Estimating the Aboveground Biomass of Robinia pseudoacacia Based on UAV LiDAR Data
, Jianjun Zhang 1,2,3, Yanni Zhang 1, Yawei Hu 1, Jiongchang Zhao 1 and Yang Li 1Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear editors and authors,
The article is based on data that can be exploited in a better way by improving at least 3 sections of the manuscript, material and methods, results, and discussion. First of all, the way of citation must be revised, and the scientific name of the species must be corrected in some cases.
It is not clear what the authors measured from ground level to compare the results and how they measured (with which instruments). Also, for the AGB estimate, it must be specified how it was estimated in the "measured" version, and the level - individual tree or stand (per hectare). A subchapter should be added on materials and methods.
Can the authors check the values ​​and units for slope and aspect included in table 1?? How did they calculate AGB from table 1? CV from table 1 is middle or high. I can only intuit the meaning and the unit.
Usually, in forestry, relationships between H and DBH are developed to estimate tree height as a function of DBH. Why do you use reverse? All the 506 trees from your 14 plots are growing in the same conditions to use in a single chart and to produce a single equation? Why didn’t you use a relationship between DBH and crown diameter?
How was the biomass from table 2 estimated? Are the coefficient produced based on 14 trees? How is it? Why W instead of AGB and D instead of DBH? What AGB is? Total one?? We do not know if the biomass from stem, branches and leaves is included.
Some plots are missing from table 3. Here are described 11 from 14. The sum of trees is 514 for 11 plots, not 506 as you described in the article. It is difficult to understand. Make it clear!
Pages 9 to 12 should be reconsidered by the authors, the result are not presented objectively. In each scatter plot you should include not a regression, but a line that indicates the equality between estimated and measured values. This helps you to easily understand the quality of the estimates. For example, in 2 plots the average tree height was underestimated and in the others 12 plots the average tree height was overestimated by 2-3 m at least, which is imprecise for average height values ​​of 6-13 m (Figure 8). In the case of estimating the average diameter, the results are unacceptable. For most plots the average diameter is overestimated with 4 to 6 cm, which is a lot because the average diameter varies between 10 and 17 cm (Figure 10). The estimates of average diameter and height lead to considerable overestimations of the AGB at plot level and watershed scale, aspects that are not highlighted in the discussion section. How much are the differences for individual tree?
The results are not discussed on specific section.
I hope that my point of view will help you to improve your manuscript for publication. In its current form, the manuscript needs changes that affect the results and conclusions.
Comments on the Quality of English Language
Minor editing of English language is necessary.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe paper discusses the estimation of aboveground biomass of Robinia Pseudoacacia. UAV LiDAR Data is used for modelling. The authors need to address the following issues:
1) The following sentence of the Abstract should be revised:
To explore the spatial distribution of aboveground biomass of Robinia pseudoacacia plantation on the scale of watershed.
2) There is confusion in the use of the terms maximum and minimum in the Abstract.
3) The citing style is not correct.
4) The following papers could bring value for the manuscript, authors should explain the novelty of their work and its contribution to the literature.
i) J Lu, H Wang, S Qin, L Cao, R Pu, G Li, J Sun. (2020). Estimation of aboveground biomass of Robinia pseudoacacia forest in the Yellow River Delta based on UAV and Backpack LiDAR point clouds. International Journal of Applied Earth Observation and Geoinformation, 86, 102014.
ii) d’Oliveira MVN, Broadbent EN, Oliveira LC, Almeida DRA, Papa DA, Ferreira ME, Zambrano AMA, Silva CA, Avino FS, Prata GA, et al. Aboveground Biomass Estimation in Amazonian Tropical Forests: a Comparison of Aircraft- and GatorEye UAV-borne LiDAR Data in the Chico Mendes Extractive Reserve in Acre, Brazil. Remote Sensing. 2020; 12(11):1754.
iii) Zhou, L.; Li, X.; Zhang, B.; Xuan, J.; Gong, Y.; Tan, C.; Huang, H.; Du, H. Estimating 3D Green Volume and Aboveground Biomass of Urban Forest Trees by UAV-Lidar. Remote Sens. 2022, 14, 5211.
6) All tables and figures should be cited in the text. For instance, Table 1 is not mentioned in the text.
7) Equations should be numbered and cited appropriately in the text.
8) The method used for estimation should be clearly mentioned in the Abstract and Introduction sections.
9) Results presented in Table 2 should be further elaborated.
10) The term “Table” should not be abbreviated as “Tab”.
11) Fig 7 should be placed after the first paragraph of section 3.3, and a similar argument holds for Figure 9.
12) The term accuracy is repeated on lines 288-289.
13) Future studies mentioned in section 4 should be presented in the Conclusion section.
Comments on the Quality of English LanguageThe quality of English is good, minor corrections are required. Please see the "Comments an Suggestions for Authors".
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsWhen the article is examined in general, it is seen that it is well structured and the results are well discussed. It must be corrected in accordance with the journal spelling rules, and the Latin name of the studied plant must be written in italics and the second word starting with a lowercase letter. It will be published after minor corrections.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsDear editors and authors,
The authors improved the manuscript mainly, but there are still features that need to be clarified. For example, the authors should revise all the manuscript in order to drop out the editing errors (in many places a space must be added).
Lines 107-108: How do you measure DBH? Using a caliper?? What is a diameter at breast height ruler?? Please, replace “is measured” with “was measured”.
Lines 109-112 should be rephrased. I don’t understand the meaning for “calculate the relationship” (line 111).
Lines 221-222: It is not true… There is a noticeable overestimation in average tree height for almost all cases. There aren’t high and low heights (between 6 m and 13 m). You should be more precise.
Lines 235-236: Be more specific, please!
Line 240 should be rephrased, you estimated the biomass.
The title of Figure 3 is good? There is just a map showing a distribution.
Line 294: DBH was estimated, not calculated.
The discussion section still needs improvement because you don’t compare (discuss) your results with literature results.
I hope that my point of view will help you to improve your manuscript for publication.
Comments on the Quality of English LanguageMinor editing of English language in necessary.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors need to address the following issues:
1) Use of imperative in lines 109-115, 240 and 325-327 should be avoided.
2) Misalignments of Table 1 should be corrected.
3) Use of first person pronouns in lines 178-182 and 309-312 should be avoided.
4) In their response letter, the authors indicated that they have added prospects for the future in the conclusion. However, there is no information about future studies in the Conclusions section. Future studies mentioned in section 4 should be restated in the Conclusions section. In scientific papers such studies are mentioned in the Conclusions part.
Comments on the Quality of English LanguageMinor editing is required.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
