22 BULLETIN 244, IT. s. DEPARTMENT OF AGRICULTURE. 



successive generations of coppice have been definitely identified ; but 

 beyond this, evidences of the past history of the tree become greatly 

 obscured. In the third generation of sprouts the rate of height 

 growth appears to be undiminished. Practically all of the root 

 system is utilized by the new generation. As an effect of the root 

 energy and stored-up food, the rate of early height growth is remark- 

 ably rapid and, within limits, increases with the age of the parent 

 tree when cut or burned back. As a rule, during the first two to four 

 years, depending upon the age of the parent, the sprouts make up 

 completely for the previous loss of time in growth. The most rapid 

 height growth observed was in a 4-year-old fire sprout stand, many 

 trees being from 5 to 8 feet in height and the tallest -9.6 feet. The 

 growth in height of thrifty stands of fire coppice, based on measure- 

 ments of both trees and whole stands up to 18 years old, is shown in 

 Table 6. The age at which trees of sprout origin grow at approxi- 

 mately the same rate as seedling trees is not precisely known. Under 

 average conditions this point is perhaps between the fifth and ninth 

 years. In general, the great acceleration in growth in fire sprouts 

 takes place at approximately the same rate in diameter and volume 

 as in height. 



CAUSE AND METHOD. 



Fire and cutting are the chief external causes for the sprouting of 

 shortleaf pine. The physiological cause lies in the capacity of short- 

 leaf pine to develop on the upper portion of the root and lower portion 

 of the stem special reproductive buds, at least one of which has the 

 same function as the central terminal bud on the stem. 



The double crook, at the upper end of the taproot of shortleaf pine, 

 characteristic of and always present in young trees, seems to be inti- 

 mately associated with its power of reproduction by sprouts. By 

 means of this double crook a horizontal section from 1 to 3 inches in 

 length, varying with the age, is formed at the upper end of the tap- 

 root. This form persists during the first 8 to 12 years, after which its 

 identity becomes lost through the increasing thickness of the annual 

 accretions. It is significant that the capacity for sprouting is coinci- 

 dent with the period during which the root maintains this character- 

 istic form. During this period adventitious stem buds are present 

 and may readily be seen along the horizontal section of the root. 

 The corky bark here is unusually thick, affording a high degroo of 

 protection against ordinary fires. 



The killing of the stem is followed by the development of a colony 

 of sprouts at the base of the stem and top of the taproot, usually from 

 6 to 1 2, as shown in figure 8, and not infrequently 1 6 to 20. Normally 

 one stem (occasionally two) assumes the function of leader, the others 

 being more or less procumbent in habit and serving as laterals or 



