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Can Forest Management Improve Water Retention Conservation Under Climate Change? A Case Study of the Republic of Korea

Forests 2025, 16(5), 862; https://doi.org/10.3390/f16050862

by Mina Hong¹, Youngjin Ko²

, Sujong Lee², Minkyung Song¹

and Woo-Kyun Lee^2,*

Reviewer 1: Anonymous

Reviewer 2:

Efrain Noa Yarasca

Reviewer 3: Anonymous

Forests 2025, 16(5), 862; https://doi.org/10.3390/f16050862

Submission received: 10 March 2025 / Revised: 17 May 2025 / Accepted: 18 May 2025 / Published: 21 May 2025

(This article belongs to the Section Forest Hydrology)

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study uses dynamic modeling to explore the impacts of climate change and forest management on forest water resources. It offers a comprehensive view by analyzing both aboveground and belowground water retention, which is highly relevant to forest management and water resource planning, especially in climate change adaptation. However, addressing its limitations and implementing suggested improvements would enhance its robustness and applicability, better supporting forest, water, and climate management in our changing world.

Specific suggestions are as follows:

It is recommended to compare model outputs with historical water retention data and field measurements to assess predictive accuracy.
It is recommended to conduct real world case studies to validate proposed "optimal management" strategies at the watershed level.
It is recommended to test the KO-G-Dynamic model's applicability to other regions and forest types beyond Korean coniferous forests.
It is recommended to incorporate spatial heterogeneity in soil properties and deeper groundwater dynamics into soil water storage calculations.
The authors are encouraged to explore additional forest management strategies such as mixed-species planting and adaptive density management.
It is suggested to integrate stochastic extreme weather events (e.g., IDF curves) to assess management strategy resilience.
The authors are encouraged to investigate how soil carbon depletion and microbial activity influence water storage in relation to forest aging.
It may be better to conduct sensitivity analyses for climate scenario variability and parameter uncertainty to strengthen reliability.
It is recommended to compare KO-G-Dynamic with global models (e.g., SWAT, InVEST) to assess universality and refine parameters. Incorporate LiDAR canopy structure, soil moisture sensors, and satellite evapotranspiration data for higher-resolution inputs.
It is recommended that the authors dedicate a section to discussing the study's limitations and uncertainties, including model assumptions, data limitations, and potential sources of error. They should also provide more context on the water retention challenges in Korean forests and how this study tackles them. Furthermore, the authors need to explore the implications of their findings and suggest practical steps for implementing the proposed watershed-based forest management approaches.
It is suggested to address potential uncertainties in the projections, such as sensitivity to different climate scenarios or forest management strategies, to enhance the robustness of the conclusions.

Author Response

Answers to Reviewers’ Comments

Title: Can Forest Management Improve Water Retention Conservation Under Climate Change? A Case Study of the Republic of Korea

We appreciate your valuable comments and suggestions; these have helped us to improve upon the quality of our manuscript. The manuscript has been revised in accordance with your suggestions. The revised manuscript has been re-checked by a native English language editor to improve readability. Please find our responses below for each comment (P and L mean page number and line number in “Revised manuscript”). We hope that you find our revised manuscript acceptable.

Comment 1

It is recommended to compare model outputs with historical water retention data and field measurements to assess predictive accuracy.

→Response

Thank you for your valuable comment on our manuscript. According to your suggestion, we assessed the predictive accuracy of our model. Due to differences in reference periods between field survey data from the National Institute of Forest Science (NIFoS) conducted in the 1990s and our study’s reference period of the 2010s (2000–2010), we compared our results with a previous study by Kim et al. (2018). Kim’s study estimated the aboveground water yield in the 2010s at 1,675 million tons yr⁻¹, while our model estimated it at 1,693 million tons yr⁻¹. Additionally, the total national water retention conservation value recently published by NIFoS differs from our result by approximately –3.3 billion tons. These details have been included in Lines 215–217 of the revised manuscript.

L215-217: Based on the simulation approach described above, the total annual water resources in the Republic of Korea were estimated to be approximately 36.9 billion tons in 2023, showing a similar trend to previous studies that reported 36.6 billion tons [8].

Added references

Bae, J.S. Key Issues and Future Prospects of Forests, Forestry, and Mountain Villages in 2023; Daejeon, Republic of Korea, 2023.

Comment 2

It is recommended to conduct real world case studies to validate proposed "optimal management" strategies at the watershed level.

→Response

Thank you for your kind advice, and we agree with your comment. We have added the relevant content to L292-300 according to your suggestion.

L292-300: Previous studies have also predicted water resource securing strategies through water-shed-level and optimal management strategies [29][40]. In this regard, the findings of this study align with these projections, demonstrating that water retention conservation increases with the implementation of sustainable forest management. However, a more detailed examination of the aboveground water yield, it was found that while forest management led to a slight decrease in the medium to long term due to the impact of stand growth and biomass, in the long term, water resource availability was facilitated by the alleviation of age class imbalance and the subsequent increase in growth and stocking.

Added references

Kim, M.; Kraxner, F.; Forsell, N.; Song, C.; Lee, W.K. Enhancing the Provisioning of Ecosystem Services in South Korea under Climate Change: The Benefits and Pitfalls of Current Forest Management Strategies. Environ. Change2021, 21(1), 6, doi:10.1007/s10113-020-01728-0.
Kim, G. S., Lim, C. H., Kim, S. J., Lee, J., Son, Y., & Lee, W. K. (2017). Effect of national-scale afforestation on forest water supply and soil loss in South Korea, 1971–2010. Sustainability, 9(6), 1017.

Comment 3

It is recommended to test the KO-G-Dynamic model's applicability to other regions and forest types beyond Korean coniferous forests.

→Response

Thank you for your detailed comment, and we apologize for the confusion in that sentence. The model can estimate forest changes not only in coniferous forests but also based on the major tree species of the study area. Therefore, based on your valuable comment, we have modified the sentence.

L108-111: To simulate water retention conservation, it is essential to first understand the dynamic changes in forests. In this study, the KO-G-Dynamic model, a Korean forest dynamic stand growth model, was used to analyze growth changes under different climate and forest management scenarios based on major tree species and forest types (Equation (1)).

