Why Intra-Annual Density Fluctuations Should Be Formed at Night? Implications for Climate–Growth Relationships in Seasonally Dry Conifer Forests

Round 1

Reviewer 1 Report

This manuscript presents the climate-latewood IADFs relationships in six conifer species under Mediterranean climate conditions. The topic of the manuscript is relatively novel, the scientific problem is outstanding, the research method is appropriate, and the research result is accurate. But the manuscript still has some problems to be revised.

 

Detailed comments are as follows:

 

1.     Line 80: The study selected a wide variety of sites and tree species, and suggested that it would be more perfect to represent these sampling sites with an overview map.

2.     Line 116 (Table 1): Elevation There was a great difference in the altitude of the six species sampling sites, and even the sampling distribution of J.thurifera was from 345m to 1350m. And, will the altitude of different tree species affect the subsequent results?

3.     Line 116 (Table 1): Mean temperature The temperature is 9.8℃ at 1350m (Olmedilla)，but temperature is 9.2℃ at 360m (R. P). Whether this is a particular sampling site with a particular climate?

4.     Line 160 (Table 2): Age at 1.3 m The age of different species will affect the IADF. Such as A. pinsapo, C. atlantica, have smaller mean age at 1.3m.

5.     Line 212: I see IADF trends interannual change in some species at Figure 2, such as IADF frequent decrease of J. thurifera in Peñaflor. Therefore, it is recommended to add a description of the trend.

6.     Lines 221-223: Tree age does affect IADF, but why is there so little correlations p<0.001, but growth rate all p<0.001? Is the study trying to show that growth rate has more influence on tree growth than age for IADF?

7.     Line 234: Recommended that you explain the meaning of the bright blue bar in the figure label.

8.     Line 235: Why did you choose to start from previous October? If the "lag effect" is taken into account, should it be explained in the methods?

9.     Line 342: I see the mean minimum temperature in March, June and July is the key constraint in SW USA (Fig. 7).

10.  Line 343: Is it necessary to outline in the figure 1 or supplemental materials If autumn temperature rising?

Author Response

Reviewer 1

 

( ) I would not like to sign my review report
(x) I would like to sign my review report

English language and style

( ) Extensive editing of English language and style required
( ) Moderate English changes required
(x) English language and style are fine/minor spell check required
( ) I don't feel qualified to judge about the English language and style

 

	Yes	Can be improved	Must be improved	Not applicable
Does the introduction provide sufficient background and include all relevant references?	( )	(x)	( )	( )
Are all the cited references relevant to the research?	(x)	( )	( )	( )
Is the research design appropriate?	(x)	( )	( )	( )
Are the methods adequately described?	( )	(x)	( )	( )
Are the results clearly presented?	( )	(x)	( )	( )
Are the conclusions supported by the results?	(x)	( )	( )	( )

 

Comments and Suggestions for Authors

This manuscript presents the climate-latewood IADFs relationships in six conifer species under Mediterranean climate conditions. The topic of the manuscript is relatively novel, the scientific problem is outstanding, the research method is appropriate, and the research result is accurate. But the manuscript still has some problems to be revised.

• I thank you for your positive comments on the ms. I have revised the queries you commented in the revised version of the article. Please note that the ms. does not only assess climate-IADFs relationships but provides mechanistic explanation on why IADFs should be formed at night.

Detailed comments are as follows:

1. Line 80: The study selected a wide variety of sites and tree species, and suggested that it would be more perfect to represent these sampling sites with an overview map.

• I added a map to the Supporting Information (new Fig. S1).

2. Line 116 (Table 1): ElevationThere was a great difference in the altitude of the six species sampling sites, and even the sampling distribution of thurifera was from 345m to 1350m. And, will the altitude of different tree species affect the subsequent results?

• Of course, climate variables depend on site elevation. However, I already accounted for the influence of the elevation gradient by considering relevant climate variables (temperature, precipitation, VPD).

3. Line 116 (Table 1): Mean temperature The temperature is 9.8℃at 1350m (Olmedilla)，but temperature is 9.2℃ at 360m (R. P). Whether this is a particular sampling site with a particular climate?

• Sorry, this was a mistake. The temperature at RP is 13.2 ºC.

4. Line 160 (Table 2): Age at 1.3 m The age of different species will affect the IADF. Such as  pinsapo, C. atlantica, have smaller mean age at 1.3m.

