Reconstruction of June–July Temperatures Based on a 233 Year Tree-Ring of Picea jezoensis var. microsperma
Round 1
Reviewer 1 Report
Here is my general comment. For details see notes in the attachment.
I consider most of the authors’ responses to my comments inadequate. Instead of a substantive argumentation and explanation, the authors merely refer to other works by Chinese authors. I inserted detailed reaction to the authors response directly to the „Response to reviewer 3“ pdf file (see attachment).
In my opinion, the manuscript still presents serious flaws and cannot be recommended for publication as only minor changes have been done.
Comments for author File: 
Comments.pdf
Author Response
Reviewer 1
Point 1. It is not relevant response to my comment. I would rather expect the reason why it was not possible to prolong the time series by new sampling of increment cores.
Response: Thank you very much for point it out. Changbai Mountain is one of the few well-protected areas in China. It has the oldest undisturbed natural forest in the northeast forest. It plays an important role in the study of the impact of global change on forest ecosystems. However, the number of trees in the Changbai Mountain were also limited. So, every tree in the Changbai Mountain forest is very treasured. According to our experience, the collection of tree cores can have a serious impact on tree growth. So it is not conducive to the sustainability of scientific research. Therefore, if it is not necessary, we will not drill the tree core. Moreover, we believe that our existing samples are suitable for paleoclimate studies. In addition, the government's efforts to protect forests have gradually increased, and it has become increasingly difficult to obtain approval procedures for collecting tree cores.
Point 2. Again not relevant response to my comment. Why authors refer to the book? I still miss the detailed information about the sampled trees (age, size, social status). This information should be added to the manuscript. I am also missing the reponse to my comments concerning the check of temporal stability in tree ring proxy-climate relationship and the check of model residuals.
Response: Thank you very much for point it out.
(1) This book was cited to prove that the PJ tree was the dominant species in the sampling sites.
(2) The age was added in Table 1
Size can be seen in Figure 4a
Social status: Three stands of 30 m × 30 m were established,PJtrees accounted for 83.8% of the basal area at breast height (1.3 m) of the sampling stands. This sentence was added in line 90-92
(3) The overall split calibration-verification tests indicated the regression model was acceptable (Table 3). The positive reduction of error (RE) and coefficient of efficiency (CE) values (Table 3) revealed that model (1) was stable and reliable. These analyses demonstrated that this regression model was valid for temperature reconstructions (Line 198-202 and Table 3)
Point 3. The authors argue with references to other studies, but these mostly present regional temperature reconstructions. However, I accept that power spectral analysis implies the connections between reconstructed July temperatures and ENSO and PDO (see chapter 4.4).
Response: Thank you very much for point it out. Sorry, our previous answer was wrong on this issue. This paper present regional temperature reconstruction (Changbai Mountain region), not large-scale climatic change. Meanwhile, from the results of this paper, the regional temperature in the Changbai Mountain area was influenced by large-scale climatic change.
Point 4. In this case, I consider it inappropriate to refer to the writing style of other authors. Repeating numbers listed in the tables is redundant. The text should be concise as much as possible.
Response: Thank you very much for point it out. The repeated model parameters are deleted
Author Response File: 
Author Response.docx
Reviewer 2 Report
I appreciate the author's efforts to improve the quality of the paper, it was modified following the suggestions of the rewievers throught the entire text. In order to reach the enough quality to publish it, I only suggest a minor language and style revision, to avoid some word repetitions, and I recommend use linkers to introduce the subsection (C) in the figure caption of the figure 8.
Author Response
Reviewer 2
I appreciate the author's efforts to improve the quality of the paper, it was modified following the suggestions of the reviewers througout the entire text. In order to reach the enough quality to publish it, I only suggest a minor language and style revision, to avoid some word repetitions, and I recommend use linkers to introduce the subsection (C) in the figure caption of the figure 8.
Response: Thank you very much for point it out. The linker was added in line 312
Author Response File: Author Response.docx
Reviewer 3 Report
General comment
The manuscript presents very interesting data on a 233 years June-July maximum temperature reconstruction base on a tree-ring record of the species Picea jezoensis from forests of the Changbai Mountain in China.
In the abstract the authors say that “During the last 233 years, there were 36 warm years, 34 cold years, accounted for 15.5% and 14.7 % of the total reconstruction years, respectively. Cold periods occurred in 1899-1913, 1955-1970 and 1975-1989, while warm periods occurred in 1881-1888.” For me there is a much more interesting pattern that strikes in Figure 7, that is in general (and without being so specific about the years as the authors did), from 1780 to 1890, the average maximum temperature of June-July was higher, compared with the period from 1900 to 1980. And then, afterwards, there is an increasing trend. Is this the beginning of a new cycle of warming temperatures as the one that occurred from 1780 to 1890? Is this due to an anthropogenic increase of CO2 that is causing globally an increase of the average temperature? Maybe it would be nice to explore this question in the discussion.
Specific comments
Line 37: please replace by “where plant growth is mainly limited by temperature”
Line 40: Delete “In growing season”
Line 40: “The drought and flood events…”
Line 65: “a large area of undisturbed temperate old-growth forest that offers an excellent opportunity for studies on climatology.”
Line 67: “Trees growing in this forest were shown to be sensitive to temperature change during the growing season.”
Line 69-70: “including January-April and February-April temperature reconstruction based on Korean pine chronologies by Shao et al., 1997 [29], and Zhu et al., 2009 [30], respectively; and September-October temperature reconstruction based on Fraxinus mandshurica chronology by Wang et al., 2012”
Line 73: Can you indicate when occurs the growing season in the Changbai Mountain forests?
