Opportunities for Research on Carbon Management in Longleaf Pine Ecosystems

Round 1

Reviewer 1 Report

I have read the article entitled " Opportunities for research on carbon management in longleaf pine ecosystems" . The manuscripts brings some inspiring insights into the carbon stocks in longleaf pins savannas,  woodlands and plantations as well as effect of natural or manmade factors on C emission and storage. However, the conclusion part should be improved and authors should consider more on practical point of view in the future researches topic for carbon management.

Author Response

Reviewer 1:

I have read the article entitled " Opportunities for research on carbon management in longleaf pine ecosystems”. The manuscripts brings some inspiring insights into the carbon stocks in longleaf pins savannas, woodlands and plantations as well as effect of natural or manmade factors on C emission and storage. However, the conclusion part should be improved, and authors should consider more on practical point of view in the future researches topic for carbon management.

To address the reviewer’s concerns, we revised Figure 1. The revised figure includes research needs are applicable to (1) forest managers and (2) the research community. We believe the revised figure helps present future research needs in a more concise manner. It also highlights the fact that research studies must be conducted to validate management strategies for sequestering C and to determine their influence on other ecosystem services. We did not make changes to the conclusion section because we believe it supports ideas presented in the new figure and is a concise summary of material presented in the main text.

Reviewer 2 Report

The study reviewed the carbon stocks and accumulation by aboveground, belowground, combined pools, and harvested wood products in longleaf pine ecosystem. The authors suggested potential strategies for enhancing C stocks and accumulation in both above ground and soil C stock in plantation and natural forest sites. Few of my observations in this manuscript are-

1. Authors have given less emphasis on belowground C dynamics. The study of C stock upto a soil depth of 10 cm may not give clear understanding of belowground carbon pools, especially coarse root and microbial biomass carbon are not covered in the review work.

2. Effect of different management strategies are not clearly mentioned or synthesized in the manuscript. Tabular representation of carbon stock and other services of longleaf pine may improve the quality of the manuscript.

3. Biodiversity status as discussed in longleaf pine ecosystem may be explained with the information of species richness, density and diversity indices to get the clear picture of the site.

4. Few photographs are not very relevant to the manuscript. Figure 1 in box format may not be very suitable for the manuscript.

5. Many references like Reference no 22, 34, 36 cited in the text part of the manuscript may be cited with the name of the author.

Overall, the manuscript is a novel contribution in the field of carbon management and suitable for this journal. So, it can be accepted for publication after minor revision as mentioned above.

Thanking You

                                                                                              

Author Response

Reviewer 2:

The study reviewed the carbon stocks and accumulation by aboveground, belowground, combined pools, and harvested wood products in longleaf pine ecosystem. The authors suggested potential strategies for enhancing C stocks and accumulation in both above ground and soil C stock in plantation and natural forest sites. Few of my observations in this manuscript are:

1. Authors have given less emphasis on belowground C dynamics. The study of C stock up to a soil depth of 10 cm may not give clear understanding of belowground carbon pools, especially coarse root and microbial biomass carbon are not covered in the review work.

We added more detail to the section on belowground C dynamics. Specifically, we added the depths to which soils were sampled for the cited studies (lines 245, 252, and 256–258). We also explained why the comparison of soils to a depth of 10 cm was made for the studies by Markewitz et al. and Butnor et al. (lines 256–258). Finally, we added information on the importance of root mass in estimates of belowground C (lines 247–250 and 258–260) and the influence of microbial communities on C dynamics (264–269).

2. Effect of different management strategies are not clearly mentioned or synthesized in the manuscript. Tabular representation of carbon stock and other services of longleaf pine may improve the quality of the manuscript.

The effect of different management strategies on C sequestration in longleaf pine ecosystems is highlighted as a research priority (lines 135–138, 170–173, and 439–432). There is a lack of studies that have addressed this topic. We added an example of comparisons of aboveground C storage over time among longleaf pine plantations and low-density, naturally regenerated stands managed with single-tree selection cutting (lines 167–170). Instead of presenting research needs in box format (Figure 1 of the original manuscript), we revised Figure 1. The revised figure includes research needs that are applicable to (1) forest managers and (2) the research community. We believe this figure is more appropriate to include in the manuscript given that researchers must validate the effectiveness of management strategies on sequestering C and determine the influence these strategies on other ecosystem services.  

