Typical Plantation Water Use Strategies Are Determined by Environmental Conditions and Plant Eco-Physiology in Beijing, China

Round 1

Reviewer 1 Report (New Reviewer)

Comments and Suggestions for Authors

This manuscript presents interesting results related to the determination of the water sources of typical tree species in different areas of Beijing and the examination of changes these water sources during the shift from the growing season to the non-growing season in typical tree species in Beijing. The adopted approach in this study was very consistent since it could provide more insights into the development of new sustainable forestry management strategies according to the water use efficiency of trees in different areas.

The manuscript was well introduced, and the authors adopted convincing methods with a discussion of the different obtained results. However, the manuscript needs moderate revisions to be suitable for publication in Forests.

General comments

- Comment 1: The English of this manuscript needs slight improvements;

- Comment 2: To be more conclusive, a 2-year experiment is needed.

 

Other comments

Abstract

1. Line 19-20: Please italicize species scientific names.

 

Introduction

2. Line 55: please change “;” to “.”.

3. Lines 59, 63, 67 and 69:  please correct the citation form. Please check throughout the manuscript.

4. Line 68: “the rocky, mountainous” please remove the coma.

5. Line 69: Please italicize species scientific names. Please check throughout the manuscript.

6. Line 71-73: please add references.

7. Line 86: please remove the space between the value and the %.

 

Materials and Methods

8. Lines 114, 125, and 129: Please add a space between the value and the unit. Please check throughout the manuscript.

9. Line 120: Please add “respectively”.

10. Line 139: please change “ECH20-5TE Soil” to “ECH20-5TE. Soil”.

11. Line 150: please check and correct.

 

Results

12. Line 217: please change “decreased significantly” to “significantly decreased”.

13. Lines 227 and 228: “indicating a strong influence of evaporation on soil and trees during the sampling period”, please remove to the discussion section.

14. Line 232; please add the significance of the abbreviations included in Figure 2.

15. Line 244: please change “temperature during” to “temperature variation during”.

16. Line 253: please change “varied significantly” to “significantly varied”.

17. Line 254: please change “differed significantly” to “significantly differed”.

18. Some words in Figures 4, 5 and 6 are fuzzy.

 

Discussion

19. Line 318: please change “varied significantly” to “significantly varied”.

20. Line 349: “value However“, please add a coma. italicize the scientific name.

21. Lines 376 and 377: you have two separate citations in the same sentence, please check.

Comments on the Quality of English Language

The English language of this manuscript needs slight revision.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report (New Reviewer)

Comments and Suggestions for Authors

Reviewer comments on "Plant water use strategies are determined by environmental conditions and plant physiology and ecology in Beijing, China" by Yujia Chen et al. Submitted to Forests.

 

This article compares the stable isotope composition of water molecules within soil, plant, and precipitation for two species of trees within the ranges adjacent to Beijing, China.

The authors find that the water sources of each species vary within mountainous sites vs. flat lands, indicating that the angiosperm species (genus Acer) obtains its water from deep sources. In contrast, the pine tree obtains water from superficial sources in the mountains but shares the hydraulic niche within plains.

 

Overall, the article is clear and nicely written, the information, as far as my limited knowledge of isotopic analysis reaches, is correctly displayed and informative, and the conclusions logically follow the results presented. Therefore, I only have minor comments for this document>

 

1. Correct the nomenclature of species across the text, including italics. The first time species are used, they should include family and authority, according to the Botanical Nomenclature rules. Posteriorly, use the abbreviated form for A. truncatum and P. tabuliformis.
2. Figure 6 should not be in a 3D display, as this figure has no z-axis. Replace the figure for regular stacked bars in 2D. The depth representation is confusing in this figure. Try to use the upper soil layer atop and the deeper at the start. The color palette would be better if using Earth Tones.
3. Figure 2 should indicate the meaning of each acronym in the figure legend, as well as the site where the experiment was performed.

 

I hope these comments are useful in improving this document, which can be a valuable contribution to direct restoration priorities in this area.

Sincerely,

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report (New Reviewer)

Comments and Suggestions for Authors

An excelente study with clear results which are also clearly presented. In case I have something to comment, it is the vinculación of the study with Beijing. Although justified due the importante of this city, I would prefer a more general approach. The study itself is interesting enough. The work to do is describing these forest ecosystem from botanical perspective, such as the origen of these forests, their relations with other similar ones in China and so on. If this aim is achieved, the study will become more general in scope and with a wider focus.

