Populus simonii Carr. Reduces Wind Erosion and Improves Soil Properties in Northern China
Round 1
Reviewer 1 Report
This is a very solid piece of research on an interesting topic. I have only minor comments as follows:
L32-35 This opening statement is OK but the references should better reflect its content. See, for example, Chappell et al. (2018), Middleton (2017).
L39-41 The authors should acknowledge that not all assessments agree about how effective these projects have been, specifically in preventing wind erosion and dust storms. See, for example, Wang et al. (2010) and Wu et al. (2013).
L44 It would be useful to acknowledge that poplars have been used as shelterbelts in many other parts of the world, such as Canada (Richardson et al., 2007) and Russia (Chendev et al., 2015).
L80 ‘more than 1,440 hours per year’: over what time period is this averaged?
Figure 1. Caption should include reference to the green dots and what they signify (a simple cross ref to Table 1 would be OK).
Table 1. Why are sites given both numbers (1-13) and Site indicators (A1-D6). What do A and D signifiy? What happened to B and C? There seems to be unnecessary confusion here.
L108 A photograph of a trap would be useful.
References
Chappell, A., Lee, J.A., Baddock, M., Gill, T.E., Herrick, J.E., Leys, J.F., Marticorena, B., Petherick, L., Schepanski, K., Tatarko, J. and Telfer, M., 2018. A clarion call for aeolian research to engage with global land degradation and climate change. Aeolian research, 32, A1-A3.
Chendev, Y.G.; Sauer, T.J.; Ramirez, G.H.; Burras, C.L. History of east European chernozem soil degradation; protection and restoration by tree windbreaks in the Russian steppe. Sustainability 2015, 7, 705–724.
Middleton, N.J., 2017. Desert dust hazards: A global review. Aeolian research, 24, pp.53-63.
Richardson, J., Cooke, J.E.K., Isebrands, J.G., Thomas, B.R. and Van Rees, K.C.J., 2007. Poplar research in Canada—a historical perspective with a view to the future. Botany, 85(12), pp.1136-1146.
Wang, X.M., Zhang, C.X., Hasi, E. and Dong, Z.B., 2010. Has the Three Norths Forest Shelterbelt Program solved the desertification and dust storm problems in arid and semiarid China?. Journal of Arid Environments, 74(1), pp.13-22.
Wu Z, Wu J, Liu J, He B, Lei T, Wang Q (2013) Increasing terrestrial vegetation activity of ecological restoration program in the Beijing–Tianjin sand source region of China. Ecol Eng 52:37–50
Author Response
Dear Editors and Reviewers:
Thanks for your letter and the reviewers’ comments concerned our manuscript entitled “Populus simonii Carr. Reduces Wind Erosion and Improves Soil Properties in Northern China” (ID:471812).Those comments are all valuable and helpful for revising and improving our manuscript, as well as the important guiding significance to our researches. We have studied all the comments carefully and made corrections, we hope the corrections meet with approval. Revised portions are marked in red in the revised manuscript. The corrections in the paper and responses to the reviewers’ comments are as following:
Response to Reviewer# 1 Comments:
1. Comment: L32-35: This opening statement is OK but the references should better reflect its content. See, for example, Chappell et al. (2018), Middleton (2017).
Response: As the reviewer suggested, we have updated the more appropriate literature in L32-35, showed in L33-36 in revised manuscript.
2. Comment: L39-41: The authors should acknowledge that not all assessments agree about how effective these projects have been, specifically in preventing wind erosion and dust storms. See, for example, Wang et al. (2010) and Wu et al. (2013).
Response: We have rewritten this part based on the reviewer’s suggestion, in L42-44 in revised manuscript. The modified statement is “however, not all assessments agree about how effective these measures have been, specifically in preventing wind erosion and dust storms [7,8].”
3. Comment: L44 It would be useful to acknowledge that poplars have been used as shelterbelts in many other parts of the world, such as Canada (Richardson et al., 2007) and Russia (Chendev et al., 2015).
Response: We are sorry for our expression negligence in this sentence. We have rewritten this part according to the reviewer’s suggestion. The modified statement is “Poplars have been used as shelterbelts in many other parts of the world, such as Canada [9] and Russia [10].”, showed in L44-45 in revised manuscript.
4. Comment: L80 ‘more than 1,440 hours per year’: over what time period is this averaged?
Response: Dust event is the weather phenomena with less than 10 km of horizontal visibility. 1,440 hours per year are the average length of dust in this region every spring (3.1-5.31) in last 20 years. Because of the high spring wind in the area and the serious desertification, the dust event in this area is frequent, which is an important source of wind and sand activities in Beijing, Tianjin and Hebei. The data came from the China Meteorological Data Network.