Line 79-80: The authors say that “The long-term reconstruction of the past temperature in growing season will enable us to better understand the climate change and update the current climate model of Changbai Mountain.” So the growing season is mainly between June-July? You said before that PJ is sensitive to the maximum temperature of those months from the previous year, so from the previous year growing season? I am a little confused. Can you explain better?
Line 96: “the selected PJ forest was an open forest, with no signs of recent fires or human disturbances
Figure 2. The legend of figure 2 is not correct concerning the temperatures.
Line 139: please remove “they were”
Line 140-142: Please simplify the paragraph. “The STD chronology with an EXP detrending was the best chronology because it contained more low frequency signals.”
Figure 4: In the legend “The dashed lines indicate the numbers of tree-ring series” I think you meant “The blue line”. The vertical dash line indicates the point where EPS was higher than 0.85.
Table 5: I would put this table as supplementary information.
Figure 6: the red and blue dots (drought and flood events, respectively) were based on which information?
Line 357: Refer to the figures in the order they appear in the text. So after Figure 6 you should refer to Figure 7, and not Figure 9.
Table 7: I would put this table as supplementary information.
Line 381-389: Please remove this paragraph, it is not necessary. Or if you want you can add this extra information to Table 7.
Line 405: “Two severe cold years in the periods from 1953–1974 and 1980–1993 in Heilongjiang Province were captured in this reconstructed series”
Line 406: “The significantly low temperature years from 1953 to1974 coincided with the slight decrease in solar activity”
Line 408: “The warm periods occurred from 1790–1800, 1845–1855 and 1857–1867 and were consistent with other results of tree-ring reconstructions in northeast China”
Line 411: I think it is more correct to talk about literature temperature reconstructions of the past 233 year. Or are you referring to historical records?
Line 419: The reconstruction of HLE refers to April-September maximum temperature? Why do you say May-October?
Line 423-424: “showed that the regional temperature variations were well captured by the reconstruction.”
Line 454-455: “The results of spectral analysis [57] showed that the reconstructed Tmax6-7 series has specific cycles, indicating that the Tmax6-7 in the CBM region may be affected by other factors.”
Line 513: You mean Figure 9?
Line 518: Can you specify in what way your reconstruction shows signs of global climate change? Looking at Figure 7a average maximum temperatures from 1780 to 1890 were higher compared with the period from 1900 to 1980, followed then by an increasing trend. But one can argue that this is a possible repetition of a warming cycle that occurred before, from 1780-1890.
Author Response
Reviewer 3
General comment
The manuscript presents very interesting data on a 233 years June-July maximum temperature reconstruction base on a tree-ring record of the species Picea jezoensis from forests of the Changbai Mountain in China.
In the abstract the authors say that “During the last 233 years, there were 36 warm years, 34 cold years, accounted for 15.5% and 14.7 % of the total reconstruction years, respectively. Cold periods occurred in 1899-1913, 1955-1970 and 1975-1989, while warm periods occurred in 1881-1888.” For me there is a much more interesting pattern that strikes in Figure 7, that is in general (and without being so specific about the years as the authors did), from 1780 to 1890, the average maximum temperature of June-July was higher, compared with the period from 1900 to 1980. And then, afterwards, there is an increasing trend. Is this the beginning of a new cycle of warming temperatures as the one that occurred from 1780 to 1890? Is this due to an anthropogenic increase of CO2 that is causing globally an increase of the average temperature? Maybe it would be nice to explore this question in the discussion.
Response: Thank you very much for point it out. This question was answered in line 264-268.
Specific comments
Line 37: please replace by “where plant growth is mainly limited by temperature”
Response: Thank you very much for point it out. The sentence was revised in line 37-38.
Line 40: Delete “In growing season”
Response: Thank you very much for point it out. The sentence was revised in line 40.
Line 40: “The drought and flood events…”
Response: Thank you very much for point it out. The sentence was revised in line 40.
Line 65: “a large area of undisturbed temperate old-growth forest that offers an excellent opportunity for studies on climatology.”
Response: Thank you very much for point it out. The sentence was revised in line 58-60
Line 67: “Trees growing in this forest were shown to be sensitive to temperature change during the growing season.”
Response: Thank you very much for point it out. The sentence was revised in line 60-61
Line 69-70: “including January-April and February-April temperature reconstruction based on Korean pine chronologies by Shao et al., 1997 [29], and Zhu et al., 2009 [30], respectively; and September-October temperature reconstruction based on Fraxinus mandshurica chronology by Wang et al., 2012”
Response: Thank you very much for point it out. The sentence was revised in line 62-65
Line 73: Can you indicate when occurs the growing season in the Changbai Mountain forests?
Response: Thank you very much for point it out. The period of the growing season was added in line 66
Line 79-80: The authors say that “The long-term reconstruction of the past temperature in growing season will enable us to better understand the climate change and update the current climate model of Changbai Mountain.” So the growing season is mainly between June-July? You said before that PJ is sensitive to the maximum temperature of those months from the previous year, so from the previous year growing season? I am a little confused. Can you explain better?
Response: Thank you very much for point it out. The growing season is between June-August. However, we found that the radial growth of the PJ tree was most significantly correlated with the temperature from June to July of the previous year.
Line 96: “the selected PJ forest was an open forest, with no signs of recent fires or human disturbances
Response: Thank you very much for point it out. The sentence was revised in line 89-90.
