Seasonal Variation of Soil Respiration in the Mongolian Oak (Quercus mongolica Fisch. Ex Ledeb.) Forests at the Cool Temperate Zone in Korea
John E. Hunt
Round 1
Reviewer 1 Report
My comments to the authors are included in the annotated pdf file
Comments for author File: 
Comments.pdf
Author Response
Reply to Reviewer’s comments
Reviewer 1
L 16. which were these variables?
☞ We revised that as "environmental parameters (Ts and SWC)" by accepting reviewer's comment. Line 16.
L 17. variable not variables
☞ We revised that as “variable” by accepting reviewer’s comment. Line 17.
L 24. these values were quite similar to empirically estimated values.
☞ We revised our manuscript by adding the following sentence. "These values were quite similar to the measured values in field." Lines 24-25.
L 24. The instead of These
☞ We revised our manuscript by changing “These” into “Our”. Line 25.
L 26. this is not obvious from the previous sentences. Delete it or support it to convince the reader.
☞ We revised our manuscript by accepting reviewer’s comment as the follows. “Our results demonstrate that the improved empirical equation is an effective tool for estimating and predicting SR variability and and provides evidence that the SR of Q. mongolica forests in the cool temperate zone of Korean Peninsula depends on Ts and SWC variables.” Lines 25-27.
L 46. from 30 to 80
☞ We revised our manuscript by accepting reviewer’s comment as the follows. "contribute from 30 to 80% to the total ecosystem respiration in forests [23-25]." Line 48.
L 55. this is because T and SWC are interrelated variables
☞ We revised our manuscript by accepting reviewer’s comment as the follows. "The SWC factor regulating SR rates is related to complex interactions in forest ecosystems, and is often confused with the response of SR to T variable [38]." Lines 56 – 57.
L 98. trees per ha
☞ We revised our manuscript by accepting reviewer’s comment. Line 100.
L 162. how many of them?
☞ We revised our manuscript to reduce misunderstanding of the readers as the follows. One study plot sized in 30 m × 30 m was established on the forest floor of the Q. mongolica forest stand beneath the Eco-towers at Mt. Nam and Mt. Jeombong, respectively. Lines 164 – 165.
L 238. SWC = Soil water content
☞ We revised our manuscript by accepting reviewer’s comment. Line 244.
L 258. Is this a statistically significant relation?
☞ We revised our manuscript to reduce misunderstanding of the readers as the follows. The seasonal SR variations were strongly correlated with T in both forest stands throughout the entire experimental period (r2=0.78-0.91, P<0.01), but had no significant correlation with the SWC (r2=0.13-0.27, P>0.05). Lines 266 – 267.
L 259-260. In which results this statement is based? Did you test for significant correlation? the correlation is between SR and SWC recorded in 5 or 10 cm depth?
Line 259-260: "
☞ We revised our manuscript as the follows to aid understanding of the readers. “The seasonal SR variations were strongly correlated with T in both forest stands throughout the entire experimental period (r2=0.78-0.91, P<0.01), but had no apparent correlation with the SWC(r2=0.13-0.27, P>0.05). However, the SR rate abruptly increased with an increase in the SWC at the 15 cm depth due to precipitation during the forest growing season (Figures 6–9). Lines 265-269.
L 307. what made the authors to decide to use these variables; SWC at 15 cm depth and daily amount of precipitation?
☞ In both study sites, the forest soil layer at a 15 cm depth is classified as a topsoil (A-layer), with large amount of plant roots and abundant soil microorganisms and organic materials, which have a stable condition without rapid drying and wetting of forest soils due to environmental disturbances. For this reason, we decided to use the observed SWC parameters at the 15 cm depth. During the growing season, we wanted to identify the effects of SWC on SR rates in relation to the rainfall events.
Fig. 14. what does this title say?
☞ ∆SR(Ts) is the difference between the observed and predicted values by Equation 4.
L 337. I think that when SWR further increase (more than 28-29%), SR tend to remain stable
☞ We revised our manuscript by accepting reviewer’s comment as the follows.
But SR tended to remain stable state in further increase of SWC. Line 346 - 347.