5. Comment: Figure 1. Caption should include reference to the green dots and what they signify (a simple cross ref to Table 1 would be OK).
Response: It is true as the reviewer suggested that we improved the caption of Figure 1. The modified statement is “Figure 1. Location of the study area in Zhangbei County, Hebei Province, China. The green circle with black dots represents the location of the field site. CK, the control site; D1, site with a forest density of 500 trees·hm-2; D2, site with a forest density of 750 trees·hm-2; D3, site with a forest density of 1025 trees·hm-2; D4 site with a forest density of 1200 trees·hm-2; D5, site with a forest density of 1425 trees·hm-2; D6, site with a forest density of 1700 trees·hm-2. A1, site with a forest age of 15 a (A1 and D2 are the same parcel); A2, site with a forest age of 21 a; A3, site with a forest age of 28 a; A4, site with a forest age of 32 a; A5, site with a forest age of 37 a; A6, site with a forest age of 41 a.”
6. Comment: Why are sites given both numbers (1-13) and Site indicators (A1-D6). What do A and D signify? What happened to B and C? There seems to be unnecessary confusion here.
Response: We are sorry for our incorrect writing. Number 1-13 indicates that we carried out positioning observations on 13 plots. A is the first letter of age and D is the first letter of density. We have remarked the parcels in Figure 1 according to the reviewer’s suggestion. When we studied the influence of age on soil wind erosion and soil improvement, we numbered the plot as A1 / A6 according to the order of age from small to large. In the study of the effect of density on soil wind erosion and soil improvement, we numbered the plot as D1 / D6 in the order of density from small to large. Considering the reviewer’s suggestion, we have improved and perfected the caption of Figure 1, showed in L90-96 in revised manuscript.
7. Comment: L108 A photograph of a trap would be useful.
Response: We have made correction according to the reviewer’s comments. The following figure is a sketch map of a trap in the field site, showed in L142-143 in revised manuscript
Figure 2. Sketch map of a trap in the field site. The unit is cm.
We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. And here we did not list the changes but marked in red in revised paper.
We appreciate for Editors/Reviewers’ warm work earnestly, and hope that the correction will meet with approval.
Once again, thank you very much for your comments and suggestions.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The manuscript entitled "Effects of sand-fixing poplar stands on wind erosion in sandy areas in Northern China" will be of interest to the Reader of Forests. I have written the majority of comments directly on the manuscript. There are several minor edits to language usage.
Consider a revision of the title suggested.
A major criticism is the figures are not very legible - suggest making the font and symbols larger.
Please review the questions regarding P in the discussion suggestion. Consider separating to a new sentence - there is some confusion in the interpretation as presented.
Comments for author File: 
Comments.pdf
Author Response
Dear Editors and Reviewers:
Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Populus simonii Carr. Reduces Wind Erosion and Improves Soil Properties in Northern China”(ID:471812).Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portion are marked in red in the paper. The main corrections in the paper and the responds to the reviewer’s comments are as flowing:
Response to Reviewer #2 Comments:
1. Comment: Consider a revision of the title suggested
Response: We have made correction according to the Reviewer’s comments. The title was revised to: “Populus simonii Carr. Reduces Wind Erosion and Improves Soil Properties in Northern China”.
2. Comment: A major criticism is the figures are not very legible - suggest making the font and symbols larger.
Response: We are very sorry for our negligence of font and symbols in the figures. We have rewritten these parts according to the reviewer’s suggestion by making figures stand alone and font and symbols larger. Also, since the journal is published in color; therefore, when the same symbols appear in the figures of this paper, we adopt different color fills to distinguish the different meanings.
3. Comment: Please review the questions regarding P in the discussion suggestion. Consider separating to a new sentence - there is some confusion in the interpretation as presented.
Response: We are sorry for our incorrect writing. We have made correction according to the reviewer’s comments. “In addition, with the increase of organic carbon, the adsorption of phosphorus by organic matter also increased. Thus when the content of soil organic matter increased, the phosphorus absorbed by organic carbon also increased, and it could improve the availability of phosphorus and reduce the fixation of phosphorus. As a result, the pore condition of soil was improved relatively, which resulted in the decrease of soil bulk density.”, showed in L393-397 in revised manuscript.
4. Comment: What is the difference between sand fixing and windbreak?
Response: The meaning of windbreak is to prevent wind damage; it mainly protects farmland, orchards and other production and living buildings by reducing wind speed. The meaning of sand fixing is to fix quicksand, regulate the climate, prevent soil from blowing, and ensure that human production activities are carried out normally. In this paper, because the study area has the double characteristics of spring multi-wind and serious land desertification, and the study area belongs to the upper wind direction of Beijing, Tianjin and Hebei (a large urban group in China), so the protective forest in this area has the effect of windbreak and sand fixing synchronously.
