Effective methods of regenerating whitebark pine (Pinus albicaulis) through direct seeding
DeMastus, Clay Robert
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Rapidly diminishing populations of whitebark pine (Pinus albicaulis) have sparked efforts to restore this ecologically important species and the communities they support. Current restoration efforts have proven to be costly, time consuming, and labor intensive. Implementation of direct seeding as a restoration method, if found effective, would likely decrease the amount of time, money, and labor expended on these efforts. This study looks at the effectiveness of direct seeding through a series of tests performed at six sites throughout the northern Rocky Mountains. The tests consist of a complete randomized block design with five blocks of eight treatments at each site. Treatments include seed treatments of warm stratification, scarification, and both warm stratification and scarification combined. Caging treatments are also implemented into each block. Testing the effectiveness of seed caching and long term survival rates of outplanted nursery grown seedling versus directly sown seeds was also carried out by planting caches next to nursery seedlings throughout each site. A logistic regression analysis consistently estimated seeds undergoing the warm stratification treatment to have the highest combined germination and survivalrates. Caging was found to be effective at increasing germination under certain circumstances as well as increasing survival possibly due to the shading properties the cages provided. Seed caching did not appear to have an effect on survival of directly sown seeds. Caching also did not appear to have an effect on germination with the exception of one site. Initial results of long term survival rates of outplanted nursery grown seedlings compared to germination and survival rates of directly sown seeds showed higher rates for the nursery grown seedlings. Additional monitoring will be needed to determine long-term survival differences. From the results of this study, it is felt that the implementation of direct seeding of warm stratified seed as a restoration method will be successful and cost effective. Caging, although found effective in this study, is felt to posses more disadvantages than advantages. Its advantages in the aspect of survival could be replaced with other microsite planting techniques. Seed caching, at this time, is not recommended as more research is needed.