Figure 2. The legend of figure 2 is not correct concerning the temperatures.
Response: Thank you very much for point it out. The legend of figure 2 was corrected
Line 139: please remove “they were”
Response: Thank you very much for point it out. “they were” was deleted in line 115.
Line 140-142: Please simplify the paragraph. “The STD chronology with an EXP detrending was the best chronology because it contained more low frequency signals.”
Response: Thank you very much for point it out. The sentence was revised in line 116-117
Figure 4: In the legend “The dashed lines indicate the numbers of tree-ring series” I think you meant “The blue line”. The vertical dash line indicates the point where EPS was higher than 0.85.
Response: Thank you very much for point it out. These were revised in line 159-162
Table 5: I would put this table as supplementary information.
Response: Thank you very much for point it out. Table 5 was put in the supplementary information.
Figure 6: the red and blue dots (drought and flood events, respectively) were based on which information?
Response: Thank you for point it out. The droughts and floods events from the records by Wen (2008)
Line 357: Refer to the figures in the order they appear in the text. So after Figure 6 you should refer to Figure 7, and not Figure 9.
Response: Thank you for point it out. This question was solved.
Table 7: I would put this table as supplementary information.
Response: Thank you for point it out. Table 7 was put in the supplementary information.
Line 381-389: Please remove this paragraph, it is not necessary. Or if you want you can add this extra information to Table 7.
Response: Thank you for point it out. This paragraph was deleted.
Line 405: “Two severe cold years in the periods from 1953–1974 and 1980–1993 in Heilongjiang Province were captured in this reconstructed series”
Response: Thank you for point it out. The sentence was revised in line 259-260.
Line 406: “The significantly low temperature years from 1953 to1974 coincided with the slight decrease in solar activity”
Response: Thank you for point it out. The sentence was revised in line 260-261.
Line 408: “The warm periods occurred from 1790–1800, 1845–1855 and 1857–1867 and were consistent with other results of tree-ring reconstructions in northeast China”
Response: Thank you for point it out. The sentence was revised in line 261-263
Line 411: I think it is more correct to talk about literature temperature reconstructions of the past 233 year. Or are you referring to historical records?
Response: Thank you very much for point it out. The words “literature temperature records” were revised by historical records in line 269
Line 419: The reconstruction of HLE refers to April-September maximum temperature? Why do you say May-October?
Response: Thank you very much for point it out. This should be April-September in 278.
Line 423-424: “showed that the regional temperature variations were well captured by the reconstruction.”
Response: Thank you very much for point it out. The sentence was revised in line 282-283.
Line 454-455: “The results of spectral analysis [57] showed that the reconstructed Tmax6-7 series has specific cycles, indicating that the Tmax6-7 in the CBM region may be affected by other factors.”
Response: Thank you very much for point it out. The sentence was revised in line 295-296.
Line 513: You mean Figure 9?
Response: Thank you very much for point it out. Figure 9 should be Fig. 9c.
Line 518: Can you specify in what way your reconstruction shows signs of global climate change? Looking at Figure 7a average maximum temperatures from 1780 to 1890 were higher compared with the period from 1900 to 1980, followed then by an increasing trend. But one can argue that this is a possible repetition of a warming cycle that occurred before, from 1780-1890.
Response: Thank you very much for point it out. From 1780 to 1890, the average maximum temperature of June-July was higher, compared with the period from 1900 to 1980. This temperature change may be related to the precipitation in the growing season. The flood disasters in the growing season of Jilin Province before 1800 were relatively small, occurring once every 5 years; the frequency and severity of flooding in 1801-1900 were increased, once every 3.5 years; the frequency of floods during the period from 1901 to 1990 was 2.8 years (Wen, 2008). (This question was answered in 264-268.)
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
I accept the author's response to most of my comments. However, I am not still satisfied with the reaction to my comments concerning the check of temporal stability in tree ring proxy-climate relationship and the check of model residuals.
If the tree-ring proxy/climate relationship is stable over the entire calibration period then the credibility of the resulting model increases.
R2, RE and CE values are fine but they are not sufficient for model verification. Linear regression has several assumptions, which must be verified using appropriate diagnostic methods. The inspection of the model´s residuals should be always included. If the residuals are randomly spread around the zero line, it confirms the reliability of the model.
I understand that it means an extra work for the authors, but the calculation of moving correlations and the visual inspection of graph of residuals are not so tough tasks and it increases credibility of the model significantly.
Author Response
I accept the author's response to most of my comments. However, I am not still satisfied with the reaction to my comments concerning the check of temporal stability in tree ring proxy-climate relationship and the check of model residuals.
If the tree-ring proxy/climate relationship is stable over the entire calibration period then the credibility of the resulting model increases.
R2, RE and CE values are fine but they are not sufficient for model verification. Linear regression has several assumptions, which must be verified using appropriate diagnostic methods. The inspection of the model´s residuals should be always included. If the residuals are randomly spread around the zero line, it confirms the reliability of the model.
I understand that it means an extra work for the authors, but the calculation of moving correlations and the visual inspection of graph of residuals are not so tough tasks and it increases credibility of the model significantly.
Response: Thank you very much for your suggestions.
1. The analysis of temporal stability in tree ring proxy-climate relationship was added in Figure 5b. To check stability of relationships between tree-ring and temperature, running correlation coefficient was calculated and Mann-Kendall Test was applied (Fig 5b). The p-value associated with the Mann-Kendall test is statistically insignificant (tau=0.122, 2-sided p-value=0.080289), suggesting the absence of a statistically significant upward/downward trend in the running correlation coefficient series (Line 130-134)
2. The Durbin-Watson (DW) was applied to analyze the residuals of the reconstruction, ranging from 1.50 to 1.72, suggesting that there is no linear trend or significant autocorrelation in the residuals (Fig. 6b-c; Table 3).
