Responses of Fine Root Morphological and Chemical Traits among Branch Orders to Forest Thinning in Pinus massoniana Plantations
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsData on the effects of thinning on the morphological and chemical characteristics of Pinus massoniana fine roots are presented in this paper. Please allow me to ask a few questions and offer some comments on the article; the responses will enhance the quality of the paper.
How long after thinning these studies were conducted is unknown. How long after thinning (in months or years) did you conduct the study?
Different terms are used by the authors to denote root fractions. Fine roots. Absorptive roots. Transport roots. Note that fine roots are not the same as absorptive roots. On the other hand, absorptive roots are not the same as fine roots. Diameter determines the fine roots (all roots in this research that are thinner than 2 mm). Physiological characteristics are the basis for classifying roots as either transport or absorptive. To distinguish between absorptive and transport roots, what criteria or features did you use?
Table 1. Because of what the increase in understory coverage occurs? Because of increased grassy or shrub layer cover?
The roots must be dug up (extracted) from the trunk itself, beginning with the main skeletal roots, in order to accurately establish the branching order of the roots. The authors used the monolith method. Approximately 1 m from the stem, monoliths were obtained. The limitation of this method is that the soil monolith contains only a portion of the root system. Therefore, the precise branching order of the roots cannot be established. The roots in the monolith will have a different root order than the roots if they are fully dug beginning at the trunk. Because of the varying sizes of the root system parts that can be found in the monolith. In addition, the order of branching roots increases with distance from the stem. Therefore, the trustworthiness of the data produced is highly dependent on how well the branching order of the roots is determined. In what way did you ascertain the proper root branching order? Specifically, the order of root branching what determined by the morphological properties of the entire root system, rather than by various fragments of the root system that may enter the monolith.
“…fine roots samples of less than 2 cm in diameter were used to determine morphology and chemistry.” (Lines 133-134). Maybe “less than 2 mm”?
“SOC and soil TN were determined using an elemental analyser (Vario Elemental III, Fischer, Germany).” (Lines 168-169). Organic soil carbon cannot be determined using this device. The dry combustion method (high temperature decomposition) estimates the total carbon content of the soil, which includes both inorganic and organic carbon. The organic soil carbon content is measured using the wet oxidation method. You must re-determine the organic soil carbon content using the correct technique.
Author Response
Data on the effects of thinning on the morphological and chemical characteristics of Pinus massoniana fine roots are presented in this paper. Please allow me to ask a few questions and offer some comments on the article; the responses will enhance the quality of the paper.
How long after thinning these studies were conducted is unknown. How long after thinning (in months or years) did you conduct the study?
Answer：Thank you very much for this question. We conducted this study in 2020, 14 years after thinning. However, we did not mention when thinning operations were implemented, which has caused confusion for you. Now we have revised it in Line 112-113.
Different terms are used by the authors to denote root fractions. Fine roots. Absorptive roots. Transport roots. Note that fine roots are not the same as absorptive roots. On the other hand, absorptive roots are not the same as fine roots. Diameter determines the fine roots (all roots in this research that are thinner than 2 mm). Physiological characteristics are the basis for classifying roots as either transport or absorptive. To distinguish between absorptive and transport roots, what criteria or features did you use?
Answer: Thank you for your question. We used the methods of Pregitzer et al. (2002) to divide the collected fine roots into 1st to 5th order roots. Brief, Distal roots in root system were the 1st order roots. The roots attached to the 1st order roots were the 2nd order roots, and so on to the 5th order roots. And roots adhered to higher order roots without branches were also divided into 1st order roots. Additionally, low-order (i.e. 1st -2nd order) roots with living cortices are mainly responsible for resource acquisition (Wang et al., 2021), and high-order (i.e. 3rd -5th order) roots that have undergone secondary growth develop secondary vascular cambium and cork cambium, which contribute to resource transportation and storage (Endo et al., 2021; Kong et al., 2017; Yu et al., 2022). Thus, we used absorptive roots and transport roots to represent low-order roots and high-order roots.
Table 1. Because of what the increase in understory coverage occurs? Because of increased grassy or shrub layer cover?
Answer: Thank you for the question. Yes. Our previous study found that the understory coverage increased with thinning intensity, including an increase in regenerated saplings, shrubs and herbs.
The roots must be dug up (extracted) from the trunk itself, beginning with the main skeletal roots, in order to accurately establish the branching order of the roots. The authors used the monolith method. Approximately 1 m from the stem, monoliths were obtained. The limitation of this method is that the soil monolith contains only a portion of the root system. Therefore, the precise branching order of the roots cannot be established. The roots in the monolith will have a different root order than the roots if they are fully dug beginning at the trunk. Because of the varying sizes of the root system parts that can be found in the monolith. In addition, the order of branching roots increases with distance from the stem. Therefore, the trustworthiness of the data produced is highly dependent on how well the branching order of the roots is determined. In what way did you ascertain the proper root branching order? Specifically, the order of root branching what determined by the morphological properties of the entire root system, rather than by various fragments of the root system that may enter the monolith.
