by TrimTheKing » 03 May 2019, 15:44
I found this when Googling, in a document from 1966 by the US Dept of Agriculture.
"In over 500,000 tests made by the Forest Products Laboratory on woods grown in the United States, no effect upon the mechanical properties of the wood due to its change from sapwood into heartwood has been found in most species.
The heartwood of oak, pine, and Douglas-fir, for example, is not intrinsically stronger than the sapwood, as has often been supposed to be the case; nor is the sapwood of hickory and ash intrinsically stronger than the heartwood, as is sometimes claimed in connection with handle stock."
Could just be that it's a widely held old view, or there could be more modern science, but if there is then it isn't widely written about from what my (admittedly not exhaustive) Googling has dug up.
Cheers
Mark