Tree and Liana Growth in Three Neotropical Dry Forests: Coherent Patterns and Individualistic Responses to Climate Variability

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors and editors. I am grateful for the opportunity to review the scientific article "Tree and liana growth in three Neotropical dry forests: coherent patterns and individualistic responses to climate variability" proposed for publication in the highly rated scientific journal "Forests (ISSN 1999-4907)". In general, the research scientific article is devoted to a relevant and interesting topic, since tropical dry forests are most susceptible to agricultural use and global warming. The article is relevant, written in simple language, I think it will be interesting to the readers of the journal. However, there are the following comments.
1. Figure 1. On geographic maps, indicate the scale, north arrow, and coordinate grid. Also in the text, indicate what programs were used to obtain the maps and in what projection they are made.
2. Section 2.2. You indicate that you use data, but do not provide them in the research results. I saw only a comparison of correlations. What data were obtained to conduct the correlation?
3. Indicate the limitations of your study in section 4.
4. Indicate in section 4 a comparison of the obtained data with other regions of the world.

5. Rewrite section 5. Everything indicated there should probably be attributed to section 4. Indicate the specific conclusions that you have obtained.

Overall, I note the high level of the scientific article and believe that it can be accepted after the comments are corrected.

Author Response

Reviewer 1

Open Review

(x) I would not like to sign my review report.

(x) The English is fine and does not require any improvement.

 

Yes   Can be improved   Must be improved  Not applicable

Does the introduction provide sufficient background and include all relevant references?

(x)   ( )   ( )   ( )

Is the research design appropriate?

( )   (x)   ( )   ( )

Are the methods adequately described?

( )   (x)   ( )   ( )

Are the results clearly presented?

( )   ( )   (x)   ( )

Are the conclusions supported by the results?

( )   ( )   (x)   ( )

 

Comments and Suggestions for Authors

Dear authors and editors. I am grateful for the opportunity to review the scientific article "Tree and liana growth in three Neotropical dry forests: coherent patterns and individualistic responses to climate variability" proposed for publication in the highly rated scientific journal "Forests (ISSN 1999-4907)". In general, the research scientific article is devoted to a relevant and interesting topic, since tropical dry forests are most susceptible to agricultural use and global warming. The article is relevant, written in simple language, I think it will be interesting to the readers of the journal. However, there are the following comments.

 

• We thank you for your positive comments on the study.

 

1. Figure 1. On geographic maps, indicate the scale, north arrow, and coordinate grid. Also in the text, indicate what programs were used to obtain the maps and in what projection they are made.

 

• Thank you, we modified the maps as indicated.

 

2. Section 2.2. You indicate that you use data, but do not provide them in the research results. I saw only a comparison of correlations. What data were obtained to conduct the correlation?

 

• In this section we described climate data and climate indices. They were used to calculate correlations with growth indices (see Figs. 5, 6 and 7 and the paragraph after Fig 7 and new Fig. 8).

 

3. Indicate the limitations of your study in section 4.

 

• Thank you, we did it.

 

4. Indicate in section 4 a comparison of the obtained data with other regions of the world.

 

• Done, we focused on previous studies across South America and in other tropical areas. This corresponds to recent pantropical studies such as Wagner et al. (2016) and Zuidema et al. (2022).

 

5. Rewrite section 5. Everything indicated there should probably be attributed to section 4. Indicate the specific conclusions that you have obtained.

 

• Done, we rewrote it as indicated.

 

Overall, I note the high level of the scientific article and believe that it can be accepted after the comments are corrected.

 

• Thanks again for your positive comments on the ms.

Reviewer 2 Report

Comments and Suggestions for Authors

Camarero and Valeriano reported here the results of a comprehensive dendrochronological study, focusing on 26 tree species and 2 liana species, sampled in three tropical dry forests located in Colombia, Ecuador and Bolivia, and aimed at assessing growth patterns, evaluating the potential of the different species to form distinct tree-rings, and investigating growth responses to climate. Their main findings were: (a) several species, including two lianas, showing distinct growth rings were clearly identified; (b) some coherent growth patterns were detected among species in the different forest sites; and (3) individualist responses to climate parameters were highlighted for some species.

