20 BULLETIN 933, U. S. DEPARTMENT OF AGRICULTURE. 
open meadows and prairies, and that the associated species came in 
later beneath the walnut, after the latter had established forest con- 
ditions. The agency of squirrels in the establishment of walnut is 
probably responsible also for the frequency of practically even- aged 
groves of walnut. Of some even-aged stands, which started within 
the memory of living man, it is known that the small fields and hill- 
sides they now occupy were seeded by squirrels in a single year. It 
is quite likely that this is the usual origin of even-aged stands that 
have sprung up without human action. Whether this is due to 
exceptionally heavy seed crops or to bad winters that killed off the 
squirrels before the nuts were dug up and eaten, or to short winters 
that did not force the squirrels to consume all .their hoard, or to a 
combination of such circumstances, can not now be told. 
reproduction is remarkably rare in the greater part of the range 
of black walnut under conditions as they now prevail. Practically all 
walnut stands are grazed by cattle, that destroy the young seedlings, 
or, still worse, by hogs that eat the nuts. Consequently, no reproduc- 
tion of walnut or anything else is taking place, and the stands are 
becoming grovelike, with open grassy floors. Even where grazing is 
excluded, however, walnut reproduction is not generally seen. This 
is difficult of explanation, but possibly it is linked with the effect of 
the settlement of the country on the number of squirrels and their 
habits. 
In western Indiana profuse reproduction is occasionally found 
along the fence rows around fields containing old walnut trees, as 
well as scatteringly on open southern slopes of draws leading down 
to the Wabash River on both the Indiana and the Illinois sides. In 
some localities in Missouri young trees are characteristically scat- 
tered on open southern slopes near hollows that contain mature wal- 
nut. The growth on these open slopes, however, will be subnormal 
and the trees will be poor. 
Conditions are much better farther eastward, and in such regions 
as southwestern and southeastern Pennsylvania, parts of West Vir- 
ginia, northern Virginia, Maryland, northern Delaware, and western 
New Jersey reproduction is locally profuse. It is usually found 
along stream courses passing through agricultural lands, pastures, 
or woodlands, although by no means exclusively limited to such sites. 
Along roadsides, the edges of wood lots, fence rows. and. in fact, 
in almost any place where there is protection and sufficient light 
young walnut is likely to be found. In all this region the reproduc- 
tion of walnut is rendered more certain than farther west, on account 
of the fact that the woodlands are not generally grazed here, while 
grazing is the rule in the Ohio Valley and westward. Even in this 
region of maximum reproduction, however, trees above 6 inches in 
diameter are seen much more frequently than seedlings. 
