Vegetation Effects on Phosphorus Runoff from Headwater Catchments in a Cool-Temperate Region with Landslides, Northern Japan

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This is a manuscript of very high quality, and the research content is of good innovation and significance. However, there are a few minor issues need to be revised, as followed,

1. The authors should introduce structure of their manuscript in the last paragraph of the Introduction section.

2. The quality of Figure 1 is very poor. Please redraw it.

3. Suggest landslide-bearing forest shorthand for the LBF, and undisturbed forest shorthand for the UF.

4. It is recommended to name the two subgraphs in Figure 2 as a and b, respectively. Other figures have similar problems.

Author Response

We greatly appreciate the reviewer’s positive comments and suggestions, which have been helpful for our revision. Detailed responses are provided below.

 

1. The authors should introduce structure of their manuscript in the last paragraph of the Introduction section.

Based on the comment, we added a description of the structure of the manuscript in the last paragraph of the Introduction section (L112–116).

 

2. The quality of Figure 1 is very poor. Please redraw it.

Based on the comment, we replaced Figure 1 with the high-resolution one.

 

3. Suggest landslide-bearing forest shorthand for the LBF, and undisturbed forest shorthand for the UF.

Based on the comment, we replaced the abbreviations, "L" and "F" with "LB" and "UF", respectively, throughout the manuscript.

 

4. It is recommended to name the two subgraphs in Figure 2 as a and b, respectively. Other figures have similar problems.

Based on the comment, we added alphabetical characters in Figure 6 to have readers more easily identify each subfigure in the main text. Because of this change, we added the alphabetical characters after "Figure 6" in the main text (L286–288, L351, L414). In the other figures, readers can identify subfigures by names of y-axes.

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript compares the phosphorus export by runoff from two forested catchments, one of both being heavily impacted by a landslide. The results agree with current knowledge. Hence, the manuscript does not add new insights but may be seen as a confirmation of current knowledge. In essence, the manuscript analyzes one large rain event. This can be regarded as the least publishable unit. This is an extremely small database for erosion research that has to consider enormous variation between events. Typically, long-term measurements are required in erosion research dealing with natural events.

Despite this rather critical scientific assessment, I recommend publishing this manuscript after minor revision, given that it is carefully prepared and has a much higher technical quality than most manuscripts I receive for review from MDPI journals.

Details:

L 38: Why increasing? Why can only an increasing frequency transport nutrients?

L 48: Delete 'cover' or explain better what you mean

L 52: What do you mean by 'soil layers'? Horizons? Horizons also exist in non-forest soils. This cannot justify a higher infiltration capacity of forest soils

L 63: Why only bacterioplankton? Isn't this also true for algae and macrophytes?

L 68: Sediment loads from forests do not necessarily act as a source of bioavailable P but often serve as a sink absorbing dissolved P, particularly when runoff from forests mixes with runoff from agricultural areas with high concentrations of dissolved P. The entire chemistry of P sorption/desorption, dissolution/precipitation needs to be better developed in this manuscript. Wrong conclusions likely result from this deficit.

L 70: Reference to rain erosivity would be better than the magnitude and frequency of precipitation. Precipitation is likely wrong, while the authors mean rain. Furthermore, precipitation frequency is expected (and already observed) to decrease while the frequency of erosive rains increases. Hence, this sentence could be more precise.

L 80: Why 'remain'?

L 101: A soil cannot be composed of andosol. Please rephrase.

L 109: The unit must be mm/yr. Please note that precipitation is a quantity while temperature is an intensity. This is why one has to carry the unit 'per year' and the other not, while both are annual values. Hence, the word 'annual' added to the variable name cannot replace the unit 'per year'.

L 115: Distributed? Do you mean located?

L 118: The remaining 13 %?

L 121: Delete 'as'

L 126: use past tense

L 130: sentence not clear

L 132: One rain gauge is insufficient, given the high spatial variability of erosive rains that change enormously within a few hundred meters. Please refer to the literature on the spatial variability of erosive rains. This lack of rain gauges is a major deficit of the study, and its implications must be discussed.

