Up until about 1990 most of your dark hardwood used for stairs and internal joinery was Brazilian Mahogany. At that point supplies became more difficult and quality became unsatisfactory.  To this end people started using sapele which is an African hardwood and had better supply prospects. We are still using predominantly sapele as the mahogany replacement. The sapele we supply is coming from managed forests in Africa and carries FSC (Forest Stewardship Council UK) certification. The timber is completely clear and fairly regular in colour and totally free from knots and sapwood.