Comment 4

It is recommended to incorporate spatial heterogeneity in soil properties and deeper groundwater dynamics into soil water storage calculations.

→Response

Thank you for your advice and suggestion. In this study, we used the mesopore ratio model, which reflects the spatial heterogeneity of soil, to predict water retention for the A and B layers. However, a limitation of this study is that it did not account for the C layer, bedrock, and deep groundwater dynamics. We plan to incorporate these aspects in future research. This has been addressed in the discussion section, specifically in L329-332.

L329-332: However, a key limitation is that the study does not fully account for the complex physiological mechanisms of forests, the impact of disturbances, and climate variability. Additionally, it does not reflect the spatial heterogeneity of soil properties below the B layer and the dynamics of deep groundwater in soil water storage calculations.

Comment 5

The authors are encouraged to explore additional forest management strategies such as mixed-species planting and adaptive density management.

→Response

Thank you for your valuable comment on our manuscript. In this study, clear-cut harvesting and thinning are implemented through density management, and climate change-appropriate species are planted in harvested areas, reflecting environmental characteristics, in order to explore strategies for water resource management. This has been elaborated in more detail in L201-203.

L201-203: In this scenario, after clear-cut harvesting and thinning, considering the legal cut and normal final age, the areas where clear-cut harvesting has occurred are assumed to be replanted with climate change appropriate species suitable for the region [26][37].

Comment 6

It is suggested to integrate stochastic extreme weather events (e.g., IDF curves) to assess management strategy resilience.

→Response

Thank you for your valuable suggestion. This study utilized annual average data derived from monthly precipitation to analyze the overall changes in water retention conservation under climate change and forest management, thus generally reflecting extreme climate factors. However, there are limitations in developing scenario strategies based on correlations with extreme climatic conditions such as IDF curves. We intend to address these limitations by refining our model to incorporate such factors in future research.

L329-333: However, a key limitation is that the study does not fully account for the complex physiological mechanisms of forests, the impact of disturbances, and climate variability. Additionally, it does not reflect the spatial heterogeneity of soil properties below the B layer and the dynamics of deep groundwater in soil water storage calculations. Future research should focus on process-based water retention conservation predictions to address these gaps [43][44][45].

Comment 7

The authors are encouraged to investigate how soil carbon depletion and microbial activity influence water storage in relation to forest aging.

→Response

Thanks for your kind comments. Microbial activity contributes to the formation of networks capable of retaining carbon and water. Furthermore, regarding the relationship with stand age, as stand age increases, the canopy expands, leading to greater evapotranspiration in the aboveground components. However, belowground, well-developed root structures enhance microbial activity and create conditions favorable for water storage. We have incorporated these points into the manuscript.

L306-311: Additionally, the A layer features pathways created by microfauna that feed on organic matter and vessels formed by decaying roots, creating a network that allows for the rapid absorption of large amounts of rainfall. The B layer, in turn, stores the water absorbed by the A layer at greater depths and releases it gradually. Although the B layer has a lower pore ratio due to its lower organic matter content, its greater depth enables it to store a larger volume of rainfall [12][41][42].

Added references

National Institute of Forest Science. Research Report on the Quantification of Public Functions of Forests; Seoul, Republic of Korea, 2010.
Zhu, X., Si, J., He, X., Jia, B., Zhou, D., Wang, C., ... & Liu, Z. (2024). Effects of long-term afforestation on soil water and carbon in the Alxa plateau. Frontiers in Plant Science, 14, 1273108.
Ma, F., Liu, Y., Qi, Y., Deng, N., Xiang, H., Qi, C., ... & Zhang, X. (2024). Tree age affects carbon sequestration potential via altering soil bacterial community composition and function. Frontiers in Microbiology, 15, 1379409.

Comment 8

It may be better to conduct sensitivity analyses for climate scenario variability and parameter uncertainty to strengthen reliability.

→Response

Thank you for your insightful suggestion. We fully agree with the importance of conducting sensitivity analyses on climate scenario variability and parameter uncertainty. However, the focus of this study is on evaluating the overall impact of climate change and forest management strategies on water retention conservation under a given scenario. Conducting full-scale sensitivity analyses would require generating additional spatial datasets and simulation outputs, which is beyond the scope of this study. We have clearly stated this as a limitation in the revised manuscript and plan to address it in future research.

L329-334: However, a key limitation is that the study does not fully account for the complex physiological mechanisms of forests, the impact of disturbances, and climate variability. Additionally, it does not reflect the spatial heterogeneity of soil properties below the B layer and the dynamics of deep groundwater in soil water storage calculations. Future research should focus on process-based water retention conservation predictions to address these gaps [43][44][45].

Comment 9

It is recommended to compare KO-G-Dynamic with global models (e.g., SWAT, InVEST) to assess universality and refine parameters. Incorporate LiDAR canopy structure, soil moisture sensors, and satellite evapotranspiration data for higher-resolution inputs.

→Response

Thank you for your meaningful suggestion. The KO-G-Dynamic model is a forest stand growth model that has been validated through multiple peer-reviewed publications, as it reflects the ecological and environmental characteristics of forests in the Republic of Korea. Relevant references using this model have been cited in this manuscript for further support. Additionally, key input data such as those from the National Forest Inventory (NFI) and effective soil depth are derived from field-based surveys, which we believe provide more precise and reliable information compared to satellite-based data.

Comment 10

It is recommended that the authors dedicate a section to discussing the study's limitations and uncertainties, including model assumptions, data limitations, and potential sources of error. They should also provide more context on the water retention challenges in Korean forests and how this study tackles them. Furthermore, the authors need to explore the implications of their findings and suggest practical steps for implementing the proposed watershed-based forest management approaches.

→Response

Thank you for your advice and suggestion. We have incorporated additional content in the manuscript regarding limitations and uncertainties, the background of forest water resources, and the watershed-based forest management approach.