L 139: Not clear. Did you sample the mineral soil on the organic layers on top of the mineral soil or some undefined mixture?

L 140: I hardly can believe that 1-ha catchments produce continuous stream water. The hydrological catchment seems to be much larger than the topographic catchment. This has important implications and must be discussed.

L 159: Does potassium peroxydisulfate really release all P from minerals (e. g. Fe phosphates, silicates, etc.)? No reference is given here. I would expect that you did NOT measure total P.

Fig. 3: A blank must be inserted between the number and the unit in the axis titles. Delete the full stop after min. The closed diamond is far too small.

L 217: one third

Fig. 4: Insert a blank between the number and the unit

Fig. 5: same remark as for Fig. 3. PP is extremely small and in a wrong relation to DP. This again indicates that you have not measured total P.

Fig. 6: Blanks are missing, and full stops are wrong.

L 289: Past tense

The entire discussion can be improved. See the remarks above. Furthermore, it is full of speculations ('could be', 'is possible', 'would be', ' suggesting' and so on). '' Please delete these speculations and do not make statements that are not supported.

I missed utterly a critical discussion of your assumptions and your approach.

L 353: Not true. Forests are not an important source of sediment-associated P to stream loads. You cannot make such a statement because you did not measure arable and urban catchments to assess the importance of forests.

L 358 to 362: Nonsense. Please delete

L 378: 'tended to be slightly higher' means that there was absolutely nothing. Please delete such speculations and restrict yourself to findings without a doubt. Such speculations are not strengthening but weakening your study.

L 532: Formatting

The entire formatting of the references appears wrong. Usually, the article titles in a reference list are not titles in a grammatical sense anymore because no main text is following; hence, they are not capitalized.

Author Response

We greatly appreciate the reviewer’s positive comments and suggestions, which have been helpful for our revision. Detailed responses are provided below.

 

• L 38: Why increasing? Why can only an increasing frequency transport nutrients?

Based on the comment, we added "magnitude and" in L38.

 

• L 48: Delete 'cover' or explain better what you mean

Based on the comment, we replaced the expression, "forest land cover in Japan is" with "forests in Japan are" in L52.

 

• L 52: What do you mean by 'soil layers'? Horizons? Horizons also exist in non-forest soils. This cannot justify a higher infiltration capacity of forest soils

Based on the comment, we replaced the sentence, "soil layers were developed in the forest" with "an aggregate structure develops in forest soils" in L55-56.

 

• L 63: Why only bacterioplankton? Isn't this also true for algae and macrophytes?

In accordance with the comment, we added "algae, and macrophytes" in L71–72.

 

• L 68: Sediment loads from forests do not necessarily act as a source of bioavailable P but often serve as a sink absorbing dissolved P, particularly when runoff from forests mixes with runoff from agricultural areas with high concentrations of dissolved P. The entire chemistry of P sorption/desorption, dissolution/precipitation needs to be better developed in this manuscript. Wrong conclusions likely result from this deficit.

Based on the comment, we added the statement, "A dissolved form of P in a forest stream can be sorbed onto the bed sediment surfaces and some of the bioavailable dissolved P is assimilated into biomass during low flows; thus, sediment loads can act as a sink of P within the stream channel [25]" in the L75–79. Because of this addition, we added the expression, "On the other hand" in L79, and related literature in the References section (L556–557).

 

• L 70: Reference to rain erosivity would be better than the magnitude and frequency of precipitation. Precipitation is likely wrong, while the authors mean rain. Furthermore, precipitation frequency is expected (and already observed) to decrease while the frequency of erosive rains increases. Hence, this sentence could be more precise.

Based on the comment, we added the sentence, "Fujibe et al. [32,33] showed that the frequency of intensive rainfall and dry weather has been increasing in Japan" in L84-85. Because of this addition, we added the literature in the References section (L577–582).

