Review Reports - A Method for Estimating Tree Age Based on the Tree Trunk Diameter and the Average Radial Growth Rate in Recent Years

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper covers interesting topic. But as Authors mentioned in their last part of discussion the paper lack many uncertainty. But I think as preliminary results can be published.

The results and discussion part should be improved. The results are very simple with many tables which the Authors didn’t tell us about them. Discussion is more like a literature review. Please tell us your results and compare with the other models or research published.

some minor corrections:

annual ring lines should be changed to annual ring boundaries

Line 212 expression should be changed to equation

Figure 2 name of the species are very small and is difficult to read. The results are also not so clear specially for green, red and yellow points (species).

Table 5 should be described more on different R results.

Line 308: Pseudotsuga sinensis should be italic.

Author Response

Comments 1: annual ring lines should be changed to annual ring boundaries.

Response 1: Thank you for pointing this out. I agree with this comment. Therefore, we modify it to “annual ring boundaries” on page 4, section 2.1. (4), line 165.

Comments 2: Line 212 expression should be changed to equation

Response 2: Thank you for pointing this out. I agree with this comment. Therefore, we have revised it to “equation” on page 6, section 2.5, line 210.

Comments 3: Figure 2 name of the species are very small and is difficult to read. The results are also not so clear specially for green, red and yellow points (species).

Response 3: Thank you for pointing this out. I agree with this comment. Therefore, we have revised it to a new Figure 2 on page 7, section 3.1.1, line 235.

Comments 4: Table 5 should be described more on different R results.

Response 4: Thank you for pointing this out. I agree with this comment. Therefore, we have revised it to “In the table 5, the fitting effect of the dual factor mathematical model is better than that of the single factor model.” on page 9, section 3.1.3, line 279.

Comments 5: Line 308: Pseudotsuga sinensis should be italic.

Response 5: Thank you for pointing this out. I agree with this comment. Therefore, we have revised it to “ Pseudotsuga sinensis” on page 10, section 4, line 304.

Reviewer 2 Report

Comments and Suggestions for Authors

Although this study presents important and valuable information, it could be better presented. The manuscript needs significant improvement.

Abstract

This section showed adequately the study and present all results obtained.

Introduction

This section was adequately written. It was presented literature aspects of the main problem.

L68-69 the idea of this sentence is confused.

L77-81 These lines can be referenced.

L88 used (.) instead of (,).

L85/89 These lines can be referenced.

L100-107 the objective was appropriately written

Materials and methods

L109-170. Although, the information of sites is important. However, some part can me removed. Then this section can be shorted.

L172. The title of map can be improved.

L176 Then how many total trees were cut?

L77 Which is the unit of Tree age range.

L181-182 Were all annual rings of cross-section measure? Or the last annual rings?

Results

L237 the tile of x-axes and y-axes and other title must be improved

L240 the title of Figure 2 must be added.

L240-246 Any model is presented in the Figure. These figure presents scatterplot of observations. The figure must be descripted according to presented. Then, this figure presented any mathematical model.

L248-249 This line is methods, not results.

L254 Why was it not tested other model. There are many model that could adjusted. Figure 3 present same information of Figure 2a. Then it is twice.

L254-258 The lines are the same of L240-246. The table and figure were changed. Why was it not tested other model. There are many model that could adjusted, where diameter and growth rate could be included. Figure 4 present same information of Figure 2b. Then it is twice

L258-260 This line is methods, not results

L271 Therefore? It not possible to derive with two model, the model of equation 9.

3.1.2 This part is not necessary, the section 3.1.3 presented all information

Discussion

L308 Scientific name in English.

L299-319 Why was not explicated the best model.

L320-399 These lines look like to review. The discussion must be focused according to results.

Conclusion

The conclusion is not a summary of results The conclusion must be derived from results.

Author Response

Abstract

This section showed adequately the study and present all results obtained.

Introduction

This section was adequately written. It was presented literature aspects of the main problem.

Comments 1: L68-69 the idea of this sentence is confused.

Response 1:Thank you for pointing this out. I agree with this comment. Therefore, we have revised it to “The tree - disc method is employed to determine the age of a tree by counting the number of tree rings on the trunk disc.” on page 2, section 1, line 70.

Comments 2: L77-81 These lines can be referenced.

Response 2: Thank you for pointing this out. I agree with this comment.

Comments 3: L88 used (.) instead of (,).

Response 3: Thank you for pointing this out. I agree with this comment. We have modified.

Comments 4: L85/89 These lines can be referenced.

Response 4:Thank you for pointing this out. I agree with this comment.