L44-54: In the Republic of Korea, the proportion of forest area has gradually declined from 63.9% in 2014 to 63.1% in 2023, and forest distribution is shifting northward due to climate change [5]. The National Institute of Forest Science (NIFoS) projects that under the SSP5–8.5 scenario, total discharge and base flow will decrease by 6.47 billion m³ and 3.36 billion m³ respectively by 2040, which is expected to intensify water shortages and drought conditions. Additionally, erosion control and greening projects implemented between 1973 and 1987 prioritized fast-growing species, leading to an increase in climate-vulnerable species and higher mortality rates [6]. In particular, data from the 5th and 6th National Forest Inventory (NFI) revealed that coniferous species exhibited a mortality rate that was 96% higher than that of other tree species [7]. Coniferous forests, which account for 38.8% of the country’s forests, exhibit higher evapotranspiration rates than broadleaf forests, reducing their capacity for water retention [8].

L288-300: According to the NIFoS, the long-term water resources outlook for the Republic of Korea predicts that water shortages and droughts will intensify due to decreasing total runoff and seasonal discharge until the 2040s [39]. Furthermore, it has been suggested that to offset the drought projections of the 2000s, between 121,000 and 393,000 hectares of forest tending would be required annually [8]. Previous studies have also predicted water resource securing strategies through watershed-level and optimal management strategies [29][40]. In this regard, the findings of this study align with these projections, demonstrating that water retention conservation increases with the implementation of sustainable forest management. However, a more detailed examination of the above-ground water yield, it was found that while forest management led to a slight decrease in the medium to long term due to the impact of stand growth and biomass, in the long term, water resource availability was facilitated by the alleviation of age class imbalance and the subsequent increase in growth and stocking.

L323-334: This study provides valuable insights by classifying and predicting forest water resource dynamics based on watershed units in response to climate change, offering a pathway for sustainable forest management. Furthermore, it departs from conventional forest management systems based on legally defined administrative boundaries and instead adopts ecologically relevant watershed units, thereby enhancing spatial applicability and reflecting environmental characteristics more accurately. However, a key limitation is that the study does not fully account for the complex physiological mechanisms of forests, the impact of disturbances, and climate variability. Additionally, it does not reflect the spatial heterogeneity of soil properties below the B layer and the dynamics of deep groundwater in soil water storage calculations. Future research should focus on process-based water retention conservation predictions to address these gaps [43][44][45].

Comment 11

It is suggested to address potential uncertainties in the projections, such as sensitivity to different climate scenarios or forest management strategies, to enhance the robustness of the conclusions.

→Response

Thank you for your valuable comment. To enhance the robustness of the conclusion, we addressed the uncertainties as limitations within the manuscript and emphasized key implications by adding relevant content to the discussion section prior to the conclusion.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The study evaluates the impact of climate change and forest management on water retention, proposing methods to ensure water resource sustainability. Results show that optimal forest management, particularly a watershed-based approach, enhances water conservation. This research highlights the role of forest management in mitigating climate change and guiding policy at national and local levels. However, the manuscript has limitations. Given the uncertainty of Global Climate Models (GCMs), relying on just one GCM is insufficient for predicting future trends. It is recommended to include at least five GCMs for more reliable results. Additionally, the study only examines one extreme climate change scenario (SSP 5-8.5); considering other scenarios would offer a more balanced perspective.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

The English could be improved

Author Response

Answers to Reviewers’ Comments

Title: Can Forest Management Improve Water Retention Conservation Under Climate Change? A Case Study of the Republic of Korea

Comment 1

The study assesses the effects of climate change and forest management strategies on water retention conservation, proposing methods to secure the sustainability of water resources. The results show that optimal forest management enhances water conservation and storage, with a watershed-based approach proving more effective in ensuring water resource availability. This research underscores the importance of forest management in mitigating climate change impacts and demonstrates how scientific predictions on water retention conservation can guide policy and improve forest planning at both national and local levels.

Despite its significance, the manuscript has notable limitations. Given the uncertainty of Global Climate Models (GCMs), as confirmed by recent studies, relying on a single GCM is insufficient for determining clear future trends. It is recommended that the authors incorporate at least five GCMs in their analysis for more reliable results. Moreover, the study only considers one climate change scenario (SSP 5-8.5); exploring other, less extreme scenarios would provide a more comprehensive and balanced view of potential future conditions.

→Response

Comment 2

Introduction, line 41: Some statements are presented without quantitative data. For example, in "In the Republic of Korea, forested areas are declining annually, and forest distribution is shifting northward due to climate change," what is the rate of decline in numerical terms? Including specific figures would strengthen the statement. Provide quantitative data throughout the introduction to contextualize the past and current situation of the study area.

→Response

Thank you for your advice and suggestion. We have added information on the recent change in the proportion of forest area relative to the national land area

L44-46: In the Republic of Korea, the proportion of forest area has gradually declined from 63.9% in 2014 to 63.1% in 2023, and forest distribution is shifting northward due to cli-mate change [5].

Added references

Korea Forest Service. Climate Change and Forests; Daejeon, Republic of Korea, 2009.

Comment 3

Line 44: Increased mortality is mentioned, but it is unclear compared to which period or conditions. How much has mortality increased relative to present or historical data? Clarifying this comparison would improve the accuracy of the argument.

→Response

Thank you for your valuable comment on our manuscript. In response to your suggestion, we have incorporated relevant content into the manuscript based on studies utilizing the 5th and 6th National Forest Inventory data, and have added the corresponding references.

L49-53: Additionally, erosion control and greening projects implemented between 1973 and 1987 prioritized fast-growing species, leading to an increase in climate-vulnerable species and higher mortality rates [6]. In particular, data from the 5th and 6th National Forest Inventory (NFI) revealed that coniferous species exhibited a mortality rate that was 96% higher than that of other tree species [7].

Added references

Kim, M.; Kraxner, F.; Son, Y.; Jeon, S.W.; Shvidenko, A.; Schepaschenko, D.; Ham, B.Y.; Lim, C.H.; Song, C.; Hong, M.; et al. Quantifying Impacts of National-Scale Afforestation on Carbon Budgets in South Korea from 1961 to 2014. Forests 2019, 10, doi:10.3390/f10070579.

Comment 4

In line 48, references are needed to support the statement: “Since below-ground storage holds more water than aboveground components, density management can help reduce evapotranspiration losses.” Please provide a citation to substantiate this claim.

→Response

Thank you for your valuable comment. In line with your suggestion, we have added a supporting reference to substantiate the statement.

