This study was conducted to quantify the carbon storage in each pool (including trees, forest floor, and soil) and to analyze the carbon cycle in a Chamaecyparis obtusa (Siebold and Zucc.) Endl. forest according to different thinning intensities. The study site was located in Gochang-gun, Jeollabuk-do, and the treatments consisted of a control (Con), a light thinning (LT), and a heavy thinning (HT), based on 3000 trees originally planted per hectare. As stand density decreased, total C storage decreased, and the annual C storage of trees and C released through soil respiration significantly increased. Net ecosystem production (NEP; Mg·C·ha⁻¹·year⁻¹), as the difference between net primary production and microbial respiration, was 1.95, 2.49, and 2.11 in the Con, LT, and HT treatments, respectively; i.e., the LT stimulated greater NEP than the Con and HT treatments. While these results show that thinning decreases total C storage of forests, proper thinning enhances carbon uptake capacity. In addition, this study can be a basic reference for the effects of thinning on forest carbon cycles. Repeated measurements of each C pool should be performed over multiple years to see the exact movement patterns of forest carbon in the future.

Climate change has been transforming forest ecosystems globally, affecting the sustainability of conventional forest management practices. This study investigates the suitable forestation area (SFA) for Larix kaempferi and Chamaecyparis obtusa and their growth potential in South Korea under various climate change scenarios. Using species distribution models (SDMs) based on machine learning ensembles, we analyzed potential spatial shifts in the climatic suitability for these species. Growth models based on field data were also developed to evaluate growth variation between Köppen–Geiger climatic zones. The results indicate a substantial reduction in the SFA for L. kaempferi, with its habitat range confined to high-altitude regions due to rising temperatures. In contrast, the forestation potential for C. obtusa is predicted to expand nationwide, particularly in inland areas, under climate change scenarios. However, extreme increases in temperature and atmospheric CO₂ concentrations exceeding 600 ppm may inhibit growth, highlighting the need for the development of adaptive management strategies. This study provides useful information for climate-resilient forestation planning by combining growth-weighted suitability indices with projected habitat shifts. These findings emphasize the importance of prioritizing high-altitude conservation zones for L. kaempferi and employing C. obtusa for inland afforestation as a means to ensure sustainable forest management and carbon neutrality objectives.

Climate change drives shifts in forest vegetation zones, and the major tree species of warm–temperate evergreen broad-leaved forests in South Korea are also expected to undergo changes in their potential distributions under future climate conditions. This study applied a Committee Averaging (CA) ensemble species distribution model to Quercus acuta, Machilus thunbergii, Quercus glauca, and Castanopsis sieboldii to project changes in their potential distributions under four Shared Socioeconomic Pathway (SSP) scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) across two future periods (2050s and 2090s). To compare interspecific differences in response more clearly, we applied a two-tier threshold scheme that distinguished potential habitat (agreement ≥0.6) from highly suitable habitat (>0.8), and we concurrently conducted a Multivariate Environmental Similarity Surface (MESS) analysis to assess predictive uncertainty arising from extrapolation into future climates. The CA ensemble models showed excellent predictive performance (AUC 0.947–0.989; TSS 0.837–0.943). For Q. acuta, M. thunbergii, and Q. glauca, potential habitat expanded consistently across all SSP scenarios, and highly suitable habitat shifted northward into parts of the central and Gangwon regions. In contrast, both the potential habitat and the highly suitable habitat of C. sieboldii contracted under most future scenarios. These results demonstrate that even species belonging to the same warm–temperate evergreen broad-leaved forest community can respond differently to future climate. The two-tier threshold scheme applied in this study was effective not only for assessing whether distributions expand but also for delineating and evaluating climatically stable core habitats. Although our findings need to be interpreted in light of the uncertainty associated with extrapolation into future climates, they can serve as useful baseline data for establishing climate-change-adaptive forest conservation and species-specific management strategies.