Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Several critical questions and remarks regarding the article by Konopka et al. titled “Biomass modeling in European beech and Norway spruce plantations: an opportunity to enhance carbon market and climate sustainability”.

The scientific novelty of this paper cannot be assessed. The authors set trivial and predictable research tasks. Why compare woody plant species that are evolutionarily distinct (Gymnosperms vs. Angiosperms)? Why compare plants with diverse growth and development strategies? Different plant species that have diverged throughout evolution have different biomass and carbon accumulation rates. The authors set trivial and predictable research tasks. Therefore, they obtained trivial and predictable results.

It is well-known fact that biomass accumulation is correlated with tree height and diameter. Such studies have been conducted for a very long time. Predictable tasks were set, predictable results were obtained, and predictable conclusions were made.

“The selected sampling and measurement sites were characterised by the frequent occurrence of European beech and Norway spruce, with stands likely originating from artificial regeneration…” (Lines 141-143). Likely originating…? One of the key selection criteria for research subjects was the origin of the stands, which had to be artificial (Lines 120). However, the authors conducted research in stands where they were not sure of the origin (likely originating…).

The authors used a destructive method for estimating biomass, but at the same time used a coefficient to calculate the carbon content. Why did the authors not directly determine the carbon content of the plant samples? The carbon content using higher-tier techniques shows variations in content depending on different species, tree components (stem, roots, and leaves), and stand age. The carbon content for each tree component or tree species determined scaling the biomass content with a carbon factor varies from 0.45 to 0.5 (Penman et al., 2003; Hirata et al., 2012). A 0.5% variation in carbon content when calculated over large areas (for example, per hectare) results in incorrect estimation of both woody plant biomass and carbon sequenced in plant biomass. For preliminary evaluation calculations, such carbon estimates in tree plants are acceptable (with certain limitations). However, such evaluation calculations cannot be used to estimate an accurate financial cost of carbon units (carbon biomass sequenced in trees) for use in the carbon market.

Therefore, this research is not necessary because the results are predictable. This study has no scientific novelty and practical relevance.

 

Literature cited:

Penman et al., 2003. IPCC Report on good practice guidance for land use, land-use change and forestry. The Intergovernmental Panel on Climate Change (IPCC).

Hirata et al., 2012. Forestry and Forestry Product. Research Institute, REDD Research and Development Centre.

Author Response

Several critical questions and remarks regarding the article by Konopka et al. titled “Biomass modeling in European beech and Norway spruce plantations: an opportunity to enhance carbon market and climate sustainability”.

The scientific novelty of this paper cannot be assessed. The authors set trivial and predictable research tasks. Why compare woody plant species that are evolutionarily distinct (Gymnosperms vs. Angiosperms)? Why compare plants with diverse growth and development strategies? Different plant species that have diverged throughout evolution have different biomass and carbon accumulation rates. The authors set trivial and predictable research tasks. Therefore, they obtained trivial and predictable results.

It is well-known fact that biomass accumulation is correlated with tree height and diameter. Such studies have been conducted for a very long time. Predictable tasks were set, predictable results were obtained, and predictable conclusions were made.

Response 1:

We feel that the reviewer’s assessment is overly critical, and we firmly believe that our work brings new and valuable knowledge to the field. Specifically:

• Allometric relationships for both species —particularly at the stand level and during the initial growth stages—are largely absent in the literature. While we have previously published models for these species, those were limited to tree-level and originating from natural regeneration.
• Existing studies on biomass in young trees rarely include the root system. Our study does incorporate this component, which we believe is a significant contribution.
• To our knowledge, no existing research provides data or models on litter production in young forest stands. This is a notable gap that our study addresses.
• While it is widely understood that biomass stock is related to tree or stand size (as measured by height, stem diameter, or age), precise quantification is essential for practical applications and scientific modeling.