 

• L 80: Why 'remain'?

Based on the comment, we changed the statement, "concentrations and molecular weights remain high DOM" to "large carbon pools exist in soil solids and solutions, which provides high concentrations and molecular weights of DOM" in L96–98.

 

• L 101: A soil cannot be composed of andosol. Please rephrase.

In accordance with the comment, we removed the statement, "The soils are predominantly composed of various pyroclastic deposits, such as tephra and andosol, and", and instead added information of soil physical properties (bulk density, soil particle density, and void ratio), based on literature, in L123–129 of in the Materials and methods section.

 

• L 109: The unit must be mm/yr. Please note that precipitation is a quantity while temperature is an intensity. This is why one has to carry the unit 'per year' and the other not, while both are annual values. Hence, the word 'annual' added to the variable name cannot replace the unit 'per year'.

In accordance with the comment, we changed the unit, "mm" to "mm y^–1" in L135.

 

• L 115: Distributed? Do you mean located?

In accordance with the comment, we changed the expression, "distributed" to "located" in L142.

 

• L 118: The remaining 13 %?

Based on the comment, we added the statement, "and the remaining 13% surfaces were covered by herbaceous vegetation" in L148–149.

 

• L 121: Delete 'as'

In accordance the comment, we deleted "as" in L115 and L120 of the previous manuscript.

 

• L 126: use past tense

In accordance with the comment, we revised "is" to "was" in L157.

 

• L 130: sentence not clear

Based on the comment, we changed the sentence, "The water level was also measured by a metal measure and the runoff volume from each weir was directly observed using a measuring cylinder monthly" to "The actual water level and the runoff volume at each weir were also measured monthly using a metal measure and a measuring cylinder, respectively" in L160–162.

 

• L 132: One rain gauge is insufficient, given the high spatial variability of erosive rains that change enormously within a few hundred meters. Please refer to the literature on the spatial variability of erosive rains. This lack of rain gauges is a major deficit of the study, and its implications must be discussed.

Based on the comment, we revised the sentence, "We targeted two forest catchment" to " We targeted two neighboring, forested headwater catchments (distance between the catchments: 370 m)" in L140–141. We believe that one rain gauge was sufficient in this study because we did not focus on spatial variability of erosive rains, but focused on effects of vegetation on stream phosphorus runoff in a cool-temperate forest. Additionally, the two catchments were located very close together, the area of the landslide-bearing forest catchment was less than 1 ha, and thus the spatial variability of rainfall hardly affected the conclusions in this study.

 

• L 139: Not clear. Did you sample the mineral soil on the organic layers on top of the mineral soil or some undefined mixture?

Based the comment, we added the statement, "which derived from humus layer in the UF catchment and some undefined mixture of humus and weathered soils in the LB catchment" in L170–171.

 

• L 140: I hardly can believe that 1-ha catchments produce continuous stream water. The hydrological catchment seems to be much larger than the topographic catchment. This has important implications and must be discussed.

Based on the comment, we added the sentence, "Each catchment has a perennial stream" in L155. It is not unnatural that approximately 1-ha catchments have perennial streams in Japan’s forests. As the reviewer indicated, it can happen that topographic area is not consistent with the representative elementary area (REA) in a small forest catchment (Wood et al. 1988). On the other hand, the phenomenon that specific runoff is largely different between similar catchment areas should be prominent during low flows because groundwater flow is not constrained within a topographic catchment but contributes to stream flow. In the present study, specific runoff was greater in the undisturbed forest (UF) catchment than in the landslide-bearing (LB) catchment during low flows and the average TP load observed during low flows little differed between the two catchments. Conversely, during an intensive rain event, the overall TP load was greater in the LB catchment than in UF catchment. Because subsurface and/or surface flow would make a larger contribution to the large TP load in the LB catchment rather than did groundwater flow during the rain event, the variability of specific runoff due to the different REAs between the catchments should little affect the P transport processes during the rain event.

