The numbers in the chart reflect the dimensional change coefficient for the various species, measured as tangential shrinkage or swelling within normal moisture content limits of 6-14 percent. Tangential change values will normally reflect changes in plainsawn wood. Quartersawn wood will usually be more dimensionally stable than plainsawn.

The dimensional change coefficient can be used to calculate expected shrinkage or swelling. In actual practice, however, change would be diminished in a complete floor, as the boards’ proximity to each other tends to restrain movement.

What all this is really saying is that the lower the change coefficient, the less your floor will move and the less your floor moves, the better.

Although some tropical woods such as Australian cypress, Brazilian cherry, merbau and wenge appear in this chart to have excellent moisture stability compared to domestic oak, actual installations of many of these woods have demonstrated significant movement in use. To avoid problems later, extra care should be taken to inform potential users of these tendencies prior to purchase.

SPECIE	CHANGE COEFFICIENT
Mesquite	.00129
Merbau	.00158
Cypress	.00162
Padauk	.00180
Teak	.00186
Wenge	.00201
Purpleheart	.00212
Mahogany	.00238
Cherry	.00248
HeartPine	.00263
Pine	.00265
Fir	.00267
Ash	.00274
Walnut	.00274
Brazilian Cherry	.00300
Pecan	.00315*
Birch	.00338
Maple	.00353
White Oak	.00365
Red Oak	.00369
Jarrah	.00396
Beech	.00431

*Hickory, often intermixed with pecan, has a rating of .00411.

Data is from The National Wood Flooring Association
"Wood Species Used in Wood Flooring"