The Interplay Between Carbon Storage, Productivity, and Native Tree Density of Agroforestry Systems

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

(1) In the abstract, when "two agroforestry ecosystems" are first mentioned, a concise definition should be provided to ensure clarity, rather than ambiguously referring to these two systems later on. (2) These three sentences (Lines 46-51) contain some logical inconsistencies and require reorganization for better coherence. (3) This sentence in Lines 77-78 ("whether...known") is not closely related to the previous one, please rephrase. (4) In this paragraph in Lines 66-78, the author fails to elaborate on the mechanisms by which changes in tree species composition influence carbon sequestration. (5) It is also unclear what information the author is trying to convey in the last sentence in Lines 81-83 ("but...too"). (6) What is asl in Line 132? (7) The formulas in the Data and Methods section are recommended to be numbered. (8) How should the equations in Table 1 that do not provide Applicability be handled? (9) For lines 270-271, it is recommended to consult with plant experts from other regions or local experts if the species or name of the tree cannot be confirmed. Is it appropriate to estimate using only the common tree species from the local area? (10) Should the uncertainties of this study (lines 293-305) be placed in the discussion section? (11) In Section 2.3, it is recommended to introduce the methods employed for data analysis in detail. (12) What do the three treatments mentioned by the author in Line 495 refer to? (13) It is suggested to use subheadings to divide the discussion into several parts, enhancing the logic and coherence of the article.

Comments on the Quality of English Language

The English could be improved to more clearly express the research.

Author Response

(1) In the abstract, when "two agroforestry ecosystems" are first mentioned, a concise definition should be provided to ensure clarity, rather than ambiguously referring to these two systems later on.

[Edited. Lines 19-22 changed to include concise definitions of both systems. “In this study, we used allometric equations to evaluate the carbon storage in biomass of two complex agroforestry systems in Bali, Indonesia – rustic where a native tree canopy is still present, and polyculture where all native trees have been removed and the canopy replaced by crop plants.”]

(2) These three sentences (Lines 46-51) contain some logical inconsistencies and require reorganization for better coherence.

[Edited. Lines 48-58 have been rewritten to make the argument more coherent. “This often involves limiting deforestation and planting trees, or allowing natural for-estation on unforested lands, because of the vast quantities of carbon that can be stored in forest biomass and soil [20]. However, forestation potential, and hence car-bon sequestration, is constrained by conflicting land use requirements, such as food production, livelihood provision, and biodiversity conservation [17]. This is especially true in developing countries such as Indonesia, which have high human population pressures and are undergoing rapid agricultural expansion and intensification [21]. Land uses combining other benefits with carbon sequestration are needed for cost-effective climate change mitigation.”]

(3) This sentence in Lines 77-78 ("whether...known") is not closely related to the previous one, please rephrase.

[Edited. Lines 86-87 now read “Whether this effect of native trees on carbon storage is consistent across locations and agroforestry types (i.e., coffee-based, cacao-based, mixed, etc.) is not known.”]

(4) In this paragraph in Lines 66-78, the author fails to elaborate on the mechanisms by which changes in tree species composition influence carbon sequestration.

[We have added more content to that paragraph: ‘It is well known that there is a variation in carbon storage between tree species [35], however, in tropical forests, tree diversity is directly increasing carbon storage potential [36]’]

(5) It is also unclear what information the author is trying to convey in the last sentence in Lines 81-83 ("but...too").

[Edited. Added another line to add to what was being conveyed. Lines 86-88 read “Trade-offs between different ecosystem services need to be considered in order to achieve the desired benefits of a particular agroforestry system, but research in this area is lacking.”]

(6) What is asl in Line 132?

[Edited. Line 146 now includes “above sea level”]

(7) The formulas in the Data and Methods section are recommended to be numbered.

[We have now numbered the formulas.]

(8) How should the equations in Table 1 that do not provide Applicability be handled?

[This is a good point. There’s not much we can do about it now. Ultimately it increases potential errors in our data but probably less than any other way we could have done it.]

(9) For lines 270-271, it is recommended to consult with plant experts from other regions or local experts if the species or name of the tree cannot be confirmed. Is it appropriate to estimate using only the common tree species from the local area?

[Now lines 291-295. Unfortunately, there is not much we can do about it now. The forests in West Bali are not well studied, and there are some species that are still not identified.  Most of the species that couldn’t be identified are uncommon so don’t have much of an effect on the results (4.6%, 163 individuals out of 3578 measured). From Chave et al. (2005), on wood densities: ‘It is recommended to use a species-level average, or, if detailed floristic information is unavailable, a stand-level average’ We have used species specific where available.. We have now modified the text.]

(10) Should the uncertainties of this study (lines 293-305) be placed in the discussion section?

[Moved the paragraph into the discussion.]

(11) In Section 2.3, it is recommended to introduce the methods employed for data analysis in detail.

[We think we introduced all statistical methods used, but please let us know if anything is unclear. We have added the threshold of significance that was missing.]