• I agree that age affects IADF formation. However, in each site sampled mature trees were of similar age. Then, their ring-width series were combined into mean site chronologies so as to reduce affect effects on growth trends and IADF production. Nevertheless, the age range considered in the study (40-92 years) is not as wide so as to greatly influence the presented results. The two species you mention correspond to young trees since those sites were plantations.

5. Line 212: I see IADF trends interannual change in some species at Figure 2, such as IADF frequent decrease of  thurifera in Peñaflor. Therefore, it is recommended to add a description of the trend.

• I commented this trend in the revised ms.

6. Lines 221-223: Tree age does affect IADF, but why is there so little correlations p<0.001, but growth rate all p<0.001? Is the study trying to show that growth rate has more influence on tree growth than age for IADF?

• Table 3 shows the obtained results. IADF production depended more on growth rate that on tree age. This finding could be due to the narrow age range considered (see my previous response). I studied mature trees but did not compare very young vs. very old trees since that was not the aim of the study.

7. Line 234: Recommended that you explain the meaning of the bright blue bar in the figure label.

• The figure legend was improved to explain the meaning of bars.

8. Line 235: Why did you choose to start from previous October? If the "lag effect" is taken into account, should it be explained in the methods?

• I explained it in the methods. I started in the prior October based on multiple studies on these species showing that most climate influence on growth corresponds to the temporal window used in Figure 3.

9. Line 342: I see the mean minimum temperature in March, June and July is the key constraint in SW USA (Fig. 7).

• 7d shows this is the case for April, June and July minimum temperatures.

 

10. Line 343: Is it necessary to outline in the figure 1 or supplemental materials If autumn temperature rising?

 

• Done; thanks for the suggestion. In most study sites autumn temperatures are significantly increasing.

Reviewer 2 Report

The MS item is of high relevance for understanding how the climate drivers of L-IADF formation at hourly to monthly long scales. The author evaluated the rather complex and interesting research questions addressed in the title, obviously with adequate statistical methods. It highlights that IADFs are formed at night and early morning in response to wet conditions and low VPD, and minimum (night) temperature is a major driver of growth in seasonally dry conifer forests. Overall, the results and conclusions are well supported by data. It is meaningful and worth being published in the journal Forests minor revision. Below I present some suggestions that the author may find helpful when improving the manuscript. It should be noted that my mother tongue is not English, and all comments on language should be cautious.

Specific comments:

1.      Lines 69-70: The hypothesis is a little sudden, without any background before. I suggest adding 2-3 sentences of background before this.

2.      I strongly recommend adding geographical location maps to show the study areas and sample sites of the three cases (see lines 103, 109 and 112).

3.      In figure 1: the anatomical image is too small, which may affect the display of the IADFs to the readers. Would you mind replacing it with a big-size picture with high resolution? In addition, I suggest that the author add a normal annual ring picture without IADFs. It is more helpful for readers to better understand IADFs. The two images can be placed in figure 1d.

4.      In figure 2: the color lines representing different sites are difficult to distinguish, although the symbols can distinguish them. I suggest the author redraw it with strong contrast color lines.

5.      In figure 3: I suggest the author remove the anatomical image from figure 3. It is already shown in figure 1.

6.      In figure 7: some bars are missing in figure 7c-d. Why? Are all the Partial correlation coefficients equal to zero? Please double-check. Besides, as lines 283-284 says “plots (c) and (d) show partial Pearson correlations by relating growth and minimum temperature after controlling for the influence of maximum temperature”. What are the red bars indicate? Are the partial Pearson correlations relating growth and maximum temperature after controlling for the influence of minimum temperature? Please specify.

7.      Line 225: growth rate (ring-width index)

8.      Line 81: was or were?

9.      Line 89: except or excepting?

10.   Line 101: was or were?

11.   Lines 104-105: Were all these climate factors used in this study? If not, delete it.

12.   Line138: add the word ‘until’ after the word ‘sandpaper’.

13.   Line 139: were measured

14.   Lines 141-145: Please check whether there is any problem in expression or grammar.

15.   Line 158: replace “to” with “for”

16.   Line 175: I want to know more about the “zero-growth concept”. Briefly introduce it.

17.   Line 193: lost a period at the end of the sentence.

18.   Line 289: night

19.   In figure S10: the latin “J. ” should be italicized.

Author Response

Reviewer 2

 