L 346. for Ts<0
☞ We revised our mistake as the follows. Ts < 0 °C
Table 1. For the period Oct-Dec the difference between observed and predicted by the equations values was much lower compared to all other time periods. This hold true for both stand forests. Please provide an explanation for this.
☞ Yes, it is true. In both Q. mongolica forests, we thought that the higher dependence of SR to soil temperatures (Ts) during the period of seasonal change from autumn (October) to winter (December) is the background.
L 416. But what about the availability in C for microorganisms. As it is presented in this study it seems that SR is controlled mainly by abiotic variables such as Ta, TS and SWC. Further these parameters are highly correlated. TS with Ta and Ts with SWC. Does this correlation induce problems in the construction of the integrated models?
☞ The soil CO2 efflux from the soil surface, which is called as the soil respiration (SR) can be characterized by biological processes containing the plant root respiration and the soil microbial respiration. The abiotic factors, such as Ta, Ts and SWC stimulate the activity of soil microbes, and ultimately change the rate of SR in forest ecosystems. For this reason, it is necessary to investigate the effects of t Ta, Ts and SWC on the high-temporal frequency of SR.
L 444. Plant photosynthetic capacity
☞ We revised our manuscript by accepting reviewer’s comment. Line 454.
L 455. the figures show a plateau rather than a decrease
☞ We revised our manuscript by accepting reviewer’s comment as the follows.
Further increases in the SWC would probably lead to a plateau in the SR rate due to reductions in soil aeration and gas diffusivity. Line 465.
L 470. variables exhibited higher variability in Mt. Nam compared to Mt. Jeombong
☞ We revised our manuscript by accepting reviewer’s comment as the follows.
However, Ts and Ta variables exhibited higher variability in Mt. Nam compared to Mt. Jeombong, and their temporal fluctuations exerted a strong influence on the seasonal variation in SR. Lines 480 – 481.
L 478 – 485.
- I can't get it. Please be more explicit
- Since this is a new result it must be presented at the Results section and not in the D
To evaluate the SR response to environmental change due to urbanization and artificial disturbances such as changes of microclimate and microbial biota, the integrated optimal regression equation (with Ts and SWC) obtained from the natural forest was tested by applying the dataset collected from the urban forest on the same time period. The potential SR values predicted by applying the measured parameters (Ts at a 5 cm depth and SWC at the 15 cm depth) on Mt. Nam (urban forest) to the integrated regression Equation 9 obtained from Mt. Jeombong (natural forest) were ~128% higher than the value estimated based on in situ values at Mt. Nam (Figure 22). This result indicates that with the exception of the winter season, SR at Mt. Jeombong is more sensitive to the main environmental parameters (Ts and SWC) than it is at Mt. Nam.
☞ We deleted this part from this study and left it for the next study.
L 485. I haven't been convinced for this last sentence.
☞ We deleted this part from this study and left it for the next study.
L 490. I cann't see in which results this statement is based on.
☞ We deleted this part from this study and left it for the next study.
L 497. phenology of what?
☞ We revised the part our manuscript by adding “vegetation” before “phenology”. Line 508.
Author Response File: 
Author Response.docx
Reviewer 2 Report
This manuscript makes a comparison in the temperature and water response of soil respiration at two different forest (with similar vegetation) in South Korea. The authors made continuous measurements using automatic chambers to measure surface flux of CO2 and also measured the soil temperature at 3 depths (plus air temperature) and soil moisture at 15 cm. They amassed a n annual data set, fitted functions to the data and created an annual model to relate fluxes to environmental conditions. This has been done before but not in these forests. The measurement of CO2 fluxes was well done under what must have be data times difficult conditions.
Overall, the manuscript is clear and well written., There are minor issues with the English but these in no way inhibited my ability to follow their reasoning. There are a couple of issues that I found perplexing and hope can be addressed by the authors. It is hard for me living in a temperate climate to get a grasp on the biophysical dynamics of a system dominated by the monsoon. Climate and soil characteristics play a central role to understanding the response of the system and need to be better explained for people not familiar with the local ecosystem.