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
General comment
The manuscript presents interesting data using tree-rings to reconstruct maximum temperatures of June-July in the region of Changbai Mountain in China. First of all, the English language needs to be revised. The aims of the research, synthesized in the last paragraph of the introduction looks like a posteriori aims, that is, you say already that Picea jeozensis will be used to reconstruct the maximum temperature of June-July but the authors give no clue why is that possible. A previous research on the species showed that tree-ring width was sensitive to the maximum temperatures of June-July? I would also like to see discussed more strongly the implications of your temperature reconstruction. Basically the authors compare their reconstruction with others (which is OK to strengthen the results) but then the discussion is lost in particular years (the warm and cold years) and nothing is mentioned about the long-term trend. If we look at Figure 5b it looks that the period 1780 to 1890 the temperatures were much warmer and there was a declining trend from 1890 forward. And even the rising trend from 1980 is below the temperatures from 1780-1890. I think it would be very interesting to discuss this long-term trend.
Specific comments
Line 37: Please rephrase the sentence, it is not well written and confusing “such as the significant changes in species distribution and abundance, plant growth in where is mainly limited by temperature”
Line 40: Please check the English of the sentence, specially the last part of the paragraph. “In growing season, the extreme high temperatures and chilling weather caused by the interannual instability of the East Asia Summer Monsoon (EASM) have seriously affected the healthy development of agriculture and forest ecosystems, such as drought and flood disaster occurred in this region.”
Line 48: Please change to “In the last few years, the temperature in northeast China has been rising”
Line 52: Please change to “which limits our understanding of the processes and mechanisms of past climatic changes in this region.”
Line 59: That authors say that “The Changbai Mountain is situated in the core area of Northeast Forest and is one of the most sensitive areas responding to temperature change of China” Can you develop further? Why do you say that this area is one of the most sensitive to temperature changes in China?
Line 62: Please change to “In the last years, some studies on temperature reconstructions…”
Line 62: Can you develop more on the results of the temperature reconstructions for this region based on tree-rings? What were the main highlights of those temperature reconstructions?
Line 67: Please change to: ”However the temperature reconstructions, especially during the growing season, are still lacking in this area. Thus, it is very important to fill this gap.”
Line 71: Any particular reason to choose the species Picea jezoensis and why do you assume that the chronologies of that species are valuable to reconstruct the maximum temperature of June-July?
Line 89: Please change to: “In the laboratory, the samples were pretreated, naturally air dried, glued to wooden holders, and then sanded with successively finer grits of sandpaper to highlight the tree rings.”
Line 114: Please change “to identify the best model for the climatic reconstruction”
Line 133: Please change “The mean ring width was 0.89mm.”
Line 143: Delete the following sentence “The relationship between the tree-ring width and climate is the basis of climate research based on tree rings analysis.”
Line 181: The authors say that “We defined Tmax6-7≥23.84°C (Mean+1σ) and Tmax6-7≤21.78 °C (Mean-1σ) as a threshold to determine the warm years and cold years, respectively” Any reason behind the establishment of these thresholds?
Line 209: Please change “which may be due to the increased forest respiration and/or evaporation of soil moisture”
Line 214: Please revise the sentence, it is confusing and the English need to be corrected “Meanwhile, the respiration consumed more accumulated matter, resulting in an increased consumption of accumulated substances, leaving less nutrients storing for the growth of the next growing season, which is not conducive to the growth of trees in the following year”
Line 219: Can you explain the following sentence? “Under normal precipitation conditions, high temperatures can cause severe droughts, while precipitation is accompanied by low temperatures” What do you mean by “precipitation is accompanied by low temperatures”? From the climatic diagram of the region, the months with more precipitation are the ones that are also warmer.
Author Response
The manuscript presents interesting data using tree-rings to reconstruct maximum temperatures of June-July in the region of Changbai Mountain in China. First of all, the English language needs to be revised. The aims of the research, synthesized in the last paragraph of the introduction looks like a posteriori aims, that is, you say already that Picea jeozensis will be used to reconstruct the maximum temperature of June-July but the authors give no clue why is that possible. A previous research on the species showed that tree-ring width was sensitive to the maximum temperatures of June-July? I would also like to see discussed more strongly the implications of your temperature reconstruction.
Response: Thank you very much for point it out. The aims of the research, synthesized in the last paragraph of the introduction was just a posteriori aims. The correlation between the radial growth of Picea jeozensis and climate factors in 1600-1700 m a. s. l has not been conducted before. We reconstruced the temperature just based on the correlation results. The implications of your temperature reconstruction was added in line 60-61.
Basically the authors compare their reconstruction with others (which is OK to strengthen the results) but then the discussion is lost in particular years (the warm and cold years) and nothing is mentioned about the long-term trend. If we look at Figure 5b it looks that the period 1780 to 1890 the temperatures were much warmer and there was a declining trend from 1890 forward. And even the rising trend from 1980 is below the temperatures from 1780-1890. I think it would be very interesting to discuss this long-term trend.
