Many seeds are not mature enough physiologically to germinate or certain inhibitors may be present. Another type of dormancy is physical dormancy such as a hard impermeable seedcoat. These dormancies are protective mechanisms for the plant that prevent death. If the seeds germinated immediately, most seedlings would not survive the weather extremes of our climate. Methods used to break dormancy in seeds include stratification and scarification.
Stratification uses low temperatures and moisture to duplicate natural conditions.
Scarification uses mechanical abrasion, heat, or acid treatment to modify the seedcoat. In many cases a combination of methods are used. Seed viability of tree species varies from a few weeks to several years. Specifics on seed collection will follow in the next newsletter. Iowa State University , Ames, Iowa.