The forests are described as “urban” and relatively undisturbed (in a reserve). Pollution may play a roll but I would have thought the main difference between the sites is the difference in climate (temperature and precipitation), soil characteristics and phenology rather than the proximity to urbane areas.
Major points:
The units for the volumetric soil water content should be in m3 water in m3 of soil (m3 m-3) not % as this can be confusing. At both sites there seems to be very little evaporation from the soil surface and only a change of 5% over the whole year. From DOY 121 to 170 there is only 40 mm of rain but soil moisture only falls by 4 %. Also, a rainfall event of 550 mm (wow) only increased the SWC by 5%. Can this really be true? I don’t know the properties of these soils, but I suggest that more details about their water holding capacity, drainage capacity, water release curves, bulk density etc, and characteristics needs to be supplied for readers to make sense of the data. Can the authors confirm using other data that these measurements are correct? Does this mean the soils are perpetually saturated, and if so what is the effect on soil respiration?
L 455 If you get 600 mm of rain in 3 days, or even 100 mm on a soil that is already close to field capacity, then the soil MUST be fully saturated with all pore spaces filled. So why wasn’t there a decrease in the SR rate? The graphs would indicate that these soils do not drain quickly and more information about their drainage capacity is required.
L 246 If there was no clear seasonal changes in SWC at Mt Jeombong (Fig 7) then why does it need to be added to the respiration equation. I would suggest from a plant point of view there is very little change in SWC at both sites, and that a decrease in SWC away from saturation (and low O2) should lead to an increase in soil respiration. Did the authors try using a stepwise multiple regression to proportion the effects of temperature and water on the soil CO2 flux?
L 250 Soil temperature and SWC are not the only variables that effect the soil CO2 flux. Surely the soil respiration, especially the autotrophic component was somehow influenced by the presence of leaves on the trees and not just temperature. This would then be a covariate to the temperature record.
L 441 – 445 The increase in SWC did not coincide with the rapid SR rise, it is the other way around. Is it really soil respiration rate or bulk movement of CO2 out of the soil by physical displacement? So the same thing could happen at low temperatures it is just the fully saturated soil conditions occur when the warmest temperatures do? The response of SR to high SWC may not be respiration rate at all but a physical movement of CO2 out of the soil when all the pore spaces are filled with water. Ie above field capacity. More info needed about the physical characteristics of the soil, what if field capacity, what is the air-filled pore space.
L 472 The Mt Nam site is 500 m lower than the Mt Jeombong site and soil temperatures are higher, which would suggest higher SR. There is literature explaining why ecosystems that are acclimated to lower temperatures have a larger response to an increase in temperature. Maybe this is what is happening here, and it has nothing to do with air pollution. I am not sure why the authors talk about urban and reserved forests and I am not sure that you can conclusively say anything about urban vs reserved forest.
Minor points
L 59 Need authority for species name
L 73 How do your measurements compare to the Ecotowers?
L 185 Not sure what “o gas” means? I gather is means no CO2
L 188 Was the Ta within a radiation shield? Was the TSS exposed to radiation or was it covered?
L 192 Not sure how the CS616 were calibrated as you would have to dig them up. I don’t think it is important to calibrate them over the year and feel this may not have been needed. The same really goes for the soil temperature probes.
L 199 “sets” is in a different font.
L 206 Did you need to account for the difference in altitude? Not sure if you need to or not.
L 203 and 213 give different time periods s-1 and hr-1, maybe best to keep them the same.
Fig 6 The authors talk about months with the highest temperature, but the graph is displayed using DOY. It would be best if you put months on the y axis of these graphs. I was surprised to see the 5 and 15 cm temperatures so close together, there seems to be very little difference between them, is this because the dense canopy is summer reduces the amount of radiation getting to the forest floor?
Fig 6 this is a chance to add on data that would be helpful eg when snow covered the ground, leaf out and leaf fall at each site.
Fig 8 You got lots of data, which is very admirable to see. Can you state somewhere exactly how many valid samples you got, was it 80% of the time or 95%. I think this is presented in Table 1 and 2. It would be good to see these number earlier in the manuscript.
