Structural Optimization of Windbreak and Sand-Fixing Forests: A Wind Tunnel Study
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsYour article is about testing different tree–shrub planting patterns in a wind tunnel to find the best design for windbreak forests that reduce wind and sand damage in desert–oasis areas. The article is well written; however, the authors are requested to address the following comments:
1. The keywords partly repeat words from the title; try adding unique terms
2. In the introduction section, the transition from general windbreak studies to your two species (Populus euphratica and Tamarix chinensis) is abrupt; add a sentence linking why these species were chosen.
3. Figure 3 is not properly labelled, make it more interactive
4. Under 2.5.1: on what basis are the wind speed zones (0–0.6, 0.6-1, and >1) chosen? justify why these cutoffs were chosen. give references if any
5. Table 2: give the R2 value to two decimal points after the decimal
6. Results for 6, 10, and 15 m/s look monotonous. can you improve upon them
7. Low efficiency is understandable, but what do you mean by negative efficiency in your study (Line 304)? Give physical meaning.
8. The discussion repeats some portion of the results instead of interpreting the results; authors are advised to reduce repetition.
9. Mention the novelty of the study by clarifying what is new in the study compared to existing wind tunnel studies.
10. sometimes "P e", sometimes "Pe" in the Table, make them consistent
11. Line 61: Guyot G et all should be Guyot et al
Author Response
We thank the reviewer for the careful reading and the constructive comments, which have helped us improve the quality and clarity of the manuscript. Below we provide a detailed, point-by-point response.
- Keywords partly repeat words from the title; try adding unique terms
Reviewer comment: The keywords partly repeat words from the title; please add unique terms.
Response: Revised. We replaced overlapping keywords with more specific terms such as arid-zone shelterbelts, wind tunnel simulation, aerodynamic efficiency, and sand-fixing forests.
- Introduction: abrupt transition to Populus euphratica and Tamarix chinensis
Reviewer comment: Please add a linking sentence to explain why these species were chosen.
Response: Revised. We added the following sentence to the end of the Introduction:
“Therefore, selecting drought-tolerant, salt-alkali-resistant native tree species with well-developed root systems and strong sand fixation capabilities, and conducting research on planting density and configuration patterns, has become a crucial approach to enhancing the effectiveness of windbreak and sand fixation forests.”
- Figure 3 is not properly labelled, make it more interactive
Reviewer comment: Improve labeling and clarity.
Response: Revised. We clarified the meaning of “H” (multiples of canopy height), marked the boundaries of the forest belt, and added annotations to indicate deceleration and acceleration zones. The caption was expanded for clarity.
- Section 2.5.1: justification for wind speed zones (0–0.6, 0.6–1, >1)
Reviewer comment: Please justify why these cutoffs were chosen, with references.
Response: Revised. We explained that a reduction of more than 40% (V/Vâ‚€ ≤ 0.6) is generally considered effective protection, while V/Vâ‚€ > 1 indicates accelerated flow due to turbulence. References were added: Heisler & Dewalle (1988), Brandle et al. (2004), Wang et al. (2018).
- Table 2: give the R² value to two decimal points
Reviewer comment: Please standardize R² presentation.
Response: Revised. All R² values are now reported to two decimal places.
- Results for 6, 10, and 15 m/s look monotonous
Reviewer comment: The presentation appears repetitive; please improve.
Response: We appreciate this helpful suggestion. We agree that presenting the three wind speeds in a more comparative manner would improve readability. However, at this stage we are unable to substantially reframe the Results section due to constraints in data presentation and formatting. We have retained the original structure for consistency with the rest of the manuscript. Nevertheless, we acknowledge the reviewer’s point and will consider restructuring this section in future work or in a more extended version of the study, where additional data visualization (e.g., comparative plots) can be incorporated.
- Clarify the meaning of negative efficiency (Line 304)
Reviewer comment: What does negative efficiency mean physically?
Response: Revised. We clarified in the 3.3.1 section:
“Negative efficiency indicates that wind speed in the leeward zone exceeded the reference flow, reflecting localized acceleration caused by turbulence or channeling effects within the canopy.”
- Discussion repeats some portion of the results
Reviewer comment: Please reduce repetition.
Response: Revised. We condensed numeric details and emphasized interpretation, mechanisms, and literature comparison. Repetition of Results was removed.
- Novelty of the study
Reviewer comment: Please clarify what is new compared to previous wind tunnel studies.
Response: Revised. We highlighted the following contributions:
Systematic comparison of tree–shrub mixtures versus pure stands.
Introduction of a fan-shaped planting layout.
Testing under multiple wind speeds (6, 10, 15 m/s).
Practical recommendations for optimal spacing in arid zones.
This novelty statement was added to both Discussion and Conclusions.
- Inconsistent abbreviations in Tables (“P e” vs. “Pe”)
Reviewer comment: Please make them consistent.
Response: Revised. All abbreviations have been standardized to Pe for Populus euphratica and Tc for Tamarix chinensis.
- Line 61: “Guyot G et all”
Reviewer comment: Correct to “Guyot et al.”
Response: Revised. The error has been corrected.
Summary
We have addressed all comments by revising the manuscript for clarity, consistency, and accuracy. We believe the revised version is substantially improved and will be clearer to readers.
Reviewer 2 Report
Comments and Suggestions for AuthorsReview of Li et al.
This fascinating modeling experiment explores in a wind tunnel several possible planting schemes for a tree and a shrub species for wind abatement in arid locations. The utility of the study is obvious. It is data-rich, well conceived, and finely illustrated, especially the Appendix. This is a positive review in favor of moving forward.
The ms. needs formatting still, including esp. the Literature cited, and the italics and proper author abbreviations (not italics, followed by periods) for species names in multiple places.
