20 BULLETIN 933, TJ. 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 Eiver 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. 