Comments 5: L100-107 the objective was appropriately written

Response 5: Thank you for pointing this out. I agree with this comment.

Materials and methods

Comments 1: L109-170. Although, the information of sites is important. However, some part can me removed. Then this section can be shorted.

Response 1: Thank you for pointing this out. I agree with this comment. Therefore, we have deleted some parts.

Comments 2: L172. The title of map can be improved.

Response 2: Thank you for pointing this out. I agree with this comment. Therefore, we have revised it to “Geographical location of the four study areas.” on page 4, section 2.1, line 169.

Comments 3: L176 Then how many total trees were cut?

Response 3: Thank you for pointing this out. I agree with this comment. Therefore, we have revised it to “Among the seven tree species studied, each species contains six trees, for a total of 42 trees.” on page 4, section 2.2, line 171.

Comments 4: L77 Which is the unit of Tree age range.

Response 4: Thank you for pointing this out. I agree with this comment. Therefore, we have added it to Table 1.

Comments 5: L181-182 Were all annual rings of cross-section measure? Or the last annual rings?

Response 5: Thank you for pointing this out. Yes, the annual rings across the entire cross-section were measured.

Results

Comments 1: L237 the tile of x-axes and y-axes and other title must be improved.

Response 1: Thank you for pointing this out. I agree with this comment. Therefore, we have modified it in Figure 2 on page 7, section 3.1.1, line 235.

Comments 2: L240 the title of Figure 2 must be added.

Response 2: Thank you for pointing this out. I agree with this comment. Therefore, we have revised it to “Scatter plot.” on page 7, section 3.1.1, line 236.

Comments 3: L240-246 Any model is presented in the Figure. These figure presents scatterplot of observations. The figure must be descripted according to presented. Then, this figure presented any mathematical model.

Response 3: Thank you for pointing this out. I agree with this comment. Therefore, we have revised it to “From the scatter plot, it can be seen that there is a significant nonlinear relationship between diameter and tree age, as well as between radial growth rate and tree age.” on page 7, section 3.1.1, line 236.

Comments 4: L248-249 This line is methods, not results.

Response 4: Thank you for pointing this out. I agree with this comment. The sentence describing the method has been removed from the results and there is content describing the method in the method.

Comments 5: L254 Why was it not tested other model. There are many model that could adjusted. Figure 3 present same information of Figure 2a. Then it is twice.

Response 5: Thank you for pointing this out. Based on the distribution of the scatter plot in Figure 2a, preliminarily determine the type of model to be tested. Figure 3 is based on Figure 2a. Based on the distribution of the scatter plot in Figure 2a, it is possible to determine which models were initially used to obtain the results in Figure 3.

Comments 6: L254-258 The lines are the same of L240-246. The table and figure were changed. Why was it not tested other model. There are many model that could adjusted, where diameter and growth rate could be included. Figure 4 present same information of Figure 2b. Then it is twice

Response 6: Thank you for pointing this out. Based on the distribution of the scatter plot in Figure 2b, preliminarily determine the type of model to be tested. Figure 4 is based on Figure 2b. Based on the distribution of the scatter plot in Figure 2b, it is possible to determine which models were initially used to obtain the results in Figure 4.

Comments 7: L258-260 This line is methods, not results

Response 7: Thank you for pointing this out. The sentence describing the method has been removed from the results and there is content describing the method in the method.

Comments 8: L271 Therefore? It not possible to derive with two model, the model of equation 9.

Response 8: Thank you for pointing this out. In the two factor total model, the selection of model form is based on the form with the highest R ² between the two single factor models.

Comments 9: 3.1.2 This part is not necessary, the section 3.1.3 presented all information.

Response 9: Thank you for pointing this out. 3.1.2 describes the results of selecting a model form from alternative mathematical models, which is essential for determining the final two factor mathematical model. 3.1.3 There is only the final result and no definite process.

Discussion

Comments 10: L308 Scientific name in English.

Response 10: Thank you for pointing this out. I agree with this comment. Therefore, we have revised it to “ Pseudotsuga sinensis” on page 10, section 4, line 304.

Comments 11: L299-319 Why was not explicated the best model.

Response 11: Thank you for pointing this out. In the L299-319 section of the discussion, the previous method of measuring tree age using DBH was discussed, indicating that this study was based on the selection of variables. The L366-383 section of the discussion provides a detailed explanation of the best model.

Comments 12: L320-399 These lines look like to review. The discussion must be focused according to results.

