FOREST TREE SEED AND SEED COLLECTING 



97 



of the tree; the fullness of the crop in different seasons, and differ- 

 ences in site, the trees on good sites producing larger seed than 

 trees on poor sites, and the seeds from one locality averaging larger 

 than those from another. The extreme variation in the size of 

 fertile seed in most species is rarely greater than 1 to 3 and usually 

 is less than 1 to 2. 



The author in his studies on the variation in the size of conifer- 

 ous seed of the same species from widely separated localities has 

 affirmed the conclusions of Rafn, 1 that seed collected at the north- 

 ern extension of a tree's range is usually smaller, and of Cieslar, 2 

 that the seed of a given species from high elevations is consider- 

 ably smaller than that from the lowlands. The following shows 

 the average size of the seed of three species collected in different 

 states and based upon the number of clean seeds per pound. 



Western yellow pine (South Dakota) 13,500 



Western yellow pine (California) 8,260 



Lodgepole pine (Montana) 109,600 



Lodgepole pine (California) 43,960 



Western white pine (Northwest Idaho) 19,100 



Western white pine (California) 10,250 



The variation in the size of western yellow pine seed is as 

 follows : 



1 Rafn, Johannes: The testing of forest seeds during 25 years. (Printed 

 by the author for private circulation.) 1915. 



2 Cieslar, A.: Uber die Erblichkeit des Zuwachsvermogens bei den Wald- 

 baumen. (Centralblatt f. d. gesamte Forstwesen, S. 7-29. 1895.) 



