According to Dan Bertalan in Traditional Bowyers of America, he quoted Dick Robertson, saying Black Locust was the best core wood (laminations) due to its brending strength, and Red Elm had very good strength either flat grain, or cross grain. He thought Osage was the strongest for risers, and used grain parallel to the string in heavy weight bows (1st Ed. pg 340 - 341). Lately, he has been using bamboo laminations and has changed the limb tapers in the both longbow and recurve to achieve desirable characteristics in his bows.