Immature gamar (Ginelina arborea, Linn.) plants at about the age of 10 to 12 years become infested with loranthus, a parasitic plant, and ultimately die if a heavy infestation occurs. Gamar of 8,12,16 and 20 years age groups, having little timber value, have been studied for the manufacture of exterior grade hardboards. Fibre analysis and solvent extractibility show that the wood will be suitable for the purpose. Fibre length, flexibility coefficient, fibre diameter, relative fibre length and other related factors arc better than those of many other tropical wood and grass species. The presence of high percentages of waxes, fats and resins makes the fibres naturally moisture resistant.

Pulps have been made by Cold Soda and Steaming processes. Both soaking and pressure impregnation methods have been tried in the Soda process. Steaming for one hour at 140 psi steam pressure has been found to be the optimum in the other process.

Additive chemicals have been used in the slurry for imparting water resistance to the boards. Fire retardant and insect repellent chemicals have been sprayed on the damp-dry mat or on the formed boards. Heat treatment and oil wax tempering were followed by applying protective coating with urea-formaldehyde glue and enamel paint.

Accelerated aging tests have been conducted according to ASTM procedures. Board specimens have been tested for physical strength, water resistance and fire rctardance. For charring tests, a device has been developed at the Forest Research Institute. Modulus of rupture values, as high as 7000 psi, have been obtained. Tempered boards absored as low as 4% by weight and 1% by volume of moisture. Even after aging tests the boards were quite water resistant, though moderate in strength.