Response: Thank you very much for point it out. The analysis of long-term trend was added in
Line195-197
Specific comments
Line 37: Please rephrase the sentence, it is not well written and confusing “such as the significant changes in species distribution and abundance, plant growth in where is mainly limited by temperature”
Response: Thank you very much for point it out. The sentence was revised in line 36-38
Line 40: Please check the English of the sentence, specially the last part of the paragraph. “In growing season, the extreme high temperatures and chilling weather caused by the interannual instability of the East Asia Summer Monsoon (EASM) have seriously affected the healthy development of agriculture and forest ecosystems, such as drought and flood disaster occurred in this region.”
Response: Thank you very much for point it out. The sentence was revised in line 40-42
Line 48: Please change to “In the last few years, the temperature in northeast China has been rising”
Response: Thank you very much for point it out. The sentence was revised in line 47-48
Line 52: Please change to “which limits our understanding of the processes and mechanisms of past climatic changes in this region.”
Response: Thank you very much for point it out. The sentence was revised in line 51-52
Line 59: That authors say that “The Changbai Mountain is situated in the core area of Northeast Forest and is one of the most sensitive areas responding to temperature change of China” Can you develop further? Why do you say that this area is one of the most sensitive to temperature changes in China?
Response: Thank you very much for point it out. The question was answered in line 60-61
Line 62: Please change to “In the last years, some studies on temperature reconstructions…”
Response: Thank you very much for point it out. The sentence was revised in line 51-52
Line 62: Can you develop more on the results of the temperature reconstructions for this region based on tree-rings? What were the main highlights of those temperature reconstructions?
Response: Thank you very much for point it out. Due to limited data analysis capabilities, we could only provide those results in this article. The main purpose of this article is to reconstruct the paleoclimate and its changes based on tree ring data
Line 67: Please change to: ”However the temperature reconstructions, especially during the growing season, are still lacking in this area. Thus, it is very important to fill this gap.”
Response: Thank you very much for point it out. The sentence was revised in line 65-67
Line 71: Any particular reason to choose the species Picea jezoensis and why do you assume that the chronologies of that species are valuable to reconstruct the maximum temperature of June-July?
Response: Thank you very much for point it out. The question was answered in line 60-67
Response: Thank you very much for point it out.
1. The reconstruction was only based on the correlation results between the radial growth of Picea jeozensis and climate factors.
2. Trees growth in Changbai Mountain were sensitive to temperature change, e.g. the temperatures change in growing season [26-28]. In the last years, some studies on temperature reconstructions have been carried out in the Changbai Mountain, including January-April temperature reconstruction based on Korean pine Chronology by Shao et al., 1997 [29], February-April temperature reconstruction based on Korean pine chronology by Zhu et al., 2009 [30], September-October temperature reconstruction based on Fraxinus mandshurica chronology by Wang et al., 2012 [31]. However, the temperature reconstructions, especially during the growing season, are still lacking in this area. Thus, it is very important to fill this gap.
Line 89: Please change to: “In the laboratory, the samples were pretreated, naturally air dried, glued to wooden holders, and then sanded with successively finer grits of sandpaper to highlight the tree rings.”
Response: Thank you very much for point it out. The sentence was revised in line 90-91
Line 114: Please change “to identify the best model for the climatic reconstruction”
Response: Thank you very much for point it out. The sentence was revised in line 114
Line 133: Please change “The mean ring width was 0.89mm.”
Response: Thank you very much for point it out. The sentence was revised in line 134
Line 143: Delete the following sentence “The relationship between the tree-ring width and climate is the basis of climate research based on tree rings analysis.”
Response: Thank you very much for point it out. The sentence was revised in line 134he sentence was deleted
Line 181: The authors say that “We defined Tmax6-7≥23.84°C (Mean+1σ) and Tmax6-7≤21.78 °C (Mean-1σ) as a threshold to determine the warm years and cold years, respectively” Any reason behind the establishment of these thresholds?
Response: Thank you very much for point it out. The method we used was based on the following article:
1. Bao, G.; Liu, Y.; Linderholm, H.W. April–September mean maximum temperature inferred from Hailar pine (Pinus sylvestris var. mongolica) tree rings in the Hulunbuir region, Inner Mongolia, back to 1868 AD. Palaeogeography Palaeoclimatology Palaeoecology. 2012, 313(1), 162-172.
2. Lyu, S.; Li, Z.; Zhang, Y. A 414-year tree-ring-based April–July minimum temperature reconstruction and its implications for the extreme climate events, northeast China. Climate of the Past. 2016, 12(9), 1879-1888.
3. Zhang, T.; Yuan, Y.; Wei, W.; Yu, S.; Zhang, R.; Shang, H.; Chen, F.; Fan, Z.; Qin, L. Tree-ring-based temperature reconstruction for the northern Greater Higgnan Mountains, China, since A.D. 1717. International Journal of Climatology. 2013, 33(2), 422-429.
Line 209: Please change “which may be due to the increased forest respiration and/or evaporation of soil moisture”
Response: Thank you very much for point it out. The sentence was revised in line 206-207
Line 214: Please revise the sentence, it is confusing and the English need to be corrected “Meanwhile, the respiration consumed more accumulated matter, resulting in an increased consumption of accumulated substances, leaving less nutrients storing for the growth of the next growing season, which is not conducive to the growth of trees in the following year”
Response: Thank you very much for point it out. The sentence was revised in line 211-213
Line 219: Can you explain the following sentence? “Under normal precipitation conditions, high temperatures can cause severe droughts, while precipitation is accompanied by low temperatures” What do you mean by “precipitation is accompanied by low temperatures”? From the climatic diagram of the region, the months with more precipitation are the ones that are also warmer.
