The Differences in Water Repellency in Root Mat (Biomat) and Soil Horizons of Thinned and Non-thinned Chamaecyparis obtusa (Siebold et Zucc.) Endl. Plantations
Round 1
Reviewer 1 Report
Manuscript forsest-2149001 aims to recognize the differences in water repellency of biomat/soil layers in the thinned and not-thinned Chamaecyparis obtusa plantations. The results of water repellency in different Japanese cypress forest may contribute to interpreting the generation of surface runoff.
However, some weaknesses exist in the manuscript.
1. The purpose of this article is not clear. This may be enhanced by adding conclusion part and reorganizing the introduction, or changing the title to match the purpose of the article.
2. As I know, the relationship between surface tension of each ethanol solution used in MED test and the volumetric percentage is not linear. Please use proper methodology for statistical analysis. For instance, using median, not the "mean and std" of volumetric percentage of ethanol.
3. The analysis methodology in 3.3 section is not clear. What time of the water contents and surface temperatures used in Figure 6? Do these points represent monthly mean of them? For this case, it should have used same point of time of three experiments (water content, surface temperature and water repellency).
4. The reason of low water repellency in snowy season was not presented or explained whether it could or not to be used in statistical analysis.
5. The experimental design section is not convincing for driving the research. For what were the authors analyzing water repellency in ARF, as the title is "The differences in water repellency in biomat and soil layers of thinned and not-thinned Chamaecyparis obtusa plantations"? Why did not discuss further about ARF results?
6. The last but not the least, the generation of surface runoff is a complex process, the unclearness of linkage between the purpose and runoff results of this article may complicates the readers.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The review of manuscript "The differences in water repellency in biomat and soil layers of thinned and not-thinned Chamaecyparis obtusa plantations" by Moein Farahnak, Takanori Sato, Yuya Otani, Koichiro Kuraji and Toko Suzaki.
The authors studied the impact of thinning, soil water content and temperature on the severity of water repellency (WR) in the upper litter layer (biomat) and topsoil layer of thinned and not-thinned Chamaecyparis obtusa plantations. The paper adds new information to the subject and could be published in Forests after some modifications. My recommendation is MAJOR REVISIONS.
The following are suggestions for revising the manuscript:
Line 19: „with” should be changed to „and both”.
Lines 22 and 215–216: „decomposition of biomat (layer) after thinning”. Could the authors provide evidence of this phenomenon? On the other hand, Leelamanie et al. (2021) presented (on p. 448) that „During the rainy season, organic matter decomposition takes place at an accelerated rate and the thickness of the litter layer decreases.”
Line 26: In the 1st paragraph of the introduction, the authors should define the soil horizons (organic O and topsoil A horizons) in which they will measure water repellency. They should mention that „litter layer” and „biomat” are synonyms and in the following text only one of the names will be used.
Lines 58–61: Finding relationships between WR and surface runoff in the thinned and not-thinned C. obtusa plantations could be mentioned as another objective.
Line 65: „OEF” should be deleted.
Lines 69–73: Climate class of the region according to the Köppen-Geiger climate classification (e.g., Kottek et al., 2006) should be added.
Line 80 and Table 1: Clay/Silt/Sand, Organic carbon (OC), CaCO3 contents, texture class and pH of the studied soil should be added.
Line 92: „50×50 cm” should be changed to „50 cm×50 cm”.
Line 92: „5×5 m” should be changed to „5 m×5 m”.
Line 93: „30×30 cm” should be changed to „30 cm×30 cm”.
Line 94: „6×6 m” should be changed to „6 m×6 m”.
Lines 109–110 and 123–124: „soil moisture sensor (ECH2OEC-5; METER Group) was positioned in a 5 cm depth” and the „WR severity was tested by dropping these solutions on the surface of biomat or soil“. Is it correct to determine dependencies between WR and SWC measured at different locations?
Lines 115–131 and Figs. 4, 5: Authors should cite where they took the water repellency classification from.