 

• L 159: Does potassium peroxydisulfate really release all P from minerals (e. g. Fe phosphates, silicates, etc.)? No reference is given here. I would expect that you did NOT measure total P.

Based on the comment, we cited literature in L193–194. This method is commonly used for the analysis of TP in natural water throughout the world.

 

• Fig. 3: A blank must be inserted between the number and the unit in the axis titles. Delete the full stop after min. The closed diamond is far too small.

In accordance with comment, we inserted a blank between the number and the unit in the axis title, deleted the full stop after min, and enlarged the sizes of closed diamonds.

 

• L 217: one third

In accordance with the comment, we revised "one thirds" to "one third" in L250.

 

• Fig. 4: Insert a blank between the number and the unit

In accordance with comment, we inserted a blank between the number and the unit in the axis titles.

 

• Fig. 5: same remark as for Fig. 3. PP is extremely small and in a wrong relation to DP. This again indicates that you have not measured total P.

Based on the comment, we revised Fig. 5. As described earlier, we also cited literature in L193–194. The analytical method in this study is commonly used for the analysis of TP in natural water throughout the world. As the reviewer indicated, this method may have some problems. However, we applied the same method to the analysis of P in stream water in both of the two catchments and compared stream P concentrations between the catchments. Therefore, the analytical method little affected the conclusions in this study. Additionally, PP concentrations measured in this study were not extremely low compared to other studies that measured TP concentrations in forest streams (Ide et al. 2008a, b; Ide et al. 2019; Komai 2004; Takeda et al. 2009).

 

• Fig. 6: Blanks are missing, and full stops are wrong.

In accordance with the comment, we revised "10min." to "10 min" in the axis titles.

 

• L 289: Past tense

In accordance with the comment, we revised "indicates" to "indicated" in L318.

 

• The entire discussion can be improved. See the remarks above. Furthermore, it is full of speculations ('could be', 'is possible', 'would be', ' suggesting' and so on). '' Please delete these speculations and do not make statements that are not supported.

Based on the comment, we changed the expressions in some places where there was a description of some evidence and/or cited literature (L357, L367, L376, L409, L413).

 

• L 353: Not true. Forests are not an important source of sediment-associated P to stream loads. You cannot make such a statement because you did not measure arable and urban catchments to assess the importance of forests.

Based on the comment, we deleted the statement, "indicating that forests are identified as an important source of sediment-associated P to stream loads" in L352–354 of the previous manuscript.

 

• L 358 to 362: Nonsense. Please delete

In accordance with the comment, we deleted the statement, "thinning and pruning were often neglected or insufficiently conducted, which resulted in high stand density and a closed canopy. The closed canopy hindered sunlight, thereby understory vegetation became scarce, and the litter layer was insufficiently developed due to the separation of litter leaves into smaller pieces[34,40–42]. Therefore, " in L358–362 of the previous manuscript. Because of this deletion, we also deleted the statement, "in the Japanese cypress plantation" in L364–365 of the previous manuscript.

 

• L 378: 'tended to be slightly higher' means that there was absolutely nothing. Please delete such speculations and restrict yourself to findings without a doubt. Such speculations are not strengthening but weakening your study.

In accordance with the comment, we replaced the expression, "tended to be" with "was" in L409.

 

• L 532: Formatting
• The entire formatting of the references appears wrong. Usually, the article titles in a reference list are not titles in a grammatical sense anymore because no main text is following; hence, they are not capitalized.

In accordance with the comment, we revised the formatting of the reference in L599–602.

 

 

Cited literature

Ide, J.; Haga, H.; Chiwa, M.; Otsuki, K. Effects of Antecedent Rain History on Particulate Phosphorus Loss from a Small Forested Watershed of Japanese Cypress (Chamaecyparis Obtusa). J. Hydrol. 2008a, 352, 322–335, doi:10.1016/j.jhydrol.2008.01.012.