A case could be made for or against adding more context. Not important, but Is it possible from literature to discuss briefly the relationship of wind speeds (and additional relevant parameters) and sand movement? What windspeeds are typical in the region of actual windbreaks? Does the deciduousness of P. euphratica matter? Actual field measurements of the living species in on-line supplementary data? Could you be more explicit about “fan-shaped layout”?
My main concern is not with the quality of the project, which seems fine. I did have trouble, however, with keeping some of the terminology straight. This may be my own “thick-headed-ness” or maybe related to translation (although the English is perfect). But in any case, I did struggle with application of terms and clarity in captions, some of which seem to be used interchangeably, or to be so similarly as to invite more explicit explanations in Sect 2, p. 19, and captions.
It could help to give more info in captions, even if that is more or less redundant with info in the text, including specifying within the captions units used in the graphics or tables. For example, in the Fig. 3 caption explain 1H, 2H etc.
In tables 2, 3, 4 “proportion” in the table columns is called “Relative Wind Speed Area Ratio” in the captions (except Table 4) and corresponds in usage to “wind speed reduction” (as applied on line 192). In Table 4 caption this proportion is called “Relative Wind Speed Area Percentage.” Equation. 2 is a ratio which reflects reduction in wind speed as on lines 192, 226, 231 etc.” Is eq. 2 (windbreak efficiency) the same as the “wind speed area ratio” and “wind speed reduction”? In the appendix the term “wind protection effectiveness (%)” comes into use without definition. Wind speed acceleration zone with percentages is unclear to me despite the discussion around line 369. What acceleration means is clear, but what do the percentages associated with acceleration in the text (e.g., line 265) and in the Table 5 (e.g., 44.11%) differ from wind speed reduction?
It seems that “tightening up” and unification of the terminology would smooth the reading, including explanation in Sect 2 and on p. 19 of every term used, and then with all units apparent in consistent table captions:
Proportion/ Relative Wind Speed Area Ratio/ Relative Wind Speed Area Percentage
Wind speed reduction
Windbreak efficiency
Win protection effectiveness (%)
Wind speed acceleration zone (with reference to %)
The fig. 5 caption mentions “the” black line, but there are two black lines in each figure, presumably the two edges of the forest belt, but this should be stated. The appearance of the species names and their authorships in Table 5 caption is a little out of place, or at least inconsistent with the preceding captions.
The layout of the upper L corner of Table 2 is visually confusing.
Typo that might be overlooked in revision: line 186 (single square bracket]
Hope this helps. To summarize, what needs attention is that the authors are so familiar with the subject matter and procedures that they might assume (for me) too much familiarity on the part of the reader. If others have same perception, easily fixed in revision.
Author Response
General Response
We thank the reviewer for the positive and constructive evaluation of our manuscript. We are pleased that the study was found to be data-rich, well designed, and clearly presented. We have carefully revised the manuscript according to the reviewer’s comments. Below we provide a detailed point-by-point response and the corresponding revisions.
Specific Responses
Terminology unification
Comment1: Terminology such as “Relative Wind Speed Area Ratio,” “Wind speed reduction,” “Windbreak efficiency,” etc., was inconsistently used.
Response: We have created a new subsection “Terminology Definition” in Section 2 to clearly define all terms and ensure consistent usage throughout the text, tables, and figures.
Figure and table captions
Comment2: Captions lacked clarity (e.g., H values in Fig. 3, double black lines in Fig. 5, inconsistent units).
Response: All figure and table captions have been revised to include units, explicit explanations of H values (as multiples of canopy height), and clarification of forest belt edges. Layout issues in Table 2 and terminology inconsistencies in Tables 2–5 have been corrected.
Species names and references formatting
Comment3: Scientific names not italicized or incorrectly formatted; literature cited section inconsistent.
Response: We standardized species names (italicized genus and species, proper author abbreviations) and reformatted the reference list according to journal guidelines.
Typographical and layout issues
Comment4: Line 186 contained a bracket typo; Table 2 layout unclear.
Response: All typographical errors were corrected, and Table 2 layout has been improved for clarity.
Additional discussion
Reviewer comment5: The reviewer suggested adding more context, such as the relationship between wind speed and sand movement, typical wind regimes in the study region, and the possible effect of P. euphratica deciduousness.
Response: We sincerely thank the reviewer for this valuable suggestion. We fully agree that additional discussion of wind–sand relationships and regional wind regimes would enhance the practical relevance of the study. However, at this stage we are unable to add substantial new material to the Discussion section due to limitations in available data and space. We have therefore noted this point as an important direction for our future work, and we will carefully consider including such contextual information in subsequent studies or an extended version of this work.Additionally, here's a brief definition and advantages of the fan-shaped layout, though it cannot be fully elaborated within the text. The fan-shaped layout refers to: using the center of the forest strip or the main tree row as the “axis,” radiating outward on both sides to form a distribution resembling a fan or wedge shape. Advantages:
â‘ Airflow Guidance:
When wind encounters the edges of the fan shape, it is gradually guided to both sides, reducing the likelihood of wind directly penetrating the forest strip.
This aids air dispersion and reduces concentrated turbulence downwind.
â‘¡ Expanded Protection Area:
Compared to rectangular layouts, the fan structure creates a broader low-wind-speed zone downwind.
â‘¢ Sand and Dust Diffusion Control:
In arid desert regions, the fan-shaped layout is more effective at mitigating wind erosion and preventing the formation of concentrated dust pathways.
â‘£ Structural Complementarity:
Different tree species can be flexibly arranged within the fan structure (e.g., poplars in the upper layer, tamarisks in the lower layer), working synergistically at varying heights and angles.
