Weed Coexistence in Eucalyptus Hybrid Stands Decreases Biomass and Nutritional Efficiency Mid-Rotation

Round 1

Reviewer 1 Report (Previous Reviewer 2)

Overall, the authors have made the suggested corrections, however the following changes still need to be made:

Results: Lines 284-285, 302-303, 311: In the text it is said that there are no statiscally  significant diferences, but in fig 3, 1st (leaf) and 2nd (branches) graphs show significant differences (means followed by different letter) ?? 

Fig 3 : In the last graph with %s the values are not well calculated. This graph and all the text relating to it need to be remade (lines: 310-321; 589-592).

Line 344: I think it is better to replace the text  “…were observed” by “--- were also observed”

Line 359: Nutrient stock (3.4) or nutriente content (4.1)? it should standardise

Line 360: In the figure 4 it is not clear whether the differences are significant or not.

Line 360-368: I think the figure gives much more information than what is referred to.

Line 402: it should replace treatment 18 by Ct 168

Line 403. It should replace control-all-the-time by Ct378.

Conclusions: Line 589-592: The meaning of the sentence is not clear.

Line 589-592: must review the calculation of this %

Author Response

Dear Reviewer,

I would like to express my sincere gratitude for taking the time to review my article. Your insightful comments and constructive feedback have been immensely valuable in improving the quality and clarity of my work.

 

All ten of your suggestions have been implemented in the paper, replacing expressions and improving the clarity of the sentences.

 

Kind regards.

Reviewer 2 Report (New Reviewer)

1.The abstract should include a general conclusion and an explanation of the relevance of the study.

2.The preface should add progress related to the effects of weed coexistence in Eucalyptus hybrid forests in this region, and thus present the issues that need to be addressed, rather than just highlighting the need for research with little reported.

3.In the part of materials and methods, the selection of sample plots should be described in detail, including the range of sample plots, the coverage of understory vegetation, apoplankton condition, the description of weed species and the unification of soil types.

4.What is the rationale for choosing to fertilize on day 90, 180 and to weed every 28 days?

5.It is recommended that the color corresponding to the first appearance of each treatment be labeled in Figure 3 instead of only in the last figure.

6.What is the coefficient of variation, an indicator that appears in Table 3? What is the purpose of it?

7.In "4.2. Forest biomass" the authors do not describe the effect of soil texture on biomass but cite relevant literature, which is relevant to reveal whether the study is relevant.

8.The authors are advised to pay attention to the comparative analysis with previous related research results to reveal the novelty of the study and the authors' contribution, and to enhance the scientific significance of the paper.

1.The abstract should include a general conclusion and an explanation of the relevance of the study.

2.The preface should add progress related to the effects of weed coexistence in Eucalyptus hybrid forests in this region, and thus present the issues that need to be addressed, rather than just highlighting the need for research with little reported.

3.In the part of materials and methods, the selection of sample plots should be described in detail, including the range of sample plots, the coverage of understory vegetation, apoplankton condition, the description of weed species and the unification of soil types.

4.What is the rationale for choosing to fertilize on day 90, 180 and to weed every 28 days?

5.It is recommended that the color corresponding to the first appearance of each treatment be labeled in Figure 3 instead of only in the last figure.

6.What is the coefficient of variation, an indicator that appears in Table 3? What is the purpose of it?

7.In "4.2. Forest biomass" the authors do not describe the effect of soil texture on biomass but cite relevant literature, which is relevant to reveal whether the study is relevant.

8.The authors are advised to pay attention to the comparative analysis with previous related research results to reveal the novelty of the study and the authors' contribution, and to enhance the scientific significance of the paper.

Author Response

Dear Reviewer,

I would like to express my sincere gratitude for taking the time to review my article. Your insightful comments and constructive feedback have been immensely valuable in improving the quality and clarity of my work.

All of your suggestions have been incorporated into the paper. Regarding your question about the timing of fertilization and weeding: Standard mineral fertilization in tropical soils, such as in Brazil, is typically done at 90 and 180 days. However, in environments like Brazil with high temperatures, weed germination and growth are favored. Therefore, it was decided to perform weeding every 28 days.

The introduction has been enhanced with the addition of a conclusion as requested. In the materials and methods section, the identified weed species were described. Figures 2 and 3 have also been improved.

Kind regards.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Please, find below some remarks and suggestions aiming to improve the manuscript, entitled “Weed coexistence in Eucalyptus Hybrid stand decrease biomass and nutritional efficiency in Mid-rotation”, submitted for publication in Forest.

