Study of the Spatial Distribution of the Bark Beetle in the Ejido Tixtlancingo

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The possibilities of protective measures against xylophagous are, unfortunately, limited. In this regard, it is extremely important to identify in advance areas with a high risk of damage to forests by insects. For this purpose, a retrospective analysis of the relationships between the intensity of damage to plantings by pests depending on the characteristics of trees, weather conditions, landscape characteristics of the territory, and so on is usually carried out.

However, the present work focuses on the spatial distribution of outbreaks in stands of major pine species.

Our experience in studying the interaction of Dendroctonus micans with trees has shown that the intensity of pest attack on trees is largely determined by the tree state, and to assess the risk of insect impact on stand, it is necessary to estimate the density function of the distribution of trees by categories of physiological state.

The authors did not propose any original methods for assessing the condition of tree state and use an indicator such as tree diameter as condition categories. It has been shown that insects prefer to attack trees of intermediate diameters. Apparently, the mass of living tissue in trees with small diameters is insufficient for effective feeding of insects, while trees with large diameters are resistant to pests. And it would be of interest to identify the reasons for the differences between the strong impact of the pest in some areas and the weak impact in other areas.

I would like not to look at a description of the geography of damage (probably important for the conditions of Mexico), but to understand what determines the observed spatial distribution of damage - variability in the condition of trees, landscape conditions or weather. The authors evaluate the similarity between the observed pine damage rates and the predicted values, but I did not see in the text descriptions of the models characterizing the damage, the very models with which the authors compare the observations. I was unable to understand the methods used by the authors to predict damage, and therefore all the figures on this topic are incomprehensible. What does damage prediction mean? How are these predictions made? What is compared with what in terms of correlation coefficients?

The scales in Fig. 5 - 8 are unclear. What do they mean – the values of the correlation coefficients? Apparently, in Fig. 8 on the scale it is the correlation coefficients (?), but what then in the scales in Fig. 5 -7, where are the scale values measured in thousands of units (areas or total number of trees affected (TTA))? It is not clear why the indicators of temperature, solar radiation and precipitation were given and where they were used in the analysis (and where was the analysis itself; I don’t think the data on the connection between the level of damage by xylophages and the diameter of trees is interesting, but well known to forest entomologists?). The manuscript's abstract gives the impression of an accounting document that does not contain any ecological analysis of insect-tree interactions.

Considering all of the above, it seems that for publication in a journal the manuscript must be greatly revised.

Author Response

Dear Reviewer:

Dear editor,

Thank you for evaluation of our manuscript. Please find our responses to the comments in this letter.

Kind regards

28 April 2024

Review Report for the manuscript

Study of the Spatial Distribution of The Bark beetle in the Ejido Tixtlancingo

 

 

The possibilities of protective measures against xylophagous are, unfortunately, limited. In this regard, it is extremely important to identify in advance areas with a high risk of damage to forests by insects. For this purpose, a retrospective analysis of the relationships between the intensity of damage to plantings by pests depending on the characteristics of trees, weather conditions, landscape characteristics of the territory, and so on is usually carried out.

However, the present work focuses on the spatial distribution of outbreaks in stands of major pine species.

Our experience in studying the interaction of Dendroctonus micans with trees has shown that the intensity of pest attack on trees is largely determined by the tree state, and to assess the risk of insect impact on stand, it is necessary to estimate the density function of the distribution of trees by categories of physiological state.

Answer:  Thank you very much for your comments; the justification for this comment is found in lines 375 to 390 of the document.

The authors did not propose any original methods for assessing the condition of tree state and use an indicator such as tree diameter as condition categories. It has been shown that insects prefer to attack trees of intermediate diameters. Apparently, the mass of living tissue in trees with small diameters is insufficient for effective feeding of insects, while trees with large diameters are resistant to pests. And it would be of interest to identify the reasons for the differences between the strong impact of the pest in some areas and the weak impact in other areas.

Answer:  In relation to your comment, the method addressed was to measure the diameter and height to calculate volume, as well as the symptoms of the tree according to the Maxican standards. The answer to this point is found in lines 125 to 136 of the document.

I would like not to look at a description of the geography of damage (probably important for the conditions of Mexico), but to understand what determines the observed spatial distribution of damage - variability in the condition of trees, landscape conditions or weather. The authors evaluate the similarity between the observed pine damage rates and the predicted values, but I did not see in the text descriptions of the models characterizing the damage, the very models with which the authors compare the observations. I was unable to understand the methods used by the authors to predict damage, and therefore all the figures on this topic are incomprehensible. What does damage prediction mean? How are these predictions made? What is compared with what in terms of correlation coefficients?

