2012 Coeur d’Alene Nursery WBP Stratification Trial

Project: Coeur d’Alene Nursery Whitebark Pine Stratification Trial

AttachmentsVarious_McLaughlin_Powerpoint    Various_McLaughlin-Robertson_Whitebark Pine for National Nursery Proceedings

Agency/Forest or Park/District: FS Coeur d’Alene Nursery, Coeur d’Alene, ID

Project coordinator: Marie McLaughlin

Contact: Nathan Robertson; Nursery Horticulturist, CdA Nursery; 3600 Nursery Road, Coeur d‟ Alene, Idaho, 83815; (208)765-7396; ndrobertson@fs.fed.us


The Coeur d‟ Alene Nursery partners with Forests within Region 1, as well as Forests in adjacent Regions and state and local cooperators to restore native plant communities and ecosystems.

Source of funding /amount

FHP: $6,360

Supplemental funding: Additional funding in the amount of $4,500 was provided by the CdA Nursery toward additional costs incurred from salaries, supplies, structure maintenance/heating/ventilation, etc.

Dates of restoration efforts

This study was conducted during the 2012 growing season at the CdA Nursery. Seeds began the stratification process in October, 2011, and continued until January/February, 2012, at which time the seedlings were planted and monitored for germination success. Data collection for this study was completed in summer, 2012. However, seedlings delivered to outplanting projects in fall, 2013 and spring, 2014 will continue to contribute to the restoration of this species for the remainder of their lives.


The Coeur d‟ Alene Nursery is a leader in whitebark pine container seedling production and continues to make efforts to increase the efficiency and economy of production practices for this unique conifer species. However, production efforts at the Nursery are compromised by difficult stratification requirements for whitebark seed, inconsistencies in germination, and very exacting seedling growing condition requirements. Despite continued efforts to streamline production and reduce costs to clients, this species continues to be our most expensive product. Efforts to reduce cost have and continue to focus on increasing germination uniformity. Additional effort toward studying differing stratification methods and timelines will allow the Nursery to better achieve a uniform whitebark seedling crop on a consistent basis while minimizing losses to germination failure and crop variability due to latent germination.

Acres/ha treated  N/A


The current protocol for stratifying whitebark pine seed is proving inadequate to provide consistent, uniform germination. It is the consensus of the Nursery staff that additional or different stratification procedures be tested for efficacy in increasing germination uniformity. To this end, we plan to create a study, in which 5-8 operational seedlots scheduled for grow-out would be subjected to 3-5 different stratification regimes. One of these being a control strat process currently used by the Nursery; the others would have varying lengths, incorporate freeze-thaw cycles, or both. These treated seedlots would then be planted into operational whitebark production greenhouses and monitored for differences in germination, including initial germination, apparent latent germination, and germination of restratified seed.

Planting? If so, source of seedlings? Resistance?

Due to the operational nature of the CdA Nursery, this study was conducted as part of a larger seedling production effort. Therefore, seed sources varied according to Region 1 and Region 4 seedling needs, and included multiple sources and potential resistance types (see Outcome).


Nursery staff determined that a study comparing the outcomes of two stratification protocols for WBP be tested for efficacy using operational seed lots from across Regions 1 and 4. The results of this study were presented at the 2012 National Nursery Symposium in Bend, Oregon, September, 2012. These results are also being published in the 2012 National Nursery Proceedings.

Monitoring since completion of the project

Due to the nature of this study, no additional monitoring was required after the initial collection of germination data. No plans for future monitoring are in place.

Will outcome meet goals?

Information relating to the interaction of stratification time, seed source, seed age, and germination potential will continue to be a topic for study at the CdA Nursery. However, the results of this study are helping the staff meet production goals efficiently, and serve as a base from which to investigate further stratification and scarification protocol refinement.

Future actions/follow up?

Additional studies relating to the timing of scarification (pre-cold stratification vs. post-cold stratification) are currently underway at the Nursery, as are trials using a 24-hour, 86 degree seed treatment to improve germination uniformity in operational whitebark sowings.

Miscellaneous comments

Thank you for funding this research effort! We look forward to continuing to provide restoration-quality whitebark pine seedlings for the northwest. Research efforts like these allow us to streamline and economize production, and will eventually reduce the cost of these valuable seedlings.