FOREST TREE SEED AND SEED COLLECTING 101 



better the seed year the larger the yield. Cox l gives the follow- 

 ing as the average yield in pounds per bushel of the fruits of 

 different species: 



Douglas fir 1 . 25 Western red cedar . 75 



Western yellow pine 1 .50 Black walnut (husked) ... 40.00 



Engelmann spruce 0.80 Butternut (husked) 40.00 



Lodgepole pine 0.25 Shagbark hickory 30.00 



Sugar pine 1 . 60 Bitternut hickory 40 . 00 



Western larch 0.50 Pignut hickory 40.00 



Sitka spruce 1 .25 Red oak acorns (clean). . . 50.00 



Western white pine 1 . 00 White oak acorns (clean) . 70 . 00 



Red pine 1 .00 Chestnut (clean) 50.00 



White pine 1 . 10 



The available data is too fragmentary to develop a compre- 

 hensive table showing the average yield per bushel'of fruit and 

 the average cost per pound for collecting tree seed. The table on 

 page 102, compiled from various sources, shows the results obtained 

 from a number of specific collections of coniferous species, collected 

 in varying amounts at different times. 



" \ 

 10. The Degree of Ripeness and the Age of the Seed in 



Relation to Quality 



All seed should be thoroughly ripe before harvesting. Usually 

 for economic reasons the sooner it is gathered after ripening the 

 better. Seed gathered a short time before maturity is not neces- 

 sarily infertile, although invariably its vitality is impaired and it 

 produces weak and inferior seedlings. 2 It is, therefore, highly im- 

 portant in the purchase of seed to know whether it was thoroughly 

 mature when gathered. 



In some species as in oak, hickory, ash, and maple, the color of 

 the fruit is indicative of ripeness. In other species as in most 



1 Cox, W. T.: Reforestation on the national forests. (U. S. Forest Service, 

 Bui. 98. 1911.) 



2 In the spring of 1904, the author gathered 100 fruits of the silver maple 

 7 days before maturity and planted them at once. A week later an equal 

 number of the mature fruits was gathered from the the same tree and planted. 

 On the eighth day after planting 79 per cent of the immature seeds germi- 

 nated, while 92 per cent of the mature seeds germinated on the sixth day 

 after planting. The seedlings from the mature seeds were more robust and 

 made more rapid growth. Two weeks after the mature seeds germinated 

 the seedlings averaged more than twice as large as those from the immature 

 ones. 



