Detecting Glucose in the Phloem to Quickly Define Latent Post-Fire Mortality in Pinus Trees in Northern Italy

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The experimental study of quantifying the glucose concentration in the phloem was used to study the latent mortality rate of trees after fires, and the conclusions drawn have certain theoretical significance and value. Therefore, I can accept the study with slight modifications. I suggest the following modifications and explanations:

(1) Is formula 1 established in this study applicable to all tree species? This is very important for others to refer to and conduct similar experiments.

(2) It is recommended that the p-value represented as "5.565455E-21" in Table 1 be modified to the scientific notation form of “5.565455 × ^10-21”.

(3) Within the paper, the author should pay attention to the standardization of the labels in the figures. For instance, in Figures 4, 5, and 6, the clarity of the font in the labels should be checked, and the overall aesthetic appearance should be considered. 

(4) To enhance the specificity of the paper, it is suggested to include a study on the glucose content in the phloem of different tree species after a fire, followed by an analysis of the results. This would improve the accuracy of determining the potential post-fire mortality rate of trees.

Author Response

Comment1: The experimental study of quantifying the glucose concentration in the phloem was used to study the latent mortality rate of trees after fires, and the conclusions drawn have certain theoretical significance and value. Therefore, I can accept the study with slight modifications. I suggest the following modifications and explanations:

Is formula 1 established in this study applicable to all tree species? This is very important for others to refer to and conduct similar experiments.

Response1: We added a sentence to clarify the use of the formula “The formula [1] established in this study is applicable for conifer species, and it must be validated for broadleaves species.”

Comment2: (2) It is recommended that the p-value represented as "5.565455E-21" in Table 1 be modified to the scientific notation form of “5.565455 × ^10-21”.

Response2: We change the p-value with “< 0.001”.

Comment3: (3) Within the paper, the author should pay attention to the standardization of the labels in the figures. For instance, in Figures 4, 5, and 6, the clarity of the font in the labels should be checked, and the overall aesthetic appearance should be considered. 

Response3: We uniformed the labels of figures.

Comment4: (4) To enhance the specificity of the paper, it is suggested to include a study on the glucose content in the phloem of different tree species after a fire, followed by an analysis of the results. This would improve the accuracy of determining the potential post-fire mortality rate of trees.

Response4: We improved the definition of the potential of the study by accepting the comment of the reviewer by adding the following text in discussion section “Our study is addressed to consider the potential to assess the vitality in early stages after fire. Our study is supported by a recent study [18] that highlights the importance of NSCs for tree survival and post-fire recovery. The study [18] observed a NSC depletion, corresponding to a carbohydrate availability limitation for maintaining tree function post-fire in Pinus ponderosa. NSC depletion may be the result of fire-caused injuries useful to define post-fire tree mortality and, then, to plan forest recovery”.

Reviewer 2 Report

Comments and Suggestions for Authors

The study presented is certainly of interest and helps to understand a phenomenon, that of delayed mortality after a wildfire, on which there is not sufficient knowledge. This phenomenon has recently been demonstrated for the first time in the Mediterranean area (Sardinia), highlighting the crucial role in post-fire forest management (see LL52-54).

The MS is interesting, however, some adjustments are needed to the MS so that it can be clearer and more focused on the topic.

First of all in the introduction which should be less dispersive and more focused (i.e. on the conifers being studied). Likewise, some statements should be better clarified: the practice of salvage logging is not useful for all Mediterranean tree species (indeed, for very few) but above all it is not a common practice in the Mediterranean area (LL43-44).

Second, the methods should be revised because they are not clear: in the results there is an anova test (L329) that is not described in the methods; the same for the correlation analysis. It is not clear how many samples were taken and why they were not taken more homogeneously. I understand the need for synthesis but I can't understand if the adopted protocol is free from the effect of other environmental factors; in any case the method should be better clarified, especially the field sampling. More generally, I believe the number of samples is too low to obtain significant data.

 

Minor points

L127: Mature plants are always a curious concept.

LL52-54: this sentence need a reference.

L128: please, use botanical nomenclature (also L186).

LL199- : When were the samples collected? Is this enough time for conifers to have delayed mortality? If I understand correctly, the samplings were done only one year later but this time would not be significant for appreciating the delayed mortality. How did you rule out the possibility that these are different phenomena?

L296: this figure is not clear (also figure 5).

LL331-332: as said before the protocol is not clear enough and above all I would be more cautious since it has not been validated in a significant way.

LL361-363: This data should be shown, being so significant.

L370: The practice of “salvage logging” is not very often used….

Author Response

Comment1: The study presented is certainly of interest and helps to understand a phenomenon, that of delayed mortality after a wildfire, on which there is not sufficient knowledge. This phenomenon has recently been demonstrated for the first time in the Mediterranean area (Sardinia), highlighting the crucial role in post-fire forest management (see LL52-54).

The MS is interesting, however, some adjustments are needed to the MS so that it can be clearer and more focused on the topic.

