Periods of past climate change offer us opportunities to investigate actual responses of organisms that can inform predictions of future responses. Three complementary approaches to inferring past responses are phylogeography, paleoecology, and ecological niche modeling (Gavin et al. 2014 New Phytol). We are particularly interested in bringing the latest genomic tools, large fossil databases, and increasingly fine-scale climate data together to infer demographic and adaptive evolutionary responses to changing environments since the last Ice Age. In earlier work, we have combined fossil (Gugger & Sugita 2010 QSR) and genetic data (Gugger et al. 2010 Mol Ecol, 2011 New Phytol) to infer responses of Douglas-fir (Pseudotsuga meziesii) to glacial-interglacial climate cycles and ancient geological change. We have also combined genetic data with niche models in California oaks to understand how past and present climates have influenced genetic diversity (Gugger et al. 2013 Mol Ecol; Ortego et al. 2012 Mol Ecol; Riordan et al. 2016 AJB) and speciation (Ortego et al. 2015 Mol Ecol).