WHITE PINE IN MIXTURE 25 



Of other coniferous trees, growing with 

 White Pine in Pennsylvania, the Jack or Pitch 

 Pine (Pinus rigiday Mill.) is the most com- 

 mon. It inhabits poor soils on the tops of 

 ridges and on high plateaus. It requires a great 

 amount of growing space, and regularly estab- 

 lishes itself in open groups. In intimate mix- 

 ture with White Pine it is usually suppressed 

 before reaching the age of fifty years. Occa- 

 sionally it occurs in patches within White Pine 

 groups. The ground under the Pitch Pine 

 woods is almost always badly covered with 

 shrubs and forest weeds. Thriving as it does 

 upon the very poorest of soils, and withstand- 

 ing fire better than any other tree of the region, 

 the Pitch Pine abundantly deserves the atten- 

 tion of foresters. 



The Norway or Red Pine {Pinus resinosa, 

 Ait.) resembles the White Pine in many re- 

 spects. It occurs only scatteringly in the sec- 

 tions of Pennsylvania under consideration. In 

 rapidity of growth it is not far behind the 

 White Pine, and it is further characterized by 

 the production of excellent timber and a very 

 straight stem. 



Yellow or Scrub Pine {Pinus virginiana, 

 Mill.)y was found so sparingly that no study of 

 its growth was made. 



