NORWAY PINE IN THE LAKE STATES. 5 



the thousand board feet. In northern Minnesota the average tree in 

 mature timber over 200 years old measured 18.7 inches in diameter. 

 Norway pine does not grow very tall. On the sandy soil of the region 

 a tree from 200 to 250 years old occasionally reaches a height of from 

 90 to 120 feet. The tallest tree recorded was 150 feet high, but the 

 accuracy of this measurement is questionable. 



The oldest tree found was 307 years old, and but few over 280 years 

 were encountered. Norway pine, however, seems to decline in vigor 

 after it reaches an age of from 200 to 230 years. 



TOLERANCE. 



For their best development Norway pine seedlings should have 

 direct sunlight. They can not endure as much shade as those of white 

 pine, but will grow in a moderate shade under a jack-pine stand, and 

 exact less light than the latter species. In small, natural openings 

 in a Norway pine stand a few white-pine trees will seed up the ground 

 ahead of Norway. This intolerance partly accounts for the earlier 

 and more thorough pruning of the latter. Even in pure stands on 

 poor soil early and clean pruning is the rule. The wind also plays a 

 part in pruning by swaying the tall, slender-boled trees, the branches 

 of which are thus brushed off in contact with those of neighboring 

 trees. This is especially the case when Norway pine occurs in mix- 

 ture with hardwoods. In its light requirement Norway pine may be 

 considered as halfway between "very intolerant" and "intermedi- 

 ate." * As a means of comparison, the classification in regard to 

 demands upon light of a few other species may be given. Balsam fir 

 is classed as very tolerant, beech tolerant, white pine intermediate, 

 Norway pine and red oak intolerant, and tamarack and cottonwood 

 very intolerant. The intolerance of Norway pine is indicated by the 

 occurrence of its reproduction; under a shade density of over 0.5 as 

 a rule it does not reproduce. It begins to reproduce abundantly 

 when the density falls to 0.3. 



REPRODUCTION. 



Norway pine seedlings need some protection against extremely hot 

 winds and drought. On the other hand, if there is too much under- 

 growth or shade from the parent stand the young growth will suffer. 

 In plantations, however, it was found that Norway pine seedlings will 

 stand sun, exposure, and weeds much better than will those of white 

 pine. 



Norway pine produces seed in abundance only at intervals of from 

 3 to 5 years. The seed falls in September and early October. Seed 



1 For a discussion of tolerance see Forest Service Bulletin 92, "Light in Relation to Tree Growth," by 

 Raphael Zon and U.S. Graves. 



