Noninvasive Sonic Tomography for Detecting Internal Defects in Old, Large Oriental White Oak in Cultural Heritage Areas

Round 1

Reviewer 1 Report

a well-organized study. acceptable without modification

Author Response

Thank you review manuscript.  

Reviewer 2 Report

"Noninvasive Sonic Tomography (SoT) for Detecting Internal Defects in Oriental White Oak (Quercus aliena Blume) in Cultural Heritage Areas" is another of the authors who use the Sonic Tomography technique to detect internal defects in living trees. Unfortunately, the manuscript has a low novelty value – the authors used the same method on native zelkova and fir trees in urban parks in China in their previous research. To increase the paper's scientific value, I suggest adding some more discussion about the effectiveness/accuracy of the ST on different tree species. Some more comments can be found in the pdf file attached.

Comments for author File: Comments.pdf

Author Response

Point 1: I suggest adding some more discussion about the effectiveness/accuracy of the ST on different tree species. Some more comments can be found in the pdf file attached. Add some discussion about how the results form this research are similar or different compared to your previous results using the same technique to examin native zelkova and fir trees in urban parks in China (there is only one sentence about it in the Conclusions part). Is the accuracy of the method similar or maybe it depends on the tree species? (line 249)

> The difference in accuracy and error rate between the three tree species was additionally discussed by comparing the research results of the zelkova and needle fir based on the explanation for the low regression equation value of the oriental white oak in lines 208-210, 223-229 , 261-264.

Point 2: Please add a short discussion how revealing the internal cavities in trees could help in protecting them from damage caused by natural phenomena - as a justification to the research conducted.

>We supplemented the study legitimacy by additionally discussing the possibility of proactive tree management, such as controlling tree crown density and strengthening trunk support, to minimize tree damage caused by natural disasters based on tree risk diagnosis. We added this information in the Introduction (lines 47-53).

Reviewer 3 Report

General: The manuscript describes a study of sonic tomography on oriental white oak, and provides new information on the accuracy of this method for detecting defects. The language and grammar is good; however, the clarity should be improved. Below the specific comments to address for each section:

Introduction (or Discussion) section:

• Please give some more context about oriental white oak as a species. What are typical densities of heartwood and sapwood? How dos the process of heartwood formation affect durability in white oaks? How is the typical moisture content distribution in living white oak trees? Etc. This could be added here in the introduction, or else, in the discussion, as it would directly relate to the testing methods and the results. Maybe this would be one discussion point of why the errors with SoT are higher for oriental white oak (lines 246-248)?

Materials and Methods section:

• Lines 81-89 belong in the introduction section.
• Lines 120-122: This should also be in the introduction, or else, be addressed in the Discussion chapter, and how it may have influenced the results and the interpretation.
• It is not clear how the 91 measurement points relate to the 18 trees. This only somehow becomes clear with Table 3 and Appendix A. Maybe already add a reference to Table 3 or Appendix A here.
• It is very difficult to grasp this section as a whole, for example how are the first (2018) and second survey (2021) related? And what is the differences or relation of ERT and RM? Is the ERT based on the RM drillings? Please add a better structure to this section, so that for any reader, it becomes easier to understand what was done.

Results section:

• Line 136: What does “defect (blue)” refer to? To figure 3? If yes, add a reference to Figure 3.. if not, please explain. Also, explain shortly, for clarity, what type of defect is meant here.
• Please add some statement on the conditions or verify if the t-tests can be applied. For example, is your data following a normal distribution?
• Lines 131-149: Very unclear. By reading this part, and looking at Figures 1 and 2, it is not possible to understand what are the differences between what is shown in Figure 1 and what is shown in Figure 2. Maybe, are these the two surveys?
• Additionally, values of 0.24 and 0.44 as correlation coefficients (?) are low to such an extent that it could be said that the data sets/methods possess no explanatory power in relation to each other at all. Drawing a regression line, as in Fig 1 and Fig 2, is somewhat misleading.
• Figure 3: Please make the legends readable. Also, in the text, there is often words that refer to density and moisture content such as “normal” (line 187) or “high” (line 216 for example). Please specify the exact values each time if possible.
• Figure 3: Top right: It reads “oT tomograms”, instead of SoT.
• Maybe consider restructuring this section too. For the understanding, it would be better to first have the comparison of SoT and ERT to the tree cross-section. Then, based on this, make the attempt to correlate SoT to EM/ERT, and not the other way around.

Author Response

포인트 1: 소개(또는 토론) 섹션:

종으로서 오리엔탈 화이트 오크에 대해 더 많은 맥락을 제공하십시오. 심재와 변재의 일반적인 밀도는 얼마입니까? 심재 형성 과정이 화이트 오크의 내구성에 어떤 영향을 줍니까? 살아있는 화이트 오크 나무의 일반적인 수분 함량 분포는 어떻습니까? 등. 이것은 테스트 방법 및 결과와 직접적으로 관련되므로 서론에 추가하거나 토론에 추가할 수 있습니다. 이것은 SoT의 오류가 오리엔탈 화이트 오크(246-248행)에 대해 더 높은 이유에 대한 하나의 논의 지점이 될 수 있습니까?

> The association with the SoT error rate revealed occurs when there are compound internal defects, such as ring cracks, cracks, decay, and cavities (lines 244-246). However, although there may be different factors that can explain the difference in error rate in different tree species, as you stated, research on the characteristics of the growing environment of the tree or physical characteristics is currently lacking. Thus, further research is deemed necessary in the future and has been mentioned in the discussion section (lines 249-251).

 

Point 2 : Materials and Methods section: Lines 81-89 belong in the introduction section.