L57-59: Since belowground storage holds more water than aboveground components, density management can help reduce evapotranspiration losses [10].

Added references

McNulty, S., Steel, A., Springgay, E., Caldwell, B., Shono, K., Pess, G., ... & Borelli, S. (2021). Managing forests for water [Chapter 3]. In: FAO, IUFRO and USDA. A guide to forest-water management. FAO Forestry Paper No. 185. Rome, Italy. Food and Agriculture Organization of the United Nations. p. 31-74. https://doi. org/10.4060/cb6473en., 31-74.

Comment 5

In line 54, the phrase “previous studies” is too vague. Which specific studies are being referred to? Cite all relevant studies to allow verification of this statement. Additionally, multiple claims throughout the introduction lack proper references. The authors should ensure that every factual statement is supported by reliable citations.

→Response

Thank you for your helpful comment. In response to your suggestion, we have reinforced the related statements with additional references to support our arguments based on previous literature.

L63-68: However, previous studies on forest water resource estimation have used statistical based predictive models and stand-level analysis, which allow for the evaluation of overall forest water resource trends [12][13][9] . While this approach has the advantage of assessing general water resource tendencies, it has limitations in evaluating resource quantities that reflect forest hydrological characteristics at the basic spatial unit level and in predicting water resources based on climate change and management strategies [14].

Added references

National Institute of Forest Science. Development of Large-Scale Forest Spatial Information-Based Methods for Forest Water Resource Assessment and Prediction; Seoul, Republic of Korea, 2018.
National Institute of Forest Science. Research Report on the Quantification of Public Functions of Forests; Seoul, Republic of Korea, 2010.
Li, Q.; Wei, X.; Zhang, M.; Liu, W.; Fan, H.; Zhou, G.; Giles-Hansen, K.; Liu, S.; Wang, Y. Forest Cover Change and Water Yield in Large Forested Watersheds: A Global Synthetic Assessment. Ecohydrology2017, 10, doi:10.1002/eco.1838.
Ford, C. R., Laseter, S. H., Swank, W. T., & Vose, J. M. (2011). Can forest management be used to sustain water‐based ecosystem services in the face of climate change?. Ecological Applications, 21(6), 2049-2067.

Comment 6

In the introduction, a literature review on climate change in the context of the article’s objectives should be included to provide a solid theoretical framework.

In the introduction, it is unclear which climate and forest management scenarios will be used in the study. Additionally, there is no review of the relevant literature and background on the topic. Incorporating these elements is essential to properly contextualize the research.

→Response

Thank you for your advice and suggestion. We have added some related references and sentences in L74-81.

L74-81: Therefore, this study aims to evaluate changes in water retention conservation under accelerating climate change and assess the impacts of both current forest management practices and policy-based management strategies, with the goal of exploring pathways for securing sustainable water resources [15][16][17][18]. Additionally, it seeks to establish standardized forest management units based on watershed-level hydrological characteristics that reflect forest physiognomy. Using these units, the study will estimate water yield under climate and forest management scenarios, contributing to national and regional forest management planning.

Added references

Mills‐Novoa, M., & Liverman, D. M. (2019). Nationally determined contributions: material climate commitments and discursive positioning in the NDCs. Wiley Interdisciplinary Reviews: Climate Change, 10(5), e589.
Pauw, W. P., Klein, R. J., Mbeva, K., Dzebo, A., Cassanmagnago, D., & Rudloff, A. (2018). Beyond headline mitigation numbers: we need more transparent and comparable NDCs to achieve the Paris Agreement on climate change. Climatic Change, 147(1), 23-29.
Grassi, G., House, J., Dentener, F., Federici, S., den Elzen, M., & Penman, J. (2017). The key role of forests in meeting climate targets requires science for credible mitigation. Nature Climate Change, 7(3), 220-226.
Moomaw, W. R., Law, B. E., & Goetz, S. J. (2020). Focus on the role of forests and soils in meeting climate change mitigation goals: summary. Environmental Research Letters, 15(4), 045009.

Comment 7

In line 82, the statement presented lacks reference. As mentioned earlier, the authors should include citations and references for each factual claim to properly support their claims.

→Response

Thank you for your kind advice. We agree with your comment and have added the relevant content along with the Forestry Statistics Yearbook, from which the data was extracted, as a reference.

L74-81: As a result, the initial stand volume of 11.31 m³/ha increased to 176 m³/ha by 2023. In particular, Gangwon Province shows a notably high stand volume of 196 m³/ha, followed by Gyeongsangnam-do with 190 m³/ha and Gyeongsangbuk-do with 184 m³/ha, all exceeding the national average [21].

Added references

Korea Forest Service. Forestry Statistics Yearbook; Daejeon, Republic of Korea, 2024.

Comment 8

In line 85, the content of this paragraph does not correspond to the description of the study area, but rather to the study objectives. Therefore, it is recommended to move it to the appropriate section to improve the manuscript’s organization.

→Response

Thank you for your insightful comment. In response, we have modified the sentence to align more appropriately with the context of the study area description.

L99-102: This region was selected as the study area to explore strategic approaches for securing sustainable water retention conservation by integrating climate adaptation and forest management, while reflecting the hydrological and ecological characteristics of watersheds in the Republic of Korea.

Comment 9

In Equation 1, what does the variable V represent? It is recommended to clearly define each variable to avoid ambiguities.

→Response

We apologize for any confusion caused. Based on your comment, we have included a detailed explanation for the variable V.

L120-124: where V is the stand volume, i represents the serial number for each stand, j denotes the year, DBH is the stand average diameter at breast height, Hm is the average tree height of the stand, and N is the stand density (trees/ha). The coefficients (a, b, and c), determined for each tree species (Table 1), were incorporated with the biomass allometric equation data developed by the NIFoS [27].

Comment 10

Equation 1 is mentioned, but the connection between the variable V and climate change variables, forest management plans, or other equations in the study is unclear. It is important to explicitly explain this relationship to improve the understanding of the model.

→Response

Thank you for your valuable comment. Additionally, in response to your suggestion, we have included the description of the relationship involving V (stand volume) in the manuscript.