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report (New Reviewer)

Comments and Suggestions for Authors

The manuscript Plant water use strategies are determined by environmental conditions and plant physiology and ecology in Beijing, China by authors: Yuja Chen, Tonggang Zha, Hongli Zhang, Lili Zhao, Ao Wang, Qingzhou Cui, Junling Song, Hengshuo Zhang, Yang Yu contains interesting information about the peculiarities of water use by trees under different water supply conditions.

This is quite an important aspect especially for modified urban landscapes and remediation zones.

The data presented is interesting and original.

The manuscript is formatted according to the rules.

However, it is not clear to me why data on size, quality and development features is not provided. They must clearly correlate with such different environmental conditions.

I consider it necessary for this work to include photographs of trees and their fragments.

It also seems wise to more clearly state the hypothesis (it should be broken down or otherwise structured) of the study in the introduction. It is difficult to understand whether it is confirmed or not given this presentation. A hypothesis cannot be stated as a self-evident truth. I think this should be highlighted in a separate paragraph and clearly formulated.

This will allow us to draw a clearer conclusion.

Overall, the manuscript requires minor corrections and additions before publication.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

I do not understand what is the contribution of this paper. The fact that plant water use strategies are determined by local environmental conditions, plant physiology, and ecological factors has been known for a long time. The data collected by the authors may be useful, but it is not contributing to our understanding of forestry and forest ecology. 

I am happy to reconsider my decision if the authors can clarify the significance of their contribution and the novelty of this work.

Reviewer 2 Report

Comments and Suggestions for Authors

The paper is generally good. I have only some notes mainly concerning clarification of the methods

·       It would be good to give more data on Beijing climate (seasonal dynamics of temperature and precipitation, not only annual means), tree species and forest stands (age, density) under study.

·       As I understood, 3 mature branches (approximately of which size/age?) were cut from each tree once a month (totally 5x3=15 branches from each tree). What was the age/size of trees? Couldn’t such sampling affect tree behavior (it depends of the size of branches sampled)?

·       No any meteorological data mentioned in the Methods section, but “other pertinent environmental parameters, such as meteorological and soil water variables” were mentioned in the Introduction (lines 92-93).

·       Maybe it would be good to add the figure of xylem and precipitation water d¹⁸O by months

·       It would be good to say something about water source partitioning algorithm (MixSIAR), especially taking into account that d¹⁸O in rain water and soil water vary much more than in xylem water.

·       According to the Google maps plain sample plot is rather close to the river. How deep is the ground water level there?

·       It makes sense to mention in the introduction high variation of rain water d¹⁸O and its possible reasons

Some other notes are in the attachment

Comments for author File: Comments.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

In their article, the authors presented interesting results of their research. In my opinion, they would be more readable after taking into account the following comments:

- in the abstract (line 13) and in the "Materials and methods" section, the authors provide the location of the research sites (lines 104 & 109), what is the nature/function of forest farms in the structure of the city of Beijing? Are they just research farms? What is the % share of forests in Beijing's ecosystem?

- why the depth of the soils was not given, and the laconic description of the permeability, composition and retention applies only to the soils for the Plains area? Soil retention capacity (pf curve) is of significant importance for soil water balance.

- Figure 1 requires changes to the description regarding the location of farms (instead of mountain area - Badaling Forest farm) etc. It is the DEM values on the map that show us where the mountains are and where the plains are; it should be indicated on the drawing that the shape reflects the boundaries of Beijing.

- Could the location of the farms in parts of Beijing with different levels of urbanization have influenced the results?

- What is the scientific meaning of "typical sunny days" in line 119?

- the description of the methodology includes information about collecting samples in 3 repetitions (line 122), are the results presented below average values for them?

- How were trees selected for analysis with roots whose range corresponded to the depth of the soil profile (line 126)?

- Why are the sampling depths described in lines 128-129 not reflected in the presentation of the results (fig.4-5)?

- Description of branch sampling methodology needs elaboration (how much, where, how) - line 123.

- why no information about the possible location of the soil water table (if any) was provided?

- it would be worth discussing the credibility of the results presented in Fig. 6.