(12) What do the three treatments mentioned by the author in Line 495 refer to?

[Now line 513. Edited. “Two agroforestry treatments and the primary forest”.]

(13) It is suggested to use subheadings to divide the discussion into several parts, enhancing the logic and coherence of the article.

[We have now added subheadings for the discussion.]

Reviewer 2 Report

Comments and Suggestions for Authors

The main research topic of the manuscript is the focus on the interaction between carbon storage, productivity, and native tree density in agroforestry systems on the island of Bali, Indonesia. The authors aim to find out how carbon storage can be optimized without negatively impacting the productivity of the agroforestry system, which is key to mitigating climate change and improving the socio-economic conditions of smallholder farmers.

In terms of originality, the manuscript provides relevant insights into the role of native trees in agroforestry in carbon storage and productivity. They consider the part where the authors specifically focus on comparing two types of agroforestry systems – rustic and polyculture – and their effects on the carbon balance to be original, an area with limited research. The study fills a gap in understanding how some agroforestry practices can affect both environmental sustainability and economic outcomes.

Suppose I compare the manuscript's contribution to other published papers in the field. In that case, the reviewed study combines detailed measurements of carbon in biomass and economic productivity, which allows for a deeper understanding of their mutual relationships. A significant value is the identification that preserving native trees in rustic systems does not have to negatively affect productivity, which can be beneficial for the correct setting of agroforestry management at the local level.

In general, the manuscript is reasonable in terms of methodology. However, some additions are appropriate, which are no longer possible at the level of the evaluated manuscript. However, the authors could use the recommendations when expanding the discussion: It would be interesting to expand the analyses to include carbon in soil and dead biomass. Furthermore, the authors should focus on analyses not only between their systems but also depending on the duration of their use (the authors could add this to the contribution if they have data on the age of the agroforestry systems used in the study).

The manuscript's conclusions are generally consistent with the presented data and analyses if I evaluate the study's conclusions. The main hypotheses were tested by measuring biomass, productivity, and density of native trees. However, some hypotheses, such as the negative correlation between the density of native trees and productivity, were not confirmed, which the authors correctly interpreted as a basis for further research.

Regarding language level, it does not contain errors and is at a reasonable level. I recommend going through the entire article and simplifying some long sentences that impair the understanding of the text.

Other suggestions for editing:

In the methodology part, add a map source and update the map with a concrete location. There could be more details.

The authors present working hypotheses at the end of the introduction. It would be more appropriate to state the study's objectives in this part. At the same time, the authors state what they found under the hypotheses - this does not belong here and should be removed.

In the first paragraph of the methodology, the authors characterize the types of evaluated localities. However, the description is relatively vague. To better understand the text, it would be more appropriate to describe the differences between "rustic" and "polyculture" agroforestry and add a graphic diagram of all three systems.

Figure 2 - b: Is it possible to also add native forest?

Author Response

The main research topic of the manuscript is the focus on the interaction between carbon storage, productivity, and native tree density in agroforestry systems on the island of Bali, Indonesia. The authors aim to find out how carbon storage can be optimized without negatively impacting the productivity of the agroforestry system, which is key to mitigating climate change and improving the socio-economic conditions of smallholder farmers.

In terms of originality, the manuscript provides relevant insights into the role of native trees in agroforestry in carbon storage and productivity. They consider the part where the authors specifically focus on comparing two types of agroforestry systems – rustic and polyculture – and their effects on the carbon balance to be original, an area with limited research. The study fills a gap in understanding how some agroforestry practices can affect both environmental sustainability and economic outcomes.

Suppose I compare the manuscript's contribution to other published papers in the field. In that case, the reviewed study combines detailed measurements of carbon in biomass and economic productivity, which allows for a deeper understanding of their mutual relationships. A significant value is the identification that preserving native trees in rustic systems does not have to negatively affect productivity, which can be beneficial for the correct setting of agroforestry management at the local level.

[We thank the reviewer for finding the paper interesting and for the suggestions provided.]

In general, the manuscript is reasonable in terms of methodology. However, some additions are appropriate, which are no longer possible at the level of the evaluated manuscript. However, the authors could use the recommendations when expanding the discussion:

• It would be interesting to expand the analyses to include carbon in soil and dead biomass.

[Unfortunately, we do not have this information now. We have a discussion point in the limitations section]

• Furthermore, the authors should focus on analyses not only between their systems but also depending on the duration of their use (the authors could add this to the contribution if they have data on the age of the agroforestry systems used in the study).

[This is an interesting discussion point and we have already mentioned this in lines 473-486.]

The manuscript's conclusions are generally consistent with the presented data and analyses if I evaluate the study's conclusions. The main hypotheses were tested by measuring biomass, productivity, and density of native trees. However, some hypotheses, such as the negative correlation between the density of native trees and productivity, were not confirmed, which the authors correctly interpreted as a basis for further research.

Regarding language level, it does not contain errors and is at a reasonable level.

• I recommend going through the entire article and simplifying some long sentences that impair the understanding of the text.

