Differential Hydrological Properties of Forest Litter Layers in Artificial Afforestation of Eroded Areas of Latosol in China
Round 1
Reviewer 1 Report
Notes are included in the attached file.
Comments for author File: 
Comments.pdf
Author Response
Dear Reviewer:
Thank you for your letter and for the reviewers' comments concerning our manuscript entitled “Vegetation restoration improves hydrological properties by forest litter layers in eroded area of Latosol,China.”(ID: sustainability-1992223). All comments are valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portion are using the "Track Changes" function in Microsoft Word. We explain point-by-point the details of the revisions in the manuscript and our responses to reviewers' comments. The main corrections in the paper and the responds to the reviewer’s comments are as flowing:
Point 1: Line 168 Bad reference to figure - figure 9 is missing.
Response 1: In Line 168 Figure 9 should be Figure 2b. We have revised in line 168: ”The mass of the SDL layer was higher than the mass of the UDL layer in all stand types (p < 0.05) (Figure 2b)”.
Figure 2. Variations in litter thickness and mass in semi-decomposed litter (SDL) layer and un-decomposed litter (UDL) layer of E. robusta, H. brasiliensis, and A. mangium. (a) Litter thickness; (b) Litter mass. For each category, different capital letters indicate a significant difference in the mean value among in three forest plantations.
Point 2: Line 227 Bad reference to figure - figure 9 is missing.
Response 2: In Line 227 Figure 9 should be Figure 4. We have revised in line 227: “After 15 min of water immersion, the water-holding ratio of SDL layer and UDL layer reached 160.69 ± 23.99% and 107.83 ± 10.56% of their holding capacity in E. robusta, respectively, while it was 175.31 ± 26.67% and 155.16 ± 20.20% in H. brasiliensis, respectively, and it was 125.23 ± 28.38% and 108.53 ± 6.39% in A. mangium, respectively (Figure 4).”
Point 3: Line 288 - 289 “… Li et al. and Chen et al. reported [3,7].” Should be ”…Li et al. [3] and Chen et al. [7] reported”
Response 3: We have revised in line 288 – 289: “These results consistent with studies by Li et al. [3]and Chen et al. reported [7].”
Point 4: Line 331 - 332 “… Li et al. and Chen et al. reported [3,7].” Should be ”…Li et al. [3] and Chen et al. [7] reported”
Response 4: We have revised in line 331 - 332: “In this study, our results showed that a rapid rise in the litter water-holding ratio among in three plantation forests and at the at the first two hours onset of the water-immersion experiment in the laboratory, which consistent with studies by Li et al. [3] and Chen et al. [7],”
Point 5: No reference in the text on Figure 4.
Response 5: We have revised in section: “3.3. Variations in Water-holding capacity of litter” as to “After 15 min of water immersion, the water-holding ratio of SDL layer and UDL layer reached 160.69 ± 23.99% and 107.83 ± 10.56% of their holding capacity in E. robusta, respectively, while it was 175.31 ± 26.67% and 155.16 ± 20.20% in H. brasiliensis, respectively, and it was 125.23 ± 28.38% and 108.53 ± 6.39% in A. mangium, respectively (Figure 4).”
Special thanks to you for your good comments.
We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper.
We appreciate for Reviewers’ warm work earnestly, and hope that the correction will meet with approval.
Once again, thank you very much for your comments and suggestions.
Author Response File: Author Response.pdf
Reviewer 2 Report
The manuscript "Vegetation restoration improves hydrological properties by forest litter layers in eroded area of ​​Latosol, China", is a well planned and executed work that studies the hydrological properties of forest litter after 20 years of monospecific reforestation, with three different species, and in an area of eroded latosol soils in China. Although the work in general does not go beyond the local scope, this is not the main limitation that I see. In fact, I think there are three lines that should be improved. First of all, the title. Vegetation restoration certainly improves the hydrological properties of eroded areas, but the text of the article does not focus on demonstrating this, as there is no unrestored control area (eroded versus afforestation). In addition, as afforestation is carried out with apparently non-native species, the term restoration is not the most appropriate and we should talk about the effect of the planted species on the hydrological properties of the forest litter (non-decomposed and semi-decomposed layers). An attempted title (where the main species do not appear) could be.
Differential hydrological properties of forest litter layers in artificial afforestation of eroded areas of Latosol in China.
The second weakness concerns the text in general and the introduction and discussion sections in particular. It is not easy at all to follow the text in English, so I would ask the authors to thoroughly review the language in order to facilitate a more fluid and understandable reading.