MAIN COMMENT

This study could provide important information for an accurate selection of woody species in the context of dendrochronological studies. Moreover, the reported findings may represent important information for understanding the growth responses to climate variability of different woody plants in tropical dry forests, which are key forest ecosystems but also some of the most exploited worldwide and potentially impacted by ongoing climate change. The inclusion of two liana species, which are often neglected, introduces an additional element of interest. The experimental design and methods are robust, as well as statistical analysis, which is also detailed reported. The discussion reflects the main results, and the few methodological limitations are recognized and briefly discussed by the authors. In general, the used terminology is accurate and sentences are well-written and clear, with only a few exceptions (see Minor comments). In summary, this manuscript could surely represent a valuable research contribution. I only have a few suggestions related to the Discussion: (1) the discussion could be better structured, perhaps using subsections, to highlights the main findings of the study in a clearer way; (2) the findings that some species showed individualistic responses to climate parameters can have important implications for dry tropical forests dynamics in the context of climate change and forest management. These implications perhaps could be better explored, and the same applies for the effect of ENSO on growth patterns. The results of this study are discussed from a predominantly applied perspective, which is understandable given the objectives set. However, I believe that this manuscript could benefit by exploring a bit also the ecological implications of the authors findings, also in the light of ongoing climate change and forest management. Below are some additional minor comments.

MINOR COMMENTS

ABSTRACT

Line 25-26: This sentence sounds a bit contradictory. Please briefly clarify which kind of "coherent, common growth patterns" were identified, and which "individualistic responses" were found. Please report the main findings of the study in a more accurate way.

To give the reader a first impression on the relevance of this study, it may be advisable to add a short sentence outlining the implications of the reported findings.

INTRODUCTION

Line 43: Perhaps you should dedicate a short paragraph to explain what are tropical dry forests, in which biogeographic regions they can be found and how they differ from other tropical forest ecosystems.

Line 63: Besides competition with trees and related consequences in tropical forest dynamics, don't you think that lianas play other important roles in tropical forests (e.g., providing microhabitat and food for many animal species, increasing ecosystem complexity, etc.)? It may be interesting to spend a few words about it, considering that this group of plants is often disregarded in conservation programs.

MATERIALS AND METHODS

Line 88: did the authors selected the trees by chance, or following some specific criteria (e.g., to avoid sampling outliers)? Moreover, please change “we extracted cores at 1.3 m of sampled trees” into “we extracted cores from sampled trees at a high of 1.3 m”, to improve clarity.

Line 93: trees are not deciduous in a certain season, and evergreen in a different one; I guess you mean that deciduous trees shed their leaves during the dry season. Please re-phrase.

Lines 99-100: please change “it has 31 tree species ha −1” into something like “is characterized by a tree species density of 31 species” (same at line 119).

Lines 111-112: 65 individuals per species, or 65 individuals in total? Please clarify and, if sample size varied among the different species, you should report it (e.g., in Table 3).

Line 125: perhaps add “family” after “Bignoniaceae”.

Line 146: please add “tool” (or “portal”) after “web.

Line 149: Dendrochronology is a scientific discipline, not a method. It is more correct to write “we used dendrochronological methods” (or approach).

Line 165: please add a reference for the statement that BAI is a more accurate measurement of growth.

Line 172-173: please specify the rationale for this choice.

Line 190: you should specify the R function used, too (not only the package).

RESULTS

Line 285: the title of section 3.3 is a bit unclear. Perhaps you could simplify it as follows: "Relationships between growth indices and climate".

Lines 286-287: “enhanced by low maximum temperatures but high minimum”: perhaps you could write “combined with” instead of “but”.

Line 325: a comma after the bracket could help readability.

Lines 330-331: s“showed a positive, but not significant correlation” is perhaps more lienar than “showed a positive correlation, but it was not significant”.

DISCUSSION

Line 338: remove “were able to”; “several”, “those”: could you be more precise, specifying how many?

Line 341: correct “hypotheses” into “hypothesis” (singular).

Lines 349-350: again, please be more precise

Lines 350-351: this sentence is a bit convoluted. Maybe better something like: “This finding stresses the importance of careful species selection in dendrochronological studies”.

Line 372: “higher variance of the PC1”: did you mean "higher variance explained by PC1"?

Lines 397-398: did you mean “was found by previous studies”?

CONCLUSION

Line 414: maybe add “However,” before “These results”.

Lines 417-418: I agree with you that “the use of gridded climate datasets is widespread”, but the fact that is widespread does not mean that this approach is always acceptable. I appreciate that the authors mentioned a potential limitation of their study, which is for sure shared among many other studies. However, I would appreciate it more to better specify when the use of gridded climate datasets can be acceptable as a substitute of local climate records, and when not. I guess it may depend on the climatic conditions of study sites, on the specific aims of the study, etc. Please be more precise, possibly with some references from literature.

TABLES AND FIGURES

Table 1: Are you sure that the degree symbol (for lat/long and temperature) is the correct one? Shouldn't it be "°"? Please also check in the main text.