3. Biodiversity status as discussed in longleaf pine ecosystem may be explained with the information of species richness, density, and diversity indices to get the clear picture of the site.

We added information on species richness to the paragraph on biodiversity status (e.g., lines 62–64).

4. Few photographs are not very relevant to the manuscript. Figure 1 in box format may not be very suitable for the manuscript.

We deleted figures with photographs (Figures 2–4) as suggested by Reviewers 2 and 3. We also revised Figure 1 as explained above.

5. Many references like Reference no 22, 34, 36 cited in the text part of the manuscript may be cited with the name of the author.

We thank the reviewer for pointing this out. For instances like these, we included names with the citations in the revised manuscript.

Overall, the manuscript is a novel contribution in the field of carbon management and suitable for this journal. So, it can be accepted for publication after minor revision as mentioned above.

Thanking You

Reviewer 3 Report

This study attempts to review carbon research in the longleaf pine ecosystem, which summarizes the characteristics of longleaf pine in mitigating climate change. However, I believe the study can be fulfilled its objective better if the following suggestions can be taken care of.

1. The abstract can be better organized with a more concise statement with fewer details; the objective and conclusion of the research must be illustrated more clearly.

2. Figures 2, 3, & 4 can be removed.

3. The authors have shown preferable properties of the longleaf pine in the mitigation of climate change and supply of ecological services. However, longleaf is not the dominant species in the southern USA, so the disadvantages should also be stated. For example, its rotation is longer, which implies that landowners with higher discount rates will not choose it.

4. Sections 2 and 3 should be combined, and so do sections 4 & 5.

5. I highly recommend that a figure or table be constructed to show the management strategies suitable for more carbon sinks in longleaf pine forests and their potential impacts on above/below ground C stocks, ecosystem stocks, and product stocks so that forest managers can quickly get the information from the manuscript.

Author Response

Reviewer 3:

This study attempts to review carbon research in the longleaf pine ecosystem, which summarizes the characteristics of longleaf pine in mitigating climate change. However, I believe the study can be fulfilled its objective better if the following suggestions can be taken care of.

1. The abstract can be better organized with a more concise statement with fewer details; the objective and conclusion of the research must be illustrated more clearly.

We did not make changes to the abstract and conclusion sections because we believe they support ideas presented in the new figure and are concise summaries of material presented in the main text. The objectives are included in the last paragraph of the introduction and we added text to that paragraph based on the reviewer’s comments below. 

2. Figures 2, 3, & 4 can be removed.

We deleted figures with photographs (Figures 2–4) as suggested by Reviewers 2 and 3.

3. The authors have shown preferable properties of the longleaf pine in the mitigation of climate change and supply of ecological services. However, longleaf is not the dominant species in the southern USA, so the disadvantages should also be stated. For example, its rotation is longer, which implies that landowners with higher discount rates will not choose it.

We added text to acknowledge the faster initial growth rates of other major commercial southern pine species (lines 104­–107). We also provide reasons why landowners might consider longleaf pine over other southern pines, especially on sites with poor to intermediate site qualities (lines 107–109).

4. Sections 2 and 3 should be combined, and so do sections 4 & 5.

We combined sections 2 and 3, and sections 4 and 5.

5. I highly recommend that a figure or table be constructed to show the management strategies suitable for more carbon sinks in longleaf pine forests and their potential impacts on above/below ground C stocks, ecosystem stocks, and product stocks so that forest managers can quickly get the information from the manuscript.

We did not create such a figure or table because more research (e.g., field studies, model simulations, and improvements to models) is needed to determine the impact of potential management strategies on C dynamics, as we explain in the manuscript. For example, research studies are needed to determine the influence of plantation conversion to a more natural condition on C accumulation; especially when comparing this to other management strategies (lines 186–192). To avoid the risk of managers thinking that these strategies are appropriate for use (until more fully evaluated), we chose not to list potential strategies in table format. However, instead of presenting research needs in box format (Figure 1 of the original manuscript), we revised Figure 1. The revised figure includes research needs that are applicable to (1) forest managers and (2) the research community. We believe this figure is more appropriate to include in the manuscript given that researchers must validate the effectiveness of management strategies on sequestering C and determine the influence these strategies on other ecosystem services.

Round 2

Reviewer 3 Report

I believe the authors have addressed all the comments properly.