Answer: 

1. But I did not see in the text descriptions of the models characterizing the damage. Answer: A spatial Poisson model was used to study the spatial distribution of bark stripper damage; and to evaluate the performance of the spatial model, the Pearson correlation coefficient was used (lines 183-185), which uses the observed data and the values predicted by the spatial model; For the year 2020: P. maximinoi, lines 268-272; P. Oocarpa, lines 274-278; P. pseudostrobus lines 280,284. For the year 2021: P. maximinoi, lines 319-323; P. Oocarpa, lines 325-329; P. pseudostrobus lines 331-335.

 

1. I was unable to understand the methods used by the authors to predict damage. Answer: El modelo utilizado es un modelo espacial que ayuda a predecir los daños en la región de estudio. Diggle et al., 1998.
2. What does damage prediction mean? Answer: The spatial Poisson model was used to study the distribution of damage caused by bark beetle.
3. How are these predictions made? Answer: The study of the spatial distribution of damage was carried out using the information observed in the 2020 and 2021 outbreaks (Figures 2 and 10).
4. What is compared with what in terms of correlation coefficients?: Answer: Pearson's correlation coefficient was used to evaluate the goodness of fit of the spatial model; it was also used to study the relationship between the damage caused in the three pine species (lines 259-263; and 310-314).

Diggle P. J., Tawn J. A., and Moyeed R. A., 1998 “Model-based geostatistics,” Journal of the Royal Statistical Society: Series C (Applied Statistics), vol. 47, no. 3, pp. 299–350.

 

The scales in Fig. 5 - 8 are unclear. What do they mean – the values of the correlation coefficients? Apparently, in Fig. 8 on the scale it is the correlation coefficients (?), but what then in the scales in Fig. 5 -7, where are the scale values measured in thousands of units (areas or total number of trees affected (TTA))? It is not clear why the indicators of temperature, solar radiation and precipitation were given and where they were used in the analysis (and where was the analysis itself; I don’t think the data on the connection between the level of damage by xylophages and the diameter of trees is interesting, but well known to forest entomologists?). The manuscript's abstract gives the impression of an accounting document that does not contain any ecological analysis of insect-tree interactions.

Considering all of the above, it seems that for publication in a journal the manuscript must be greatly revised.

Answer: 

1. Pearson's correlation coefficient was used to evaluate the goodness of fit of the model. For the year 2020: P. maximinoi, lines 268-272; P. Oocarpa, lines 274-278; P. pseudostrobus lines 280,284. For the year 2021: P. maximinoi, lines 319-323; P. Oocarpa, lines 325-329; P. pseudostrobus lines 331-335. This coefficient was also used to study the relationship between the damage caused in the three pine species (lines 259-263; and 310-314).

 

2. In the discussion, lines 420-444, the relationship between bark stripper damage and temperature and precipitation variables was addressed. Solar radiation and wind speed variables were omitted from the study because there is no adequate equipment to measure them, and the monitoring stations are very far from the diagnosed area.

 

3. Regarding the ecological analysis of insect-tree interactions, it is found in lines 407-418.

We appreciate your comments, which have been of great importance to our research group, and we hope to meet your expectations in the present document. Best regards.

 

 

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The bark beetles of the Dendroctonus genus, as pests that cause ecological imbalance and significant economic losses in the forest industry of North and Central America's coniferous forests, necessitate rapid analysis of their spatial distribution patterns and the implementation of control measures. In this study, the author conducted a survey of trees within the occurrence area of Tixtlancingo ejido, collecting data on diameter, height, topography, altitude, slope, temperature, precipitation, fires, and stand structure. Spatial predictions were made for bark beetle damage in 2020 and 2021, and the damage patterns of different years and tree species were analyzed. This is crucial for forestry workers to carry out pest management efforts. However, there are still some contents in the article that require further modification, as detailed below.

1.Line 26-29: “The abiotic factors that most influence their distribution and abundance are water availability, temperature (Chow and Nicolson, 2024; De la Vega and Schilman, 2015; Clark, 2019), humidity, precipitation and altitudinal gradient (Safranyik et al., 2010; Rubín et al., 2015; Soto-Correa et al., 2019).”, Introduction said, the abiotic factors that have the greatest impact on the distribution and abundance of beetles of Dendroctonus genus are described, but there is no analysis in the discussion part on how water availability, temperature, humidity, and precipitation affect the spatial distribution of beetles. It is recommended to add some information.