L108-116: To simulate water retention conservation, it is essential to first understand the dynamic changes in forests. In this study, the KO-G-Dynamic model, a Korean forest dynamic stand growth model, was used to analyze growth changes under different climate and forest management scenarios based on major tree species and forest types (Equation (1)). This model reflects the environmental and ecological characteristics of the Republic of Korea and can annually predict the growth of temperate forests based on stand volume dynamics. By incorporating climate change and forest management scenarios, it predicts future changes in forest resources and can support the development of optimal forest management plans [24][7][25][26].

Comment 11

Some figures are not mentioned throughout the manuscript (Figure 1 for example). The authors are advised to review and ensure that all figures and tables are properly referenced in the text.

→Response

Thank you for your helpful comment. We apologize for any confusion caused. Based on your suggestion, we have inserted the previously missing figure reference into the main text of the manuscript.

L84-88: The study area is situated within the forested regions of the Republic of Korea, covering longitudes from 124°54′ to 131°6′ and latitudes from 33°9′ to 38°45′. The watersheds are categorized into major watersheds (21), medium watersheds (117), standard watersheds (850), and catchment areas (35,951). Effective soil depth varies between 0 and 150 cm, depending on forest type and environmental conditions (Figure 1) [19][20].

L176-177: In this study, baseline data were established to analyze water retention conservation under forest management strategies for climate change adaptation (Figure 2).

Comment 12

In line 106, a table is mentioned, but it is missing. The authors should verify and correct this omission.

→Response

Thank you for your thoughtful comment. During the preparation of the manuscript, we referred to the corresponding table through the cited reference. Accordingly, we have revised the section based on your suggestion.

Comment 13

Reference 19 could not be found online, making it impossible to verify the statement mentioned.

→Response

Thank you for your valuable comment. There was an issue in translating the original Korean title into English, and we have now corrected it to the appropriate representative title.

L447-449: Son, Y.M.; Kim, R.H.; Lee, G.H.; Pyo, J.K.; Kim, S.W.; Hwang, J.S.; Lee, S.J.; Park, H. Carbon Emission Factors and Biomass Allometric Equations by Species in Korea. National Institute of Forest Science; Seoul, Republic of Korea, 2010.

Comment 14

References 8 and 9 were not found in public repositories, preventing the verification of the assertions provided by the authors in the paragraph at line 129. It is recommended that all references are accessible for verification.

→Response

Thank you for your insightful comment. In response to your suggestion, we have added the relevant link after the corresponding reference.

L412-419:

National Institute of Forest Science. 20 Key Facts About Forest Water Resources; Seoul, Republic of Korea, 2015. https://east.forest.go.kr/kfsweb/cop/bbs/selectBoardArticle.do;jsessionid=e7PJCSdVdCbPhzY2lKaBYX1Zb5WaNFIiQYQoVsnlcbLRSAttvpBoEM4yHeBebnyq.frswas02_servlet_engine5?nttId=3053426&bbsId=BBSMSTR_1008&pageUnit=10&pageIndex=36&searchtitle=title&searchcont=&searchkey=&searchwriter=&searchWrd=&ctgryLrcls=&ctgryMdcls=&ctgrySmcls=&ntcStartDt=&ntcEndDt=&mn=NKFS_02_15_01
National Institute of Forest Science. Research Report on the Quantification of Public Functions of Forests; Seoul, Republic of Korea, 2010. https://scienceon.kisti.re.kr/commons/util/originalView.do?cn=TRKO201200009611&dbt=TRKO&rn=

Comment 15

Line 167: It is recommended to include references for each of the sources mentioned.

→Response

Thank you for your detailed comment. In response to your suggestion, we have added citations to all the mentioned sentences.

L191-203: To simulate water retention conservation under different forest management conditions, the Normal and Ideal forest management scenarios were established and formally defined in this study. These strategies were designed to reflect current operational practices and policy-optimized approaches, respectively. For forest management scenarios, thinning and clear-cutting areas were determined based on stand volume and domestic wood supply data from the 6th National Forest Plan and 4th Five-Year Forest Tending Promotion Plan. For the current forest management scenario, the 'Normal Forest Management' involves approximately 120,000 ha of forest trending annually, while the 'Ideal Forest Management' scenario, based on optimized forest planning, assumes approximately 200,000 ha of forest tending [25]. In this scenario, after clear-cut harvesting and thinning, considering the legal cut and normal final age, the areas where clear-cut harvesting has occurred are assumed to be replanted with climate change appropriate species suitable for the region [26][37].

Added references

Hong, M.; Song, C.; Kim, M.; Kim, J.; Roh, M.; Ko, Y.; Cho, K.; Son, Y.; Jeon, S.; Kraxner, F.; et al. Modeling-Based Risks Assessment and Management of Climate Change in South Korean Forests. Forests 2023, 14, doi:10.3390/f14040745.
Ko, Y.; Song, C.; Fellows, M.; Kim, M.; Hong, M.; Kurz, W.A.; Metsaranta, J.; Son, J.; Lee, W.K. Generic Carbon Budget Model for Assessing National Carbon Dynamics toward Carbon Neutrality: A Case Study of Republic of Korea. Forests 2024, 15, doi:10.3390/f15050877.
Hong, S. Y., Kim, L. H., Choe, E. Y., Jang, Y. S., Hyeon, B. G., Son, Y. G., ... & Ha, S. G. (2011). Soil Environmental Information System "Heuktoram". Magazine of the Korean Society of Agricultural Engineers, 53(1), 27–
Hong, M.; Song, C.; Kim, M.; Kim, J.; Lee, S. gee; Lim, C.H.; Cho, K.; Son, Y.; Lee, W.K. Application of Integrated Korean Forest Growth Dynamics Model to Meet NDC Target by Considering Forest Management Scenarios and Budget. Carbon Balance Manag 2022, 17, doi:10.1186/s13021-022-00208-8.

Comment 16

Line 129: The phrase "many studies" is used, but no specific sources are cited. The corresponding references should be included to support this statement.

→Response

Thank you for your valuable comment on our manuscript. In response to your suggestion, we have included a reference that substantiates the relevant content in the manuscript.