>We feel the lines still belong to the Materials and Methods section since it describes the place that was studied.

 

Point 2 : Lines 120-122: This should also be in the introduction, or else, be addressed in the Discussion chapter, and how it may have influenced the results and the interpretation.

> We have made the necessary changes.

 

Point 2 : It is not clear how the 91 measurement points relate to the 18 trees. This only somehow becomes clear with Table 3 and Appendix A. Maybe already add a reference to Table 3 or Appendix A here.

>The tree numbers of the eighteen trees in the 85 measurement points were added to Table 4 (previously Table 3) to indicate each tree with its corresponding MPs. The tree number and measurement points are already marked in Appendix A, so nothing was changed.

 

Point 2 : It is very difficult to grasp this section as a whole, for example how are the first (2018) and second survey (2021) related?

>The field survey was conducted twice because of physical difficulties. The following was conducted to verify the accuracy and error rate difference of the SoT measurement method regarding oriental white oaks. ① six trees to be logged in 2018 had their SoT measured before being logged. Then, the actual tree cross-section and SoT tomograms after logging were directly compared to quantitatively calculate the areas of the actual defects and estimated defects. ② the drilling resistance measurement results and the length of the defect in the SoT tomograms were statistically analyzed for the 18 additional tree samples in 2021 to verify the statistical significance of the SoT measurement values.

 

Point 2 : And what is the differences or relation of ERT and RM? Is the ERT based on the RM drillings? Please add a better structure to this section, so that for any reader, it becomes easier to understand what was done.

> ERT and RM are two completely different measurement methods. ERT can estimate the type of defect (cavity, decay) detected by the SoT and can be utilized as sub-data by being pragmatic in identifying initial decay with more sensitivity. A more detailed explanation of ERT was added (lines 133-138). RM involves using electric drills to measure the relative tree density and is the most commonly used method in tree diagnostics.

 

Point 2 : Results section: Line 136: What does “defect (blue)” refer to? To figure 3? If yes, add a reference to Figure 3.. if not, please explain. Also, explain shortly, for clarity, what type of defect is meant here.

>Line 202 detail the statistical analysis of the 85 measurement points of the 18 trees, and the reference data is in Appendix A. The defect (blue) in line 136 can be misunderstood, so it was deleted. ‘Defect’ usually refers to decay, cavity, and cracks. It is difficult to check the type of inner defect with the technology currently available.

 

Point 2 : Please add some statement on the conditions or verify if the t-tests can be applied. For example, is your data following a normal distribution?

>Eighty analytical data samples were used in this study. We assumed that normality was conformed under the central limit theorem and conducted the t-test.

* Sheldom M. Ross. "Introductory Statistics," Section 7.4. Academic Press, 2017.

 

>Point 2 : Lines 131-149: Very unclear. By reading this part, and looking at Figures 1 and 2, it is not possible to understand what are the differences between what is shown in Figure 1 and what is shown in Figure 2. Maybe, are these the two surveys?

>The data on the whole tree (previously fig. 1) and those on what is assumed to be a ring crack were removed in the first draft of the paper. Statistical analysis after separating the versions (previously fig. 2) was conducted, but this process had the limitation of assuming the existence of a ring crack. Thus, the author decided not to arbitrarily remove data during the revision of the paper and reanalyze the 85 pieces of data after removing outliers in the IQR (interquartile range) before the analysis to enhance the accuracy and reliability of the statistical analysis results. Finally, t-test and regression analysis were conducted once each, based on the 85 pieces of data to conclude there were no significant differences between the two groups (drilling resistance measurement & SoT) in the t-test, and a significant regression equation was derived.

 

Point 2 : Additionally, values of 0.24 and 0.44 as correlation coefficients (?) are low to such an extent that it could be said that the data sets/methods possess no explanatory power in relation to each other at all. Drawing a regression line, as in Fig 1 and Fig 2, is somewhat misleading.

> R2=0.405 refers to the coefficient of determination and refers to a coefficient of correlation about twice as large when converted into a coefficient of correlation. In addition, the coefficient of crystallization and the corresponding formula was added next to the regression equation, so the trend line of the regression equation should not cause any more confusion. The design of the table was modified to suit the eyes better (Fig. 2).

 

Point 2 : Figure 3: Please make the legends readable. Also, in the text, there is often words that refer to density and moisture content such as “normal” (line 187) or “high” (line 216 for example). Please specify the exact values each time if possible.

> The absolute values of the electrical resistance and high moisture content cannot be determined because of the characteristics and limitations of the ERT measuring equipment. Therefore, the measurements are calculated as relative values and are expressed as colors. In other words, the moisture content and the distribution of high and low conductive areas can only be determined by color and depth. Thus, we could only use phrases such as ‘blue-high water content’ or ‘red-lower water content’ in the legends we made using the “PiCUS 3 Treetronic Manual”.

 

포인트 2: 그림 3: 오른쪽 상단: SoT 대신 "oT tomograms"로 표시됩니다.

>이 오류를 수정했습니다.

 

Point 2 : 이 부분도 구조조정을 고려해볼 수 있다. 이해를 위해 먼저 SoT와 ERT를 트리 단면과 비교하는 것이 좋습니다. 그런 다음, 이를 기반으로 SoT를 EM/ERT와 연관시키려고 시도합니다. 그 반대는 아닙니다.

>① SoT•ERT를 나무의 단면과 비교한 후 단락을 재구성하여 ② SoT, 드릴링 저항 측정 결과, 통계 분석 결과를 이 순서대로 제시하였다.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The manuscript has been supplemented and corrected. I recommend it for publishing.

Author Response

Thanks for the review.