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Evaluation of sites for the reestablishment of the American chestnut (Castanea dentata) in northeast Georgia, USA

Zhang, Siyu, Bettinger, Pete, Cieszewski, Chris, Merkle, Scott, Merry, Krista, Obata, Shingo, He, Xingyuan, Zheng, Haifeng
Landscape ecology 2019 v.34 no.4 pp. 943-960
Castanea dentata, altitude, blight, deciduous forests, land ownership, landowners, multi-criteria decision making, planning, planting, public lands, seedlings, soil properties, topographic aspect, trees, uncertainty analysis, Georgia
CONTEXT: The American chestnut (Castanea dentata, hereafter called chestnut), a valuable tree species that was once common in the last century in the eastern USA, is currently nearly extinct due to blight. Many efforts have been made to develop blight-resilient seedlings of this species, and an associated challenge is to identify the most suitable sites for its restoration. OBJECTIVES: Our objectives were to identify the suitable sites for planting blight-resistant chestnut seedlings and the environmental parameters associated with the suitability assessment. Furthermore, we considered land ownership due to practical planning and management implications. METHODS: Our study area is located in northeast Georgia, USA. We used global sensitivity and uncertainty analysis to select four environmental factors, as criteria in multi-criteria decision analysis, to create suitability maps for chestnut reestablishment. RESULTS: The results indicate that chestnut is sensitive to elevation, precipitation during the driest month (PDM), normalized difference of water index (NDWI), ground slope, and topographic aspect. Soil attributes did not play a significant role in determining the site suitability. Deciduous forests were the most suitable sites for chestnut reestablishment, while over 99% of the suitable sites fall within the federal lands. The occurrence of chestnut may be expected to increase in areas with high elevations and steep slopes. CONCLUSIONS: This study identifies the most critical environmental variables in northern Georgia for assuring a successful reestablishment of chestnut with the new blight-resistant strains of this species. It also identifies silvicultural prescriptions that may help landowners with the reestablishment process and its success.