216 NEBRASKA STATE HORTICULTURAL SOCIETY. 



Black Walnut. — Seedlings from some states were injured during the 

 first winter in the nursery and have been injured more or less severely 

 every winter since. The trees from other states have never been appre- 

 ciably injured, even in the severest winters. The illustration, figure 5, 

 shows this difference well. The photograph was taken June 1, 1904, as 

 the trees were starting on their eighth season of growth after having 

 passed through a comparatively mild winter. Most of the injury shown 

 in the case of the South Carolina and Georgia trees occurred during 

 the more severe winter of 1902-03, as seen in figure 5 at a and b, but 

 there was some injury in the following winter, 1903-04, as shown in 

 figure 5 at c, d, e, f, and g. It is also noticed from the illustration that 

 the trees from South Dakota and Nebraska seed suffered no injury during 

 either of these winters, the growth being continued in each case from 

 the terminal bud. 



That there is a direct connection here between winter injury and 

 degree of maturity may be seen from figure 6, which is from a photo- 

 graph taken September 30, 1902. The tree from South Dakota seed was 

 well prepared for winter, having ripened both its twigs and its 

 leaves. The Nebraska tree was not far behind. It had lost most of its 

 leaves. The trees from North Carolina, South Carolina, and California, 

 on the other hand, were still in an immature growing condition, having 

 lost scarcely a leaf. Figure 7 shows the condition of the young twigs 

 of trees from South Dakota and South Carolina some ten days earlier. 

 Even at this early date the South Dakota tree had lost most of its 

 leaves. Figure 8 shows that by October 15th the Nebraska tree had 

 lost all its leaves, while the trees from California and Oklahoma seed 

 were no more nearly ready for winter than the South Dakota tree was 

 a full month before, and the trees from South Carolina, North Carolina, 

 and Georgia had even then lost almost none of their leaves. As a 

 matter of fact, they actually held their leaves some two weeks longer 

 and finally got ready for winter after the Nebraska tree had been ready 

 a month and the South Dakota tree had been waiting a good six weeks. 



That the difference in the time of shedding the leaves is accompanied 

 by a real difference in the maturity of the new growth of these black 

 walnut trees may be seen from figure 9. The twigs are shown as they 

 appeared September 19, 1902, after the leaves had been removed. The 

 terminal buds were well developed in the South Dakota and Nebraska 

 twigs and the wood was thick and firm, while in case of the twigs from 

 South Carolina and North Carolina trees the terminal buds were imma- 

 ture and the layer of wood near the top scarcely differentiated from 

 the pith. 



The fall maturity and the winter injury of trees from all the states 

 represented in the test have been noted a number of times during the 

 nine years' growth of the trees. From all these observations the trees 

 from the different states are rated as to the earliness of their maturity 

 in fall and also according to their resistance to cold during winter. 



