cells. Two dichotomous keys were developed and can be used to identify the wood carving species. The standard names (or where these are absent Swahili or Kamba names) have been included in the keys to help in identification. Additional information on the species are also provided to assist in further identification e.g. local names, tree characteristics, wood characteristics, geographical distribution and uses. The 52 species have also been ranked in order of suitability for carving based on macroscopic features, density and hardness. They are classified into 3 categories; major (4), minor (7) and alternative (41). The alternative ones are further classified into 3 groups i.e. high potential (23), medium potential (15) and low potential (3).