Quantifying Forest Litter Fuel Moisture Content with Terrestrial Laser Scanning

Round 1

Reviewer 1 Report

The authors present an experiment by which to assess accumulated vegetation moisture in forest systems using TLS. The paper is well structured, the wording allows understanding of the experiment. The only suggestion is to improve the explanation of the results by providing tables that explain, numerically, the graphical results shown in the figures. The methodology section describing the procedure by which the intensity level recorded by the scanners is transformed into reflectance could also be expanded.

 

Line 57. …..with these attributes. What attributes? This sentence could be better worded

 

Line 163-165. This sentence should also discuss or consider the option of LIDAR flights with UAVs.

 

Line 310……. It was logistically infeasible to collect spectral reflectance curves of every sample at every distance at each time interval. This sentence adds nothing and it is debatable whether such an action could have been taken and whether it would add to the quality of the work.

 

Point 2.2.2 Spectrometer Data Collection. Were calibration standards of the reference target used?

 

Line 357 Care was taken to ensure that no points that were returns from the sample trays or tray bottoms were included. This part is a delicate process in the process. It could be detailed and accompanied by graphical documentation. Was the task supported by classifications by level of intensity?

 

Figure 6. What setting do the figures show? This should be included in the figure caption. The equations resulting from the adjustment could also be added.

 

Figure 7. Same as figure 6

 

Line 435. What is the significance coefficient?

 

Point 3. In general, this point in each of the sub-sections would be better explained if for each figure a table is added with the type of adjustment made, the parameters of the adjusted equation, coefficient of determination and coefficient of significance.

Author Response

Thank you so much for the review of our manuscript. We have made changes so please review the updated manuscript. We have outlined the changes made in response to your feedback in the attached document. Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Dear authors,

I reviewed the paper entitled “Quantifying forest litter fuel moisture content with terrestrial laser scanning” by Jonathan L. Batchelor et al.

The paper makes a comparative analysis of two TLS to estimate moisture data from dead forest litter along with 3D structure of wildland fuels/vegetation. For that, some samples, control and test data, were used in a laboratory experiment. It consists of scanning sample trays of each material along the time during a drying process until the sample moisture reaches ambient relative humidity. In addition, using a field spectrometer, spectral reflectance values were recorded during the same drying interval. The results are very promising regarding the use of lidar data to detect and quantify fuel moisture across a range of forest litter types.

The paper is well-designed and written. The introduction is long but it gives a good overview of the research problem and the final goals are clearly stated. The data and method section describes the data and methodology in great detail, making the experiment reproducible. The results are clearly presented and widely discussed. The conclusions are supported by the results of the experiment.

My only concern is that it is an experiment in a laboratory under controlled conditions but what would be the performance in field measurements in real work under different environmental conditions? This fact is contemplated by the authors, so the current paper is a good starting point for this research line.

Author Response

Thank you so much for the review of our manuscript. We have made changes so please review the updated manuscript. We have outlined the changes made in response to your feedback in the attached document. Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

Overall, the study is of relevance to the fields of both remote sensing and fuel moisture and the authors should be commended on producing a quality manuscript. Research bringing these fields together is of great importance and the reviewer believes that this manuscript will make a unique contribution to the literature. Prior to publishing I believe the manuscript can be improved with the implementation of some changes.

I have summarised my suggestions into significant and minor changes in the attached document. 

Comments for author File: Comments.pdf

Author Response

Thank you so much for the review of our manuscript. We have made changes so please review the updated manuscript. We have outlined the changes made in response to your feedback in the attached document. Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

The authors have provided a comprehensive response to the suggestions made in the initial review.  The reviewer recognises that balancing the suggestions of all reviewers is challenging especially when it comes to expanding or making things more concise.

Regarding the regression breakpoint of 100% - the added statement by the authors does clarify the selection of this value being subjective. It could be mentioned in the discussion that further research could investigate the capacity of TLS to detect moisture changes under fibre saturation point and/or any physical processes driving the selection of 100%.

Overall, the authors should be congratulated on this study and the detailed nature of this paper - it is a unique contribution to the literature.