L 256. You used the terms spring and autumn, and April and May and then the graph has DOY. I know it easier to plot DOY but it’s harder for the reader to equate these terms.
L 264 Fig 8 and 9 should have the same y axis maximum 2500 so the graphs are comparable. Make the SE lines on both graphs the same density, thickeness and colour. Again, some idea snow lie would help explain the missing data in Fig 9.
L 250 What are the +/- mean is this the range the sd or the SE. Is this the variation between chambers?
L286. You had soil temperature at 3 different heights, which one did you use to fit these equations?
L 288 Not sure what “are valid” really means?
L 298 There is a typo, what does el mean?
L 296 Use the same y scale for both sites
L 300 why doesn’t Fig 13 have the predicted vales at T < 0 degrees displayed?
L 312 Fig 14 is squashed and needs to be better presented
L 325 It took me a while to get my head around the graph I sort of understand it but it might need a bit more explanation.
Fig 20 Anyone would be happy to see this, but not sure of the explanation?? Just worried that all of the zero values might affect the r2 value, can this be checked?
L453 I think you mean 0 ℃
Author Response
Reviewer 2
Reply to reviewer’s comments
Major points:
# 1.
- The units for the volumetric soil water content should be in m3 water in m3 of soil (m3 m-3) not % as this can be confusing. At both sites there seems to be very little evaporation from the soil surface and only a change of 5% over the whole year. From DOY 121 to 170 there is only 40 mm of rain but soil moisture only falls by 4 %. Also, a rainfall event of 550 mm (wow) only increased the SWC by 5%. Can this really be true? I don’t know the properties of these soils, but I suggest that more details about their water holding capacity, drainage capacity, water release curves, bulk density etc, and characteristics needs to be supplied for readers to make sense of the data. Can the authors confirm using other data that these measurements are correct? Does this mean the soils are perpetually saturated, and if so what is the effect on soil respiration?
- L 455 If you get 600 mm of rain in 3 days, or even 100 mm on a soil that is already close to field capacity, then the soil MUST be fully saturated with all pore spaces filled. So why wasn’t there a decrease in the SR rate? The graphs would indicate that these soils do not drain quickly and more information about their drainage capacity is required.
- L 441 – 445 The increase in SWC did not coincide with the rapid SR rise, it is the other way around. Is it really soil respiration rate or bulk movement of CO2 out of the soil by physical displacement? So the same thing could happen at low temperatures it is just the fully saturated soil conditions occur when the warmest temperatures do? The response of SR to high SWC may not be respiration rate at all but a physical movement of CO2 out of the soil when all the pore spaces are filled with water. Ie above field capacity. More info needed about the physical characteristics of the soil, what if field capacity, what is the air-filled pore space.
☞ We revised our manuscript by accepting reviewer’s comment. That is, we revised a sentence “the volumetric SWCs……” on lines 190-191 into “……and the volumetric soil water content (SWC, 0-100 vol% = [Vw m3 (the volume of water) /Vt m3 (the bulk volume of soil)] × 100) at the 15 cm depth was obtained with a time-domain reflectometry (TDR) probe (CS-616; Campbell Scientific Inc., Utah, USA).”
On the other hand, as the reviewer points out, the rainfall event of 550 mm for a day didn’t occur in Q. mongolica forests in both Mt. Nam and Mt. Jeombong.
We added the following information on measuring precipitation in lines 188-190 to aid understanding of the readers. “In both study sites, the precipitation was measured at hourly intervals using a weighing bucket rain gauge (Model-R301, Weather Tec. Seoul, Korea) installed and mounted on the top of eco-tower at the height of 30 m above ground".
The precipitation observed and analyzed at each research site is the precipitation outside the forest, and the actual precipitation reaching the forest floor inside the forest canopy due to the development of the forest canopy and the expansion of the leaf area index during the summer growing season is far less than that of regional precipitation.