Introduction:

Although the objectives are clear, the context of the study (to my opinion) is not well defined. I found that various aspects have been unnecessarily mixed up in the introduction section, and they are all lacking details that can help to understand the ideas behind each of the mentioned aspects. I would suggest to rewrite the introduction by considering the following paragraphs that need to be elaborated a bit more:

-        Lines 39-46; lines 53-58; lines 64-70; and lines 71-76.

As for the material and method, it is well established I would just suggest the authors to provide more descriptions of the data analysis process, they only mentioned the statistical analysis. It would be interesting to get an understanding of how they carried out the data analysis and justifying why the application of the statistical methods. I also think that section 2.1 and 2.2 can be combined since the two refer to the area of study.

In the results section:

In line 201, Figure 3 instead of Table 3. And there is no Table 3 in the manuscript, so they might change the numbers of tables 4 and 5.

In section 3.1 the mixing of the terms control and coexistence can be confusing, authors could try to make it clear. I think using more terms Groupe 1 and Groupe 2 can be less confusing.

In lines 213 and 215 (and through the text), the “p” related to the statistical significance might be written using cursive characters.

Page 8, Figure 4 instead of Figure 2.

The Turkey test might be reconsidered for leaf biomass and branches (Figure 2A and 2B), page 8. It looks like Coex. and Contr. 28d. present significant differences (in Fig.2A); and Coex.140d. seems significantly different from the rest in (Fig.2B). And I would suggest lowercase for the letter indicating the differences between means (as it has been done in Table 4). And in the figure caption providing the meaning of A, B, …, F.

In line 261, I suggest “3.3. Nutrient concentrations” like in table 4, instead of “3.3. Nutrient contents”

Page 9, in Table 4 (page 9), are Twigs referring to Branches?

Lines 274-278: the description does not reflect the results in Table 4. Since there are no significant differences, I think it is not correct to describe them like there were differences.

Lines 274-278: The only significant differences indicated in table 4 are related to the chemical element B.

Finally, I would suggest to organize the description in section 3.3 by following the order provided in Table 4.

In line 293, I suggest “3.4. Nutrient Stock” like in Table 4, instead of “3.4. Amount of nutrients”. Actually, the terms “Nutrient contents” in line 261 and “Amount of nutrients” in 293 can be confusing.

Pages 11, “Figure 5” instead of “Figure 3”.

The discussion section can be improved so that we can understand what the study was meant for. I would suggest rewriting this section by focusing on the most important finding mentioned in the result section. And then providing concise interpretations and comparisons with previous findings. To my opinion, the currently provided discussion is too long with vague interpretations. At some point, it looks like an introduction to the topic. My suggestion is to rewrite it concisely with an extension of no more than 2 pages.

 

Reviewer 2 Report

The paper is well-written, organized, and follows a logical structure. However, the methodology lacks detail, making it difficult to reproduce the study. The study design as outlined in the Methods section suffers insufficient detail.

The manuscript can be considered worth publishing  after the following modifications:

Materials and Methods: Line 131 and 184: It is not clear if replicates of the experimental treatments were used or not.

The randomized block design often involves repetitions of treatments within different blocks, which helps to control experimental variability and increase the precision of results. In this type of design, the experimental treatments are randomly allocated within blocks, which are groups of experimental units that are similar in terms of relevant characteristics. Each block consists of multiple experimental units, and each treatment is repeated within each block. Repeating treatments in different blocks is an important strategy to reduce the impact of uncontrolled variations in the experimental units. For example, in an agricultural and forest experiment, soil characteristics such as fertility, moisture, and texture may vary in different parts of the field. By dividing the field into blocks and repeating the treatments in each block, it is possible to control these local variations and obtain more accurate estimates of treatment effects.

Materials and Methods: Line 140, Figure 2: Period :“all the time” must indicate the number of days

Materials and Methods: Line 150: instead of bark and wood you should indicate in all text: Stembark and Stemwood if bark and wood are from stem.

Results: Line 201: Is referred to as Table 3 but it does not appear in the manuscript.

Results: Line 203: DAP or DBH?

Results: Line 223: Is this Figure 3 called in the text?

Results: Line  232 and 254 : Figure 2 or Figure 4?

Results: Table 4: Line268: Twigs or branches? instead of bark and wood you should indicate: Stembark and Stemwood

Results: Line 276-278: Please rephrase the sentence using terms that indicate a possible justification rather than a certain one. Moreover, the differences are not significant.

Results: Line 279-280 and 287-289: repeat text

Results: line 297 and 323: Figure 3 or Figure 5?

Results: line 298: missing mention of Fe

Results: Line  322: instead of bark and wood or stem you should indicate: Stembark and Stemwood

Results: Line 326: How nutrient utilization efficiency was calculated?

