A PEDUNCULATED AND A SESSILE OAK. 
247 
Each piece was one inch square, and was sustained by supports 
two feet apart, the weight being applied to the middle of the length. 
As a result of these experiments Tredgold concluded that “ The 
strength, elasticity, toughness, and hardness of the sessile-fruited 
oak would render it superior for ship-building, were it not so 
inferior in durability between wind and water to the Q.pedunculate/,, 
or stalk-fruited kind.” This last statement, an opinion generally 
held, has, however, been controverted, but Hartig’s experiments 
afford some ground for it, a wood which contains when green so 
much moisture that it weighs considerably more than that of 
Q. pedunculata, and when dry rather less, will probably when 
under water absorb more moisture and consequently be more liable 
to decay than one which contains comparatively little moisture or 
sap when green. 
A few more-recent opinions may now be quoted. Grigor, in his 
* Arboriculture ’ (1881), says: “The first [Q. pedunculata'] is the 
most approved tree, as it produces the best timber. The timber of 
sessiliflora bears a strong resemblance to that of the Spanish chestnut, 
. . . Its greatest recommendation is that it grows more freely 
than the other sorts when young, particularly in an inferior soil 
and situation; but afterwards the difference in the growth of the 
trees, and in their ultimate size, is hardly perceptible.” Stevenson, 
in ‘ The Trees of Commerce’ (1888), remarks: “The most valuable 
is the Q. pedunculata , a tree remarkable for the zigzag form of its 
branches, . . . The other species, the Q. sessiliflora , is a more 
free-growing tree, . . . it is a fact that the sessile oak is an 
inferior wood, one which in some cases is called the ‘ Chestnut oak,’ 
the wood often being mistaken for chestnut.” In the sixth edition 
of Brown’s ‘ Forester,’ by Msbet (1894), it is stated that Q. sessili¬ 
flora in durability almost equals Q. pedunculata , but is somewhat 
softer and easier to work, and that when young the timber is of 
a more open texture than that of the common oak of the same age, 
but as it becomes older it is found to be nearly as compact and 
solid as that of the latter. The specific gravity of pedunculata is 
here given as 1*04 when green, and O’76 when seasoned in the air; 
and of sessiliflora as 1*01 when green, and 0*74 when seasoned, 
a statement which does not agree with the results of Hartig and 
Tredgold ; while Schlich, in his ‘Manual of Forestry’ (vol. ii, 1891), 
differs still more from them in giving the specific gravity of the 
wood of pedunculata as 0*86, and of that of sessiliflora as 0*74. 
Lastly, Professor Boulger, in his useful work on ‘ Wood’ (1902), 
says that Quercus pedunculata is quick-growing, but does not 
produce so great a length of stem as sessiliflora ; that the wood 
is lighter in colour, but ‘ ‘ generally more compact, denser, and 
tougher, and therefore better for purposes where strength is 
a primary consideration; ” and also that sessiliflora is “ apparently 
generally less dense in its timber,” and “also perhaps more liable 
to shakes.” 
The rate of growth of a tree must affect the density of its wood, 
the slower-growing tree of nearly allied species being at least most 