In the result of preliminary study conducted before near the our research sites of Mt. Nam and Mt. Jeobong, soil types were classified into brown forest soil at both sites (Dystric Cambisols according to FAO-UNESCO). The maximum water holding capacity (Vw max %) of forest soil in these areas, which can be absorbed and maintained against gravity, indicated a range of 52.3 ± 1.2 % to 60.5 % 3.1 % (data did not show).
Based on the results of the maximum water holding capacity (Vw max %) obtained from the preliminary study above mentioned, it is unlikely that forest soil will become saturated at both research sites due to increased soil moisture caused by rainfall throughout the year.
Seasonal changes of water content in the forest soil of the cool-warm temperate zone of the Korean Peninsula, which belong to the Asian monsoon climate zone, show a relatively moderate trend. In addition, data from other relevant literature and observations also showed similar values to the results of this study (Joo et al. 2011, Jeong et al. 2017, Lee 2018).
As the reviewer suggested, if the long-term heavy rainfall, direct surface runoff and flooding were caused by extreme weather events, resulting in sufficient water saturation of forest soil in both regions, and since then decreasing over time, soil water contents observed in Mt. Nam (Fig. 6) and Mt. Jeombong (Fig. 7) would rise further and maintain such high soil water contents over a longer period of three days or more.
## 2.
- L 246 If there was no clear seasonal changes in SWC at Mt Jeombong (Fig 7) then why does it need to be added to the respiration equation. I would suggest from a plant point of view there is very little change in SWC at both sites, and that a decrease in SWC away from saturation (and low O2) should lead to an increase in soil respiration. Did the authors try using a stepwise multiple regression to proportion the effects of temperature and water on the soil CO2 flux?
☞ The effect of soil water content (SWC) on the soil CO2 efflux (SR) has rarely been studied in the forest ecosystem of cool temperate regions. Although the SWC is less important in the seasonal change of SR than in the dynamics of soil temperature (Ts), it could modify the temperature dependence of SR during the forest growing season using the multiple regression.
### 3.
- L 250 Soil temperature and SWC are not the only variables that effect the soil CO2 flux. Surely the soil respiration, especially the autotrophic component was somehow influenced by the presence of leaves on the trees and not just temperature. This would then be a covariate to the temperature record.
☞ The soil CO2 efflux from the soil surface, which is called as the soil respiration (SR) can be characterized by biological processes containing the plant root respiration and the soil microbial respiration. Although net primary production and litter fall supply in forest ecosystems are important drivers of SR, the biological processes are mainly controlled by environmental factors, such as temperature and soil water content. For this reason, it is necessary to examine the effects of temperature (T) and soil water content (SWC) on the high-temporal frequency of SR in forest ecosystems.
#### 4.
- L 472 The Mt Nam site is 500 m lower than the Mt Jeombong site and soil temperatures are higher, which would suggest higher SR. There is literature explaining why ecosystems that are acclimated to lower temperatures have a larger response to an increase in temperature. Maybe this is what is happening here, and it has nothing to do with air pollution. I am not sure why the authors talk about urban and reserved forests and I am not sure that you can conclusively say anything about urban vs reserved forest.
☞ Mt. Jeombong, where is not only the nature well preserved, but also is located
at a high altitude above sea level, has a lower soil temperature than Mt. Nam
located in the urban center of the metropolitan city. Q10 values shown in Fig. 10
(Mt. Nam) and Fig. The 11 show that the soil respiration rate responds to more
sensitively to temperature rise in the Mt. Jeombong than in Mt. Nam.
Based on these results, if Mt/ Nam area, which has increased temperature because it is located at a lower altitude than Mt. Jeombong and urbanization effect is added, has well-preserved soil conditions such as Mt. Jeombong, it is estimated that soil respiration rate, which functions as the most important factor in the carbon budget of forest ecosystem, would increase more than the current level. In this study, the effect was assessed by substituting the temperature and soil water content of Mt. Nam with the formula obtained from Mt. Jeombong (Figure 22 and Discussion section 4.2). In fact, Sung et al. (1998) revealed that the soil microbe of Mt. Nam, which plays an important role in soil respiration, has changed due to direct and indirect effects of humans.
But we deleted this part from this study and left it for the next study.