 

Ide, J.; Chiwa, M.; Otsuki, K. Phosphorus Budgets in the Mountainous Watershed of a Plantation Forest of Japanese Cypress (Chamaecyparis Obtusa) Considering Increased Concentrations of Stream Phosphorus in Storm Events. J. Japan Soc. Hydrol. Water Resour. 2008b, 21, 205–214, doi:10.3178/jjshwr.21.205.

 

Ide, J.; Takeda, I.; Somura, H.; Mori, Y.; Sakuno, Y.; Yone, Y.; Takahashi, E. Impacts of Hydrological Changes on Nutrient Transport From Diffuse Sources in a Rural River Basin, Western Japan. J. Geophys. Res. Biogeosciences 2019, 124, 2565–2581, doi:10.1029/2018JG004513.

 

Komai, Y. Budget and Runoff Characteristics of Phosphorus in Forested Watershed. J. Japan Soc. Water Environ. 2004, 27, 591–594.

 

Takeda, I.; Fukushima, A.; Somura, H. Long-Term Trends in Water Quality in an under-Populated Watershed and Influence of Precipitation. J. Water Environ. Technol. 2009, 7, 293–306, doi:10.2965/jwet.2009.293.

 

Wood, E.F.; Sivapalan, M.; Beven, K.; Band, L. Effects of Spatial Variability and Scale with Implications to Hydrologic Modeling. J. Hydrol. 1988, 102, 29–47, doi:10.1016/0022-1694(88)90090-X.

 

Reviewer 3 Report

Comments and Suggestions for Authors

This study investigated the effects of vegetation on phosphorus runoff in a cool-temperate forest in northern Japan between the undisturbed (F) and the landslide-bearing small forest (L) catchments. But many problems be also concerned, like the logical structure of the introduction is unclear; the description of the materials and methods are not comprehensive; and the discussion is insufficient. Due to the above reasons, the authors should make a major revision to this manuscript. Also, some issues listed as follows need to be improved or explained more specifically.

1. The reason for the reduction in splash erosion due to the decrease in arboreal vegetation in lines 49-52 is also related to canopy height. When the effective canopy height is exceeded, splash erosion cannot be reduced.

2. Lines 47-59, the situation of nutrient loss is closely related to forest coverage, but research in other regions is lacking.

3. Relevant studies on nutrient loss in the study object (temperate forests) should also be added, and previous research should be summarized.

4. As mentioned below, the study area chose regions with landslides. The introduction lacks research on this aspect.

5. It is suggested to add the basic physical properties of the soil in the two study areas (mechanical composition, organic matter).

6. Lines 255-256, the concentrations of PP in the F watershed and DP in the L watershed are not proportional to the runoff. It is suggested to add the relevant correlation coefficients in the figures.

7. Lines 270-278, why only the relationship between PP and SS? What about the other indicators?

8. It is suggested to add from the perspective of the study object (temperate forests), such as relevant research on dominant tree species, in the discussion section.

9. Lines 290, it is suggested to add the role of litter in nutrient accumulation.

10. Lines 316-318, the insufficient canopy interception is also significantly correlated with the canopy height.

11. Lines 325-328, it is recommended to add relevant data (soil mechanical composition). Why are the sediment particles transported in the L watershed finer?

12. Lines 339-341, it is suggested to add relevant references.

13. It is recommended to add relevant legends to all figures to simplify the annotation content.

14. Standardize the font size of each part in the figures.

15. It is suggested to optimize the language structure and grammar throughout the article.

Comments on the Quality of English Language

Extensive editing of English language required

Author Response

We greatly appreciate the reviewer’s critical comments and suggestions, which have been helpful for us to provide clear and concise revisions. Detailed responses are provided below.

 

1. The reason for the reduction in splash erosion due to the decrease in arboreal vegetation in lines 49-52 is also related to canopy height. When the effective canopy height is exceeded, splash erosion cannot be reduced.

Based on comment, we deleted the statement, "and subsequently the soil splash detachment" in L51–52 of the previous manuscript to avoid readers' confusion.

