Is there a table/rule of thumb for equivalence of hardwoods and softwoods for loading and/or deflection over a span? For example, a 1x3 oak plank is equal to a 1x4 maple is equal to a 2x4 dimensional fir/pine? Just curious, of course it seems that this is never done due to cost, but it's just general interest. I've seen tables with densities and tensile/compressive strengths.. Thanks!