Some Azote's on Jack Pine. g 



appear at the early age of ten years, but in close stands they do 

 not appear until 5 to 10 years later. This early fruiting partly 

 explains the persistent re-appearance of the tree on areas which 

 have been burnt over repeatedly within the last 60 years. 



Where the soil is deep and loamy, and other conditions are 

 favorable, seed production is delayed, but the increased quality of 

 the seed balances the later fruiting. 



The period of maximum seed production lies between the ages 

 of 40 and 90 years. 



"At a rough approximation a normally developed tree, 15" 

 diameter and 90 years old, would produce annually 300 to 500 

 cones, with 10 to 30 seeds per cone (the larger the cone the more 

 the number of seeds per cone)." It will be seen that seed produc- 

 tion from a mature Jack Pine forest would reach considerable 

 proportions, but as there is practically no reproduction under the 

 mature stand the seed produced counts for little unless the area is 

 burnt over, when the viable seed is at once awakened into activity. 

 Ten days after a fire had passed over the Clearwater country 

 (Summer 1910) Jack Pine seedlings i to 2 inches high were 

 growing (scores of thousands to the acre) over large portions of 

 the district. 



During growing seasons of excessive dryness the production 

 of seed is more abundant than at other times, but no definite 

 alternation of seed years has been observed. 



Cones may persist on the branches from 10 to 25 years, or even 

 longer and are serotinous. It has been said that fire is the only 

 medium by which cones release their seed, but this is certainly not 

 entirely true, for a fair percentage of the cones open when still on 

 the tree, to be sure, after several years ; the cones becomes dry, 

 contract, open and the seed is released. During dry summers 

 many cones are opened when in a wet season they would remain 

 closed. Soon after opening on the tree, limbs bearing cones may 

 be broken oiT by the wind, or trees are blown over and squirrels, 

 etc., bring cones to the ground. Then the sun opens many cones, 

 but a large percentage are never opened until expanded by sudden 

 heat — by fire — when the seed falls on the fresh mineral soil to 

 germinate and restock the area. 



Germinating power of Jack Pine is high, namely, 60% to 7S%' 

 and it is retained for many years, provided the cone is sealed. 



The facility of reproduction after fires, and the inability of 



