~ 263 ~ Journal of Pharmacognosy and Phytochemistry 2017; 6(4): 263-266 E-ISSN: 2278-4136 P-ISSN: 2349-8234 JPP 2017; 6(4): 263-266 Received: 06-05-2017 Accepted: 07-06-2017 Heena Gupta Department of Forest Products, College of Forestry, Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni- Solan, H.P., India KR Sharma Department of Forest Products, College of Forestry, Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni- Solan, H.P., India Chander Lekha Department of Forest Products, College of Forestry, Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni- Solan, H.P., India Bhupender Dutt Department of Forest Products, College of Forestry, Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni- Solan, H.P., India Correspondence Heena Gupta Department of Forest Products, College of Forestry, Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni- Solan, H.P., India Potentials of Lantana Camara L. leaf extract treatment for the dimensional stability of some lesser known wood species Heena Gupta, KR Sharma, Chander Lekha and Bhupender Dutt Abstract Wood is a hygroscopic material that shrinks and swells to different extents in three anatomical directions. The dimensional changes that accompany the shrinking and swelling of wood are major sources problems in the structural utilization of wood. Therefore, the present investigation was carried out to test the potentials of Lantana camara L. methanol leaf extract for the dimensional stability of wood samples of some lesser known wood species viz. Pinus roxburghii Sargent, Celtis austral L., and Bombax ceiba L. of size 5cm x 2.5cm x 2.5cm (longitudinal x radial x tangential) treated at different concentrations viz. 0.25%, 0.5%, 1%, 1.5% and 2.0%. These samples were analysed for swelling and shrinkage in three different planes viz. longitudinal, radial and tangential and the results revealed highest swelling and shrinkage in tangential plane followed by radial plane and longitudinal plane. Pinus roxburghii Sargent wood samples were recorded with the highest swelling and shrinkage in all the three planes. Among the treatments, 1.5% was observed with maximum swelling and 2% concentration with minimum shrinkage. The treated samples exhibited good dimensional stability as compared to untreated samples. Thus, the plant extract offers a great potential in improving the dimensional stability of wood without adversely affecting the environment. Keywords: wood, dimensional stability, shrinkage, swelling, longitudinal, radial, tangential Introduction Wood is hygroscopic material and it changes dimensions with changing moisture content because the cell wall polymers contain hydroxyl and other oxygen containing groups that attracts moisture through hydrogen bonding. The hemicelluloses are the most hygroscopic components in the wood cell wall, but cellulose and lignin also contribute to hygroscopicity. Moisture swells the cell wall and the wood expands until the cell wall is saturated. Water beyond this point is free water in the cell lumen and does not contribute to further expansion. It is reversible process and the wood shrinks with loss of moisture (Stamm, 1964) [15] . Wood is an anisotropic material, which means that it shrinks and swells to different extents in three anatomical directions, shrinking most in the direction of the annual growth rings (tangentially), about one-half as much across the rings (radially) and only slightly along the grain (longitudinally) (Anonymous, 1999) [1] . As the S2 layer of the wood cell wall is generally thicker than the other layers combined, the molecular orientation of this layer largely determines how shrinkage occurs. Most of the chain molecules in the S2 layer are oriented almost parallel to the long axis of the cell (with micro fibril angles of 10-30°). When water enters between the cellulose chains in the S2 layer it forces the chains apart, causing transverse (radial and tangential) swelling, while any change in the longitudinal direction will be minor (Bowyer et al. 2003, Siau 1984) [2, 14] . Stresses will arise in the wood due to moisture gradients between the surface and the interior and unbalanced stresses can result in surface warping, twisting and checking. Wood constituent polymers, during exterior use are readily degraded by weathering. The main problem associated with wood under outdoor use are its dimensional instability due to moisture absorption or desorption, breakdown of wood polymers by UV light and its decay by micro-organisms (Feist and Hon, 1984) [5] . Chemical modification of cell wall polymers is one of the effective methods to induce dimensional stability, UV resistance and biological resistance in wood (Rowell, 2005) [15] . The dimensional stability can be improved by bonding cell wall polymers with hydrophobic groups or bulking cell wall polymers with bonded chemicals. Resistance to ultraviolet radiations can be achieved by bonding UV absorbers or blockers to lignin (Kiguchi and Evans, 1998) [7] . Although chemical modification of cell wall polymers through conventional wood preservatives is one of the effective methods to induce dimensional stability in wood (Rowell, 2005) [12] but these are said to cause environmental