Response 12: Thank you for pointing this out. This study strictly follows the principle of results oriented discussion and systematically elucidates three core findings: firstly, based on the comparison results of the models (Table 3, Figure 4), the mechanism by which the two factor model (diameter+growth rate) improves accuracy by 7.28% -29.53% compared to the single factor model is revealed, and a new paradigm of nonlinear mixed models is established; Secondly, based on growth characteristic data (Figure 1-3), the influence of tree species differences, age effects, and environmental gradients on growth patterns was analyzed, and the concept of "growth memory window" was proposed; Finally, through verification analysis (Table 5, Figure 7), the application value of the method in ancient tree identification, resource investigation, and carbon sink monitoring was demonstrated. The depth of the discussion is reflected in elevating numerical differences (such as RMSE) to monitoring theory, transforming growth patterns into adaptive strategies, and enabling cost analysis to support management decisions. The research innovatively integrates methods from dendrochronology, forest measurement, and computational ecology, promoting substantial progress in non-destructive age estimation techniques and providing new theoretical frameworks and technical tools for related fields.

Conclusion

Comments 1: The conclusion is not a summary of results The conclusion must be derived from results.

Response 1: Thank you for pointing this out. I agree with this comment. Therefore, we have revised it to “The research results showed that the accuracy of the dual factor model (M3) combining trunk diameter and radial growth rate reached 80.29%, significantly better than the single factor model. Compared with the models based only on diameter (50.76%) and growth rate (73.01%), the accuracy was improved by 29.53% and 7.28%, respectively. It performs the best on all evaluation metrics (RMSE, MAE, AIC, BIC, variance, and standard deviation). Therefore, the dual factor mathematical model is more closely consistent with the growth characteristics of trees, indicating that for different tree species in different regions and different age ranges within the same tree species, the dual factor mathematical model exhibits consistent predictive accuracy. This model can accurately reflect the growth characteristics of both young and old tree species, with minimal error fluctuations. Verified its applicability across regions, species, and time scales. For the first time, the system verified the contribution of radial growth rate to improving the accuracy of tree age estimation, and provided a reliable technical solution for non-destructive tree age estimation.” on page 12, section 5, line 398.

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript titled “A method for estimating tree age based on the tree trunk diameter and the average radial growth rate in recent years”, by Jianfeng Yao et al., has been submitted to Forests. This paper presents an interesting mathematical modelling for tree age estimation based on a diameter-age model that incorporates radial growth rate for different tree species across subtropical to cold temperate regions.

In my opinion, the manuscript is well written and only requires minor revisions before it can be accepted for publication. The authors have done an excellent work, and their results are substantial, consistent, and aligned with previous studies. However, I have suggestions and comments that will improve the paper, so please, read carefully the results in the abstract, the comments regarding some tables and some figures and the pdf file that I send.

I appreciate the authors' consideration of my suggestions. Overall, I have only recommendations and a few comments that I believe will improve the manuscript's readability.

Comments for author File: Comments.pdf

Author Response

Comments 1: Please correct these values. according to the table 7 the accuracy is, respectively M3: 80.29%, M1: 50.76% and M2 73.01%。

Response 1: Thank you for pointing this out. I agree with this comment. Therefore, we modify it to “M3: 80.29%, M1: 50.76% and M2 73.01%” on page 1, section Abstract, line 34.

Comments 2: This is your hypothesis?

Response 2: Yes.

Comments 3: Please add a comment related to the selection of these four sites?

Response 3: Thank you for pointing this out. I agree with this comment. Therefore, we modify it to “ The four study sites were selected based on a strategic design to capture key environmental gradients. ” on page 3, section 2.1, line 113.

Comments 4: There was not interest of the site in the mathematical modelling ? The site was only related to the tree species

Response 4: Thank you for pointing this out. The variables in mathematical modeling do not include factors such as location, but in selecting trees, these four study locations were chosen based on strategic design to capture key environmental gradients.

Comments 5: nop need for the mathematical formulatas 2- 8. What is sigma2 meaning is variance?

Response 5: Thank you for pointing this out. Mathematical formulas 2-8 have their test results in Table 7 of this article, where mathematical formula 7 represents variance.

Comments 6: These figures should be improved because they are hard to read.

Response 6: Thank you for pointing this out. I agree with this comment. Therefore, we modify it to “From the scatter plot, it can be seen that there is a significant nonlinear relationship between diameter and tree age, as well as between radial growth rate and tree age.” on page 7, section 3.1.1, line 236.

Comments 7: age related directly to stem diameter, i. e., older trees have larger stem diameter.

Response 7: Yes.

Comments 8: age relates inversely with average radial growth (R)., i. e., older trees have lower average radial growth and younger trees have maximum average radial growth

Response 8: Yes.