Table 2: very nice.

Author Response

Open Review

(x) I would not like to sign my review report.

(x) The English is fine and does not require any improvement.

 

Yes   Can be improved   Must be improved  Not applicable

Does the introduction provide sufficient background and include all relevant references?

( )   (x)   ( )   ( )

Is the research design appropriate?

(x)   ( )   ( )   ( )

Are the methods adequately described?

(x)   ( )   ( )   ( )

Are the results clearly presented?

(x)   ( )   ( )   ( )

Are the conclusions supported by the results?

(x)   ( )   ( )   ( )

 

Comments and Suggestions for Authors

Camarero and Valeriano reported here the results of a comprehensive dendrochronological study, focusing on 26 tree species and 2 liana species, sampled in three tropical dry forests located in Colombia, Ecuador and Bolivia, and aimed at assessing growth patterns, evaluating the potential of the different species to form distinct tree-rings, and investigating growth responses to climate. Their main findings were: (a) several species, including two lianas, showing distinct growth rings were clearly identified; (b) some coherent growth patterns were detected among species in the different forest sites; and (3) individualist responses to climate parameters were highlighted for some species.

 

MAIN COMMENT

This study could provide important information for an accurate selection of woody species in the context of dendrochronological studies. Moreover, the reported findings may represent important information for understanding the growth responses to climate variability of different woody plants in tropical dry forests, which are key forest ecosystems but also some of the most exploited worldwide and potentially impacted by ongoing climate change. The inclusion of two liana species, which are often neglected, introduces an additional element of interest. The experimental design and methods are robust, as well as statistical analysis, which is also detailed reported. The discussion reflects the main results, and the few methodological limitations are recognized and briefly discussed by the authors. In general, the used terminology is accurate and sentences are well-written and clear, with only a few exceptions (see Minor comments). In summary, this manuscript could surely represent a valuable research contribution.

 

• Thanks for your positive comments on our study.

 

I only have a few suggestions related to the Discussion: (1) the discussion could be better structured, perhaps using subsections, to highlights the main findings of the study in a clearer way; (2) the findings that some species showed individualistic responses to climate parameters can have important implications for dry tropical forests dynamics in the context of climate change and forest management. These implications perhaps could be better explored, and the same applies for the effect of ENSO on growth patterns. The results of this study are discussed from a predominantly applied perspective, which is understandable given the objectives set. However, I believe that this manuscript could benefit by exploring a bit also the ecological implications of the authors findings, also in the light of ongoing climate change and forest management. Below are some additional minor comments.

 

• Thanks for your suggestions. We extended a little the discussion parts you commented. We avoided using subsections because this is not standard in the journal style.

 

MINOR COMMENTS

ABSTRACT

Line 25-26: This sentence sounds a bit contradictory. Please briefly clarify which kind of "coherent, common growth patterns" were identified, and which "individualistic responses" were found. Please report the main findings of the study in a more accurate way.

To give the reader a first impression on the relevance of this study, it may be advisable to add a short sentence outlining the implications of the reported findings.

 

• Thanks for your suggestions. We modified the abstract following your recommendations.

 

INTRODUCTION

Line 43: Perhaps you should dedicate a short paragraph to explain what are tropical dry forests, in which biogeographic regions they can be found and how they differ from other tropical forest ecosystems.

 

• Thanks for your suggestions. We did it.

 

Line 63: Besides competition with trees and related consequences in tropical forest dynamics, don't you think that lianas play other important roles in tropical forests (e.g., providing microhabitat and food for many animal species, increasing ecosystem complexity, etc.)? It may be interesting to spend a few words about it, considering that this group of plants is often disregarded in conservation programs.

 

• Thanks for your suggestions. We added this point of view.

 

MATERIALS AND METHODS

Line 88: did the authors selected the trees by chance, or following some specific criteria (e.g., to avoid sampling outliers)? Moreover, please change “we extracted cores at 1.3 m of sampled trees” into “we extracted cores from sampled trees at a high of 1.3 m”, to improve clarity.

 

• Thanks for your suggestions. We modified the text. We selected mature trees and this was also added to the revision.

 

Line 93: trees are not deciduous in a certain season, and evergreen in a different one; I guess you mean that deciduous trees shed their leaves during the dry season. Please re-phrase.

 

• Thanks for your suggestions. We rephrased the text.

 

Lines 99-100: please change “it has 31 tree species ha −1” into something like “is characterized by a tree species density of 31 species” (same at line 119).

 

• We changed it.