Minor points
L 59 Need authority for species name
☞ We revised our manuscript by accepting reviewer’s comment. Line 61.
L 73 How do your measurements compare to the Ecotowers?
☞ On the Eco-Tower, air temperature, humidity, and precipitation were measured, and soil temperature and soil moisture content were measured on the forest floor. Then, the relationship between these microclimate factors and soil respiration rate was analyzed.
L 185 Not sure what “o gas” means? I gather is means no CO2
☞ We revised our manuscript by accepting reviewer’s comment as the follows.
“calibrated with CO2 zero gas (pure nitrogen)”. Line 188.
L 188 Was the Ta within a radiation shield? Was the TSS exposed to radiation or was it covered?
☞ Ta and Tss sensors were ventilated solar radiation shield.
L 192 Not sure how the CS616 were calibrated as you would have to dig them up. I don’t think it is important to calibrate them over the year and feel this may not have been needed. The same really goes for the soil temperature probes.
☞ We revised the part as the follows to reduce misunderstanding of the readers.
“All sensors were calibrated at six – month interval.” Line 199.
TDR CS616 (Campbell Scientific Inc., USA) is calibrated by applying a method of Topp et al. (1980) and calibration of sensors and instruments installed on the Eco-towers for observation is regularly conducted by professional management engineers.
L 199 “sets” is in a different font.
☞ Thank you for your kind point for error. We revised the part by deleting the word.
L 206 Did you need to account for the difference in altitude? Not sure if you need to or not.
☞ No. The difference in altitude is reflected on the temperature. But we explained the difference in altitude to compare the difference of SR between both sites.
L 203 and 213 give different time periods s-1 and hr-1, maybe best to keep them the same.
☞ Thank you for your kind point for error. We revised the part as the follows.
mg CO2 m−2 s−1. Line 220.
Fig 6 The authors talk about months with the highest temperature, but the graph is displayed using DOY. It would be best if you put months on the y axis of these graphs. I was surprised to see the 5 and 15 cm temperatures so close together, there seems to be very little difference between them, is this because the dense canopy is summer reduces the amount of radiation getting to the forest floor?
☞ We revised Figs. 6 and 7 by accepting reviewer’s comment.
During summer season, mature canopy and high leaf area index of deciduous broadleaved forest are thought to have affected soil temperature changes by blocking the amount of radiation from the sun reaching the forest floor. Consequently, the soil temperature measured at the depth of 5 cm and 10 cm, respectively, was not much different, but showed a distinct seasonal change.
Fig 6 this is a chance to add on data that would be helpful e.g. when snow covered the ground, leaf out and leaf fall at each site.
☞ We revised Figs. 6 and 7 by expressing “Snow-covered season, Litter fall season, No leaf season” by accepting reviewer’s comment.
Fig 8 You got lots of data, which is very admirable to see. Can you state somewhere exactly how many valid samples you got, was it 80% of the time or 95%. I think this is presented in Table 1 and 2. It would be good to see these number earlier in the manuscript.
☞ Thank you. We cited Tables 1 and 2, which showed the number of valid samples and the result of analyses, to reduce the volume of our manuscript.
L 256. You used the terms spring and autumn, and April and May and then the graph has DOY. I know it easier to plot DOY but it’s harder for the reader to equate these terms.
☞ We revised our manuscript as the follows to reduce misunderstanding of the readers. Lines 260-264.
“The daily mean SR increased markedly from the spring (DOY 60 to DOY 151: 75–399 mg CO2 m−2 h−1 at Mt. Nam; 49–367 mg CO2 m−2 h−1 at Mt. Jeombong) to the summer seasons (DOY 152 to DOY 243: 835–1960 mg CO2 m−2 h−1 at Mt. Nam and 801–1195 mg CO2 m−2 h−1 at Mt. Jeombong), and then decreased gradually from autumn (DOY 244 to DOY 334: 90–551 mg CO2 m−2 h−1 at Mt. Nam; 98–305 mg CO2 m−2 h−1 at Mt. Jeombong) to winter (DOY 335 to DOY 59:”
L 264 Fig 8 and 9 should have the same y axis maximum 2500 so the graphs are comparable. Make the SE lines on both graphs the same density, thickeness and colour. Again, some idea snow lie would help explain the missing data in Fig 9.