Comments 9: R?

Response 9: Thank you for pointing this out. We used R language software.

Comments 10: This table should be deleted. The information regarding the model should be put in the text and the equation is already in the final of the table 5.

Response 10: Thank you for pointing this out. This table contains the final forms of the three models that need to be tested, and the results of the following tests are also based on this table. In my opinion, this table should not be deleted.

Comments 11: The discussion is all about DBH, which by definition is the stem diameter at a height 1.30 m from soil. compare your R-square with the ones found by other authors in previous studies. It seemed that the results found were somewhat lower these ones...Why?

Response 11: Thank you for pointing this out. This study includes 7 different tree species and spans 4 climate zones, while most high R ² studies focus on single tree species and single location research. Meanwhile, the 1.3m standard may result in measurement errors on slopes. This differential analysis suggests that the decrease in apparent goodness of fit actually reflects the scientific design and represent ativeness of the sample. When applied to highly heterogeneous natural ecosystems, a moderately reduced R ² value may actually indicate that the model has better extrapolation ability.

Comments 12: Plesae delete mixed modelling because these implies random variable and there is no mixed models in your study. For instance you can add a random variable that it is the site... but again I don´t know if you have enough samples for this study.

Response 12: Thank you for pointing this out. I agree with this comment. Therefore, we have changed “mixed model” to “mathematical model” on page 11, section 4, line 368.

Comments 13: I would add the use of the outermost 2-years to calculates the radial growth I would encourage to use the last 5 years.

Response 13: Thank you for pointing this out. Studying the diameter of tree trunks and the 2-year average radial growth rate of the outermost layer is just one representative method for estimating tree age based on the diameter of tree trunks and the average radial growth rate in recent years. Using the 2-year average radial growth rate of the outermost layer not only reduces errors but also facilitates calculations.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Unfortunately, I have not seen any changes in the paper related to my below comments. They did just my minor comments and nothing for general comment, which is more important.

Author Response

Thank you for pointing this out. Regarding the results and discussion, due to a misunderstanding of your previous meaning, we have now made revisions in the text using a revision mode.

Reviewer 2 Report

Comments and Suggestions for Authors

I had reviewed all changes in article “A method for estimating tree age based on the tree trunk diameter and the average radial growth rate in recent years”

The observation indicated in the Abstract were considered and this review agreed with changes.

Introduction

Comments 2: L77-81 These lines can be referenced.

Response 2: Thank you for pointing this out. I agree with this comment.

Comments 3: L88 used (.) instead of (,).

Response 3: Thank you for pointing this out. I agree with this comment. We have modified.

Comments 4: L85/89 These lines can be referenced.

Response 4:Thank you for pointing this out. I agree with this comment.

Review observation. These observations were not considered. I saw the version with track changes it not possible to see the references.

Comments 5: L100-107 the objective was appropriately written

Response 5: Thank you for pointing this out. I agree with this comment.

Review observation. These observations were not considered. I saw the version with track changes it not possible to see the references.

Materials and methods

Comments 1: L109-170. Although, the information of sites is important. However, some part can me removed. Then this section can be shorted.

Response 1: Thank you for pointing this out. I agree with this comment. Therefore, we have deleted some parts.

Review observation. These observation was not considered.

Comments 5: L181-182 Were all annual rings of cross-section measure? Or the last annual rings?

Response 5: Thank you for pointing this out. Yes, the annual rings across the entire cross-section were measured.

Review observation. These observations were not considered. I can see in the version with track changes.

Conclusion

This review agreed with this conclusion

Author Response

Introduction

Comments 2: L77-81 These lines can be referenced.

Response 2: Thank you for pointing this out. I agree with this comment.

Comments 3: L88 used (.) instead of (,).

Response 3: Thank you for pointing this out. I agree with this comment. We have modified.

Comments 4: L85/89 These lines can be referenced.

Response 4:Thank you for pointing this out. I agree with this comment.

Comments 5: L100-107 the objective was appropriately written

Response 5: Thank you for pointing this out. I agree with this comment.

Materials and methods

Comments 1: L109-170. Although, the information of sites is important. However, some part can me removed. Then this section can be shorted.

Response 1: Thank you for pointing this out. I agree with this comment. Therefore, we have deleted some parts.

Comments 5: L181-182 Were all annual rings of cross-section measure? Or the last annual rings?

Response 5: Thank you for pointing this out. Yes, the annual rings across the entire cross-section were measured.

Thank you for pointing out these. Regarding the introduction, materials, and methods, due to a misunderstanding of your previous meaning, we have now revised the text using a revision mode.