This study aimed to delineate the seed transfer zone of Pinus densiflora. After generating transfer functions based on growth characteristic data from 10 pine test sites for 36 seed sources and six bioclimatic variables, the critical seed transfer distance for each climate variable was calculated. Based on our results, seed transfer zones were delineated by overlaying maps for all climate variables. In the pine provenance test, seeds from eastern Korea generally showed superior growth at each test site. Temperature-related variables accounted for a higher proportion of the selected bioclimatic variables than precipitation-related variables. Additionally, warm-to-cold seed transfer in eastern Korea and cold-to-warm seed transfer in central and southern Korea were overestimated, widening the seed-transfer zone. Examining the long-term growth of the trees, introducing additional variables, and applying a model with a higher level of rationality to the transfer function are necessary for delineating the optimal seed-transfer zone.

Multi-stem Korean red pine (Pinus densiflora f. multicaulis Uyeki) is known as the forma of Korean red pine and is distributed in both Korea and Japan. Unlike Korean red pine having one or two main stems, it grows with many stems which are branched from the lower part of the tree trunk. Owing to its unique stem shape and ornamental value, it has been used as a precious ornamental tree. A total of 14 individuals with distinct characteristics were collected between 1998 and 2000 to develop new cultivars in Pinus spp. with high added value. After asexual propagation through grafting, at least 20 seedlings per tree were planted in a test field and the phenotypic characteristics were investigated. Based on the results, three individuals were re-selected and tested for uniformity and stability for 3 years. Finally, one individual with evident conical crown form was renamed as ‘Yedasol’ and was registered as a new cultivar in 2021. In addition, ‘Yedasol’ has high ornamental value derived from its thinly cracked gray-brown bark, soft needle leaf, reddish-purple male strobilus, and dense cone arrangement (Registration No. 255).