Exploring the Effects of Thinning on Cunninghamia lanceolata Lamb. Carbon Allocation in Southwestern China Using a Process-Based Model

Round 1

Reviewer 1 Report

I carefully read the submitted manuscript. This study evaluated thinning effects to young Cunninghamia lanceolata plantation with using process-based model. For the fast growth, Cunninghamia lanceolata is one of the most important tree species for sustainable forestry in near future. Topic is suitable for Forests, manuscript is clearly written and easy to follow the story. I suggest some very minor suggestion on attached file.

 

That's all.

Comments for author File: Comments.pdf

Author Response

Question 1. It's a very minor suggestion, but I think the unified citation style should be better.

Author name [citation] xxx or Author name xxx [citation]?

Response: Thanks for the reviewer’s kind suggestion. We have unified this issue and this form of Author name [citation] was unified in revised manuscript.

 

Question 2. I think citation should be needed. On R 'citation ( )' would return the citation information of R and their packages.

Response: Line 235 A reference [35] was added in revised manuscript.

 

Other changes: Line 114 Cunninghamia lanceolata was replaced by “Cunninghamia lanceolate”.

Special thanks to you for your good comments.

Reviewer 2 Report

This work proposed a good way to investigate the effects of thinning intensity on the carbon allocation of Cunninghamia lanceolata (Lamb.) Hook, Which provides a strong reference for the efficient operation and management of Cunninghamia lanceolata plantations in China. Some problems need the authors to revise:  

1. As far as the effects of thinning concerned, thinning can improve the individual growth of C. lanceolata, but we can’t get the conclusion that thinning can improving carbon storage of C. lanceolata plantation because we don’t take all of the trees into account. So, please check the conclusion again.
2. Cunninghamia lanceolata should be in italicized.
3. Please unify the hm² and ha in this paper. Please check the unit of volume,hm³ in figure 5.
4. This paper predicted the average DBH and height till the age of 25 years based on the data between the tree age of 13 years to 19 years. There are two problems need to rethink: 1)how long can the model predict about the growth of Cunninghamia lanceolata? 2)why there is no carbon storage predication between the tree age of 20 years to 25 years?
5. In front of this paper, three layers soil sample were collected, including 0–20, 20–40, 60–80, and 80–100 cm depth, but there anything about the effects of soil depth on soil carbon storage. Please enrich the contents on vertical distribution of soil carbon.

Author Response

Question 1. Thinning can improve the individual growth of C. lanceolata, but we can’t get the conclusion that thinning can improving carbon storage of C. lanceolata plantation because we don’t take all of the trees into account.

Response: Considering the Reviewer’s suggestion, we have revised and updated our conclusion, Line 580 “and improve the soil carbon sequestration” has been deleted in revised manuscript.

 

Question 2. Cunninghamia lanceolata should be in italicized.

Response: We feel sorry for our carelessness. In our resubmitted manuscript, the incorrect writing is revised. Thanks for your correction.

 

Question 3. Please unify the hm² and ha in this paper. Please check the unit of volume, hm³ in figure 5.

Response: We sincerely thank the reviewer for careful reading, we have carefully checked the manuscript and corrected the Unit errors accordingly.

 

Question 4. This paper predicted the average DBH and height till the age of 25 years based on the data between the tree age of 13 years to 19 years. How long can the model predict about the growth of Cunninghamia lanceolata?

Response: Thanks for the reviewer’s suggestion.

Related responses have been added into discussions as follows: Lines 509-512 “Model prediction is theoretically possible. However, accurate prediction of CROBAS-CL model may take more considerations in practice, for example, the life cycle of trees, relationship between tree species differentiation and naturally sparse process, and the upper limit of C. lanceolata age should also be important influencing factors”.

 

Question 5. Why there is no carbon storage predication between the tree age of 20 years to 25 years?

Response: Thanks for pointing out this problem.

Related responses have been added into discussions as follows: Lines 438-445 “CROBAS-CL model uses functional relationships and carbon balance modelling to de-scribe tree growth and biomass allocation, and simulate the carbon allocations in each part for a plantation by DE algorithm. Therefore, the result of model prediction is the carbon allocations in the various organs of C. lanceolata plantations under different thinning intensities during the following six years of thinning. However, the impact of thinning on carbon allocations of plantation ecosystems needs to be further achieved through correlations and differences between carbon storage in forests, litters and soils, which to reflect the dynamic variations of carbon content in the plantations”. Meanwhile, some incoherent discussions were deleted in updated manuscript.

 

Question 6. In front of this paper, three layers soil sample were collected, including 0–20, 20–40, 60–80, and 80–100 cm depth, but there anything about the effects of soil depth on soil carbon storage. Please enrich the contents on vertical distribution of soil carbon.

Response: Thanks for your kind suggestion.

Actually, I would like to make some clarification. In previous field survey, we collected the vertical soil, however, we analyzed only the carbon content in topsoil samples of 0–20 cm depth for this manuscript for some reasons. So related information about the contents on vertical distribution of soil carbon was deleted in Materials and Methods.

Please see the attachment.

Author Response File: Author Response.docx