Populations of forest trees and other native plants are genetically different from each other, and adapted to different climatic conditions. Therefore, natural resource managers must match the climatic adaptability of their plant materials to the climatic conditions of their planting sites. Generally, local populations are optimally adapted to their local climates, or nearly so; thus, local seed sources are usually recommended for reforestation and restoration. Typically, this has been accomplished using geographically defined zones (e.g., seed zones or breeding zones) or seed transfer rules that specify a geographic or climatic distance beyond which populations should not be moved. However, these recommendations assume that climates are stable over the long-term—an assumption that is unlikely given projected climate change.

Because populations are genetically adapted to their local climates, the health and productivity of native or newly established ecosystems will likely decline as climates change. Climate models are now available that can be used to define zones based on climate rather than geography, or calculate climatically based seed transfer limits. Once climatic transfer limits have been defined, natural resource managers can explore options for responding to climate change through assisted migration.

This web tool was tailored for matching seedlots and planting sites, and can be used to map current or future climates based on selected climate change scenarios. Although it was designed for seedlot selection, it can be used by anyone interested in mapping climates defined by temperature and water availability. The SST allows the user to control many input parameters and can be customized to reflect the management practices, climate change assumptions, and risk tolerance of the user.

The tool is currently available for western North America. Its developers are working to expand the geographic extent to include Alaska and eastern North America. The SST is most valuable as a planning and educational tool because of the uncertainty associated with climate interpolation models and climate change projections. 

SST Steps:

1. Select Objective: Find seedlots for your planting site, or planting sites for your seedlot

2. Select Location: Click on the map or enter coordinates to locate your seedlot or planting site

3. Select Climate Scenarios: Select historical, current, or future climates for your seedlots or planting sites

4. Select Transfer Limit Method: Enter a custom limit or use an existing zone to calculate a transfer limit

5. Select Climate Variables: Use a variety of climate variables to match your seedlot or planting site

6. Map Your Results: The map shows where to find appropriate seedlots or planting sites