Response: Thank you very much for point it out. According to the correlation analysis, the Tmax 6-7 showed significantly negatively correlate with average precipitation during June and July(r=0.5)
Reviewer 2 Report
The paper titled "Reconstruction of June-July temperatures from tree-2 rings in the Changbai Mountain, China" is well written, and the content is properly described and explained by the authors. I think that it is an interesting topic adequately exposed through the entire text, and supported by the figures and tables needed. I only suggest a few changes with the aim to improve this paper, which are shown in the next lines:
I suggest a small text revision to avoid repetitions and to improve the drafting of some paragraphs.
I suggest to put together figures 7 and 9, both show similar information, and you can reduce the number of figures. I also recommend to change the asterisk color, because in present form is poorly visible, especially in figure 9.
Next, I remark a few little mistakes that would be revised by the authors:
Lines 49-51. Please, rephrase. There are some repetitions of "understanding"
Line 84. Better in plural, "fires", and "disturbances"
Line 144. "Tree-ring analysis", please correct.
Lines 150-160. This paragraph can be better drafted, avoiding repetitions of "current year/previous year".
Line 214. stored carbohidrates?, instead of "accumulated matter"?
Line 216. available, better than "conducive"?
Lines 226-232. Please rewrite, avoiding repetitions of the word "periods". The last paragraph seems to be incomplete, please check it.
Figure 5a. There is a mistake in the figure caption/legend, the colors of the observed and reconstructed curves are exchanged, please correct.
Author Response
The paper titled "Reconstruction of June-July temperatures from tree-2 rings in the Changbai Mountain, China" is well written, and the content is properly described and explained by the authors. I think that it is an interesting topic adequately exposed through the entire text, and supported by the figures and tables needed. I only suggest a few changes with the aim to improve this paper, which are shown in the next lines:
I suggest a small text revision to avoid repetitions and to improve the drafting of some paragraphs.
I suggest to put together figures 7 and 9, both show similar information, and you can reduce the number of figures. I also recommend to change the asterisk color, because in present form is poorly visible, especially in figure 9.
Response: Thank you very much for point it out. The asterisk color in Figure was revised.
Next, I remark a few little mistakes that would be revised by the authors:
Lines 49-51. Please, rephrase. There are some repetitions of "understanding"
Response: Thank you very much for point it out. The sentence was revised in line 48-50
Line 84. Better in plural, "fires", and "disturbances"
Response: Thank you very much for point it out. The sentence was revised in line 85
Line 144. "Tree-ring analysis", please correct.
Response: Thank you very much for point it out. The sentence “The relationship between the tree-ring width and climate is the basis of climate research based on tree rings analysis.”was deleted
Lines 150-160. This paragraph can be better drafted, avoiding repetitions of "current year/previous year".
Response: Thank you very much for point it out. The sentence was revised in line 150-158
Line 214. stored carbohidrates ?, instead of "accumulated matter"?
Response: Thank you very much for point it out. We think "accumulated matter" could be right in this sentence
Line 216. available, better than "conducive"?
Response: Thank you very much for point it out. The wore was revised in line 212
Lines 226-232. Please rewrite, avoiding repetitions of the word "periods". The last paragraph seems to be incomplete, please check it.
Response: Thank you very much for point it out. The sentence was revised in line 223-229
Figure 5a. There is a mistake in the figure caption/legend, the colors of the observed and reconstructed curves are exchanged, please correct.
Response: Thank you very much for point it out. The mistake was revised in Fig 5
Reviewer 3 Report
The manuscript “Reconstruction of June-July temperatures from tree-rings in the Changbai Mountain, China” by Jiang et al. aims to reconstruct June-July maximum temperatures for the period 1772-2004 and to explore connections between reconstructed temperatures and ENSO cycles and sea surface temperatures of the western equatorial Pacific. In principle, the study matter is of interest, because temperature reconstructions back to the past, out of the period covered by instrumental measurements, enable to better understand the ongoing climate change. However, the manuscript presents several flaws and cannot be recommended for publication now.
The tree-ring data obtained in 2005 were used for this study (l. 86). I consider it as a weakness of the study because the calibration period covers 46 years only (1959-2004, see l.116). If new samples would be taken, the calibration period would be greatly extended.
The samples were taken in old-growth forest stand (l. 83, 84). I suppose diverse tree structure including multi-layered canopy and canopy gaps, varying tree heights and diameters. In this sense I miss the detailed information about the stand and sample trees (age, size, social status).
Negative exponential curve was used to standardize the raw tree-ring data (l. 97). For old trees little affected by competition, negative exponential can be a good choice. But I'm not sure if this is the case (see above). This method must be used with a big carefulness, as it may not be appropriate for closed stands and stands with a complex disturbance history. I would strongly recommend to follow the approach described by Esper et al. 2010 (Trends and uncertainties in Siberian indicators of 20th century warming): apply several detrending techniques: RCS, signal free approach, negative exponential, splines and may be more. Then evaluate R2, RE and CE scores of the model for different index chronologies and choose the best one.
When calibrating the regression model, it is appropriate to check the temporal stability in tree-ring proxy/climate relationship. For this purpose several techniques could be applied: moving correlations, moving response functions or more advanced stochastic response functions (Visser et al. 2010). Ideally, the tree-ring proxy/climate relationship should be stable over the entire calibration period.
When presenting regression model it is important to show how the residuals of the model looks like. Homoscedasticity of residuals should be checked. Scatterplot of residuals against explanatory variable reveals if some nonlinear relationship exists between the proxy and explanatory variable. Statistics of the model such as r, R2, SE are fine but not sufficient. Also consider the use of scaling instead of least-squares regression as some studies have shown that long-term variability is suppressed in most regression schemes (e.g. Storch et al. 2004).