 

Lines 111-112: 65 individuals per species, or 65 individuals in total? Please clarify and, if sample size varied among the different species, you should report it (e.g., in Table 3).

 

• We clarified it. That info is provided in Table 3 (No. series).

 

Line 125: perhaps add “family” after “Bignoniaceae”.

Line 146: please add “tool” (or “portal”) after “web.

 

• We corrected both.

 

Line 149: Dendrochronology is a scientific discipline, not a method. It is more correct to write “we used dendrochronological methods” (or approach).

 

• We corrected it and we FULLY agree.

 

Line 165: please add a reference for the statement that BAI is a more accurate measurement of growth.

 

• We added it.

 

Line 172-173: please specify the rationale for this choice.

 

• We explained it.

 

Line 190: you should specify the R function used, too (not only the package).

 

• We added it.

 

RESULTS

Line 285: the title of section 3.3 is a bit unclear. Perhaps you could simplify it as follows: "Relationships between growth indices and climate".

 

• We rephrased it as you suggested.

 

Lines 286-287: “enhanced by low maximum temperatures but high minimum”: perhaps you could write “combined with” instead of “but”.

Line 325: a comma after the bracket could help readability.

 

• We rephrased it as suggested.

 

Lines 330-331: s“showed a positive, but not significant correlation” is perhaps more lienar than “showed a positive correlation, but it was not significant”.

 

• We rephrased it as you suggested.

 

DISCUSSION

Line 338: remove “were able to”; “several”, “those”: could you be more precise, specifying how many?

Lines 349-350: again, please be more precise

Line 341: correct “hypotheses” into “hypothesis” (singular).

 

• We rephrased them to be more precise and corrected line 341.

 

Lines 350-351: this sentence is a bit convoluted. Maybe better something like: “This finding stresses the importance of careful species selection in dendrochronological studies”.

 

• We rephrased it as you suggested. Thanks for the suggestion.

 

Line 372: “higher variance of the PC1”: did you mean "higher variance explained by PC1"?

Lines 397-398: did you mean “was found by previous studies”?

 

• We rephrased it as you suggested.

 

CONCLUSION

Line 414: maybe add “However,” before “These results”.

 

• We rephrased it as you suggested.

 

Lines 417-418: I agree with you that “the use of gridded climate datasets is widespread”, but the fact that is widespread does not mean that this approach is always acceptable. I appreciate that the authors mentioned a potential limitation of their study, which is for sure shared among many other studies. However, I would appreciate it more to better specify when the use of gridded climate datasets can be acceptable as a substitute of local climate records, and when not. I guess it may depend on the climatic conditions of study sites, on the specific aims of the study, etc. Please be more precise, possibly with some references from literature.

 

• We rephrased and discussed it as you suggested.

 

TABLES AND FIGURES

Table 1: Are you sure that the degree symbol (for lat/long and temperature) is the correct one? Shouldn't it be "°"? Please also check in the main text.

 

• We checked it.

 

Table 2: very nice.

 

• Thanks a lot for such careful and constructive revision.

Reviewer 3 Report

Comments and Suggestions for Authors

This paper reported the dendrochronological potential of 26 tree species and 2 lianas species in tropical dry forests, where tree-ring studies were largely understudied. Although it is difficult to identify the tree ring boundaries for tropical tree species, recent studies have confirmed that some tree species can be potentially cross-dated. This study certainly provides such evidence. Obviously, this draft is timely and very important for improving our understanding of which tropical tree species can be used for past climate reconstruction as well as how tree growth of tropical trees respond to climate changes. The draft was well written and constructed. I have several questions that maybe considered. 

L324-336, Although the correlation between growth indices and ENSO-related climate indices were reported, the time series of growth indices and ENSO-related climate indices were not found in this draft. To better see how yearly growth variability corresponds to ENSO-related climate indices, I would suggest adding such information.

L363-365, Besides the stand structures, long-term climate change and increased CO2 were also involved in the ascending of BAI curves of tree species in Colombian and Ecuadorian TDFs, please comment.
L345-361, why other tree species did not have distinct ring boundaries, is there any species-specific reasons?

Author Response

Open Review

(x) I would not like to sign my review report

Quality of English Language

research.

(x) The English is fine and does not require any improvement.

 

Yes   Can be improved   Must be improved  Not applicable

Does the introduction provide sufficient background and include all relevant references?

(x)   ( )   ( )   ( )

Is the research design appropriate?

(x)   ( )   ( )   ( )

Are the methods adequately described?

(x)   ( )   ( )   ( )

Are the results clearly presented?

