94 



ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 51 



Fig. 86. — White pine is 

 called a five-needle pine be- 

 cause its needles are pro- 

 duced in bundles of five (right 

 inset) and each bundle is 

 held together by a common 

 sheath. Left inset shows nu- 

 merous bundles of needles at- 

 tached to the tip portion of a 

 branch. 



and about V-> inch long. By July of their second year these green 

 cones are 4-6 inches or more in length and hang downward on 

 long stalks. They turn brown and shed their seeds by autumn 

 and drop to the ground during the following winter and spring. 

 The dark gray bark of white pine is fairly thick on large trees 

 and is divided into broad, continuous ridges by shallow% longi- 

 tudinal, connecting fissures. 



White pine is used extensively as a specimen tree in orna- 

 mental plantings. However, it is susceptible to the destructive 

 white pine blister rust disease which has been found in some 

 plantings in northern Illinois. Also, some insects such as sawfly, 

 white pine weevil, pine needle scale, and pine bark aphid may 

 attack white pines. 



Jack pine, with its ragged outline, may grow to a height of 

 only 15-40 feet and have a broad, open, stunted, irregular crown, 

 or grow to a height of 60 feet and become picturesque with age. 

 This tree thrives on poor, dry, sandy or rocky soil. The stout, 

 stiff, %- to 114-inch-long needles, sometimes curved and twisted, 

 grow in bundles of tw^o. The pollen-bearing cones are oblong and 

 occur in clusters at the base of the new growth. The smaller seed- 



