Some Common Hardwoods. 



401 



The study suggested that the value of r lay between 2 and 2.5. 

 If the value be 2 then the expansion of the crown is a linear func- 

 tion of time. This is interesting ^hen we remember the curves 

 for both height and diameter. If the value of /• be 2, then it 

 takes double the time to double the crown, and when the crown 

 reaches 32 feet in diameter there is an abrupt termination of 

 lateral growth. This deduction is an objection to the suggested 

 manner of expansion of the crown. Yet we are familiar with the 

 apparent constancy of the size of the crown of mature trees. A 

 detailed study of the sapling forests does not reveal any rapid 

 expansion of the crown comparable to the growth in height and 

 diameter. The relation between crown class and age seems to be 

 that at about 8 years the 4 ft. crown class has reached maximum 

 congestion and suppression occurs, and about 16 years the 8 ft. 

 crown class is congested. From these figures we find that the 32 ft. 

 crown class would be reached in 64 years. This seems somewhat 









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