Using the Error-in-Variable Simultaneous Equations Approach to Construct Compatible Estimation Models of Forest Inventory Attributes Based on Airborne LiDAR
Round 1
Reviewer 1 Report
The topic of the article is interesting and may fit within the scope of the journal. In this manuscript, the simultaneous equations with the error-in-variable method based on airborne lidar data for four forest types are constructed. The problem of incompatibility in the simultaneous estimation of multiple stand variables is solved while ensuring accuracy. The manuscript has abundant experimental data and a heavy workload. However, in the introduction, results, and conclusions, there are some aspects that have not been adequately evaluated and therefore the article requires major revision.
The main concern to be addressed is the following:
Why use the error-in-variable method to construct simultaneous equations? I recommend that relevant content should be supplied in the introduction.
I recommend supplying a table detailing all the alternative lidar-derived variables.
I have many doubts about the results: why the response of the same variable in different tree species is inconsistent, for example, CC is positively correlated with H of Fir, while it is negatively correlated with other tree species. There are many similar problems in Table 2, which I think should be explained in the discussion.
How do you consider the spatial autocorrelation among sample plots in the model development?
Why don't you use seemly related regression rather than error-in-variable simultaneous with independent dependent variables?
Furthermore, I feel that the overall clarity of the manuscript should be improved. There are many typos and vague expressions in the manuscript. I provide multiple instances below that I feel should be clarified below. In general, I did not comment on smaller grammatical errors throughout. I think the paper needs more English expression.
Line 103: Please correct the title of Figure 1: “Study area and region and distribution of the field plots.”
Line 127 Please correct “the study area was 11,741.0 × 103 ha ”
Lines 130-133 Please check the scientific name of the plant
Line 138 Should read “The field plots in the eastern and western regions and Nanning…” instead of “The field plots in the eastern, western and Nanning regions…”?
Line 158 What is meant by “the average trees”? Trees with average height or trees with average diameter at breast height? Please clarify.
Line 178 Why Fir and Eucalyptus have approximate D, but quite different G. Is it because the density difference is large? I recommend adding stand density variables in Table 1.
Lines 230-232 I suggest deleting “(any density variable other than CC)”
Line 287: What package in R was used? The package should be named and cited appropriately.
Author Response
Dear Reviewers.
Thank you very much for your constructive comments and suggestions on the original manuscript. We accept all your comments and suggestions.
We have great respect for your serious and rigorous scientific attitude and high theoretical level.
Best wishes.
The authors
Author Response File: 
Author Response.docx
Reviewer 2 Report
The manuscript handles the comparison of basic stand attribute estimations(mean stand height, mean dbh, basal area and stand volume) with simultaneous equations and independent models which were both based on airborne LIDAR data. The outputs give useful information especially for forest planners and managers. English quality is good. The similarity index, (gave as 29% using Ithenticate - 18% when excluding references) can be considered in accepted levels. However, some suggestions/corrections were given as follows to increase the quality of the manuscript:
v Page 2, line 81: The situation on the other types of remote sensing data such as satellite images or aerial photos should be given after the sentence of “……..is obviously insufficient.”
v Page 2, line 92: A full stop is needed after the sentence of “….the best SEq”
v Page 3, line 103: The heading of the Figure 1 should be corrected. The word “and” used two times.
v Page 3, line 127: The number of “3” in “103 ha” should be used as superscript.
v Page 3, line 128: Latin name of the given species as “Cunninghamia lanceolate” should be written in italics.
v Page 4, line 131: Latin name of the given species as “Pinus massoniana” should be written in italics.
v Page 4, line 131: Latin name of the given species as “P. yunnanensis var. tenuifolia” should be written in italics.
v Page 4, line 132: Latin name of the given species as “P. massoniana” should be written in italics.
v Page 4, line 132: Latin name of the given species as “P. elliottii” should be written in italics.
v Page 4, lines 160-162: Did you make a t-test to see whether the allometric equations fit or not? A further explanation is needed.
v Page 5, table 1: The precision of the values given under the diameter at breast height column is too high. It is given in nearly micrometers. One digit is enough.
v Page 5, table 1: The above mentioned situation is also valid for the values given under the mean stand height values. The precision is in centimeters, one digit is enough.
v Page 5, line 192: It is better to cite “TerraSolid” and give it in the references.
v Page 6, line 246: Which algorithm or approach used during the iterations? Further explanation should be given. The information given lines between 286-288 are valid? This information can be given here.
v Page 7, line 265: The reference given as “Tang and Wang, 2001” should be checked. (Tang et al., 2001 according to page 19 line 587.
v Page 7, lines 273-274: It is better to combine those two sentences.
v Page 7, equations 7, 8, 9: It is better to give information such as “H and G are endogenous variables in equation 7” under the equations.
v Page 8, line 298: Could you please check the reference given as “Wood et al., 2011”? It is given as “Woods” on page 19, line 604.
v Page 20, lines 548-549: The reference of “Kershaw et al., 2017” was not mentioned in the text.
Author Response
Dear Reviewers.
Thank you very much for your constructive comments and suggestions on the original manuscript. We accept all your comments and suggestions.
We have great respect for your serious and rigorous scientific attitude and high theoretical level.
Best wishes.
The authors
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Thank the authors for their revision. I think the response and revision are appropriate.