Results: Line 332: lacks the definition of EUN

Results: Table 5, line 350: Twigs or branches? instead of bark and wood you should indicate: Stembark and Stemwood

Should indicate the units of the table (kg of biomass ha^-1/ kg of nutriente? )

Results: Line 270: MS?

Results:Line 372: decrease or increase? The sentence is not properly constructed. Please rephrase the sentence.

Results:Line 420- 421: the % values appear to be reversed.

Results: Line 449: it should be noted that these are the results of the present study .

Results: Line 452-455: confusing sentence. Please rephrase.

Results: Line 476-479: The results for some nutrients (namely Ca, B, Fe and Mn) do not seem so similar to those obtained in this study. Please rephrase the sentence.

Results: Line 512- 513: Only S presented a distinc EUN in relation to the presente study?

Results: Line 518 - 520: It should indicate if they are values in the total biomass

Conclusions: Line 524 and 525: where do these numbers come from 82.3 and 73.5%? In figure 2 line 253, appears to have other values.

Conclusions: Line 530: the control up to 168 days promoted the highest stock for cooper in wood componente?

Conclusions:Line 533: it should be noted that these are not statistically significant diferences. Please rephrase the sentence.

Conclusions:Line 534-537: it must be noted that with a weed control up to 168 days, a productivity tends to be even higher than with a control during the whole period, (which should be indicated in days) and mention that this can reduce the use of herbicides. Please rephrase the sentence.

No reference is made to the results obtained between treatment group 1, which aimed to determine the period before the intervention(PBI), and group 2(TIPP). It should be emphasised that weed control is most important at an early stage in eucalyptus stands.

In conclusions it should also mention the weaknesses of the study and indicate what are the directions for the future.

 

Reviewer 3 Report

The main aim of the study entitled “Weed coexistence in Eucalyptus hybrid stand decrease biomass and nutritional efficiency in mid-rotation” is to assess the extent to which weeds, coexisting with eucalyptus plantations in different periods and for different time lengths, affect biomass and nutrient efficiency (concentration and storage) of hybrid Eucalyptus stands in the Pampa biome in South Brazil. The underlying, main aim of the study seems to be the identification of the best weed management strategy that may be adopted in eucalyptus plantations in order to maximise productivity. To address this aim, the authors carried out a complex manipulation experiment where 24 treatments were applied immediately after eucalyptus plants were planted. Treatments consisted in weed removal and were defined on the basis of the period in which weeds were present and the number of days weeds coexisted with eucalyptus plants; treatments followed a period-duration gradient where, on one extreme, a continuous presence of weed was guaranteed until response variables were recorded and, on the other extreme, weeds were removed for the entire period. However, for the major response variable analysed in this study (biomass and nutrient levels), only 5 out of 24 treatments were considered, with the authors finding that the presence of weeds reduced eucalyptus biomass and nutrient efficiency and that weed removal up to 168 days from plantation promoted the greatest productivity.

I consider the topic to be both in line with the research aspects followed by the journal and potentially interesting since it provides the bi-dimensional aspect of weed management (effects of period and duration of weed presence on plantation productivity). However, although I “feel” the intentions of this research are interesting and the raw material valuable, unfortunately I found severe drawbacks in the entire manuscript, especially in the Introduction and Methods which, as a result of their lack of clarity and essential information, impeded me a sufficient interpretation of Results and Discussions/Conclusions. In particular, the presentation of Material and methods was insufficient (especially regarding the experimental design and the criteria followed for treatment selection and response variables measures), thus not allowing the study to be potentially replicated. The manuscript is also characterised by an incorrect use of English which, sometimes, strongly compromises the comprehension of the manuscript. This is the reason why I suggest the authors get the manuscript proof read by an independent copy-editing service, which would enable future reviewers to be more helpful in highlighting drawbacks and possible solutions.

Overall, I think the authors should re-write substantial sections of their manuscript in order to make it accessible to readers, paying a lot of attention to the description of the aims, the research framework, the methods used, the outlay of results and development of discussions and conclusions.

Given all the drawbacks present in the current version of the manuscript, I cannot recommend it for publication in Forests in the present state. However, I invite the authors to resubmit their work after substantial revision is carried out.

Please see the attached PDF to see the "Point-to-point comments" for each section.

Comments for author File: Comments.pdf

As already stated in the "Comments and Suggestions for Authors", the manuscript is  characterised by an incorrect use of English which, sometimes, strongly compromises the comprehension of the manuscript. This is the reason why I suggest the authors get the manuscript proof read by an independent copy-editing service, which would enable future reviewers to be more helpful in highlighting drawbacks and possible solutions.