( ) I would not like to sign my review report
(x) I would like to sign my review report

English language and style

( ) Extensive editing of English language and style required
( ) Moderate English changes required
(x) English language and style are fine/minor spell check required
( ) I don't feel qualified to judge about the English language and style

 

	Yes	Can be improved	Must be improved	Not applicable
Does the introduction provide sufficient background and include all relevant references?	( )	(x)	( )	( )
Are all the cited references relevant to the research?	(x)	( )	( )	( )
Is the research design appropriate?	(x)	( )	( )	( )
Are the methods adequately described?	(x)	( )	( )	( )
Are the results clearly presented?	(x)	( )	( )	( )
Are the conclusions supported by the results?	(x)	( )	( )	( )

 

Comments and Suggestions for Authors

The MS item is of high relevance for understanding how the climate drivers of L-IADF formation at hourly to monthly long scales. The author evaluated the rather complex and interesting research questions addressed in the title, obviously with adequate statistical methods. It highlights that IADFs are formed at night and early morning in response to wet conditions and low VPD, and minimum (night) temperature is a major driver of growth in seasonally dry conifer forests. Overall, the results and conclusions are well supported by data. It is meaningful and worth being published in the journal Forests minor revision. Below I present some suggestions that the author may find helpful when improving the manuscript. It should be noted that my mother tongue is not English, and all comments on language should be cautious.

 

• I thank you for your positive comments on the ms. I have revised the ms. following your suggestions.

 

Specific comments:

1. Lines 69-70: The hypothesis is a little sudden, without any background before. I suggest adding 2-3 sentences of background before this.

• Done, thank you. I introduced the hypothesis.

 

2. I strongly recommend adding geographical location maps to show the study areas and sample sites of the three cases (see lines 103, 109 and 112).

• I added a map (new Fig. S1) for the Spanish sites (lines 103 and 109).

 

3. In figure 1: the anatomical image is too small, which may affect the display of the IADFs to the readers. Would you mind replacing it with a big-size picture with high resolution? In addition, I suggest that the author add a normal annual ring picture without IADFs. It is more helpful for readers to better understand IADFs. The two images can be placed in figure 1d.

• I added a bigger size picture of the IADFs. However, I did not add a picture of a normal annual ring because of the lack of space.

 

4. In figure 2: the color lines representing different sites are difficult to distinguish, although the symbols can distinguish them. I suggest the author redraw it with strong contrast color lines.

• I replotted the figure using bars or different contrasts and the result was similar. Therefore, I opted for presenting the initial figure 2.

 

5. In figure 3: I suggest the author remove the anatomical image from figure 3. It is already shown in figure 1.

• Done.

 

6. In figure 7: some bars are missing in figure 7c-d. Why? Are all the Partial correlation coefficients equal to zero? Please double-check. Besides, as lines 283-284 says “plots (c) and (d) show partial Pearson correlations by relating growth and minimum temperature after controlling for the influence of maximum temperature”. What are the red bars indicate? Are the partial Pearson correlations relating growth and maximum temperature after controlling for the influence of minimum temperature? Please specify.

• Partial correlations were calculated between minimum and maximum temperatures only for those months when one of these two variables showed significant correlations with growth rates (ring-width indices). This is now indicated in the revised legend of the figure and in the methods. The legend has been clarified to improve the interpretation of the figure.

 

7. Line 225: growth rate (ring-width index)

• Done, I corrected it.

 

8. Line 81: was or were?

• Done, I corrected it.

 

9. Line 89: except or excepting?

• Done, I corrected it.

 

10. Line 101: was or were?

• Done, I corrected it.

 

11. Lines 104-105: Were all these climate factors used in this study? If not, delete it.

• Done, I corrected it.

 

12. Line138: add the word ‘until’ after the word ‘sandpaper’.

• Done, I corrected it.

 

13. Line 139: were measured

• Done, I corrected it.

 

14. Lines 141-145: Please check whether there is any problem in expression or grammar.

• Done, I rephrased it.

 

15. Line 158: replace “to” with “for”

• Done, I replaced it.

 

16. Line 175: I want to know more about the “zero-growth concept”. Briefly introduce it.

• Done, I introduced it.

 

17. Line 193: lost a period at the end of the sentence.

• Done, I corrected it.

 

18. Line 289: night

• Done, I corrected it.

 

19. In figure S10: the latin “J. ” should be italicized.

• Done.