First of all in the introduction which should be less dispersive and more focused (i.e. on the conifers being studied). Likewise, some statements should be better clarified: the practice of salvage logging is not useful for all Mediterranean tree species (indeed, for very few) but above all it is not a common practice in the Mediterranean area (LL43-44).

Response1: We improved the description of the introduction section.

Comment1: Second, the methods should be revised because they are not clear: in the results there is an anova test (L329) that is not described in the methods; the same for the correlation analysis. It is not clear how many samples were taken and why they were not taken more homogeneously. I understand the need for synthesis but I can't understand if the adopted protocol is free from the effect of other environmental factors; in any case the method should be better clarified, especially the field sampling. More generally, I believe the number of samples is too low to obtain significant data.

Response2: We thank reviewer to give us suggestion to improve the study. The following are our changes to implement the text description.

We improved the description of the data analysis section.

Regarding “the adopted protocol is free from the effect of other environmental factors”, We detailed the text by adding the following information “The trees were sampled in an area with a surface of 12 hectares, eastern exposure and an average slope of 17%.”

Concerning the comment “the number of samples is too low to obtain significant data”, the sample size in our case is part of the early stages of conducting and assessing the potentiality of the proposed protocol. In establishment of protocol, we processed more samples, but in the preparing the scientific paper, we replicated the analysis by adopting a sample size suitable to be duplicated. Different investigations, different in terms of sample size, were conducted with the same methodology and achieving equivalent results. Therefore, ideally, samples should not be small and, contrary to what one might think, should not be excessive. The aim of this paper is to provide a user-friendly protocol with a reasonable sample size to consider in a field study.

 

Minor points

Comment3: L127: Mature plants are always a curious concept.

Response3: We agree and simplified the description with “two trees of Pinus pinea”.

Comment4: LL52-54: this sentence need a reference.

Response4: We added two references.

Comment5: L128: please, use botanical nomenclature (also L186).

Response5: We improved the description of trees species.

Comment6: LL199- : When were the samples collected? Is this enough time for conifers to have delayed mortality? If I understand correctly, the samplings were done only one year later but this time would not be significant for appreciating the delayed mortality. How did you rule out the possibility that these are different phenomena?

Response6: We improved the description of the text by adding the following text “The time sampling was defined according to a previous study [18], where post-fire tree mortality and recovery patterns in Pinus ponderosa were assessed at different timesteps post-fire (4 days–16 months).”

Comment7: L296: this figure is not clear (also figure 5).

Response7: We improved the description of captions of figures and their graphical resolution.

Comment8: LL331-332: as said before the protocol is not clear enough and above all I would be more cautious since it has not been validated in a significant way.

Response8: Thank you for the comment that gave us the suggestions to clarify details of our study. We solved the previous comments of both reviewers, and we believe that the protocol description is now improved.

Comment9: LL361-363: This data should be shown, being so significant.

Response9: We detailed the text “However, during February 2024, trees characterized in 2022 were assessed by showing a satisfactory prediction of death in 61% of cases”.

Comment10: L370: The practice of “salvage logging” is not very often used….

Response10: We improved the text by adding “The practices of safeguarding, restoration and “salvage logging” are becoming more and more common in Tuscany as well as in other areas around the world. These practices allow to mitigate further post-fire forest and soil degradation and to minimize commercial wildfire injury”.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The author made revisions based on my comments.

Author Response

Thank you for the positive reply.

Reviewer 2 Report

Comments and Suggestions for Authors

I have no further comments but I note that some aspects of the previous review have been completely ignored by the authors.

Sme doubts about the protocol remain unresolved; I'm still convinced that the number of samples is too small and the authors' response does not clarify this aspect which I find fundamental. the text cited as a methodological reference (reference 18) seems to concern "live oaks" (Quercus virginiana P. Miller) and does not study conifers.

The introduction was not revised as requested.

 

 

Author Response

Comment1: Some doubts about the protocol remain unresolved; I'm still convinced that the number of samples is too small and the authors' response does not clarify this aspect which I find fundamental. the text cited as a methodological reference (reference 18) seems to concern "live oaks" (Quercus virginiana P. Miller) and does not study conifers.

Response1: We realize that the number of samples seems too small, but we believe it is appropriate to define an initial protocol, which, obviously, can be implemented for future researches.  Furthermore, the proposed number of samples comes from several experimental field samplings, and we believe it is the best solution for implementing the protocol in the field. Taking into account the glucose sample data, recorded in the field, and sizing the sample according to its distribution and its standard deviation (0 for D, 16.18 for L, and 21.28 for X), a sample of 10.45 would have been sufficient. Therefore, we oversized the sample size to reduce the probability of type I error, except for D plants, which always recorded values of 0, for this reason we collected fewer samples.

Comment2: The introduction was not revised as requested.

Response2: Thank you for stimulating the revision of the introduction section. We rephrased sentences and updated references, as you can read in the revised version of the manuscript.

Author Response File: Author Response.docx