Checking, splitting and presence of moulds in Neem (Azadirachta indica) wood and carved products: causes and possible solutions

Abstract

Neem (Azadirachta indica) is one of the main good woods for carving being promoted, in Kenya, to replace the over-exploited indigenous species like Muhugu (Brachylaena huillensis) and Mutamaiyo (Olea africana) among others. However, Neem wood and carvings easily crack and mould. There was need therefore to determine the reasons for these and to suggest solutions on how to arrest or control these two major problems. A three day study was carried out at Akamba Carving Co-operative in Mombasa in Coast Province in order assess the existing conditions and appropriateness of current methods used to dry Neem, establish (state) appropriate drying techniques to ensure recommended moisture levels are achieved and recommend proper handling and storage methods for Neem logs to reduce checking. The moisture content of randomly chosen logs and carved products was determined using a moisture meter, the heartwood proportion of these logs and some carved items measured, an audit of the drying kilns carried out and causes of moulds assessed. The study reveals that the checking could be due to growth and drying stresses. All the cracking in the logs is noted to be originating from the pith, which is the weakest point in a log. The cracking appears to be accelerated by the exposure of the logs to direct sunrays and wind in an open yard and the likely uneven distribution rate of moisture loss at the pith, heartwood and sapwood. The proportion of heartwood in logs is found to be about 51% and that in carved stool tops as about 60 %. It is concluded that there is need for more controlled drying of the carved Neem products; presence of moulds in the carved items is due to high moisture content in the sapwood and warm and damp conditions in the show rooms; cracking is more pronounced in large carved items; lack of a shed at the log yard promotes the end checking and finally it is necessary to understand the factors that influence the checking of the Neem before concrete guidelines to curb the problem can be developed. In the short term, improvements in some of the practices at the society to ensure that better quality products are produced have been recommended. A study on drying behaviour and properties of Neem has also been recommended.