(x)   ( )   ( )   ( )

Are the conclusions supported by the results?

(x)   ( )   ( )   ( )

 

Comments and Suggestions for Authors

This paper reported the dendrochronological potential of 26 tree species and 2 lianas species in tropical dry forests, where tree-ring studies were largely understudied. Although it is difficult to identify the tree ring boundaries for tropical tree species, recent studies have confirmed that some tree species can be potentially cross-dated. This study certainly provides such evidence. Obviously, this draft is timely and very important for improving our understanding of which tropical tree species can be used for past climate reconstruction as well as how tree growth of tropical trees respond to climate changes. The draft was well written and constructed. I have several questions that may be considered.

 

• We thank you for the positive comments on the study.

 

L324-336, Although the correlation between growth indices and ENSO-related climate indices were reported, the time series of growth indices and ENSO-related climate indices were not found in this draft. To better see how yearly growth variability corresponds to ENSO-related climate indices, I would suggest adding such information.

 

• We understand your suggestion. However, the manuscript contains 7 figures which we consider more than enough. Further, we found several significant correlations between growth indices with monthly SOI and PDO values which will require adding several figures. Humbly, we consider no more figures are required to show this information. Nevertheless, we have added an additional figure to illustrate one of the strongest relationships found for a Bolivian tree species.

 

L363-365, Besides the stand structures, long-term climate change and increased CO2 were also involved in the ascending of BAI curves of tree species in Colombian and Ecuadorian TDFs, please comment.

 

• We commented on these two potential drivers.

 

L345-361, why other tree species did not have distinct ring boundaries, is there any species-specific reasons?

 

• We briefly commented on these aspects since several factors explain tree-ring formation in the study TDFs including climate seasonality, functional traits, cambium phenology and phylogeny.

 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors and editors. I have read the responses to the comments and would like to note the following. 
1. Although missing elements of cartographic design have been added to the map, questions remain about its accuracy and quality. Perhaps it should be redrawn. It is also not clear in which program it was made and there are questions about the accuracy of the added data. In addition, I would like to point out that a coordinate grid cannot consist of only one parallel and one meridian. 
2. No response has been received to the comment. What kind of climate data is used? What is their sample? In the results, you need to show and describe the data that you received, and then analyze the data itself. 
3. I am satisfied with the response to the comment.
4. I am partially satisfied with the answer. I believe that the literature review can be increased. 
5. I am partially satisfied with the answer. It may be worth mentioning some quantitative indicators obtained by the authors. 
6. Additionally, I recommend that you indicate in the response to the reviewer the line numbers in the manuscript of the article where the recommended changes were made.

Author Response

Dear authors and editors. I have read the responses to the comments and would like to note the following. 
1. Although missing elements of cartographic design have been added to the map, questions remain about its accuracy and quality. Perhaps it should be redrawn. It is also not clear in which program it was made and there are questions about the accuracy of the added data. In addition, I would like to point out that a coordinate grid cannot consist of only one parallel and one meridian. 

• Dear reviewer. We added the required elements to the map that you requested by indicating the projection and the software used to modify it. As it is clearly stated in the legend, the map was modified from "Pennington R.T.; Prado, D.E.; Pendry, C.A. 2000. Neotropical seasonally dry forest and Quaternary vegetation changes. J. Biogeogr. 27, 261–273" because it is a very nice description of American TDFs. The map provides an approximate description of Neotropical Dry Forests and it is NOT a main issue of this manuscript which deals with dendrochrnological aspects. We do not think it is necessary to provide a complete grid system for the objectives of this study. We do think that adding the scale and one parallel and meridian is more than enough given that the exact coordinates of the stuy sites are given in table 1.

2. No response has been received to the comment. What kind of climate data is used? What is their sample? In the results, you need to show and describe the data that you received, and then analyze the data itself. 

• Honestly, we do not understand the point. There is a complete description of the climate data used in lines 139-150 of the manuscript and how they were correlated with growth indices (lines 194-197). We do not need to show climate trends because the objectives of the study are to analyze climate-growth relationships and not climate trends.

4. I am partially satisfied with the answer. I believe that the literature review can be increased. 

• We respectfully disagree given that the manuscript contains 78 references and some of them are global analyses of climate-growth relationships in the tropics.

 
5. I am partially satisfied with the answer. It may be worth mentioning some quantitative indicators obtained by the authors. 

• We added some quantitative results to the revised conclusions (lines 444-448).

6. Additionally, I recommend that you indicate in the response to the reviewer the line numbers in the manuscript of the article where the recommended changes were made.

• Done.