☞ We revised our manuscript by accepting reviewer’s comment.
L 250 What are the +/- mean is this the range the sd or the SE. Is this the variation between chambers?
☞ They mean SD, which is the variation among chambers.
L286. You had soil temperature at 3 different heights, which one did you use to fit these equations?
☞ We used the temperature measured in 5 cm depth in Equations (4) and (5).
We expressed the facts as the legend on Figs. 10 and 11 and explained them in lines 281-282.
L 288 Not sure what “are valid” really means?
☞ We revised our manuscript as the follows to aid understanding of the readers. Equation (4) (r2 = 0.91, Q10 = 3.0) and Equation (5) (r2 = 0.84, Q10 = 3.7) are valid for the Ts at 5 cm depth, which is above 0 °C, and the rate of SR (Ts) for Ts < 0 °C is near-zero value. Lines 295-297.
L 298 There is a typo, what does el mean?
☞ Thank you for your kind point for the error. We revised it.
L 296 Use the same y scale for both sites
☞ We revised Fig. 13 as the same size as Fig. 12 by accepting reviewer’s comment.
L 300 why doesn’t Fig 13 have the predicted vales at T < 0 degrees displayed?
☞ As the result of application of Equation (5) (r2 = 0.84, Q10 = 3.7), the rate of SR(Ts) near to 0 when Ts is below 0 °C (Fig. 13). Lines 295-297.
L 312 Fig 14 is squashed and needs to be better presented
☞ We revised Figs. 14 and 15 by accepting reviewer’s comment.
L 325 It took me a while to get my head around the graph I sort of understand it but it might need a bit more explanation.
☞ We explained the content related to Line 325 in lines 314-320 and 341-347.
Fig 20 Anyone would be happy to see this, but not sure of the explanation?? Just worried that all of the zero values might affect the r2 value, can this be checked?
☞ We obtained a lot of valid observational data in Mt. Nam and they overlapped on Fig. 20. But they did not significantly affect the r2 values of correlation. And the values of the SR rate, which were measured in field and predicted, existed above or near zero, but there were no values below zero.
L453 I think you mean 0 ℃
☞ Thank you for your kind point for the error. We revised it. Line 463.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
I see the revised version and I feel that there are comments that were not fully addressed.
First of all it was exhaustive trying to find in which part of the article, the text has been changed as a response to comments. The authors had to highlight the changes. Further the number of the lines that mentioned at the response letter was that of the previous version and not of the revised one. This made checking difficult.
However, there are some points that were not clarified.
- The authors said that during the period Oct to Dec there was a stronger dependence of SR on Ts. Specifically they use this explanation for the slight differences in SR between empirical and modeled data the period Oct to Dec. Did their data show this? And if there is such a strong relation which is the reason?
- I asked from authors to add a paragraph in their discussion that it will discuss the dependence of SR on substrate availability but they didn’t do this. I give some references relevant to this issue:
Wang et al. 2003 -. Relationships of soil respiration to microbial biomass, substrate availability and clay content
Eberwein et al. 2015 - Carbon availability regulates soil respiration response to nitrogen and temperature
- 344 This is too trivial to be presented as the main conclusion.
l.480-481 So, one study plot in each forest I guess. And you use eight chambers in each plot or four chambers in Mt. Nam and four in Mt. Jeomborg?
- 581 statistically significant correlated not strongly
- 581-583 “However, the SR rate abruptly increased with an increase in the SWC at the 15 cm depth due to precipitation during the forest growing season (Figures 6–9)” This is response of authors in the response letter but differed with the text presented in lines 581-583.
l.637 The authors must describe ΔSR at the legend of the figure 14 since its figure must be understandable without the text
l.661 “tended to remain at stable state”
Author Response
I answered faithfully for the reviewer's comments. I am attaching herewith the reply letter. Best regards.
C.S. Lee
Author Response File: Author Response.pdf
