Forests are important for maintaining ecological balance. Eucalyptus,widely used in afforestation,can grow well in a wide range of agroclimatic conditions ranging from tropical very dry to moist forest life zones and the economic return of the plant is also very high. Amongst the other things the wood quality of Eucalyptus depends on its lignin content. The process of lignification and its deposition is a very complicated process.The activities of lignification related parameters like the precursors,enzymes involved in the biochemical pathway of lignin formation,environmental factors regulate the process of lignin content in a plant. The aim of this work is to identify the wood quality of the plant by some simple biochemical parameters and so to designate the woods of the plants useful for making timber or paper pulp.