f^^)2j FOREST SERVICE 



mummim foust & raue EXPERmm STAnofi 



OCDEN UTAH 



No. 26 December 1955 



^ EFFECTS OF ORIGIN AND STORAGE METHOD ON THE GERMINATIVE 

 CAPACITY OF PONDEROSA PINE SEED 



James D. Curtis, Forester 

 Division of Forest Management 



One of the most vexing problems in the management of ponderosa pine 

 (Pinus ponderosa Laws.) is the difficulty of securing both natural and 

 artificial regeneration in adequate amount. The problem is aggravated 

 by the lack of periodicity of ample seed crops and it therefore becomes 

 necessary to store seed to be used in artificial regeneration for vary- 

 ing lengths of time. While recent work (l) in pollen storage suggests 

 that seed stored suitably may retain its viability indefinitely, prac- 

 ticability and economic necessity frequently dictate mere convenient and 

 conventional methods of storage. 



OTHER IlsrVESTIGATIONS 



Several investigators have reported on the germination of ponderosa 

 pine and other coniferous seed after different periods of storage (2, 

 3^, 5^) and have established useful facts to serve as guides in the han- 

 dling of seed after collection and until the time of sowing. It has 

 been shown that for ponderosa pine: 



a. Stratification in moistened poat or sand will hasten and 

 slightly improve germination of some seed lots. 



b. Germination capacity can be as high as 87 percent after 11 

 to 20 years of storage at a constant temperature not exceed- 

 ing 41° F. 



c. Seed to be stored should be dried to 6- to lO-percent mois- 

 ture content, oven-dry weight basis. 



d. If sxored in dry condition at close to a constant temperature 

 of 40° F., seed can show higher germination than fresh seed 

 from the same lot. 