In the classification proposed by Doerr (1998), the Ethanol % (thresholds) for slight, moderate, strong, very strong and extreme WR are 3, 5, 8.5, 13, 24 and 36%, respectively.
Lines 176–184 and Fig. 6: Instead of weak relationships between WR and both water content and surface temperature, the authors could present relationships between WR and surface runoff in the thinned and not-thinned C. obtusa plantations at Obora Experimental Forest.
References:
Doerr, S.H., 1998. On standardizing the "Water Drop Penetration Time" and the "Molarity of an Ethanol Droplet" techniques to classify soil hydrophobicity: a case study using medium textured soils. Earth Surface Processes and Landforms, 23, 663–668.
Kottek, M., Grieser, J., Beck, C., Rudolf, B., Rubel, F., 2006. World map of the Köppen-Geiger climate classification updated. Meteorologische Zeitschrift, 15, 259–263.
Leelamanie, D.A.L., Piyaruwan, H.I.G.S., Jayasinghe, P.K.S.C., Senevirathne, P.A.N.R., 2021. Hydrophysical characteristics in water-repellent tropical Eucalyptus, Pine, and Casuarina plantation forest soils. Journal of Hydrology and Hydromechanics, 69, 4, 447–455.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
General comments:
Thanks for your kind replies.
Question: Why was evapotranspiration mentioned while it was never discussed in manuscript?
Specific comments:
Line 81: Check the name of sites in Figure 1b, e.g. “ORF” -> “OEF”.
Line 234: Check the precipitations of two sites whether they were correct.
Line 235: Please add the reference.
Line 239: Were you supposed to delete "These findings support a higher WR of biomat than soil layers"? Please check again.
Line 250: "conclusion" -> "Conclusion"
Line 255: "thinned"? I guess it should be "not-thinned"
Author Response
Response to Reviewer 1 Comments
Point 1: Why was evapotranspiration mentioned while it was never discussed in manuscript?
Response 1: Thank you very much for your question about ET. We added more explanations in the results and discussion sections about ET (Lines 209-211, 280-281, and 287-289)
Point 2: Line 81: Check the name of sites in Figure 1b, e.g. “ORF” -> “OEF”.
Response 2: Thank you very much for your keen attention to detail. We are sorry for our mistake. We changed “ORF” to “OEF” in Fig 1b.
Point 3: Line 234: Check the precipitations of two sites whether they were correct.
Response 3: Thank you for your attention to precipitation in the OEF site. We double-checked and corrected it. The total precipitation in OEF was 2090.9 mm, of which 1441 mm and 649.9 mm were precipitated in 2021 and 2022, respectively (Lines 275-276).
Point 4: Line 235: Please add the reference.
Response 4: Thank you very much for your suggestion. We added a relevant reference to that sentence (Lines 277 and 457-458).
Point 5: Line 239: Were you supposed to delete "These findings support a higher WR of biomat than soil layers"? Please check again.
Response 5: Thank you very much for your comment. We double-checked it. We believe this sentence is necessary for the discussion.
Point 6: Line 250: "conclusion" -> "Conclusion"
Response 6: We are sorry for our mistake. We changed "conclusion" -> "Conclusion" (Line 294).
Point 7: Line 255: "thinned"? I guess it should be "not-thinned"
Response 7: We are sorry for our mistake. We changed “thinned” to “not-thinned” (Line 302).
Reviewer 2 Report
The authors revised the manuscript taking into account almost all my suggestions. My recommendation is ACCEPT.
The following is a suggestion for revising the manuscript:L. 352: Citation 32 is incomplete. "Meteorologische Zeitschrift, 15, 259–263." is missing.
Author Response
Response to Reviewer 2 Comments
Point 1: The authors revised the manuscript taking into account almost all my suggestions. My recommendation is ACCEPT.
The following is a suggestion for revising the manuscript:L. 352: Citation 32 is incomplete. "Meteorologische Zeitschrift, 15, 259–263." is missing.
Response 1: We would like to express our deep gratitude for accepting our MS. We are sorry for the mistake in the reference. "Meteorologische Zeitschrift, 15, 259–263." was added (Lines 434-435).