Last but not least, I'm not sure whether this regional temperature reconstruction based on limited number of trees (33) can be used for exploring large-scale climatic change.
Besides these principal remarks, I have several comments on the formal layout of the manuscript.
l. 130 the abbreviation HadlSST11°SST is not explained
l.143-147 fits better the Materials and methods part
l. 166 here the model parameters are repeated, should be replaced by a reference to Table 3
l. 225, 227 in the Discussion part it is not usual to refer to the figures
l. 233-247 chap. 4.3 fits better Results part
Some sentences are difficult to understand: l. 38, 209, 219-220
l. 496-497 caption of the Fig. 3 should be improved. Description of the panel a) and b) is missing
Regardless of the previous criticism, I find the study interesting and considerable amount of work was carried out. Therefore I encourage the authors to improve the methodology and to rework the manuscript for next submission.
Author Response
The manuscript “Reconstruction of June-July temperatures from tree-rings in the Changbai Mountain, China” by Jiang et al. aims to reconstruct June-July maximum temperatures for the period 1772-2004 and to explore connections between reconstructed temperatures and ENSO cycles and sea surface temperatures of the western equatorial Pacific. In principle, the study matter is of interest, because temperature reconstructions back to the past, out of the period covered by instrumental measurements, enable to better understand the ongoing climate change. However, the manuscript presents several flaws and cannot be recommended for publication now.
The tree-ring data obtained in 2005 were used for this study (l. 86). I consider it as a weakness of the study because the calibration period covers 46 years only (1959-2004, see l.116). If new samples would be taken, the calibration period would be greatly extended.
Response: Thank you for point it out. We followed the method by Zhang et al.,2014, which used the calibration period covers 49 years only (1960-2008) see the paper “A tree-ring based precipitation reconstruction for the Mohe region in the northern Greater Higgnan Mountains, China, since AD 1724” Quaternary Research 82 (2014) 14–21
The samples were taken in old-growth forest stand (l. 83, 84). I suppose diverse tree structure including multi-layered canopy and canopy gaps, varying tree heights and diameters. In this sense I miss the detailed information about the stand and sample trees (age, size, social status). Negative exponential curve was used to standardize the raw tree-ring data (l. 97). For old trees little affected by competition, negative exponential can be a good choice. But I'm not sure if this is the case (see above). This method must be used with a big carefulness, as it may not be appropriate for closed stands and stands with a complex disturbance history. I would strongly recommend to follow the approach described by Esper et al. 2010 (Trends and uncertainties in Siberian indicators of 20th century warming): apply several detrending techniques: RCS, signal free approach, negative exponential, splines and may be more. Then evaluate R2, RE and CE scores of the model for different index chronologies and choose the best one. When calibrating the regression model, it is appropriate to check the temporal stability in tree-ring proxy/climate relationship. For this purpose several techniques could be applied: moving correlations, moving response functions or more advanced stochastic response functions (Visser et al. 2010). Ideally, the tree-ring proxy/climate relationship should be stable over the entire calibration period. When presenting regression model it is important to show how the residuals of the model looks like. Homoscedasticity of residuals should be checked. Scatterplot of residuals against explanatory variable reveals if some nonlinear relationship exists between the proxy and explanatory variable. Statistics of the model such as r, R2, SE are fine but not sufficient. Also consider the use of scaling instead of least-squares regression as some studies have shown that long-term variability is suppressed in most regression schemes (e.g. Storch et al. 2004).
Response: Thank you for point it out. According to the book “Editorial Committee for Forestry of Jilin, 1988. Forest of Jilin. China Forestry Press, Beijing (in Chinese)”. Picea jezoensis were the dominant trees in the sampling site, so, we used negative exponential curve to standardize the raw tree-ring data. The revision was added in line 82-83
Last but not least, I'm not sure whether this regional temperature reconstruction based on limited number of trees (33) can be used for exploring large-scale climatic change.
Response: Thank you for point it out. We think that 59 cores from 33 PJ trees can be used for exploring large-scale climatic change. From example:
Tongwen Zhang: A total of 40 cores (5.15 mm diameter) from 20 trees were collected at breast height in September, 2008. from the paper “A tree-ring based precipitation reconstruction for the Mohe region in the northern Greater Higgnan Mountains, China, since AD 1724” Quaternary Research 82 (2014) 14–21
Zhongjie Shi: In total, 44 radii from 26 trees were used for drought reconstruction.
“Growth–climate response and drought reconstruction from tree-ring of Mongolian pine in
Hulunbuir, Northeast China” Journal of Plant Ecology Volume 9, Number 1, Pages 51–60.
