Belowground Biomass and Root:Shoot Ratios of Three Willow Cultivars at Two Sites

Round 1

Reviewer 1 Report

The paper entitled “Biomass inventory of willow biomass crop components show that root:shoot ratios are similar across sites and cultivars though trend lower with higher yielding stands.” aimed to investigate above and below ground biomass inventory (foliage, stems, stools, coarse and fine roots) on three cultivars of short rotation willow biomass crops at two sites. This manuscript must be considered after major revision. The results are not complete, and authors did not talk about all the figures and tables in results but discuss about those. The file that is uploaded as a supplementary file is the manuscript not supplementary.

 

1.       Title must be comprehensive and short and understandable. The title is too long and hard to understand.

2.       Introduction is too long. Summarize introduction in maximum 4 or 5 paragraphs.

3.       If there is no difference between two sites, why the authors consider both?

4.       It is better to have a schematic figure of the site, rows, and plots to understand better.

5.       LN 145-148: Did you test the nutrient concentrations? If yes, show the numbers in the table.

6.       LN 150: what are the numbers for each species?

7.       What do you mean by cultivar? You mean species?

8.       Did the authors use cores by increasing the distance from the trunk? Why did you consider only depth because roots grow horizontally as well as vertically.

9.       LN 254-262: Are these refers to the results? If yes, please replace to the results.

10.   Put the figures and tables immediately after the text that you cite those. Also, the quality and resolution of the figures 1 and 2 are not good. Replace with the better one.

11.   The manuscript has not the same font in the whole text.

12.   LN 571: what is GHG Analysis? What is GHG stands for? The authors did not talk about it in material and methods. You must explicit the abbreviations when you use those for the first time in the text, you use it only in introduction without explicit.

13.   What is table S1 talk about? Is it a supplementary or appendix? Also, you never talk about this table in the text.

14.   Discussion is hard to follow. You use table 4 in discussion without talking about this table in results.

15.   Where is table 3? You have table 4 but not table 3?

 

Author Response

Here are point by point responses to reviewer #1 comments. Reviewer comments are numbered and each response is listed as 1. and inset below the comment.

1. Title must be comprehensive and short and understandable. The title is too long and hard to understand.
   1. Title was shortened to “Belowground biomass and root:shoot ratios of three willow cultivars at two sites,”
2. Introduction is too long. Summarize introduction in maximum 4 or 5 paragraphs.
   1. Some editing was done to shorten the introduction. For example, three lines were removed from the second paragraph. Other minor changes were made in other paragraphs. We think it is important to summarize the literature on this topic so there is context for this study.
3. If there is no difference between two sites, why the authors consider both?
   1. Asking the question “Is there a difference in R:S ratios between sites? was an objective of this study. The question of whether root:soot ratios in willow biomass crops varies across sites is unknown and needs to be understood. This study provides some new data on this issue.
4. It is better to have a schematic figure of the site, rows, and plots to understand better.
   1. A diagram was added as Figure 1 to illustrate the layout of an individual plot and the rows where individual plants were selected within the plot for this study.
5. LN 145-148: Did you test the nutrient concentrations? If yes, show the numbers in the table.
   1. The only item we tested for was carbon content. This data is reported in Table 4 in the paper.
6. LN 150: what are the numbers for each species?
   1. The numbers for each cultivar are from the breeding and selection program. It is important to include these because other studies with these cultivars only report these numbers and not the cultivar name (e.g. Fish Creek, Oneida). This will allow readers to link these results to other studies with the same cultivars.
7. What do you mean by cultivar? You mean species?
   1. A cultivar is a plant that has been selected for some desirable traits and is then propagated to maintain those traits. This term is widely used in plant breeding and selection programs and in horticulture. The willow cultivars are the result of a breeding and selection program and have been chosen for traits such as yield, disease resistance and form.
8. Did the authors use cores by increasing the distance from the trunk? Why did you consider only depth because roots grow horizontally as well as vertically.
   1. The area that was selected for excavation is defined on lines 184 – 187 and represents the area of a single willow plant in the planting design. Because entire root systems were excavated for each 15 cm layer there was no spatial information from this sampling design. We agree that horizontal distance influences root distribution but this study was not designed to address that question. A different sampling design would be required to answer that question. The design allows up to scale up and provide estimates of below ground biomass on a per hectare basis.
9. LN 254-262: Are these refers to the results? If yes, please replace to the results.
   1. The plot level yield results are part of another study reported in reference 32. A note was added at line 261 to clarify where to find this information. It was used in this study as a check to see if there might have been bias in the selection of individual plants for root excavation. We have chosen to leave this information here since it is from another study and not a primary result of this study.
10. Put the figures and tables immediately after the text that you cite those. Also, the quality and resolution of the figures 1 and 2 are not good. Replace with the better one.
    1. Figures were moved so that they are in place right after the first reference in the text. The resolution of figure 1 and 2 (now 2 and 3) were improved. Figure one was redone as a stacked figure that the data is clearer and easier for the reader to see and interpret.
11. The manuscript has not the same font in the whole text.
    1. Checked and corrected where needed.
12. LN 571: what is GHG Analysis? What is GHG stands for? The authors did not talk about it in material and methods. You must explicit the abbreviations when you use those for the first time in the text, you use it only in introduction without explicit.
    1. The first use of GHG is on like 102. We corrected this error by inserting the term greenhouse gas (GHG) at this first use.
13. What is table S1 talk about? Is it a supplementary or appendix? Also, you never talk about this table in the text.
    1. Table S1 was originally a supplemental table but was inserted by the journal in the paper so it has been renumbered as table 4 and this reference in the text has been updated. It summarizes the data for the carbon content of the different plant parts and is provided so it is clear how biomass was converted to carbon content. This information may also be of interest to other researchers since there is limited information for several of the plant parts reported here such as coarse and fine roots, leaves, and stool.
14. Discussion is hard to follow. You use table 4 in discussion without talking about this table in results.
    1. Table 4 (now labeled Table 3) is a summary of the data that is available on root:shoot ratios in the literature and is used to discuss the influence of factors such as cultivar and site. Since this is not part of primary data from this research trial but a summary of information from other papers, it is inserted in the discussion rather than the results section. It is used in the discussion to put the results of this research in context, particularly related to the questions of whether site and willow cultivar impact R:S ratios.
15. Where is table 3? You have table 4 but not table 3?
    1. Thank you for noting this. There was an error in table numbering and this, along with the comment in 13, has been addressed by renumbering tables and correcting references in the text.