A first example can be the last paragraph of the introductory section, in which the authors state two objectives. The first related to their experiment itself, and the second related to the comparison of their data with those obtained by other researchers from other forest ecosystems. After objectives the text goes on:
The information can be used to provide reference for the optimization of stand structure, reconstruction the vegetation restoration arrangement, and guiding ecological engineering construction in eroded area of Latosol.
Honestly, I think that the authors know what they mean by these sentences, but for the reader they are very general sentences that are not justified based on the results obtained and, therefore, cannot be considered as an extension of the objectives.
The results are well exposed and the differences for the three species are significant, taking into account the similarity in age and density of the repopulations (Table 1). However, there is one data that I do not understand very well; which is canopy density (Table 1) (maybe tree canopy coverage in a fraction of 1?) and another that I am missing, which is the density of the plantation and the survival rate at 20 years. Similarities and differences are shown in the discussion with coniferous, broadleaf, deciduous and permanent leaf species, but there is a statement in the conclusions that cannot be related to the results, although it seems logical from the hydrological point of view.
"Additionally, from the management perspective, a thick and dense litter layer may favor the delay and decrease in the formation of surface runoff, minimizing the splash erosion, and may be considered favorable to rainfall infiltration and potential streamflow enhancement. Strategic removal of some unhealthy E. robusta and H. brasiliensis trees and plant A. mangium, which is transform artificial pure forest into mixed forest and likely to improve the hydrological effects in mixed forest"
I will comment about it. It will be necessary new experiences (or references about experiences relatives to mixed forest with the species studied) in which the incorporation of new individuals of different species in patches more or less extensive, could be “forestry efficient” in the sense of the growing of the new forest (producing similar rates in relation with litter accumulation and decomposition). Today, there is growing evidence of the convenience of replanted mixed forests as more efficient systems in terms of a more complete provision of ecosystem services but this asseverations should be tested with other data over than the accumulation and hydrological properties of forest litter in monospecific afforestation.
All this in reference to the commented phrase. The first paragraph ("Additionally, from the management perspective, a thick and dense litter layer may favor the delay and decrease in the formation of surface runoff, minimizing the splash erosion, and may be considered favorable to rainfall infiltration and potential streamflow enhancement) is realistic in the paper context. The second one (Strategic removal of some unhealthy E. robusta and H. brasiliensis trees and plant A. mangium, which is transform artificial pure forest into mixed forest and likely to improve the hydrological effects in mixed forest") is speculative and should be probed.
Author Response
Dear Reviewer:
Thank you for your letter and for the reviewers' comments concerning our manuscript entitled “Vegetation restoration improves hydrological properties by forest litter layers in eroded area of Latosol,China.”(ID: sustainability-1992223). All comments are valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portion are using the "Track Changes" function in Microsoft Word. We explain point-by-point the details of the revisions in the manuscript and our responses to reviewers' comments. The main corrections in the paper and the responds to the reviewer’s comments are as flowing:
Point 1: The manuscript "Vegetation restoration improves hydrological properties by forest litter layers in eroded area of ​​Latosol, China", is a well planned and executed work that studies the hydrological properties of forest litter after 20 years of monospecific reforestation, with three different species, and in an area of eroded latosol soils in China. Although the work in general does not go beyond the local scope, this is not the main limitation that I see. In fact, I think there are three lines that should be improved. First of all, the title. Vegetation restoration certainly improves the hydrological properties of eroded areas, but the text of the article does not focus on demonstrating this, as there is no unrestored control area (eroded versus afforestation). In addition, as afforestation is carried out with apparently non-native species, the term restoration is not the most appropriate and we should talk about the effect of the planted species on the hydrological properties of the forest litter (non-decomposed and semi-decomposed layers). An attempted title (where the main species do not appear) could be: Differential hydrological properties of forest litter layers in artificial afforestation of eroded areas of Latosol in China.
Response 1: Thank you very much for your constructive comments.The title have been changed to: ” Differential hydrological properties of forest litter layers in artificial afforestation of eroded areas of Latosol in China”.
Point 2: The second weakness concerns the text in general and the introduction and discussion sections in particular. It is not easy at all to follow the text in English, so I would ask the authors to thoroughly review the language in order to facilitate a more fluid and understandable reading.
A first example can be the last paragraph of the introductory section, in which the authors state two objectives. The first related to their experiment itself, and the second related to the comparison of their data with those obtained by other researchers from other forest ecosystems. After objectives the text goes on:
The information can be used to provide reference for the optimization of stand structure, reconstruction the vegetation restoration arrangement, and guiding ecological engineering construction in eroded area of Latosol.