Jixi Gao: At the end of September 2009, we sampled 52 cores collected from 26 living trees of P. sylvestris var. mongolica in Xishan Forest.” Precipitation variability in Hulunbuir, northeastern China since 1829 AD reconstructed from tree-rings and its linkage with remote oceans. Journal of Arid Environments 95 (2013) 14e21
Yu Liu: Two increment cores in the different directions were taken from each of 15 individual tree. “Tree‑ring‑width‑based PDSI reconstruction for central Inner
Mongolia, China over the past 333 years” Clim Dyn (2017) 48:867–879
Xianliang Zhang: Fifty-two cores were sampled from 25 living Da hu rian larch trees (2 to 3 cores tree–1) at breast height using an increment borer in a forest relatively undisturbed by human activities” Temperature reconstruction (1750–2008) from Dahurian larch tree-rings in an area subject to permafrost in Inner Mongolia, Northeast China” CLIMATE RESEARCH Vol. 47: 151–159, 2011
Feng Chen: In total, 25 cores (5 mm) and 41 cores (12 mm) from 25 trees were collected with increment borers.” Tree-ring-based reconstruction of precipitation in the Changling Mountains, China, since A.D.1691” Int J Biometeorol (2012) 56:765–774
Zong Shan Li: In total, 57 cores were crossdated successfully and used for subsequent analysis. “Tree ring-based temperature reconstruction over the past 186 years for the Miyaluo Natural Reserve, western Sichuan Province of China” Theor Appl Climatol (2015) 120:495–506
Yonghong Zheng: 51 increment cores from 25 trees were sampled at SNG (31° 25.8′ N, 110° 16.2′ E), with 2 or 3 increment cores sampled from each tree. February–May temperature reconstruction based on tree-ring widths of Abies fargesii from the Shennongjia area in central China. Int J Biometeorol (2016) 60:1175–1181
Besides these principal remarks, I have several comments on the formal layout of the manuscript.
l. 130 the abbreviation HadlSST11°SST is not explained
Response: Thank you for point it out. This was explained in line 130
l.143-147 fits better the Materials and methods part
Response: Thank you for point it out. The sentence “The relationship between the tree-ring width and climate is the basis of climate research based on tree rings analysis” was deleted
l. 166 here the model parameters are repeated, should be replaced by a reference to Table 3
Response: Thank you very much for point it out. We think this belong to the article writing style. We referred to the writing style of the following article:
1. Wang, Y.; Liu, Y. Reconstruction of March–June precipitation from tree rings in central Liaoning, China. Climate Dynamics. 2016, 49(9-10), 1-11.
2. Liu, Y.; Zhang, X.; Song, H.; Cai, Q.; Li, Q.; Zhao, B. Tree-ring-width-based PDSI reconstruction for central Inner Mongolia, China over the past 333 years. Climate Dynamics. 2016, 48(3-4), 867–879.
3. Bao, G.; Liu, Y.; Linderholm, H.W. April–September mean maximum temperature inferred from Hailar pine (Pinus sylvestris var. mongolica) tree rings in the Hulunbuir region, Inner Mongolia, back to 1868 AD. Palaeogeography Palaeoclimatology Palaeoecology. 2012, 313(1), 162-172.
4. Lyu, S.; Li, Z.; Zhang, Y. A 414-year tree-ring-based April–July minimum temperature reconstruction and its implications for the extreme climate events, northeast China. Climate of the Past. 2016, 12(9), 1879-1888.
l. 225, 227 in the Discussion part it is not usual to refer to the figures
Response: Thank you very much for point it out. We also think this belong to the article writing style. We referred to the writing style of the following article:
5. Wang, Y.; Liu, Y. Reconstruction of March–June precipitation from tree rings in central Liaoning, China. Climate Dynamics. 2016, 49(9-10), 1-11.
6. Liu, Y.; Zhang, X.; Song, H.; Cai, Q.; Li, Q.; Zhao, B. Tree-ring-width-based PDSI reconstruction for central Inner Mongolia, China over the past 333 years. Climate Dynamics. 2016, 48(3-4), 867–879.
7. Bao, G.; Liu, Y.; Linderholm, H.W. April–September mean maximum temperature inferred from Hailar pine (Pinus sylvestris var. mongolica) tree rings in the Hulunbuir region, Inner Mongolia, back to 1868 AD. Palaeogeography Palaeoclimatology Palaeoecology. 2012, 313(1), 162-172.
8. Lyu, S.; Li, Z.; Zhang, Y. A 414-year tree-ring-based April–July minimum temperature reconstruction and its implications for the extreme climate events, northeast China. Climate of the Past. 2016, 12(9), 1879-1888.
l. 233-247 chap. 4.3 fits better Results part
Response: Thank you very much for point it out. We think this paragraph is appropriate in the discussion section. We referred to the writing style of the following article:
9. Wang, Y.; Liu, Y. Reconstruction of March–June precipitation from tree rings in central Liaoning, China. Climate Dynamics. 2016, 49(9-10), 1-11.
10. Liu, Y.; Zhang, X.; Song, H.; Cai, Q.; Li, Q.; Zhao, B. Tree-ring-width-based PDSI reconstruction for central Inner Mongolia, China over the past 333 years. Climate Dynamics. 2016, 48(3-4), 867–879.
11. Bao, G.; Liu, Y.; Linderholm, H.W. April–September mean maximum temperature inferred from Hailar pine (Pinus sylvestris var. mongolica) tree rings in the Hulunbuir region, Inner Mongolia, back to 1868 AD. Palaeogeography Palaeoclimatology Palaeoecology. 2012, 313(1), 162-172.
12. Lyu, S.; Li, Z.; Zhang, Y. A 414-year tree-ring-based April–July minimum temperature reconstruction and its implications for the extreme climate events, northeast China. Climate of the Past. 2016, 12(9), 1879-1888.
Some sentences are difficult to understand: l. 38, 209, 219-220
Response: Thank you very much for point it out.
The sentence in line38 was revised in line 36-38
The sentence in line 209 was revised in line 206-207
The sentence in line 219-220 was revised in line 217-218
l. 496-497 caption of the Fig. 3 should be improved. Description of the panel a) and b) is missing
Response: Thank you very much for point it out.
The sentence was revised in line 493-496
