Seed sources, seedling culture, and common garden design
Seeds were collected from 30 maternal trees representing 10 populations (3 maternal trees/population; Fig. 1b) occurring across the Pinus strobiformis - P. flexilis hybrid zone in Arizona, Colorado, New Mexico, and Texas (Menon et al ., 2018). Cones were dried and processed prior to seed sowing and the first growth season in the Research Greenhouse at Northern Arizona University as described in Bucholz et al . (2020). Replicates of each maternal family in two gardens were planted into 107 cm × 117 cm × 91 cm raised bed garden boxes constructed at two Southwest Experimental Garden Array (SEGA) common gardens in the Kaibab National Forest, AZ (Fig. 1) also as described in Bucholz et al . (2020). Sets of seedlings from one tree are mixed-sib families (maternal families), and it is unknown whether seedlings within a maternal family are full or half siblings. Further details about seed sources and common garden design are detailed in Bucholz et al . (2020).