Assessment of Climate-Related Decline in Subalpine Conifers of South Korea Using a Field-Based Scoring Framework

Subalpine conifer forests in South Korea are increasingly exposed to climate-related stress, yet simple and repeatable field criteria for describing tree decline remain limited. Here, we propose a field-based scoring framework for assessing observed decline status in three subalpine conifer species: Abies koreana, Abies nephrolepis, and Picea jezoensis. Field surveys were conducted in major subalpine regions, and nine visually observable tree-condition indicators were recorded from pre-classified healthy and decline-affected populations. Among the evaluated indicators, vigor, crown form, branch dieback, and resin secretion showed the clearest and most consistent differences between the pre-classified groups. Finally, these four indicators were used to calculate a core decline-condition score on a five-point scale, with higher scores indicating more severe observed decline symptoms. The score showed internal consistency with the field classification of the surveyed populations. Thus, the proposed framework provides a practical starting point for rapid field screening and future integration with physiological or molecular indicators of stress responses in subalpine conifers.