Comparison between Empirical Models and the CBM-CFS3 Carbon Budget Model to Predict Carbon Stocks and Yields in Nova Scotia Forests

Round 1

Reviewer 1 Report

General comments

The Manuscript compares two estimates of carbon stocks by seven pools at various scales in the province of Nova Scotia, Canada obtained by two different approaches. The study is of local character and importance, but presents an interesting exercise in comparing how large-scale model (CBM-CF3) performs in comparison with the locally derived model. The aim of the study was not to select the best model or to improve CBM-CF3 model but to compare their estimates at different scales.

The manuscript is generally well written, although difficult to follow due to (too) many variables and combinations (two models, 7 pools, 5 forest communities, 4 different scales and 4 hypothetical forests). I would suggest to the Authors to consider leaving out the “hypothetical forests”, but it is not mandatory.

Other than the above consideration, the manuscript would benefit from the revision of the Section 2.6 of the Materials and Methods which is difficult to understand. There are several other minor issues which are specified below.

Specific comments

L5. It is customary to state only names without titles under the list of Authors.

L146 “discounted from the total measurement”. Please be more precise what is meant by “total measurement”? The tree volume was not measured, but only dbh, height etc.

L156. Please specify if the stumps of harvested trees have been accounted for in CWD? (Note: In my view the [28] is not sufficiently clear on that, stating “In BC, CWD is most often defined as downed dead wood, which includes sound and rotting logs and uprooted stumps.”). Also, were the dead roots of harvested trees accounted for (and where)?

L208 “... used for calculating Following [30], ... “ Seems like a part of the sentence is missing after “calculating”.

L242 “on DBH and DBH and height “ Please check if this is ok, or two times mentioning DBH is a typo.

L258 – 274 The section 2.6 is very hard to understand. I am not sure which data from the PSP were used as inputs to the CBM-CFS3 model, how the model was run (especially since it seems harvest and disturbance were not considered in modelling) and what was the output? After several readings my understanding was that the Authors used PSP plot data (plot age, DBH, height, species, etc.) grouped into categories “forest community” as an input to CBM-CF3 model in order to obtain merchantable volume at the plot/tree (?) level which was then used to calculate carbon in each of the 7 pools used in this study, and then to make age dependent models of carbon in 7 pools. However, I am still not sure if I understood it well. Hence, I would recommend this section to be revised.

L334 “CMB”?

L654 “Supplementary Materials:”?

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Dear authors,

thank you very much for this interesting study and manuscript based on really long-term data collecting. I also hinghly appreciate the amount of the research plots! In my opinion, the whole study is described clearly, maybe the Results chapter could be more brief, sometimes I lost the idea. However, I can´t judge, wheter some of the results (meaning the lots of numbers) could be missed in the text and replaced by a table. In Discussion, the are also the uncertainties described, as they response some of the questions I have had during reading the previuos text. I think, this research has a pottential to be helpful for another studies, as you resumes in Conclusions, I clearly understand the purpose and subsequent utility.

I have only a few technical notes:

Line 38 - I don´t understand what "Tier" is. Is it a French expression? May be I have a stupid question, but I have never met this, as I am from the Central Europe.

Line 208 - I think something (maybe a point?) is missing between "calculating" and "Following".

Discussion - Is seems that there are double-spacings between some sentences - line 499, 533, 535, 543, .. but I can be wrong, as I hace only pdf version of the manuscript.

I wish you a good luck with publishing!

Author Response

Please see the attachment.

Author Response File: Author Response.docx