 

2. Lines 47-59, the situation of nutrient loss is closely related to forest coverage, but research in other regions is lacking.

In accordance with the comment, we added the sentence, "They also suggested that the effectiveness of forest buffers against increased nutrient concentrations during storms was little different between coniferous and broad-leaved forests, while forest coverage has been recognized as one of the important factors influencing nutrient concentrations in river basins" and cited literature in L62–67.

 

3. Relevant studies on nutrient loss in the study object (temperate forests) should also be added, and previous research should be summarized.

Based on the comment, we added the sentence, "Ide et al. [26] showed that intensive rainfall following dry conditions caused a rapid increase in particulate P load from a temperate forested catchment" in L85–88 in consideration of the context.

 

4. As mentioned below, the study area chose regions with landslides. The introduction lacks research on this aspect.

Based on the comment, we added the sentence, "Because bare soil surfaces in the landslide areas has little capacity to moderate surface water infiltration, rainfall directly removes soil nutrients, and surface runoff often transports particulate nutrients from soils to water courses" in L44–47 to make clearer a topic about landslide effects on nutrient transport, which had described in the first paragraph of the Introduction section.

 

5. It is suggested to add the basic physical properties of the soil in the two study areas (mechanical composition, organic matter).

In accordance with the comment, we added information of soil physical properties (bulk density, soil particle density, void ratio), based on literature, in L123–129 of in the Materials and methods section. We also added information of the surface layers on the landslide scars (i.e., the weathered layer), as landslide scoured the shallow soils (i.e., humus), in L145–146. Because of these additions, we removed the statement, "The soils are predominantly composed of various pyroclastic deposits, such as tephra and andosol, and" in L100–101 of the previous manuscript.

 

6. Lines 255-256, the concentrations of PP in the F watershed and DP in the L watershed are not proportional to the runoff. It is suggested to add the relevant correlation coefficients in the figures.

Based on the comment, we added alphabetical characters in Figure 6 to have readers more easily distinguish subfigures of it. Because of this addition, we also added the alphabetical characters of Figure 6 in the main text (L286–288, L351, L414). The third paragraph of the section 3.3 explains regression analyses of the relationships between element loads and runoff, which showed that PP load was not significantly proportional to runoff in the F catchment (Figure 6c; test for regression slope, p = 0.054). Thus, we did not delineate the regression line in Figure 6c. On the other hand, DP load was significantly proportional to runoff in the L catchment (Figure 6f). We also replaced Figure 6 with the high resolution one to have readers more easily recognize the regression lines in it.

 

7. Lines 270-278, why only the relationship between PP and SS? What about the other indicators?

Based on the comment, we added the sentence, "SS has been recognized as a carrier of nutrients in forest streams and particularly tends to adsorb and bond with P" in L352–353. Because of this addition, we cited some literature and added the expression, "In the present study" in L353–354.

 

8. It is suggested to add from the perspective of the study object (temperate forests), such as relevant research on dominant tree species, in the discussion section.

Based on the comment, we added the sentence, "Leaf litter is not only an important source of soil nutrients but also a primary source of dissolved organic matter in forested headwater streams [60–64] and some studies have shown that DOC load was greater in deciduous broad-leaved forests than in other forests, such as coniferous and mixed forests" and related literature in L395–400.

 

9. Lines 290, it is suggested to add the role of litter in nutrient accumulation.

Based on the comment, as described earlier, we added the statement, "Leaf litter is not only an important source of soil nutrients but also a primary source of dissolved organic matter in forested headwater streams" and related literature in L395–397.

 

10. Lines 316-318, the insufficient canopy interception is also significantly correlated with the canopy height.

Based on the comment, we replaced the expression, "forest canopy" with "forest vegetation" in L345 and changed the statement, "canopy interception" to "canopy and litter interception" in L346.

 

11. Lines 325-328, it is recommended to add relevant data (soil mechanical composition). Why are the sediment particles transported in the L watershed finer?

