Janka Hardness Ratings for Various Species of Wood (pounds)
Hardness is defined as resistance to indentation
using a modified Janka hardness test, measured by the load
required to embed a 11.28-mm (0.444-in.) ball to one-half
its diameter. Values presented are the average of radial and
tangential penetrations.(1)
(1) The Wood Handbook - Wood as an engineering material, USDA, General Technical Report 113.