*Douglas Fir is listed as both a Class 2 and Class 3 timber, UK grown Douglas Fir is Class 4
*European Larch also listed as both Class 2 and Class 3 timber, UK grown European Larch is Class 4
*Siberian Larch is in both Class 2 and 3, Siberian grown Larch being Class 3
*UK grown Western Red Cedar is in both Classes 3 & 2. Class 3 Western Red Cedar is UK grown, Class 2 from America and Canada
*Massaranduba is listed as both Class 1 & 2 as durability can vary
*Kebony is listed as both Class 1 & 2 as durability can vary