Growth Measurement Data for Six Underutilized Tree Species Across Three Cold Hardiness Zones in Florida

Urban warming and increasing variability in cold extremes are reshaping tree performance across Florida, driving interest in assisted range expansion as a strategy for developing climate-resilient urban forests. This study integrated a statewide survey of 310 professionals with a multisite field trial to assess the performance of underutilized tree species—Araucaria heterophylla, Bulnesia arborea, Exothea paniculata, Guaiacum officinale, Krugiodendron ferreum, and Vachellia farnesiana—across three USDA hardiness zones. Species were selected based on survey priorities for hardiness, low maintenance, and drought tolerance, and were planted in April 2023 at Davie (reference site), Gainesville (assisted range expansion), and Quincy (assisted species migration). Survival and growth were monitored through November 2024. Survival varied markedly by site, with 97% survival in Gainesville, 83% in Davie, and only 10% in Quincy. While several species exhibited complete survival at the Davie and Gainesville sites, most failed at Quincy, resulting in species-level survival of 67% for A. heterophylla, B. arborea, and G. officinale, 60% for K. ferreum, and 33% for E. paniculata. Vachellia farnesiana demonstrated the greatest climatic breadth, achieving 87% overall survival and limited persistence at the coldest site. Collectively, these findings indicate that assisted range expansion into climates similar to Gainesville is feasible for a limited subset of species, whereas colder sites remain unsuitable for many subtropical taxa, underscoring the importance of site-specific, trial-based species selection in urban forestry.