2. Line 60-62: “The objective of this study was to determine the current and potential spatial distribution of the bark strippers Dendroctonus frontalis and Dendroctonus mexicanus that affect the forests of the Tixtlancingo ejido”, There is no potential spatial distribution analysis in the text. Can we make some simple predictions or analysis about the future distribution of beetles belonging to Dendroctonus genus?

3.Line 129-130: “data were collected on diameter, heights, topography, altitude, slope, temperature, precipitation, fires, stand structure”, Does fire have an impact on the spatial distribution of bark beetles of the Dendroctonus genus? If so, what kind of impact would it have?

4. Tables 1-3 express climatic factors in months, but the number and volume of affected pines are counted on a yearly basis. We cannot know the impact of monthly climatic factors on pine trees from them. Can we add in the discussion section: what kind of impact does the combination of monthly climatic conditions have on the spatial distribution of Dendroctonus frontalis Simmermann, 1868 and Dendroctonus mexicanus Hopkins, 1905?

5.Line 215-217: “it can be observed that air temperature was higher in June (28.780 °C), while solar radiation was higher in April (296.272 W/m²) and wind speed was higher in May (2.202 m/s).”. What impact do solar radiation and wind speed have on this study? It is recommended to further analyze their significance. If they have no impact, it is suggested to remove these data.

6. Tables 4-5: What conclusions can be drawn from the data of "Percentage of volume affected" and "Percentage of pine trees affected" in the tables? It is recommended to provide further explanation and merge the two tables.

7.Line 239-240: “Figures 2, 3 and 4 show the total number of trees affected (TTA) by the bark stripper in each of the pine species in 2020.”, Can we analyze the distribution of infected pine trees based on climatic conditions, forest stand composition, and other factors?

8.Line 355-358: “In 2020 the bark stripper affected P. maximinoi to a greater extent and P. oocarpa in second place”” Regarding the year 2021, we can see that the bark stripper 357

affected P. oocarpa to a greater extent, followed by P. maximinoi”, Can you explain the reason for this phenomenon?

9.Line 379-380: “a preference for diameter categories of 30 cm for 2020 and 50 cm for 2021.”, Can you further elaborate on why there is such a tendency for pest invasion?

10.Line 409-410: “From the spatial analysis it was observed that, depending on the pine species, the damage by the bark stripper changes its spatial pattern” , It is suggested to take the three types of pine trees mentioned in this study as examples to further analyze how bark strippers change their spatial distribution pattern.

Author Response

Dear editor,

Thank you for evaluation of our manuscript. Please find our responses to the comments in this letter.

for the manuscript

Study of the Spatial Distribution of The Bark beetle in the Ejido Tixtlancingo

The bark beetles of the Dendroctonus genus, as pests that cause ecological imbalance and significant economic losses in the forest industry of North and Central America's coniferous forests, necessitate rapid analysis of their spatial distribution patterns and the implementation of control measures. In this study, the author conducted a survey of trees within the occurrence area of Tixtlancingo ejido, collecting data on diameter, height, topography, altitude, slope, temperature, precipitation, fires, and stand structure. Spatial predictions were made for bark beetle damage in 2020 and 2021, and the damage patterns of different years and tree species were analyzed. This is crucial for forestry workers to carry out pest management efforts. However, there are still some contents in the article that require further modification, as detailed below.

1.Line 26-29: “The abiotic factors that most influence their distribution and abundance are water availability, temperature (Chow and Nicolson, 2024; De la Vega and Schilman, 2015; Clark, 2019), humidity, precipitation and altitudinal gradient (Safranyik et al., 2010; Rubín et al., 2015; Soto-Correa et al., 2019).”, Introduction said, the abiotic factors that have the greatest impact on the distribution and abundance of beetles of Dendroctonus genus are described, but there is no analysis in the discussion part on how water availability, temperature, humidity, and precipitation affect the spatial distribution of beetles. It is recommended to add some information.

Answer: Thank you for your comments. Regarding your comment, the justification is found in lines 419-454.

2. Line 60-62: “The objective of this study was to determine the current and potential spatial distribution of the bark strippers Dendroctonus frontalis and Dendroctonus mexicanus that affect the forests of the Tixtlancingo ejido”, There is no potential spatial distribution analysis in the text. Can we make some simple predictions or analysis about the future distribution of beetles belonging to Dendroctonus genus?