L146-163: Many studies in the Republic of Korea have measured the mesopore ratio of parent rock and soil types distributed across the country and calculated the average soil depth by multiplying it by the area [31][32][33]. Based on these findings, the NIFoS developed an advanced estimation formula for the mesopore ratio in the A and B layers of broadleaf, conifer, and mixed forests. The formula utilizes soil mesopore ratio data derived from the site conditions of surveyed forest types and based on the increase in stand age (Equation (3-1, 3-2, 3-3, 3-4, 3-5, 3-6)) [12]. Based on the results of stand age increase analyzed earlier, this study simulated belowground water storage.

Added references

Jin, Y.; Jeong, S.; Jeong, S.; Lee, D. Assessment on the Forest Conservation Value Considering Forest Ecosystem Services: The case of Gapyung-gun. Journal of Environmental Impact Assessment. 2015, 24(5), 420-431.
Song, H.S.; Lee, K.; Jun, E.; A Study on Forest Conservation Charge Applying the Concept of Complete Restoration. The Korea Spatial Planning Review 2015, 85(6), 3-22.
Kim, J.H.; Lee, K.H.; Park, C.W.; Seo, J.W.; Son, Y.M; Kim, K.H.; Youn, H.J.; Park, C.R.; Lee, S.W.; Oh, J.S. Nonmarket Valuation of Forest Resource in korea. The Journal of Korean institute of Forest Recreation. 2006. 10(2), 7-15.

Comment 17

In Section 2.5, more information on climate change variables, such as precipitation and temperature, should be provided for clarity. Additionally, the selection of the General Circulation Model (GCM) should be justified. It is also important to indicate whether a bias evaluation of the GCMs was conducted using historical observations. If so, the results should be presented either in the article or as supplementary material.

→Response

Thank you for your valuable comment. In this study, average temperature and average precipitation were applied in the forest growth model, and average precipitation was also used in the forest water resource model. For the detailed climate data of South Korea, we utilized projected climate variables derived from the 5ENSMN ensemble models (GRIMs, RegCM, WRF, CCLM, HadGEM3-RA), which were generated using MK-PRISM, a statistical climate dataset calibrated to Korean topography based on national observation data. The climate variables used have been visualized and added as a figure in the manuscript.

L181-185: For future climate change data, average temperature and precipitation derived from the 5ENSMN models (GRIMs, RegCM, WRF, CCLM, HadGEM3-RA), based on MK-PRISM, were applied. These data, representing the detailed SSP5-8.5 scenario for the Republic of Korea, were applied at a 1 km × 1 km resolution for the period 2021–2100 (Figure 3) [34].

Figure 3. Climate trends in the Republic of Korea based on observed data and the SSP5-8.5 scenario (2011–2100): (a) Annual mean temperature (°C), (b) Annual precipitation (mm).

Added references

Kim, J.U.; Sang, J.; Kim, M.K.; Byun Y.H.; Kim, D.H.; Kim, T.j. Future Climate Projection in South Korea using the High-Resolution SSP Scenarios based on Statistical Downscaling. Journal of Climate Research 2022. 17(2), 89-106.

Comment 18

In the same section, more details on soil characteristics should be included, such as soil types and their respective proportions within the study area.

→Response

Thank you for your helpful comment. As per your suggestion, we have cited a reference that includes more detailed information

L186-191: To simulate forest changes, data from the 1:5,000 forest type map and the 6th NFI, including forest type, species, age class, site index, DBH, and canopy density, were used [35]. Slope information was derived from Digital Elevation Model (DEM) data provided by the National Geographic Information Institute (NGII) [26]. Soil characteristics, including soil type distribution and effective soil depth, were obtained from the national soil map for model execution [36].

Added references

Hong, S. Y., Kim, L. H., Choe, E. Y., Jang, Y. S., Hyeon, B. G., Son, Y. G., ... & Ha, S. G. (2011). Soil Environmental Information System "Heuktoram". Magazine of the Korean Society of Agricultural Engineers, 53(1), 27–40.

Comment 19

In line 190, the paragraph in line 190 under “Results” does not properly belong to the results section but rather to the methodology. Please review the entire manuscript and reorganize the paragraphs accordingly.

In line 196, the phrase “previous studies” is mentioned, but no specific studies are cited. The authors are requested to identify which studies are being referred to and to provide the numerical data from these studies for comparison, or to clearly state the assertions made by the previous studies. Please clarify this detail.

→Response

Thank you for your valuable comment on our manuscript. According to your suggestion, we revised the paragraph and rearranged the related citation accordingly.

L215-224: Based on the simulation approach described above, the total annual water resources in the Republic of Korea were estimated to be approximately 36.9 billion tons in 2023, showing a similar trend to previous studies that reported 36.6 billion tons [8].

Furthermore, the analysis indicated that if an ideal forest management approach, based on the 6th National Forest Plan and the 4th Five-Year Forest Tending Plan, aligned with climate change adaptation policies, were implemented instead of the cur-rent normal forest management practices, additional water retention of 0.309 billion tons could be secured in the 2030s (2026-2035), 0.702 billion tons in the 2050s (2046-2055), and 1.188 billion tons in the 2080s (2076-2085) (Figure 4).

Comment 20

In line 199, it is not clear which forest management approach is being referred to in the study. Please provide a clear description of the forest management approach used.

→Response

Thank you for your advice and suggestion. We have revised the sentence to clearly define the forest management approach.

L218-224: Furthermore, the analysis indicated that if an ideal forest management approach, based on the 6th National Forest Plan and the 4th Five-Year Forest Tending Plan, aligned with climate change adaptation policies, were implemented instead of the cur-rent normal forest management practices, additional water retention of 0.309 billion tons could be secured in the 2030s (2026-2035), 0.702 billion tons in the 2050s (2046-2055), and 1.188 billion tons in the 2080s (2076-2085) (Figure 4).

Comment 21

The values in Figure 3 are labeled with the years 2030, 2050, and 2080. What are the periods for the average of these point values? This is not mentioned earlier in the methodology section. Please clarify.

→Response

Thank you for your insightful comment. In response, we have included the specific 10-year ranges corresponding to each representative decade in the manuscript.

Comment 22

Several figures refer to the “ideal forest management scenario,” but this term is never defined or described in the manuscript. The authors are requested to provide a clear definition and explanation of this scenario.

→Response

Thank you for your comment. We have clarified this in Section 2.5, Data Preparation and Modification.

