Assessing the Allometric Scaling of Vectorized Branch Lengths of Trees with Terrestrial Laser Scanning and Quantitative Structure Modeling: A Case Study in Guyana
Round 1
Reviewer 1 Report
This study explores the allometric relationships between tree branch lengths in 3D scalar and vector modes based on TLS and QSM. I believe it is an interesting study, however, I have a few concerns before I recommend it for publication.
1. The purpose of this study should be better addressed and defined, although there is some description at the end of the intro part, still it does not clearly what is the meaning and why this work should be carried out.
2. The authors only tested the tropical tree dataset, it should be narrowed into this scope in this paper, as it may have different behaviour for other forest types.
3. The study site and methodology are not clear, for example, we don't know the tree species, forest conditions and other forest parameters. Also, we don't know the scanning information like the point density, scanning angles, etc.
4. line 98, is that ten trees or ten plots are used in this study, if it was only ten trees used, then the results are not very convincing to support your findings.
5. Results parts are basically repeated patterns for similar comparison, it did not bring forward too much new information, I would suggest the authors re-organize this part to increase the readability.
6. A log-log linear model is not very convincing and even reach some R2 less than 0.5, it should be better justified why choose this allometric model.
7. One of the highlights of this paper is the use of QSM, but I did not see the advantages of this approach in the main text.
English is mostly okay to read
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The author explores the allometric scaling between tree branch lengths in vector mode through terrestrial laser scanning data and quantitative structure modeling. The idea is interesting and the manuscript is generally clearly written. I only have some minor concerns about the details of data processing and the descriptions provided in the article.
1. I suggest providing more detailed descriptions of concepts such as scaling exponent and the SMA method to facilitate readers' understanding.
2. Although a validated dataset from others is used, I recommend supplementing basic information about the experimental trees and point cloud data, such as tree height, tree species, whether they are isolated individual trees or trees in competitive forest stands, and whether the data were collected during the leafy or leafless period. This will help to demonstrate the rationality and objectivity of the sample data selection.
3. While TLS can provide high-density point clouds, it is essential to be aware that in complex forest scenes, there might be instances of missing data in the point cloud due to factors such as canopy occlusion, especially in the upper parts of tall tree canopies. It is prudent to consider the potential impact of such missing data on the accurate extraction of branch lengths. Following the tree crown modeling, it would be valuable to clearly explain the method used to extract branch attributes, whether it was accomplished through automated algorithms or manually measured through sampling. Additionally, it would be beneficial to assess the precision of the results based on branch lengths and ensure their acceptability.
4. The tree crown branch structures and the different branch variables could be organized in appropriate charts or tables, which will be more reader friendly.
5. In Figures 2-4 and 7-9 (a, d, g), there seems to be a clear boundary of data points at Y=-2. This is an interesting phenomenon. It would be better to provide corresponding analysis and explanations.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
For the scope of the study maybe best addressed in the title as well since it only has ten plots in tropical areas.
English are okay but can be improved
Author Response
Dear reviewers,
We would like to thank you for your careful reading, helpful comments, and constructive suggestions, which has significantly improved the presentation of our manuscript. A point-by-point response is as below.
Comments and Suggestions:
For the scope of the study maybe best addressed in the title as well since it only has ten plots in tropical areas.
Response: As you suggested, due to the limitation of the study data, it would be better to add the scope of the study in the title, so we changed the title to “Assessing the allometric scaling of vectorized branch lengths of a tree with terrestrial laser scanning and quantitative structure modeling: a case study in Guyana”, highlighted in the text with the red-color.
Thanks again for your comments and suggestions.