Answer: Given the available information, the objective of the work was adjusted only to a study of the spatial distribution of the damage caused by the bark beetle in the diagnosed area. In the Discussion section, the spatial distribution of damage was justified in terms of environmental factors, lines 419-443

3.Line 129-130: “data were collected on diameter, heights, topography, altitude, slope, temperature, precipitation, fires, stand structure”, Does fire have an impact on the spatial distribution of bark beetles of the Dendroctonus genus? If so, what kind of impact would it have?

Answer: The fire impact on the spatial distribution of the bark stripper is found in lines 392-404

4. Tables 1-3 express climatic factors in months, but the number and volume of affected pines are counted on a yearly basis. We cannot know the impact of monthly climatic factors on pine trees from them. Can we add in the discussion section: what kind of impact does the combination of monthly climatic conditions have on the spatial distribution of Dendroctonus frontalis Simmermann, 1868 and Dendroctonus mexicanus Hopkins, 1905?

Answer: The temperature and precipitation variables, as well as the measurements of damage caused by the bark stripper correspond to the same time period.  Measurements of climatic variables were for the months of April through June, Tables 1 and 2; monitoring of damage caused by the bark beetle was also for the months of April, May and June, lines 203-217. Discussion of this item is addressed in lines 419-443; and lines 481-495.

5.Line 215-217: “it can be observed that air temperature was higher in June (28.780 °C), while solar radiation was higher in April (296.272 W/m²) and wind speed was higher in May (2.202 m/s).”. What impact do solar radiation and wind speed have on this study? It is recommended to further analyze their significance. If they have no impact, it is suggested to remove these data.

Answer: Possibly, these variables may have an impact on the behavior of the bark beetle, but we did not have the analytical instruments to make such measurements, so we considered your suggestion to eliminate these data from the report. Possibly, these variables may have an impact on the behavior of the bark beetle, but we did not have the analytical instruments to make such measurements, so we considered your suggestion to eliminate these data from the report.

6. Tables 4-5: What conclusions can be drawn from the data of "Percentage of volume affected" and "Percentage of pine trees affected" in the tables? It is recommended to provide further explanation and merge the two tables.

Answer: Your recommendation was considered; Tables 4 and 5 were merged (Table 3). The conclusion of the percentage of volume and pine trees affected can be found in lines 224-229.

7.Line 239-240: “Figures 2, 3 and 4 show the total number of trees affected (TTA) by the bark stripper in each of the pine species in 2020.”, Can we analyze the distribution of infected pine trees based on climatic conditions, forest stand composition, and other factors?

Answer: With respect to climatic conditions it is found in lines 419-443; mass composition is found in lines 375-390; other factors such as fire is found in line 392-404, and pest-host interaction is found in lines 406-417.

8.Line 355-358: “In 2020 the bark stripper affected P. maximinoi to a greater extent and P. oocarpa in second place”” Regarding the year 2021, we can see that the bark stripper 357

affected P. oocarpa to a greater extent, followed by P. maximinoi”, Can you explain the reason for this phenomenon?

Answer: The explanation of this behavior in the species is justified in lines 345-366.

9.Line 379-380: “a preference for diameter categories of 30 cm for 2020 and 50 cm for 2021.”, Can you further elaborate on why there is such a tendency for pest invasion?

Answer: For an explanation of this behavior, see lines 359-366.

10.Line 409-410: “From the spatial analysis it was observed that, depending on the pine species, the damage by the bark stripper changes its spatial pattern”, It is suggested to take the three types of pine trees mentioned in this study as examples to further analyze how bark strippers change their spatial distribution pattern.

Answer: With respect to this observation, it is planned to analyze in the future the distribution patterns of the pest with respect to the host species. This is Discussed in lines 468-472.

 

We appreciate your comments, which have been of great importance to our research group, and we hope to meet your expectations in the present document. Best regards.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors answered all the reviewer’s questions, the article can be published

Author Response

Thank you very much for your comments and contributions, they have been very helpful for this research and future investigations.

King Regards

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The study identified a period between 2020 and 2021 between Dendroctonus frontalis Simmermann, 1868, and Dendroctonus mexicanus Hopkins, 1905 Spatial distribution within the Tixtlancingo ejido. It establishes a baseline for monitoring the damage caused by these beetles, supporting progress towards the 2030 Sustainable Development Goals (SDGS) agenda. At the same time, the study detailed the effects of diameter, height, topography, elevation, slope, temperature, precipitation, fire, stand structure and other data on the spatial distribution of beetles, which is crucial for pest control. Therefore, this study is of great significance. I think there is no further content in this article that needs to be revised, and I agree to the publication of this article.

Author Response

Thank you very much for your comments and contributions, they have been very helpful for this research and future investigations.

King Regards

Author Response File: Author Response.pdf