Some Notes on Jack Pine. 



II 



Rate of Growth. 



Comparing the following figures and tables derived from 

 studies in Western Ontario with those obtained for Jack Pine for 

 other regions, e. g. Minnesota, and northern Saskatchewan, it is 

 found that relatively the pine of the district compares most 

 favorably with them all, and indeed outstrips the growth in 

 Minnesota, while the Pine of the Lac Seul region is a much 

 inferior tree. It may be said that nowhere else does the Jack 

 Pine reach better development than in the district studied. 



Seedlings grow very little during the first five years of its 

 existence while it is establishing a firm root system needed to 

 compete with the ever thirsty aspen and birch. On well drained 

 soils the sapling soon shows its quick response to favorable con- 

 ditions of soil and light, so that by the first decade it is 8 feet 

 high. 



The annual growth after the establishment of the root system 

 is from i to 1.5 feet. This rate holds fairly uniform for about 

 40 years, after which it steadily decreases, falling to an imper- 

 ceptible amount at 100 years. 



Height of growth is a very good indication of soil conditions, 

 for while on fertile soils the mature tree reaches 80 feet to 86 

 feet, on poor, wet, cold soils a mature height growth of 60 feet is 

 very good. 



TABLE No. 4. 



Height Groivth on Average Soil Conditions. 



The following tables of diameter growth are based on a com- 

 plete stem analysis of one hundred trees taken under fairly aver- 

 age and normal conditions of growth. 



