FIGURE 6 - Bi-plots showing (a) predicted variation in genetic composition from GF-X and (b) variation in untransformed environmental conditions (each colored point is a climate grid cell within a subset of the range of balsam poplar containing the sample populations). Locations of the 42 populations within each of these spaces are indicated by three letter population codes. The VT and IH common gardens are indicated by a red dot and red triangle respectively. Colors in (a) represent gradients in genetic turnover derived from transformed environmental predictors; locations with similar colors are expected to harbor populations with similar genetic composition. In (b), color similarity corresponds to environmental similarity uninformed by genetic patterns. Labeled vectors indicate the direction and magnitude of gradients with greatest contribution (y=latitude, elev=elevation, bio2=mean diurnal range, bio10/bio11=mean summer / winter temperature, bio18/bio19=summer/winter precipitation). Genetic offsets are approximately the Euclidean distance from each population to the common gardens in (a), whereas climate transfer distances are approximately the Euclidean distance from each population to the common gardens in (b), though note that variation in higher dimensions is not shown.