Inefficiency of Tree Evolution
In a typical mature forest, the canopy can be thought of as an aerial meadow, just like a rolling grassland prairie, but raised on stilts. The canopy is gathering solar energy at much the same rate as a grassland prairie would. But a substantial proportion of the energy is wasted by being fed straight into the stilts, which do nothing more useful than loft the meadow high in the air, where it picks up exactly the same harvest of photons as it would — at far lower cost — if it were laid flat on the ground.
~ Dr. Richard Dawkins (1941-03-26 age:77), The Greatest Show on Earth: The Evidence for Evolution Page 210.