PhD

The present research entitled “Wood property variation in jack trees (Artocarpus heterophyllus Lam.) grown in Thrissur district, Kerala" was carried out in the Department of Forest Products and Utilization, College of Forestry, Kerala Agricultural University, Vellanikkara, Thrissur, during 2017-2020. The species belonging to the family Moraceae and popularly known as jackfruit tree, is one of the important timber species commonly found in the homegardens of Kerala. The objective of this study was to assess the variation in physical, chemical, anatomical and mechanical properties of Jack wood (Artocarpus heterophyllus Lam.) between different altitudinal zones (Lowland, Midland and Highland) and girth classes within these altitudinal zones of Thrissur district, Kerala. Samples of Jack wood were collected from the three altitudinal zones (Lowland, Midland and Highland) of Thrissur district belonging to three girth classes viz., 30 cm - 60 cm, 60 cm - 90 cm. and 90 cm -120 cm, following stratified random sampling techniques. In the case of physical properties such as color, moisture content, green specific gravity, oven dry specific gravity, volumetric shrinkage, tangential shrinkage and radial shrinkage, analysis showed variation between the zones for the all the three types of shrinkages. Chemical analysis of the wood for water soluble and chemically soluble extractives showed significant variation in the case of alcohol benzene soluble extractives and for NaOH soluble extractives. Rest of the parameters such as cold-water soluble extractives, hot water-soluble extractives, holocellulose content, klason lignin content, cellulose content, hemicellulose content and ash content showed no significant variation. Jack wood is diffuse porous with aliform parenchyma surrounding solitary vessels, sometimes forming bands and broad to finely arranged rays. The anatomical parameters when analyzed, showed significant variation for ray morphological characteristics whereas vessel morphology, fibre morphology and ecoanatomical properties showed no significant variation. The mechanical parameters studied which includes static bending, tension, compression and its sub parameters showed no significant variation except for Modulus of Elasticity compression perpendicular to grain.
Simple correlation coefficients obtained between physical and chemical parameters, four were found to be positive and significant at 1% level of significance, two were found to be positive and significant at 5% level of significance whereas, one was reported as negatively correlated and significant at 1% and one was reported as negatively correlated and significant at 5% level of significance. The simple correlation coefficients obtained between physical and anatomical parameters, three were found to be positive and significant at 1% level of significance, two were found to be positive and significant at 5% level of significance whereas, one was reported as negatively correlated and significant at 1% and one was reported as negatively correlated and significant at 5% level of significance. Simple correlation coefficients obtained between physical and mechanical parameters, twenty were found to be positive and significant at 1% level of significance, ten were found to be positive and significant at 5% level of significance whereas, one was reported as negatively correlated and significant at 1%. The simple correlation coefficients obtained between chemical and anatomical parameters, one was found to be positive and significant at 5% level of significance, one was found to be negative and significant at 5% level of significance whereas, one was reported as negatively correlated and significant at 1%. Simple correlation coefficients obtained between chemical and mechanical parameters, eleven were found to be positive and significant at 1% level of significance, nine were found to be positive and significant at 5% level of significance whereas, one was reported as negatively correlated and significant at 5%. The simple correlation coefficients obtained between anatomical and mechanical parameters, eight were found to be positive and significant at 1% level of significance, three were found to be positive and significant at 5% level of significance whereas, three was reported as negatively correlated and significant at 5%. Coefficient of determination (R2) was observed to be more than 0.70 for oven dry specific gravity, tangential shrinkage and radial shrinkage when regressed with physical and chemical parameters. When regressed between physical and anatomical parameters R2 was observed to be more than 0.70 for green specific gravity, tangential shrinkage, radial shrinkage and volumetric shrinkage. Coefficient of determination (R2) was observed to be more than 0.70 for green specific gravity, tangential shrinkage, radial shrinkage and volumetric shrinkage when regressed with physical and mechanical parameters.