A method of data analysis for a set of elastic constant measurements is app
lied to data bases for wood and cancellous bone. For these materials the id
entification of the type of elastic symmetry is complicated by the variable
composition of the material. The data analysis method permits the identifi
cation of the type of elastic symmetry to be accomplished independent of th
e examination of the variable composition. This method of analysis may be a
pplied to any set of elastic constant measurements, but is illustrated here
by application to hardwoods and softwoods, and to an extraordinary data ba
se of cancellous bone elastic constants. The solid volume fraction or bulk
density is the compositional variable for the elastic constants of these na
tural materials. The final results are the solid volume fraction dependent
orthotropic Hooke's law for cancellous bone and a bulk density dependent on
e for hardwoods and softwoods.