Scott Leavengood of OSU was kind enough to pull together this list of resources for those of you interested in learning more about wood hardness.
ASTM Standard D143, 2009, “Standard Test Methods for Small Clear Specimens of Timber,” ASTM International, West Conshohocken, PA, 2009, www.astm.org. 31 p.
ASTM Standard E10, 2012, “Standard Test Method for Brinell Hardness of Metallic Materials,” ASTM International, West Conshohocken, PA, 2012, www.astm.org. 32 p.
ASTM Standard D7136, 2012. “Standard Test Method for Measuring the Damage Resistance of a Fiber-Reinforced Polymer Matrix Composite to a Drop-Weight Impact Event,” ASTM International, West Conshohocken, PA, 2012, www.astm.org. 16 p.
Bektas, I., M.H. Alma, and N. As. 2001. Determination of the relationships between Brinell and Janka hardness of eastern beech (Fagus orientalis Lipsky). Forest Products Journal 51(11/12):84-88.
Forest Products Laboratory. 1999, “Wood Handbook—Wood as an Engineering Material,” Gen. Tech. Rep. FPL–GTR–113. Madison, WI: USDA, Forest Service, Forest Products Laboratory. 463 p.
Niemiec, S., G.R. Ahrens, S. Willits, and D.E. Hibbs. 1995. Hardwoods of the Pacific Northwest, Research Contribution 8. Forest Research Laboratory, Oregon State University.
And more casual but interesting stories and looks at Janka:
Elizabeth Baldwin is Environmental Compliance Officer for Metropolitan Hardwood Floors. In her 25 plus year career in the wood industry has visited over 70 countries and hundreds of facilities of all sizes and types. She describes herself as a “jack of all wood trades.” Familiar with jungles of all sorts–having camped out along the Amazon and walked the halls of Congress–she blogs for the NWFA on both environmental and regulatory issues for educational and informational purposes only. Her blog is not intended and should not be construed as legal advice. Persons seeking legal advice on compliance with CARB, TSCA, the U.S. Lacey Act or any other law, regulation, or compliance requirement/claim should consult with the regulatory agency directly and/or a qualified legal professional.