This studyexamined the relationships between fibre dimensional characteristics namely fibre length, fibre diameter, lumen and cell wall thickness and shrinkage beharviour of 25-year-old Gmelina arborea. Five trees with clear bole were randomly selected and felled from Oluwa Forest Reserve. Wood samples were systematically sampled at base 10%, middle 50% and top 90% of the merchantable height. Radiallythe wood samples were partitioned into outerwood, middlewood and innerwood. The mean fibre length, fibre diameter, cell wall thickness and lumenobtained for Gmelina arborea were 1.24mm, 21.21μm, 18.31μm and 1.81μm respectively.The mean radial shrinkage, tangential shrinkage and volumetric shrinkage obtained were 4.47%, 6.46% and 11.32%. Fibre dimension decrease from base to top and increased from innerwood to outerwood. Shrinkage characteristics increase from base to top and decrease from outerwood to innerwood.Statistical analysis conducted to testthe significance of the variability in the properties examined were significant at 5% probability level. Effect of anatomical properties was best observed in volumetric shrinkage and was followed by tangential shrinkage with and radial shrinkage