Based on the comment, we added the sentence, "Soil disturbances, such as landslide, break the structure of soil aggregates and thus the fine fraction would become enrich in the sediment particles transported from the landslide area during rain events" and related literature in L361–364.

 

12. Lines 339-341, it is suggested to add relevant references.

Based on the comment, we added related literature in L376 and removed the expression, "/or" from L340 of the previous manuscript to avoid readers' confusion.

 

13. It is recommended to add relevant legends to all figures to simplify the annotation content.

Based on the comment, we added the legends that show differences in runoff and concentration data between the two catchment and simplified the annotation content in Figures 4 and 7.

 

14. Standardize the font size of each part in the figures.

Based on the comment, we adjusted the font size of each part in the figures by changing the scale of each figure.

 

15. It is suggested to optimize the language structure and grammar throughout the article.

Based on the comment, we corrected redundant expressions, English grammar and words throughout the manuscript (L142, 143, 151, 157, 160–162, 250, 318). The manuscript also has been proofed by a native English-speaking editor from Editage, an English editing company recommended by several international academic publishers (receipt number: ZNYHH_7).

 

Reviewer 4 Report

Comments and Suggestions for Authors

Manuscript ID Forests-2791686 “Effects of vegetation on phosphorus runoff from a small forest catchment in a cold temperate landslide region, northern Japan” submitted to Forest as a Brief Report. However, it far exceeds the number of words and numbers recommended by MDPI, as it has a total of more than 6500 words and from the summary to conclusions has more than 4500 words, in addition to 7 figures.

 The manuscript addresses relevant topics in the face of extreme events in the scenario of worsening climate change.

 

 The section “small forest catchment” should be eliminated from the title of the manuscript, as the repercussion of the study is not just local.

 

 When organizing the text, citations and references must be adjusted to Forests norms. The attached text contains suggested corrections.

 

 Figures 1 need to be improved as pointed out in attached text.

 

 The study, in the form of a Brief Report, covers a small area in northern Japan, with support based mainly on Japanese scientific literature.

 

 However, considering that the manuscript does not correspond strictly to a Brief Report and that characteristics of the area are not exclusive to that region, I suggest that the manuscript can be modified into an article, expanding the scope of the research, which can provide greater consistency to the study, especially if the data obtained is compared with those from other similar areas. around the world.

 

Comments for author File: Comments.pdf

Author Response

We greatly appreciate the reviewer’s positive comments and suggestions, which have been helpful for our revision. Detailed responses are provided below.

 

• The section “small forest catchment” should be eliminated from the title of the manuscript, as the repercussion of the study is not just local.

Based on the comment, we changed the expression, "a small forest catchment" to "headwater catchments" in the title of the manuscript.

 

• When organizing the text, citations and references must be adjusted to Forests norms. The attached text contains suggested corrections.

Based on the attached text, we corrected the text, citations and references.

 

• Figures 1 need to be improved as pointed out in attached text.

In accordance with the comment, we replaced Figure 1 with the high-resolution one.

 

• The study, in the form of a Brief Report, covers a small area in northern Japan, with support based mainly on Japanese scientific literature. However, considering that the manuscript does not correspond strictly to a Brief Report and that characteristics of the area are not exclusive to that region, I suggest that the manuscript can be modified into an article, expanding the scope of the research, which can provide greater consistency to the study, especially if the data obtained is compared with those from other similar areas. around the world.

Thank you so much for your positive suggestion. However, this study examined just an intensive rain event and is at a preliminary stage as the reviewer#2 indicated. Further research is thus needed to more accurately understand P transport processes from cool-temperate forest catchments by targeting multiple rain events with different rainfall intensities, as described in the last part of the manuscript. Therefore, we think it is better to publish our work as a brief report.

 

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

English language fine. No issues detected.

Reviewer 4 Report

Comments and Suggestions for Authors

The authors adequately addressed this reviewer's suggestions.