Reviewer 2 Report

The authors of the paper "Biomass inventory of willow biomass crop components show that root:shoot ratios are similar across sites and cultivars though trend lower with higher yielding stands." available to me have written a very interesting article. However, there are some weaknesses that must be eliminated before this article is presented to the public.

As an international reader, I find the statement that the climatic conditions are comparable for both locations completely inadequate: Please explain this as briefly as is required!

The same applies to the pedological basis: naming the texture of the soil can only be the first step.

Of course, if you describe that you fertilize nitrogen every year, it would also be very helpful if I could learn about other important components of plant nutrition (P, Ca, K, Mg, S). On line 144 you describe that the soil pH in Tully is lower than in Belleville.........fine and good, but where is it? At 4, at 8? These basics need to be pointed out much more precisely!

L. 149-158: Some of the statements in this paragraph are completely irrelevant and misleading. It doesn't matter why you picked these 3 cultivars, which produced which growth results and when! You have picked these 3 cultivars for this paper because they are the most promising ........... that’s it.

You describe that three harvests took place before that: 2006, 2009 and 2012. It would be very helpful if you would at least name the harvest yields from these years.

The x-axis heading must be inserted in both Figure 1a and 1b.

I find Table 1 very confusing due to the immense amount of data. Please consider whether a systematic subdivision - and thus the presentation of the results in 2 or 3 tables - could not better ensure clarity.

The partial graphics of Figure 2 must be numbered with a, b, c, etc. Then the sub-graphic heading and the structure of the four lower sub-graphics must be removed, since they are identical to the two upper graphics. Aim for clarity, avoid information overload!

I have the same problem with Table 4 as with Table 1: far too much information, some of which is unnecessary and makes the whole thing confusing: Can't you, for example, summarize the 3 lines from a publication by Volk (2002)? The same applies to the R:S ratios in Stadnyk (2010).

I would like to point out the following minor technical errors:

L. 186 following: Authors should always put a space between special characters and numbers or not, and between numbers and their units. Please check the entire paper for this!

Author Response

Response to reviewer #2 comments are inserted. Responses are listed as 1. and inset below each comment.

 

As an international reader, I find the statement that the climatic conditions are comparable for both locations completely inadequate: Please explain this as briefly as is required!

1. Data on annual precipitation and growing degree days was added. Details of the climate of the two sites is explained in more detail in reference 32. The sentence that used this reference was expanded to make this clear.

The same applies to the pedological basis: naming the texture of the soil can only be the first step.

Of course, if you describe that you fertilize nitrogen every year, it would also be very helpful if I could learn about other important components of plant nutrition (P, Ca, K, Mg, S). On line 144 you describe that the soil pH in Tully is lower than in Belleville.........fine and good, but where is it? At 4, at 8? These basics need to be pointed out much more precisely!

1. 1. There are several sentences on the soil conditions at these two sites reported in the paper. Additional key information was added such as pH and organic matter levels. A sentence was added to clearly tell the reader that additional details are found in reference 34
2. 149-158: Some of the statements in this paragraph are completely irrelevant and misleading. It doesn't matter why you picked these 3 cultivars, which produced which growth results and when! You have picked these 3 cultivars for this paper because they are the most promising ........... that’s it.
   1. 1. We intentionally picked these three cultivars for this study so it is important to explain the reasoning behind this selection. If this was a random selection of three of the 18 cultivars in this trial then no explanation would be needed. We intentionally selected high yield cultivars from these trials, since that is what is going to be deployed. We have left the paragraph in place as it is.

