Hygroscopic property of Neem (Azadirachta indica A. Juss.): an experimental determination of the Shrinkage characteristics

A pioneer effort is made in this study to carry out an experimental determination of shrinkage
characteristics of neem (Azadirachta indica A. Juss) wood on its linear, volumetric, and
coefficient values with the hope of ascertaining its utilization potential as timber. Three study
locations were randomly selected from defined vegetation zones of north eastern Nigeria for
the study. These are Maiduguri (Sahel savanna) Yola (Sudan savanna), and Bauchi (Guinea
savanna). Forty five (45) tree samples of neem trees were randomly selected and felled, from
which 135 wood specimens were extracted and prepared using Romanian Standard for the
research. The analysis of variance (ANOVA) was used to analyze the obtained data. Results
showed that the tree species has an average tangential linear shrinkage of 12.74%, radial
linear shrinkage of 6.26%, longitudinal linear shrinkage of 1.15%, and volumetric shrinkage of
19.12%. The coefficients of tangential, radial, and longitudinal shrinkage were 0.00674,
0.00339, and 0.00061 respectively. The analysis of variance revealed insignificant differences
of shrinkage between the three vegetation zones, the sampled trees, as well as between the
tree trunk sections. Since the shrinkage value of neem wood compares favorably with some
local wood species used for timber, neem wood could be considered suitable for timber
production.