L194-203: For forest management scenarios, thinning and clear-cutting areas were determined based on stand volume and domestic wood supply data from the 6th National Forest Plan and 4th Five-Year Forest Tending Promotion Plan. For the current forest management scenario, the 'Normal Forest Management' involves approximately 120,000 ha of forest trending annually, while the 'Ideal Forest Management' scenario, based on optimized forest planning, assumes approximately 200,000 ha of forest tending [25]. In this scenario, after clear-cut harvesting and thinning, considering the legal cut and normal final age, the areas where clear-cut harvesting has occurred are assumed to be replant-ed with climate change appropriate species suitable for the region [26][37].

Comment 23

Figure 6 presents values for different horizons; however, the manuscript uses the term “layer” instead of “horizon” throughout. Are these terms referring to the same concept? The authors should ensure consistency in terminology across the manuscript.

→Response

Thank you for your careful observation. 'Layer' and 'horizon' were used interchangeably in the manuscript to refer to the A and B soil zones. However, to ensure consistency and avoid confusion, we have revised the manuscript to consistently use the term 'layer' throughout, in alignment with the terminology used in the figures and modeling approach

L206-270 (Figure 6):

Figure 7. Forest soil belowground water storage under different scenarios.

Comment 24

The study lacks clarity in defining the forest management approach adopted or proposed for the study. Although the discussion implicitly suggests that appropriate species tend to reduce evapotranspiration, there is no dedicated section explaining these measures in detail. It is recommended to clearly define and explain the forest management strategy applied in the study.

→Response

Thank you for your helpful comment. Although the forest management strategy was described in Section 2.5, we agree that clarification was needed. To address this, we revised the introductory sentence of the section to explicitly define the two forest management scenarios—Normal and Ideal—and their roles in simulating water retention conservation

L186-203: To simulate forest changes, data from the 1:5,000 forest type map and the 6th NFI, including forest type, species, age class, site index, DBH, and canopy density, were used [35]. Slope information was derived from Digital Elevation Model (DEM) data provided by the National Geographic Information Institute (NGII) [26]. Soil characteristics, including soil type distribution and effective soil depth, were obtained from the national soil map for model execution [36]. To simulate water retention conservation under different forest management conditions, the Normal and Ideal forest management scenarios were established and formally defined in this study. These strategies were designed to reflect current operational practices and policy optimized approaches, respectively. For forest management scenarios, thinning and clear-cutting areas were determined based on stand volume and domestic wood supply data from the 6th National Forest Plan and 4th Five-Year Forest Tending Promotion Plan. For the current forest management scenario, the 'Normal Forest Management' involves approximately 120,000 ha of forest trending annually, while the 'Ideal Forest Management' scenario, based on optimized forest planning, assumes approximately 200,000 ha of forest tending [25]. In this scenario, after clear-cut harvesting and thinning, considering the legal cut and normal final age, the areas where clear-cut harvesting has occurred are assumed to be replanted with climate change appropriate species suitable for the region [26][37].

Comment 25

The discussion references aspects that are not clearly defined in the manuscript. For instance, certain provinces, such as Gangwon, are mentioned, but they are never introduced or discussed earlier in the manuscript. It is important to remember that the discussion should provide an explanation of the research findings in the context of existing literature. The authors should ensure that all terms and locations referenced in the discussion are properly defined and introduced earlier in the manuscript.

→Response

Thank you for your insightful comment. In response to your suggestion, we have introduced the relevant provinces—Gangwon, Gyeongsangnam-do, and Gyeongsangbuk-do—in the Study Area section of the manuscript (Lines 93–96).

L93-96: As a result, the initial stand volume of 11.31 m³/ha increased to 176 m³/ha by 2023. In particular, Gangwon Province shows a notably high stand volume of 196 m³/ha, followed by Gyeongsangnam-do with 190 m³/ha and Gyeongsangbuk-do with 184 m³/ha, all exceeding the national average [21].

Comment 26

The study should include a section dedicated to its limitations and potential directions for future research. This would provide a more balanced approach and help contextualize the findings within the challenges and opportunities for future studies.

→Response

Thank you for your valuable comment on our manuscript. According to your comment, we have created a separate paragraph in the Discussion section to address the study’s limitations and suggest directions for future research

Comment 27

The information provided as supplementary material consists of web pages, which likely serve as sources from the database used in the study. However, many of these pages could not be accessed, likely due to their limited public availability. It is strongly recommended that the URLs of these web pages be cited as references within the manuscript, rather than being included as supplementary material.

→Response

Thank you for your comment. The websites listed in the Supplementary Materials are public platforms operated by respective government agencies. We have re-verified the URLs and updated them with the most recent links, and the relevant information has also been described in the main text of the manuscript.

L368-378: Forest data are available online through the Forest Big Data Exchange of the Republic of Korea (https://www.bigdata-forest.kr/), climate data can be obtained from the Korea Meteorological Administration (http://www.climate.go.kr/home/CCS/contents_2021/32_2_user_analysis.php), watershed data are accessible through the Korea Water Resources Corporation (https://www.vworld.kr/dtmk/dtmk_ntads_s002.do?dsId=30004), and soil data can be obtained from the Ministry of Land, Infrastructure, and Transport (https://www.vworld.kr/dtmk/dtmk_ntads_s002.do?svcCde=DT&dsId=DAT_0000000000000106).

Comment 28

Furthermore, the authors are kindly requested to provide more concrete and specific information used in the study, such as classified and explicit data, tables, databases, or repositories, as part of the supplementary material. To ensure transparency and reproducibility, it is strongly advised that the authors upload all relevant data to a public repository. This will allow reviewers and the scientific community to verify, replicate, and cross-check the results. The repository should include essential data, such as climate change information for the analysis period, land cover data, and any relevant maps or tables.

→Response

Thank you for your comment. We agree with your comment and have included the information on the data used in this study in the Supplementary Materials in the form of URLs

Comment 29

In conclusion, the manuscript would benefit from improvements in both the introduction and methodology sections, where more precise and detailed information should be provided. The discussion should better reflect the interpretation of the results, offering clear explanations for the underlying reasons behind the findings. It is crucial to contextualize the results within the existing literature by making comparisons, highlighting consistencies, and addressing any inconsistencies when compared to recent research articles. This will enhance the overall clarity and depth of the manuscript.

