Fire Hardening Wood

Pictured is a fire hardened spear point, dated at over 400,000 years old, discovered in 1911 in England.  It is the oldest known worked wooden implement, known as the Clacton spear.  Everything I have ever read about making wooden spears involves hardening the point in the super heated soil, or coals of a fire.  I thought this was interesting... a team of British researchers conducted tests in 2016 on the effects of fire hardening on wooden spearpoints.  After treating, and subjecting wooden shafts to impact, they concluded that fire treating did ‘slightly’ harden the point, but also ‘significantly’ weakened it by making it 35% more brittle. They surmised that the appearance of purposeful fire hardening, may more so have been the byproduct of charring the tip, so that it could be more easily shaved or abraded into a sharp point.  It was more about reducing the time and labor to produce a sharp point on a wooden shaft.  As a side bar, flintknapper Jack Cresson, in the Bulletin of Primitive Tecnology, conducted experiments with hardwood pressure flakers, fire hardening some for flintknapping stone points. He concluded that the fire treatment did nothing to increase the efficiency of the pressure flaker flintknapping.  As a thought, perhaps burnishing (polishing by rubbing with a bone) the point, compressing the wood fibers, after forming the point might be more efficient.  Any thoughts?