32 THE COMMERCIAL HICKORIES. 



LENGTH OF LIFE. 



The hickories are long-lived trees, though not as long-lived as oaks. 

 Pecan probably reaches the greatest age. A tree on the St. Francis 

 River in Arkansas was 382 years old, 146 feet high, and 48 inches in 

 diameter. The section of big shellbark in the Morris K. Jesup collec- 

 tion in the American Museum of Natural History in New York shows 

 340 annual rings. The oldest shagbark and the oldest pignut found 

 grew in West Virginia and were each 350 years old. Mockernut is 

 apparently shorter lived. Several trees, however, in the Mississippi 

 Valley were over 260 years old. Water hickory, nutmeg hickory, and 

 particularly bitternut, are even shorter lived than the mockernut. 

 Mature trees of shagbark and pignut are usually from 200 to 300 years 

 old and grow in the virgin forest' along with white oak and other long- 

 lived species. 



SUSCEPTIBILITY TO INJURIES. 



Though comparatively free from serious dangers and diseases, 

 hickory, in common with all other trees, is subject to various injuries. 



A serious injury from the commercial standpoint, though of little 

 danger to the life of the tree, is what is known as "birdpeck." This 

 is a discoloration of the wood caused chiefly by the work of the sap- 

 sucker, which, especially in the spring, drills into the cambium of the 

 tree after the sap. The hole cuts off the flow of sap, and a black 

 streak from one-eighth to three-eighths inch wide extends a foot or 

 so above and below the wound along the line of the pores affected. 

 This streak probably does not affect seriously the strength or tough- 

 ness of the wood, but it does affect the appearance, and the prejudice 

 against " streaky hickory" is very strong. 



Birdpecks are most prevalent in trees on south slopes and in situ- 

 ations where the sap will flow most quickly on warm winter days or 

 in the early spring. The damage is very extensive, and an immense 

 amount of wood perhaps as much as 10 per cent of the merchantable 

 material is left in the woods on account of birdpeck. 



The living hickory trees support a large number of different kinds 

 of insects, some feeding on the leaves, others on the nuts, and still 

 others on the bark and wood of the twigs, branches, and trunks, but 

 there is only one species responsible for any extensive dying of the 

 trees. This is the hickory barkbeetle (Scolytus quadrispinosus) 

 which, during the past ten years, has been directly responsible for the 

 death of so much of the best hickory timber throughout the area in 

 which the hickory grows, but especially in the northern section of its 

 distribution, from Connecticut to Wisconsin. Wood of the living 

 trees, especially of the younger ones, is injured to some extent by 

 wood-boring grubs or larvre of several species of long-horned beetles 

 of the genus Goes. The wood of dying and dead trees, and of saw- 

 logs, handles, poles, and other unseasoned products with the bark on, 