Answer: Thank you for your question. We dug soil profiles to obtain soil blocks, and thus collected soil samples. Subsequently, an intact fine root system of Pinus massoniana was harvested by discovering the roots in soil blocks, similar to some studies (Wada et al, 2019), which can ascertain the proper root branching order. We apologize for blurring this process in the manuscript and have now revised it.
“…fine roots samples of less than 2 cm in diameter were used to determine morphology and chemistry.” (Lines 133-134). Maybe “less than 2 mm”?
Answer: Thank you for your reminder. We are so sorry for this error, and now the sentence have been revised.
“SOC and soil TN were determined using an elemental analyser (Vario Elemental III, Fischer, Germany).” (Lines 168-169). Organic soil carbon cannot be determined using this device. The dry combustion method (high temperature decomposition) estimates the total carbon content of the soil, which includes both inorganic and organic carbon. The organic soil carbon content is measured using the wet oxidation method. You must re-determine the organic soil carbon content using the correct technique.
Answer: Thank you for your question and reminder. We determined the SOC concentration using an elemental analyser after removing carbonate by phosphoric acid. After adding acid, almost no bubbles were observed, so we used the total carbon concentration as organic carbon concentration (Sun et al., 2021; Wang et al., 2012). Now we added the relevant description in Line 167.
References:
Endo, I.; Kobatake, M.; Tanikawa, N.; Nakaji, T.; Ohashi, M.; Makita, N. Anatomical Patterns of Condensed Tannin in Fine Roots of Tree Species from a Coolerate Forest. Ann Bot 2021, 128, 59–71, doi:10.1093/aob/mcab022.
Kong, D.; Wang, J.; Zeng, H.; Liu, M.; Miao, Y.; Wu, H.; Kardol, P. The nutrient absorption–transportation hypothesis: optimizing structural traits in absorptive roots. New Phytol 2017, 213, 1569–1572, doi: 10.1111/nph.14344.
Pregitzer, K.S.; DeForest, J.L.; Burton, A.J.; Allen, M.F.; Ruess, R.W.; Hendrick, R.L. Fine Root Architecture of Nine North American Trees. Ecol Monogr 2002, 72, 293–309, doi:10.1890/0012-9615(2002)072[0293:FRAONN]2.0.CO;2.
Sun X D, Wang G, Ma Q X, Liao J H, Wang D, Guan Q W, Davey L. J. Organic mulching promotes soil organic carbon accumulation to deep soil layer in an urban plantation forest. Forest Ecosystems, 2021, 8:2. DOI: 10.1186/s40663-020-00278-5
Yu, W.; Wang, C.; Huang, Z.; Wang, D.; Liu, G. Variations in the Traits of Fine Roots of Different Orders and Their Associations with Leaf Traits in 12 Co-Occuring Plant Species in a Semiarid Inland Dune. Plant Soil 2022, 472, 193–206, doi:10.1007/s11104-021-05208-0
Wang, S.; Wang, W.; Wang, S.; Yang, L.; Gu, J. Intraspecific Variations of Anatomical, Morphological and Chemical Traits in Leaves and Absorptive Roots along Climate and Soil Gradients: A Case Study with Ginkgo Biloba and Eucommia Ulmoides. Plant Soil 2021, 469, 73–88, doi:10.1007/s11104-021-05149-8.
Wang, X., Wang, J., Zhang, J., 2012. Comparisons of three methods for organic and inorganic carbon in calcareous soils of northwestern China. PLoS One 7.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe topic addressed is also interesting for the application aspects it may have. However, there is no mention of the latter. The results are well presented even if there is difficulty in following them in the discussion. There is too much speculation in the exposition of the conclusions which need to be revised.
Points to clarify/review:
- Abstract: line 25 MBC?
- Keywords: insert keywords that are not in the title
-Experimental design: when was the thinning done? A year earlier or more ?
Author Response
The topic addressed is also interesting for the application aspects it may have. However, there is no mention of the latter. The results are well presented even if there is difficulty in following them in the discussion. There is too much speculation in the exposition of the conclusions which need to be revised.
Answer: Thank you for your suggestion. We have revised discussion and conclusion regarding to it logic and grammar.
Points to clarify/review:
- Abstract: line 25 MBC?
Answer: Thank you for your question and reminder. MBC is the abbreviation for microbial biomass carbon, and we revised it in abstract part.
- Keywords: insert keywords that are not in the title
Answer: Thank you for your suggestion. The keywords have been changed to “forest thinning; fine root; morphological traits; root chemistry; absorptive root; soil nutrient”.
-Experimental design: when was the thinning done? A year earlier or more ?
