USDA Forest Service

Pacific Southwest Research Station

Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Using provenance test data to inform ecological restoration in the Tahoe Basin

Principal Investigators:
Jessica Wright, USDA Forest Service, Pacific Southwest Research Station
Aurore Bontemps, Department of Evolution and Ecology, University of California, Davis
Alejandra Martínez-Berdeja, Department of Evolution and Ecology, University of California, Davis
Johanna Schmitt, Department of Evolution and Ecology, University of California, Davis

Proposal [pdf]

Final Report [pdf]

CDF files and supplemental PDF [zip]

Using the Computable Document Format (CDF) tool [pdf]

Project Summary

Climate change is anticipated to impact California Forests into the future. Meanwhile, the frequency of forest fires is predicted to increase. One result of stand-replacing forest fires is a lack of living trees to produce seeds for the next generation. In these cases, often a Forest will decide to plant trees as part of their post-fire ecological restoration activities. When this decision is taken, managers are faced with the question of where to source their seeds for the reforestation project. Traditionally, the California Seed Zone map, guides planting decisions. Seeds are sourced from a single seed zone and 500 foot elevation band. In the Tahoe Basin, the seed zone is 772. While the seed zone map has existed for over 40 years, and has been used with much success, it is a geographically based system. Given the anticipated impacts of climate change, there is a question of whether or not a more climate-based system is more appropriate. A climate-based system could take into account both current climate, as well as modeled predicted climate.

The question of using climate to source seeds for ecological restoration is the focus of this project. This question is important to managers on the Basin who need to think about a 100 to 200 year rotation in any planting project. If current models are right, the climate experienced by those trees in 200 years will be very different from the climate they are experiencing today.

To tackle that question, we turned to the best source of data currently available- provenance tests. Provenance tests involve sources of trees from across the species range (or a smaller, focal part of the range), planted into a common garden or gardens. The trees are measured for growth and survival on a regular basis. By comparing trees from different sites, we can gain an understanding of how the source of origin is related to growth patterns. In this report we assess how effectively we can use climate to describe tree performance.