5. Comment: Are these hybrid poplar clones? The scientific name of poplar needed be listed in the paper.
Response: We are sorry for our negligence of the scientific name of poplar. We have corrected according to the reviewer’s comments. And we have defined the scientific name of poplar in the title section of the article, showed in L48-49 in revised manuscript.
6. Comment: Please add the wind direction in the Figure 1. What is the part between parcels?
Response: We are very sorry for our negligence of the wind direction in the Figure 1. As reviewer suggested that we have shown the main wind direction was showed in Figure 1. The part between parcels is bare land, and we have added this description in section 2.2. Experimental design considering the reviewer’s suggestion. In addition, we emphasized in the description that A1 and D2 are the same parcel, showed in L90-96 in revised manuscript.
7. Comment: Please add units to explain crown extension in Table 1.
Response: We are very sorry for our negligence of the units of average crown extension in Table 1. As reviewer suggested that we have perfected the units in all tables in the paper, showed in L113 in revised manuscript.
8. Comment: This study was carried out only in spring, would there be differences if fall measurements?
Response: It is true as reviewer suggested that this study was carried out only in spring. It is very important to study the effect of windbreak and sand-fixing of forests under the strong wind weather in spring. Because of the strong wind in spring and the worst growth of forests in one year, and the serious soil desertification. As reviewer suggested that in the next study, we will research the effect of wind and sand fixing of forests under different seasonal conditions on this basis. In addition, we look forward to the discussion section on the future study. “Our current research is only carried out during the spring strong wind erosion season, which will provide important information to regional and national decision makers. However, in different seasons, such as summer and autumn and other windy weather, the effect of windbreak and sand fixation of forests has not been reported, this study will be the focus of the future research.”, showed in L393-397 in revised manuscript.
9. Comment: Please add citation in 2.5 Data analysis.
Response: It is really true as reviewer suggested, we have added three references about spring main wind in 2.5 Data analysis.
10. Comment: What do different poplar forests mean in 2.5 Data analysis?
Response: It is true as reviewer suggested, we have rewritten this sentence. The modified statement is ”To quantitatively evaluate the wind resistance effects of poplar forests with different ages and densities.”, showed in L160-161 in revised manuscript.
11. Comment: you did not control the wind direction, you evaluated at only the spring season.
Response: We are very sorry for our incorrect writing, as the reviewer suggested that we have rewritten this sentence. The modified statement is “we designated the wind direction for the NW orientation.”, showed in L348 in revised manuscript.
12. Comment: Why the height of the measured wind speed is two meters?
Response: Internationally, in the field of wind and sand fixing, wind speed monitoring research is usually set to a height of two meters, such as WEQ, RWEQ model agreed wind speed refered to the wind speed of 2 meters height and so on. Because the wind speed at a height of two meters can only be measured in the field, it is more accurate than the data obtained by remote sensing satellite, and this height is relatively close to the near stratum, which can reflect the real wind speed of the near stratum under different site conditions. The monitoring of wind speed at the height of two meters will provide guiding significance for the wind and sand fixing effect and operation and management of the different sites.
13. Comment: The meaning of the last sentence of the second paragraph is unclear in 4.2 Impacts of poplar stand density and age on soil properties.
Response: We are very sorry for our incorrect writing. Considering the reviewer’s suggestion, we have rewritten this sentence. The modified statement is “It is also possible that, when the stand density exceeds a certain critical value, due to the influence of narrow tube effect, wind speed in forest increases relatively, and soil wind erosion increases relatively, and then the fine particulate matter which is easily disturbed by wind in the soil surface is relatively reduced, which leads to the relative coarsening of soil particles.”
14. Comment: The expression on “the other nutrients” in the third paragraph of 4.2 Impacts of poplar stand density and age on soil properties
Response: As reviewer suggested that we have rewritten this part “Finally, with increasing forest age, the development of undergrowth herbs constitutes an important part of net primary productivity, and the decomposition of these plants results in substantial inputs of C, N, and other nutrients improved organic C stimulates microbial communities making nutrients available C .”
15. Comment: Why is there no unit of drying degree?
Response: Drying degree characterizes the degree of climate dryness. The internationally accepted definition is the ratio of the average annual evaporation to the annual precipitation, so the unit is 1.
16. Comment: There is also a need to modify in terms of language usage.
Response: As the reviewer suggested that we have further refined the language usage in the paper.
We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. And here we did not list the changes but marked in red in revised paper.
We appreciate for Editors/Reviewers’ warm work earnestly, and hope that the correction will meet with approval.
Once again, thank you very much for your comments and suggestions.
Author Response File: Author Response.docx