Honestly, I think that the authors know what they mean by these sentences, but for the reader they are very general sentences that are not justified based on the results obtained and, therefore, cannot be considered as an extension of the objectives.
Response 2: We appreciate your constructive suggestions. Our manuscript have to extensive editing of English language and style.
Point 3: The results are well exposed and the differences for the three species are significant, taking into account the similarity in age and density of the repopulations (Table 1). However, there is one data that I do not understand very well; which is canopy density (Table 1) (maybe tree canopy coverage in a fraction of 1?) and another that I am missing, which is the density of the plantation and the survival rate at 20 years. Similarities and differences are shown in the discussion with coniferous, broadleaf, deciduous and permanent leaf species, but there is a statement in the conclusions that cannot be related to the results, although it seems logical from the hydrological point of view.
Response 3: Thank you very much. (1) “canopy density in Table 1” was the “tree canopy coverage in a fraction of 1”, and we have revised in Table 1.
(2) The tree density of Eucalyptus robusta and Acacia mangium was approximately 625 trees per ha, with the trees spaced in grids of 4 m × 4 m. And the tree density of Hevea brasiliensis was approximately 500 trees per ha, with the trees spaced in grids of 5 m × 4 m.
(3) Due to the implement of the State Key Forestry Ecological Projects by Hainan Provincial Government, Eucalyptus robusta, Hevea brasiliensis, and Acacia mangium after planted, the plantation were well cared by the staff of Mahuangling Soil and Water Conservation Monitoring Station. If they found the death of trees, and they replanting trees at the right moment. The survival rate was above 90%.
(4) In the conclusions, we suggest the preservation and restoration of mixed forests by removing some unhealthy E. robusta and H. brasiliensis trees and planting A. mangium should be strengthened to improve water conservation capacity, which mainly because of Hainan Forestry Bureau want to transform artificial pure forests to mixed forests in this area, especially the E. robusta forest.
Point 4: "Additionally, from the management perspective, a thick and dense litter layer may favor the delay and decrease in the formation of surface runoff, minimizing the splash erosion, and may be considered favorable to rainfall infiltration and potential streamflow enhancement. Strategic removal of some unhealthy E. robusta and H. brasiliensis trees and plant A. mangium, which is transform artificial pure forest into mixed forest and likely to improve the hydrological effects in mixed forest"
I will comment about it. It will be necessary new experiences (or references about experiences relatives to mixed forest with the species studied) in which the incorporation of new individuals of different species in patches more or less extensive, could be “forestry efficient” in the sense of the growing of the new forest (producing similar rates in relation with litter accumulation and decomposition). Today, there is growing evidence of the convenience of replanted mixed forests as more efficient systems in terms of a more complete provision of ecosystem services but this asseverations should be tested with other data over than the accumulation and hydrological properties of forest litter in monospecific afforestation.
Response 4: Thank you very much. The Hainan Forestry Bureau want to transform artificial pure forests to mixed forests in this area, especially the E. robusta forest. And we suggest planting A. mangium after strip-thinning E. robusta trees and then transform pure forests to mixed forests.
Point 5: All this in reference to the commented phrase. The first paragraph ("Additionally, from the management perspective, a thick and dense litter layer may favor the delay and decrease in the formation of surface runoff, minimizing the splash erosion, and may be considered favorable to rainfall infiltration and potential streamflow enhancement) is realistic in the paper context. The second one (Strategic removal of some unhealthy E. robusta and H. brasiliensis trees and plant A. mangium, which is transform artificial pure forest into mixed forest and likely to improve the hydrological effects in mixed forest") is speculative and should be probed.
Response 5: Thank you very much. The transform artificial pure forest into mixed forest and likely to improve the hydrological effects in mixed forest should be further studies
Special thanks to you for your good comments.
We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper.
We appreciate for Reviewers’ warm work earnestly, and hope that the correction will meet with approval.
Once again, thank you very much for your comments and suggestions.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
I think the authors have worked well along the lines suggested in the review, without addressing major changes beyond the title and some discussion paragraphs. The text becomes much more readable, although the objectives paragraph (lines 69-73) shows a typo in the text and has to be rewritten again. I reproduce the text that must be corrected.
In this study, three typical forest plantations in an eroded area of Latosol in Mahuangling Watershed were selected, including Eucalyptus robusta, Hevea brasiliensis, and Acacia mangium forests, and we quantified the litter thickness, mass, and hydrological [email protected] ecological engineering construction in the eroded area of Latosol.
