Response of Alpine Timberline to Permafrost Degradation on Changbai Mountain

Round 1

Reviewer 1 Report

This manuscript uses the freezing number model and support vector machine method to analyze the surface frost number and alpine timberline over the past 20 years in Changbai Mountain, the highest peak in Northeast China,' which helps to understand the impact of climate change on Alpine Timberline and Permafrost Degradation. However, there are still some important contents that have not been clearly introduced and need to be revised:
1. L25: It is necessary to add a description of the scientific value or significance of the research results of the paper.

2. L56-73: mainly describes the vegetation situation of Changbai Mountainits ,with the geological environment effect mechanism, and it is suggested to describe in the discussion.

3. L80-84: it is necessary to point out the scientific problem in the last of the introduction.

4. L356-358: “the year of the maximal value of the elevation of the alpine timberline 2015>>2011>>2000>>2005>2021”. It is necessary to explain the reasons for this change in the discussion.
6. L366-423: It is necessary to supplement the discussion part of the article with some necessary references.
7. In the discussion section, the author explained more about the response mechanism of geological environment to permafrost and forest line changes, E.g. Section 4.1. However, there is not enough supporting research in the paper.
8. The conclusion needs to reflect the new findings from your research.

Author Response

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Reviewer 2 Report

1.       Results section only presents your own results, rather than quoting other people’s research results, such as reference[50]、[51]、[52]. Please check and correct.

2. It is suggested that the discussion section should be reorganized, adding comparison between the permafrost in the Changbai Mountain region and other regions or related studies. By conducting comparisons with other studies, we can evaluate the reliability and universality of our findings, thereby enhancing the scientific value of our research. Discussing the response of alpine timberline to permafrost degradation.

Author Response

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Reviewer 3 Report

This paper analyzes the impact of permafrost degradation on alpine timberline in Changbai Mountains by combining ground meteorological stations and remote sensing data, which has certain highlights and innovations. However, there are some shortcomings in the paper that need to be improved.

1. The abstract introduces a lot of research background, and lacks the summary and conciseness of research results.

2. L74-L78: The significance and contribution of the research are not explained.

3. L101: In Figure 1, please indicate the distribution range of alpine permafrost in the Changbai Mountains.

4. It is recommended to simplify the more common methods in 2.3 Methods, such as M-K test.

5. In 3.1, is the NDVI value of the forest area or the whole study area?

6. L229-L231: Precipitation is only based on meteorological station data, which cannot represent its spatial impact on permafrost. In addition, permafrost refers to the frozen soil of two years or more, and the change of one year cannot reflect the change of permafrost.

7. L366-L423: There is a lack of literature in the discussion to support your results and a discussion of how your results compare to those in the existing literature.

8. L424: The conclusion should not be a repeat of the previous results.

Author Response

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Reviewer 4 Report

Review of the manuscript:

Response of Alpine Timberline to Permafrost Degradation in Changbai Mountain

Authors: Wei Shan, Guangchao Xu, Yan Wang, Lisha Qiu, Ying Guo, Chengcheng Zhang

In the permafrost zone, the conditions for the development of vegetation are closely related to the state of the permafrost. The authors study Changbai Mountain, as the highest peak in northeast China, as well as an area of permafrost where vegetation has an obvious vertical distribution pattern and timberline has clear boundaries. The alpine treeline zone is a generally accepted indicator of global warming. In this study, the authors analyze the frost extent and structure of timberline by combining ground-based and remote sensing data using a frost number model and support vector machines. The authors found that the rise of vegetation upslope is extremely sensitive to changes in the structure of permafrost over the past 20 years and lags about one year behind changes in precipitation. As in all similar studies in different parts of the planet, the authors show that under the influence of permafrost degradation, the rate of upward migration of alpine forest increases.

Undoubtedly, the results obtained are interesting and relevant. The methods used correspond to a high professional level.

It is worth noting that the results obtained are similar to similar studies in other parts of the planet. The general trend is the same. The authors probably shouldn't list too many "well-known" results in the Conclusions section. It is better to focus on the specific results of their research - are they likely to be able to find differences in the overall result that were identified on their mountain compared to other regions? Perhaps this is where the significance of this study lies.

Author Response

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Round 2

Reviewer 3 Report

The author responded to all my concerns and suggested acceptance for publication.