A common use of Janka hardness ratings is to determine whether a species is suitable for use as flooring. Take a look at the hardness of hickory vs. any other domestic hardwood and a few other imports:
Hickory / Pecan, Satinwood 1820
Afzelia / Doussie 1810
Bangkirai 1798
Rosewood 1780
African Padauk 1725
Blackwood 1720
Merbau 1712
Kempas 1710
Locust 1700
Highland Beech 1686
Wenge, Red Pine 1630
Tualang 1624
Zebrawood 1575
True Pine, Timborana 1570
Peroba 1557
Kambala 1540
Sapele / Sapelli 1510
Curupixa 1490
Sweet Birch 1470
Hard Maple / Sugar Maple 1450
Coffee Bean 1390
Natural Bamboo (represents one species) 1380
Australian Cypress 1375
White Oak 1360
Tasmanian Oak 1350
Ribbon Gum 1349
Ash (White) 1320
American Beech 1300
Red Oak (Northern) 1290
Caribbean Heart Pine 1280
Yellow Birch 1260
Movingui 1230
Heart Pine 1225
Carbonized Bamboo (represents one species) 1180
Cocobolo 1136
Brazilian Eucalyptus / Rose Gum 1125
Makore 1100
Boreal 1023
Black Walnut 1010
Teak 1000
Sakura 995
Black Cherry, Imbuia 950
Boire 940
Paper Birch 910
Cedar 900
Southern Yellow Pine (Longleaf) 870
Lacewood, Leopardwood 840
Parana 780
Sycamore 770
Shedua 710
Southern Yellow Pine (Loblolly and Shortleaf) 690
Douglas Fir 660
Larch 590
Chestnut 540
Hemlock 500
White Pine 420
Basswood 410
Eastern White Pine 380
Balsa 100
Maybe this helps explain why saw chains get a little dull cutting hickory.