OA BULLETIN 523, U. S. DEPARTMENT OF AGRICULTURE. 
medium sized trees. The silvicultural conditions for growing such | 
trees are a good soil and abundant growing space. 
Svecies—Table 10 indicates that distinction between species is of 
little importance in judging mechanical values. Thus while one lot 
of white ash was the best of any tested, two other lots ranked below 
one of green ash. 3 
With the exception of black ash, which will be considered later, 
the differences in mechanical properties of the various species of ash - 
are the same as would be expected in trees of the same species with 
varying specific gravities. In general, however, ash species growing 
under natural conditions will rank about as follows in relative 
strength as a beam or post: White ash, green ash, blue ash, Biltmore 
ash, pumpkin ash, black ash. Pumpkin ash and black ash usually are 
found growing under unfavorable conditions (wet swamps and slow 
growth) for putting on dense wood; while white, blue, and Biltmore. 
ash occur naturally on more favorable sites; green ash occurs about _ 
half on sites with defective drainage and half on sites where the 
drainage is sufficient, but always on rich alluvial soil. (See Pls. VII, — 
VIII, and 1X.) 
A further classification of the relative strength of the different 
species, of importance to future growers of ash timber, may be made 
on the basis of uniformly fast growing, small to mueditins sized trees, 
growing under favorable conditions, such as would be secured under 
proper management. From this sedacuount the species probably 
would rank as follows: White ash, green ash, Biltmore ash, blue ash, 
and black ash. It would be hard to say whether pumpkin ash would 
precede or follow blue ash, where grown under favorable conditions. 
This ranking of species is based on Table 10, consideration being 
given at the same time to rate cf growth (rings per inch), age (or 
size), character of site, and the conditions given in Table 11. These - 
factors account for apparent variations in the relative strength of 
the different species. Thus the blue ash in the table has a relatively 
high rank because of the unusually favorable conditions for putting 
on dense wood under which the specimen trees grew—all the trees 
were predominant and grew in an open stand on limestene soil. It 
will be seen, also, that the blue ash falls below green ash of Missouri 
in strength, although equalling it in weight and having fewer rings per 
inch. Black ash, on the other hand, if grown under favorable condi- 
tions, might reasonably be expected to produce much stronger timber 
than the table mdicates—nearly equal to blue ash, to which it is 
botanically closely related. 
The tests on black ash in the green condition indicated almost 
double as much moisture content as the tests on any of the other 
ashes. Black ash is the hghtest of the ashes tested, is very weak, 