You describe that three harvests took place before that: 2006, 2009 and 2012. It would be very helpful if you would at least name the harvest yields from these years.

1. A sentence was added to point the reader to the harvests over three rotations at these sites (see line 136).

The x-axis heading must be inserted in both Figure 1a and 1b.

1. Both figures were updated and the resolution was improved.

I find Table 1 very confusing due to the immense amount of data. Please consider whether a systematic subdivision - and thus the presentation of the results in 2 or 3 tables - could not better ensure clarity.

1. These results are from the same analysis so we think they are best represented in a single table. We have edited the table and the column headers to clarify the information in the table so it is easier for a reader to understand.

The partial graphics of Figure 2 must be numbered with a, b, c, etc. Then the sub-graphic heading and the structure of the four lower sub-graphics must be removed, since they are identical to the two upper graphics. Aim for clarity, avoid information overload!

1. The resolution of the image was improved and the layout of the data with the sites in the columns and the cultivars in the rows was explained in the caption.

I have the same problem with Table 4 as with Table 1: far too much information, some of which is unnecessary and makes the whole thing confusing: Can't you, for example, summarize the 3 lines from a publication by Volk (2002)? The same applies to the R:S ratios in Stadnyk (2010).

1. We think that this summary of R:S ratios in the literature is useful to illustrate both the limited information available and the range of values reported. It emphasizes a key underlying motivation for this research, that a better understanding of R:S ratio is needed if we are going to understand the GHG balances of these systems. Edits were made to reduce the number of lines for the Volk reference so that the only time separate lines are created in the table for a single reference are when different sites are reported. We previously tried to summarize this data graphically but it was difficult to understand and more confusing than helpful. We have left this table in place because we think that by pulling together information from the literature it adds value for the reader.

I would like to point out the following minor technical errors:

1. 186 following: Authors should always put a space between special characters and numbers or not, and between numbers and their units. Please check the entire paper for this!
   1. Thank you for noting this inconsistency. This was corrected and the paper reviewed to ensure that the use of spaces between numbers and their units was consistent.

Round 2

Reviewer 1 Report

Dear Authors,

Great job!

Author Response

Thank you for your input. No changes made based on positive response

Reviewer 2 Report

Dear authors,

The manuscript in front of me has been revised. Unfortunately, the advice of the experts was only followed in a few cases and apparently only very reluctantly. At this point I would like to remind you that the reviewers not only have the task of checking the quality of the manuscripts but also of helping to improve them!

Reviewer 1's suggestion that the introduction should be streamlined so that it would be acceptable to all readers of the journal forests was only inadequately followed.

My advice to briefly show meteorological and pedological key data of the two locations was only followed in certain places or reference was made to other publications. It is not the task of the interested reader to obtain this fundamental data, but that of the authors! As it is now in the manuscript, it is very difficult to read! I have given a positive example below, which should look familiar to the authors!:

Amichev, B.Y.; Hangs, R.D.; Bélanger, N.; Volk, T.A.; Vujanovic, V.; Schoenau, J.J.; Van Rees, K.C.J. First-Rotation Yields of 30 803 Short-Rotation Willow Cultivars in Central Saskatchewan, Canada. BioEnergy Research 2014, doi:10.1007/s12155-014-9519-4.

“Thirty willow cultivars were obtained from the State University of New York—College of Environmental Science and Forestry (SUNY-ESF) and planted in 2007 at the University of Saskatchewan (latitude 52.126632; longitude 106.608294; elevation 510 m above sea level) at Saskatoon, Saskatchewan, Canada. The study site was located in the Elstow Plain ecodistrict of the Moist Mixed Grassland ecoregion within the Prairies ecozone of Saskatchewan (Fig. 1) SLC, [25]. The soils at this site are heavy clay Sutherland Orthic Vertisol [26]. Mean annual precipitation at this site is 375 mm, mean annual temperature is 2 °C, and the average number of frost days is 253 annually [27].”

My following remark, which I have to repeat at this point, was simply ignored:

The partial graphics of Figure 2 (now Fig. 3) must be numbered with a, b, c, etc. Then the sub-graphic heading and the structure of the four lower sub-graphics must be removed, since they are identical to the two upper graphics. Aim for clarity, avoid information overload!

This consolidating graphic must be revised. Because of the information overload, it is simply bad and cannot be accepted for publication.

In the attached file I have "handwritten" clarified what I mean.

Best regards

Comments for author File: Comments.pdf

Author Response

Please see attached file with responses to reviewers. 

Author Response File: Author Response.docx