199 WOODY PLANTS OF MASSACHUSETTS. 
oak cannot be readily found, for axle-trees, saws it into planks 
for barn-floors, and applies it to many other purposes. For tide 
mills, it is preferable to oak timber, as it is not attacked by 
worms when in salt water. 
Its defects are that it shrinks much and irregularly, and there- 
fore warps, that it is liable to the attacks of worms, and decays 
rapidly when exposed to moisture. As is the case with most 
other woods, that is most valuable which has grown most rapid- 
ly, and which, in consequence, has least of the red heart-wood. 
That of the pignut is heaviest, next in succession the shellbark 
and mockernut, in the proportion, when green, of 31, 29, and 25. 
As fuel, hickory is preferred to every other wood, burn- 
ing freely, even when green, making a pleasant, brilliant fire, 
and throwing out great heat. Charcoal made from it is 
heavier than that from any other wood, but it is not considercd 
more valuable than that of birch or alder. The ashes of the 
hickories abound in alkah, and are considered better for the 
purpose of making soap than any other of the native woods, 
being next to those of the apple tree. 
The shellbark hickory ought to be cultivated for its nuts. 
These differ exceedingly in different soils and situations, and of- 
ten on individual trees growing in immediate proximity. There 
is a common idea, which seems to be well founded, that the ex- 
cellence of the nut is proportioned to the roughness of the bark. 
An observation of the elder Michaux encourages us to hope that 
the fruit may be greatly improved by cultivation. He says that 
the fruit of the common European walnut, in its natural state, 
is harder than that of the pacanenut, and inferior to it in size 
and quality.* 
The species of hickory common in Massachusetts, are four: 
1. The Shellbark, with five large leaflets, a large nut, of 
which the husk is deeply grooved at the seams, and with a 
rough, scaly trunk; 
2. The Mockernut, with seven or nine lcaflets, a hard, thick- 
shelled nut, and leaflets and twigs very downy when young, and 
strongly odorous ; 
* N. A. Sylva, I, p. 137. 