→Response

Thank you for your valuable comment. We have addressed the 29 comments you provided by incorporating more specific and precise information, clarifying the differences from previous literature, and ultimately improving the overall quality of the manuscript. We sincerely appreciate your thoughtful feedback.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Title
The manuscript's title is appropriated. A minor suggestion would be to explicitly reference the modeling approach used (e.g., KO-G-Dynamic model) to increase clarity.

Scope and Novelty
The manuscript addresses an increasingly relevant issue in the context of climate change: the intersection between forest management practices and water retention. Its novelty lies in the integration of forest dynamic stand growth modeling with aboveground and belowground water resource prediction at watershed-scale units.

Abstract
The abstract is well-written. It could be further strengthened by briefly mentioning the specific tools/models used and the importance of watershed-scale resolution for water management policy.

The introduction is comprehensive. However, the literature review could better differentiate the current study from prior modeling efforts to sharpen the perceived gap this research fills.

Methods
One potential improvement would be to summarize model assumptions and their limitations more explicitly.
Also, L105-111 are equal to explanation of Eq 1 from https://cbmjournal.biomedcentral.com/articles/10.1186/s13021-022-00208-8, even the reference used is the same. Please rewrite.

The discussion would benefit from expanded reflection on socio-political feasibility and cost considerations of implementing large-scale watershed-based management. Inclusion of recommendations for integrating these findings into future forest or water resource governance would enhance its applied relevance.

Author Response

Answers to Reviewers’ Comments

Title: Can Forest Management Improve Water Retention Conservation Under Climate Change? A Case Study of the Republic of Korea

Comment 1

Title

The manuscript's title is appropriated. A minor suggestion would be to explicitly reference the modeling approach used (e.g., KO-G-Dynamic model) to increase clarity.

→Response

Thank you for your advice and suggestion. However, as this study integrates not only the KO-G-Dynamic forest dynamic stand growth model but also aboveground and belowground water resource models, we believe that the current title appropriately reflects the comprehensive nature of the research. After discussion with the co-authors, we have decided to retain the original title.

Comment 2

Scope and Novelty

The manuscript addresses an increasingly relevant issue in the context of climate change: the intersection between forest management practices and water retention. Its novelty lies in the integration of forest dynamic stand growth modeling with aboveground and belowground water resource prediction at watershed-scale units.

→Response

Thank you very much for your positive feedback and for recognizing the novelty of our integrated modeling approach. We truly appreciate your acknowledgment of the study’s contribution to climate change and forest–water resource research.

Comment 3

The abstract is well-written. It could be further strengthened by briefly mentioning the specific tools/models used and the importance of watershed-scale resolution for water management policy.

The introduction is comprehensive. However, the literature review could better differentiate the current study from prior modeling efforts to sharpen the perceived gap this research fills.

→Response

Thank you for your valuable comment. According to your suggestion, we have revised the abstract and to introduction reflect the related content.

L22-27: Notably, watershed-based forest management offers a more practical management unit than conventional legal boundaries, as it reflects hydrological flow and the ecological characteristics of forest environments. Furthermore, the watershed-based forest management scenario demonstrated greater feasibility in securing water resources. This study provides foundational data for climate change adaptation and sustainable forest management and may aid national and local forest planning.

L63-73: However, previous studies on forest water resource estimation have used statistical based predictive models and stand-level analysis, which allow for the evaluation of overall forest water resource trends [12][13][9]. While this approach has the advantage of assessing general water resource tendencies, it has limitations in evaluating resource quantities that reflect forest hydrological characteristics at the basic spatial unit level and in predicting water resources based on climate change and management strategies [14]. Moreover, forest water retention conservation must account for the varying storage capacities of aboveground and belowground components, necessitating separate assessments for each. A watershed-based standard forest unit water retention conservation model is essential to improve predictions of future water resources and support policy decision-making.

Comment 4

Methods

One potential improvement would be to summarize model assumptions and their limitations more explicitly.

Also, L105-111 are equal to explanation of Eq 1 from https://cbmjournal.biomedcentral.com/articles/10.1186/s13021-022-00208-8, even the reference used is the same. Please rewrite.

→Response

Thank you for your valuable comment. We have added the previously omitted content and revised the explanation accordingly.

Comment 5

→Response

Thank you for your insightful comment. We agree that considering the socio-political feasibility and economic aspects of implementing watershed-based forest management would increase the applied value of this study. Accordingly, we have added a paragraph in the discussion section (Line 320–345).

L320-345: The models used in this study have been widely applied in both domestic and international research and have been published in academic literature [37][29][12]. Furthermore, the findings of this study were validated by comparison with previous re-search, reinforcing their significance [39]. This study provides valuable insights by classifying and predicting forest water resource dynamics based on watershed units in response to climate change, offering a pathway for sustainable forest management. Furthermore, it departs from conventional forest management systems based on legally defined administrative boundaries and instead adopts ecologically relevant watershed units, thereby enhancing spatial applicability and reflecting environmental characteristics more accurately. However, a key limitation is that the study does not fully account for the complex physiological mechanisms of forests, the impact of disturbances, and climate variability. Additionally, it does not reflect the spatial heterogeneity of soil properties below the B layer and the dynamics of deep groundwater in soil water storage calculations. Future research should focus on process-based water retention conservation predictions to address these gaps [43][44][45].

Since the era of erosion control and greening, the Republic of Korea has consistently worked to secure forest water resources. Recently, the increasing importance of forest water resources, driven by worsening water shortages, has been emphasized in the 6th National Forest Plan. In response to the declining supply of forest water resources, there is a growing focus on expanding water retention conservation through forest tending and strengthening the management of designated water retention conservation zones. As a result, a watershed-based forest management system has been established, with plans formulated to secure forest water resources [23]. This study not only provides foundational data for national and regional forest planning by spatially predicting

water resources in watershed-based standard forest units in response to climate change but also contributes scientifically to climate adaptation policies.

Author Response File: Author Response.pdf

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Can Forest Management Improve Water Retention Conservation Under Climate Change? A Case Study of the Republic of Korea

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