To identify the reference ecosystem conditions of a damaged forest, we developed a community development scenario using a syntaxonomic approach. To facilitate this choice, we sought to provide a framework based on ecological theory, specifically on the relationship between vegetation and environmental properties. We identified forest composition species in 216 sample plots from Mt. Gariwang, a representative temperate deciduous forest in South Korea, and divided them into 13 species groups, including the Quercus mongolica Fisch.-Fraxinus rhynchophylla Hance community and eight vegetation types. In addition, nine major environmental properties that explain community composition, including elevation, were identified through multivariate analysis. A physiognomy map enabled the identification that the area must be large and the habitat must be continuous to help determine the reference ecosystem. In conclusion, plant–environmental interaction analysis is a valuable tool for identifying reference communities or source locations for seed migration in relation to various habitats. These reference ecosystems provide insights into the restoration of damaged areas and an overview of important considerations for restoring the relationships between biodiversity and ecosystem function.

Kiwoong Lee, Soon Jin Yun, Minsoo Kim, Hee Moon Yang and A Reum Kim*. J Ecol Environ 2024;48:. https://doi.org/10.5141/jee.23.079

Trees in degraded forest areas are generally exposed to water stress due to harsh environmental conditions, threatening their survival. This study simulated the environmental conditions of a degraded forest area by constructing an artificial rainfall slope and observing the physiological responses of Pinus densiflora to control, mulching, and waterbag treatments. P. densiflora exhibited distinct isohydric plant characteristics of reducing net photosynthetic rate and stomatal transpiration rate through regulating stomatal conductance in response to decreased soil moisture, particularly in the control and waterbag treatments. Additionally, the trees increased photochemical quenching, such as Y(NPQ), to dissipate excess energy as heat and minimize damage to the photosynthetic apparatus. However, these adaptive mechanisms have temporal limitations, necessitating appropriate measures. Under extreme drought stress (DS45), mulching treatment showed 4.5 times and 2.2 times higher in PI_abs and SFI_abs than in the control, and after the recovery period (R30), waterbag and mulching treatment showed similar levels, while PI_abs and SFI_abs in the control were only 45% and 75% of those in the mulching and waterbag treatments, respectively. Specifically, mulching extended the physiological mechanisms supporting survival by more than a week, making it the most effective method for enhancing the planting ground in degraded forest areas. Although the waterbag treatment was less effective than mulching treatment, it still significantly contributed to forming better growth conditions compared to the control. These findings highlight the potential for mulching and waterbag treatments to enhance forest restoration efforts, suggesting future research and application could lead to more resilient reforested areas capable of withstanding climate change-induced drought conditions.

Identifying suitable habitats for ecosystem restoration is critical for conserving globally threatened biodiversity. Baseline data on the distribution and range of biogenic habitat-forming species at high spatial resolution are essential for informing habitat management strategies and preserving ecosystem integrity. We identified suitable sites for habitat restoration by integrating community ecological data for Quercus mongolica Fisch. ex Turcz., a valuable restoration tree species, with insights from ensemble modeling. Habitat suitability was predicted using an ensemble species distribution model. A total of 89 occurrence records and nine environmental variables were used to develop the single algorithm models. Model performance was assessed using the Receiver Operating Characteristic (ROC) curve and the True Skill Statistic (TSS). Future habitat suitability was evaluated using projected climate change scenarios. Under more extreme climate change scenarios, the future suitable habitat of Q. mongolica is projected to gradually contract toward the high-altitude areas of Mt. Gariwang. The primary environmental variable is elevation, and rising temperatures due to climate change negatively impact habitat suitability for Q. mongolica. Therefore, adaptation measures must be established to mitigate these impacts, such as protecting the reference ecosystems of Q. mongolica. This integrated approach offers a nature-based solution for guiding climate change-integrated restoration programs in Mt. Gariwang and globally.

Forest thinning is a critical silvicultural practice for managing forest structure and enhancing various ecosystem services, yet its long-term impacts on trade-offs among these services remain complex. This study evaluated ecosystem services 17 years after thinning (applied in 2007) in a 40-year-old Pinus koraiensis plantation on Mt. Gari, Republic of Korea, to evaluate the effects of thinning on ecosystem services and to examine the magnitude of trade-offs between ecosystem services across different thinning treatments. Three thinning treatments were implemented in 2007: (1) control, (2) light thinning (~35% removal of stand density), and (3) heavy thinning (~65% removal of stand density). A total of 12 plots were established to assess ecosystem services 17 years after thinning. Measured variables included aboveground carbon storage (trees), understory species richness (shrubs and herbs), soil moisture, soil organic carbon, and total soil nitrogen. Relative benefits and trade-offs were quantified using standardization and root mean square error, and differences across treatments were tested using one-way. Relative benefits and trade-offs were analyzed to assess the effects of thinning on ecosystem services and how relationships among ecosystem services changed across treatments. Significantly higher aboveground carbon storage was observed in the control plot than in the other plots. The heavy-thinning plots showed the highest values for species richness and soil moisture, whereas the light-thinning plots showed the highest values for soil organic carbon and total soil nitrogen. Generally, high trade-offs were observed for pairs involving aboveground carbon storage, while pairs involving species richness showed lower trade-offs. To detect clear relationships among ecosystem services, further in-depth research and long-term monitoring are required to identify complex interactions and trade-offs.

This study investigated the effects of thinning intensity on tree radial growth and physiological responses to drought in an approximately 43-year-old Pinus koraiensis plantation. To analyze tree-ring width, a total of sixty wood cores (5 mm) were collected from three thinning treatments applied in 2007: control (Con), light thinning (LT), and heavy thinning (HT). Drought vulnerability indices were examined across three distinct drought periods (2000–2001, 2007, and 2014–2016), and intrinsic water use efficiency (WUE_i) was estimated from stable carbon isotope analysis (Con vs. HT). Thinning increased basal area increment (BAI) in both the LT and HT groups, with the strongest and most persistent response observed in the HT group. During the 2007 drought, trees in thinned plots, particularly those in the HT group, showed higher resistance and resilience than trees in the Con group. The increased indices during the 2000 and 2007 drought periods predominantly reflected immediate thinning-induced growth release. WUE_i in the HT group increased relative to the Con group during both the 2007 and 2014–2016 drought periods; however, the underlying physiological mechanisms differed, with enhanced net photosynthetic capacity immediately after thinning in 2007 and a likely consistent reduction in stomatal conductance during the 2014–2016 drought. Although constrained by a non-replicated stand design, this site-specific long-term case study provides valuable insights into the multi-decadal growth and physiological trajectories of conifer plantations responding to climate stress.