Study on the Water Mechanism of Sparse Grassland Decline of Ulmus pumila L.

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors conducted an interesting study on the impact of different environmental factors on the sap flow regulation in the drought affected tree species. They showed that among other factors the predominant diagnostic factor of the tree decline is the reaction of the sap flow on VPD change after the rainfall. The results look interesting for publications. However, some clarifications should be needed.

Overall, it is not clear what the mechanism is behind the observed consistently increased sap flow due the VPD increase. One would oppositely think that the reduction in the canopy size due to decline would reduce its transpiring capacity through leaf stomata and the respective sap flow.

Particularly:

This statement is not clear: " Within this plot, Ulmus individuals were distributed in patches, including those with mild, moderate, severe, and extremely severe decay". Does it mean that there were patches of the mild, moderate, severe, and extremely severe decayed trees, or that within the different patches were trees with the different decay stages? The first case would suggest that there are some systematic non-tree related differences significantly affecting the experiment design.

This statement is not clear: " Furthermore, we employed a random sampling method to grid the plot and measured soil moisture at three randomly selected orientations for a time-series investigation before and after rainfall." Have the soil moisture measurements been done near the measured trees to be representative?

This statement is not clear: " The results indicate that sap flow velocity on rainy days was significantly lower than in the days preceding rainfall, particularly when rainfall exceeded 5 mm"

Figures 6 and 8  - very hard to follow. Could you please consider changing the figures.

Kind regards

Author Response

Thank you very much for the feedback of your article. The specific reply is shown in the annex.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear author

The study’s purpose is generally clear but consider briefly specifying why studying Ulmus pumila L. in arid regions is essential.

The abstract lacks in the presentation of results. The average sap flow rates provided are informative but could be made more concise. Perhaps summarize the range or average decline rather than listing each rate or indicate stages only if they align with distinct physiological observations. The last sentence of abstract feels cut off. The abstract should end with a brief statement on how these findings contribute to managing or understanding the decline of Ulmus pumila L. under arid conditions.

There is a transitional gap between paragraphs of the Introduction section. The significance of the study is missing in introduction. The novel aspect and clear objectives.

The heading 2 (study area) should be part of Material and method section. Please reorganize the contents.

Line100: The 22-sample size is quite small for such a huge population.

Section 3.2: The detail of experiment design is not clear. What statistical design was adopted?

The results are obvious and simple but with good presentation. However, I recommend to adopt some advanced analytical techniques or model for in-depth interpretation of results.

The discussion should be improved by citing more references from literature.

Author Response

Thank you very much for the feedback of your article. The specific reply is shown in the annex.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

12.11.2024

 

The manuscript entitled "Study on the water mechanism of sparse grassland decline Ulmus pumila L." was reviewed.

 

The manuscript presents holistic approach to dissect prevailing conditions leading to Ulmus pumila L. decline. Well presented study and just few comments were raised. Therefore, I recommend the publication of this manuscript in "Forests” after taking care of the minor comments.

 

1. General:

- The manuscript language is good.

- The scientific name should be italicized all over the manuscript including the title; Ulmus pumila L.

 

2. Materials and methods:

- Lines 166-174: for the "Meteorological data acquisition", standard weather stations have sensors at 4-6 ft above ground level. However, the entire canopy of stress under investigation are exposed to weather conditions at all levels starting at ground level up to several meters above ground. Therefore, your conclusions are biased towards the 4-6 ft level. You should have measurements for temperature, RH and wind speed for at least three levels along tree height. Please reply to this major factor.

 

3. Results:

- Well presented

- Figure (4): the scale presented in the pane A is not correct, please adjust as in panel b.

 

4. References:   

- Please cite  more recent articles as only 30% of cited articles are published in the last five years.

 

 

 

Author Response

Thank you very much for the feedback of your article. The specific reply is shown in the annex.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I am pleased that the authors paid attention and clarified the comments I made in the previous round of review. The quality of presentation in manuscript is significantly improved and I think it can now be accepted for publication.

Kind regards,

Reviewer 2 Report

Comments and Suggestions for Authors

The revisions have been accepted.