[We have now checked the readability of the text and edited some sections also based on the recommendations.]

Other suggestions for editing:

 

• In the methodology part, add a map source and update the map with a concrete location. There could be more details.

[Details now added.]

• The authors present working hypotheses at the end of the introduction. It would be more appropriate to state the study's objectives in this part. At the same time, the authors state what they found under the hypotheses - this does not belong here and should be removed.

[We changed the wording of this section.]

• In the first paragraph of the methodology, the authors characterize the types of evaluated localities. However, the description is relatively vague. To better understand the text, it would be more appropriate to describe the differences between "rustic" and "polyculture" agroforestry and add a graphic diagram of all three systems.

[We refer the reviewer to the paragraph lines xx for a detailed description of the three habitats of investigation. We have also now added a diagram with differences between rustic and polyculture, we hope that it helps visualise the differences.]

 

• Figure 2 - b: Is it possible to also add native forest?

[All trees in the native forest are necessarily native (there are no crops in the primary forest) so adding this to the figure would add no information not presented in the text in line 376.]

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,

 

the topic of the work is interesting and current. However, I would like to make a few suggestions and remarks.

The introductory part of the paper is too long and should be shortened and concise. Focus on the essence.

The question arises, why did you do this? and how does it compare with CCS technology?

You mention forests, what kind of trees? give a picture...

Also, have you compared the results with similar systems

You should have done some physico-chemical analysis.

How do you know and in what quantity a certain type of wood collects carbon dioxide?

Does it collect only CO2 or have you noticed other gases or heavy metals?

Link the results and discussion in more detail.

Author Response

Dear Authors,

the topic of the work is interesting and current. However, I would like to make a few suggestions and remarks.

[We thank the reviewer for finding the paper interesting and for the suggestions provided.]

• The introductory part of the paper is too long and should be shortened and concise. Focus on the essence.

[We think 1 page and a half of introduction is quite standard, but we are open to specific suggestions on where to shortened it.]

• The question arises, why did you do this? and how does it compare with CCS technology?

[We are not sure that it would be relevant to introduce CCS as our paper is not a technology paper, it is a field work paper with comparisons between different habitats and with relationships between carbon storage in different habitats, density of native trees, and productivity.]

• You mention forests, what kind of trees? give a picture...

[We have now added a diagram of with the composition of rustic system and polyculture system. The forest is a rainforest, and the list of trees are available in the appendix.]

• Also, have you compared the results with similar systems

[The results have been compared with similar systems in Indonesia within the discussion, now added a subheading to make it easier to find.]

• You should have done some physico-chemical analysis.

[For this paper we focused on carbon storage in trees and bushes. We agree that other physico-chemical characteristics would be important but that was not the focus on the paper. We did discuss the important at lines 545-550]

• How do you know and in what quantity a certain type of wood collects carbon dioxide?

[The quantity of carbon stored in different species has been found through the scientific literature, as detailed in the methods section, particularly in Table 1.]

• Does it collect only CO2 or have you noticed other gases or heavy metals?

[We did not collect data on gases or heavy metals sequestered by trees, we only used allometric equations available in literature.]

• Link the results and discussion in more detail.

[We have now added subheadings in the discussion so hopefully it is easier to follow the structure]

 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

In comparison to its previous iteration, we are pleased to observe that the author has implemented modifications and enhancements across the majority of the content. Nevertheless, there remain some aspects which necessitate further refinement.

(1) The author responded that there was no established method to address the equations for which applicability was not specified in Table 1. It is recommended that these exceptional cases be thoroughly discussed within the uncertainty analysis section of the discussion.

(2) Currently, the revised version has added numbering to the formulas. However, in the mdpi format, the numbering of formulas is usually at the end of each line, not at the beginning..

(3) In section 2.3 on data analysis, the author did not introduce any modifications. Importantly, terms such as "ANOVA" and "Games-Howell test" necessitate detailed explanations and clarifications. Given that some readers may be unfamiliar with these statistical methods, it is crucial to provide a brief explanation of what ANOVA (Analysis of Variance) represents and the specific application of the Games-Howell test.

Comments on the Quality of English Language

The English could be improved to more clearly express the research.

Author Response

(1) The author responded that there was no established method to address the equations for which applicability was not specified in Table 1. It is recommended that these exceptional cases be thoroughly discussed within the uncertainty analysis section of the discussion.

[we have now added more content in the discussion section 4.3]

(2) Currently, the revised version has added numbering to the formulas. However, in the mdpi format, the numbering of formulas is usually at the end of each line, not at the beginning..

[we have now edited the numbers]

(3) In section 2.3 on data analysis, the author did not introduce any modifications. Importantly, terms such as "ANOVA" and "Games-Howell test" necessitate detailed explanations and clarifications. Given that some readers may be unfamiliar with these statistical methods, it is crucial to provide a brief explanation of what ANOVA (Analysis of Variance) represents and the specific application of the Games-Howell test.

[We have now added the required edits in the data analysis section]