The U.S. Forest Service, Oregon State University, and the Conservation Biology Institute have launched a free web-based decision-support tool to help natural resource managers match seedlots (seed collections from a known origin) with planting sites based on climatic information.  The new web-based mapping application, called the Seedlot Selection Tool (SST), can be used to map either current climates or future climates based on selected climate scenarios. The tool is particularly valuable for considering options for responding to climate change. Because plant populations are generally considered to be locally adapted, climate change will likely lead to declines in health and productivity of native ecosystems. The SST will allow consideration of seedlots that may be adapted to future climates, a management option often referred to as assisted migration or assisted gene flow.