Natural tree populations spend many generations adapting to their home climate.  Climate change is predicted to exceed natural rates of population adaptation causing maladapted populations.  Inter-tree competition may compound this, reducing growth and species population survival.  This study evaluates 36 natural populations of Juglans nigra distributed across the native range in a common garden experiment.  Generalized mixed linear models were developed; predicting tree growth and survival as a function of additive and interactive climate-competition effects.