Answer：Thank you very much for this question. The thinning practice was conducted in 2006, 20 years after planting. We added relevant description in Line 112-113.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe work focus on fine root morphological and chemical traits among branch orders to forest thinning in Pinus massoniana plantations and is suitability for Forests. The research take up the subject at the new outlook. The methods are appropriate, but their presentation and presence of the objectives should be corrected. The profile of soil and results of the soil properties are not the research problem and should be presented in methods. Eventually, the objectives should be changed. The chemical analysis methods should be thoroughly described.
When was the thinning? How many times?
Some problems, but not all:
Line 100: hm2.?
Line 101-102, 107-108: Precise, the references are insufficiently.
Line 107: 100 m. What do you mind?
Line 135: How long?
Lines 158-172: Results?
Figure 3 is unreadable.
The results needed minor changes. The discussion is very chaotic and should be rethinking and rewritten.
Lack of strictly conclusions.
Comments on the Quality of English LanguageIt's fine.
Author Response
The work focus on fine root morphological and chemical traits among branch orders to forest thinning in Pinus massoniana plantations and is suitability for Forests. The research take up the subject at the new outlook. The methods are appropriate, but their presentation and presence of the objectives should be corrected. The profile of soil and results of the soil properties are not the research problem and should be presented in methods. Eventually, the objectives should be changed. The chemical analysis methods should be thoroughly described.
Answer：Thank you for your suggestion. We have restructured the methods and results by incorporating the results of soil properties into the methods, making the results more prominent on our topic. And we supplemented the description of chemical analysis methods.
When was the thinning? How many times?
Answer：Thank you very much for this question. The thinning practice was conducted only once in 2006, 20 years after planting. We added relevant description in Line 112-113.
Some problems, but not all:
Line 100: hm2.?
Answer: Thank you for your question. Yes. The forest area in National Forest Park is 1,879.73 hm2.
Line 101-102, 107-108: Precise, the references are insufficiently.
Answer: Thank you for your suggestion. We added some references here.
Line 107: 100 m. What do you mind?
Answer: Thank you for your question. What is being said here is that the average elevation of the research site is about 100 m.
Line 135: How long?
Answer: Thank you for your question. We completed the scanning and determination of fine root morphology within two weeks.
Lines 158-172: Results?
Answer: Thank you for your question. We have removed the results of this section.
Figure 3 is unreadable.
Answer: Thank you for your suggestion and reminder. Now we have modified it to increase readable.
The results needed minor changes. The discussion is very chaotic and should be rethinking and rewritten.
Answer: Thank you for your suggestion. We have revised the results and reorganized the discussion to make it more logical and readable.
Lack of strictly conclusions.
Answer: Thank you for your suggestion. We revised conclusions to make it more specific and clear.
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsAll the issues I cared about were addressed by the authors. The manuscript has been carefully revised. Thanks to the authors for their work.
Author Response
All the issues I cared about were addressed by the authors. The manuscript has been carefully revised. Thanks to the authors for their work.
Answer：We are glad to receive your encouragement and recognition. Thank you for your suggestions and comments. These comments are all valuable and very helpful for improving our paper.
Reviewer 3 Report
Comments and Suggestions for AuthorsA few problems to the correction:
Line 31: alphabeticaly;
Line 108: 100 m What do you mean? Above the sea level? difference in levels? slope?
Line 109: sligthly acidic: - pH?
Line 110: 10-100cm??? It's impossible.
Line 127: Fine roots? What do you mean at this work? Precise.
The Conclusions are still unsufficiently. The manuscript is very informative, you should formulate more conclusions.
Comments on the Quality of English Language
The language is OK. It may be more fluently.
Author Response
A few problems to the correction:
Line 31: alphabeticaly;
Answer：Thank you for your suggestion. We have sorted the keywords alphabetically.
Line 108: 100 m What do you mean? Above the sea level? difference in levels? slope?
Answer：Thank you for your question. It is 100 m above sea level, we revised it in manuscript.
Line 109: sligthly acidic: - pH?
Answer: Thank you for your reminder. The soil pH of Forest Park is about 4.5, and we revised it in manuscript.
Line 110: 10-100cm??? It's impossible.
Answer: Thank you for your reminder. We have rechecked the relevant information, the soil depth in Forest Park, rather than thinning plots, is approximately 10–100 cm.
Line 127: Fine roots? What do you mean at this work? Precise.
Answer: Thank you for your question. We first collected the intact root systems with diameter less than 2 mm, that is fine roots. Then we used the methods of Pregitzer et al. (2002) to divide the collected fine roots into 1st to 5th order roots, which were used to determined and analyzed.
The Conclusions are still unsufficiently. The manuscript is very informative, you should formulate more conclusions.
Answer: Your consideration is very important for the revision of our paper. Thank you so much. We've added related content now, and further revised the Conclusions, hopefully it's better than before. In order to avoid repetition and wordy, we try to make the sentences concise and readable. If you have any other suggestions, we will make further revisions.