As for comparing the two species—spruce and beech—the rationale is clear. Spruce is the most widespread evergreen species and beech is the dominant deciduous species in Central Europe, and both are common across much of Eurasia. Given their differing strategies in leaf retention, we hypothesized that they would exhibit contrasting carbon dynamics. One might expect that the deciduous beech would lose (transfer from biomass to necromass via litter) more carbon annually than spruce. However, our results show this is not the case. We have included this hypothesis at the end of the Introduction section. Moreover, this hypothesis has been linked to one of the reasons why we did this kind of research.

 

Comments 2:

“The selected sampling and measurement sites were characterised by the frequent occurrence of European beech and Norway spruce, with stands likely originating from artificial regeneration…” (Lines 141-143). Likely originating…? One of the key selection criteria for research subjects was the origin of the stands, which had to be artificial (Lines 120). However, the authors conducted research in stands where they were not sure of the origin (likely originating…).

Response 2: We acknowledge that the expression in Lines 141–143 was incorrect. The use of the word “likely” was a mistake. All stands included in the study are of exclusively man-made origin. We apologize for this oversight and have corrected the text accordingly.

 

Comments 3: The authors used a destructive method for estimating biomass, but at the same time used a coefficient to calculate the carbon content. Why did the authors not directly determine the carbon content of the plant samples? The carbon content using higher-tier techniques shows variations in content depending on different species, tree components (stem, roots, and leaves), and stand age. The carbon content for each tree component or tree species determined scaling the biomass content with a carbon factor varies from 0.45 to 0.5 (Penman et al., 2003; Hirata et al., 2012). A 0.5% variation in carbon content when calculated over large areas (for example, per hectare) results in incorrect estimation of both woody plant biomass and carbon sequenced in plant biomass. For preliminary evaluation calculations, such carbon estimates in tree plants are acceptable (with certain limitations). However, such evaluation calculations cannot be used to estimate an accurate financial cost of carbon units (carbon biomass sequenced in trees) for use in the carbon market.

Response 3:

Our previous results, along with findings from various studies, indicate that the carbon content in European beech and Norway spruce typically ranges between 48.5% and 51.0%, often clustering around 50%. For example, Mathews (1993), in the book “The Carbon Content of Trees”, demonstrated through a large dataset that the carbon content in beech fluctuated between 48.5% and 50.5%, while in spruce it ranged from 47.0% to 50.3%.

In fact, using 50% as the carbon content is a fairly standard approach in many previous studies. Thus, for instance Andrzej Wegiel and Krzysztof Polowy (Forests 2020, 11, 240; doi:10.3390/f11020240) stated:

“Based on many studies, an overall carbon concentration of 50% of tree biomass has been assumed and widely accepted [8–10].”

References were: [8] Sedjo, R.A. Forests: A tool to moderate global warming. Environ. Sci. Policy Sustain. Dev. 1989, 31, 14–20. [9] Dewar, R.C.; Cannell, M.G. Carbon sequestration in the trees, products and soils of forest plantations:An analysis using UK examples. Tree Physiol. 1992, 11, 49–71. [10] Hollinger, D.Y.; Maclaren, J.P.; Beets, P.N.; Turland, J. Carbon sequestration by New Zealand’s Plantation forests. N. Z. J. For. Sci. 1993, 23, 194–208.

By the way, what would we have gained if we had performed our own chemical analyses on the sampled biomass in the measured stands? Most likely, we would have obtained values between 49% and 51%, with an average still close to 50%. In that case, the outputs would reflect a specific carbon amount based on newly developed biomass models and the carbon content derived from our own analyses. However, stands located on different sites could still exhibit biomass carbon concentrations that vary by ±1.5%.

In our view, we have developed biomass models and used them to estimate the amount of carbon sequestered in the biomass. We believe this represents a useful tool for future negotiations within the carbon credit market. Of course, one might argue that the carbon content is not 50% but, for example, 47%. This, however, simply opens the door for further negotiation. If someone requires a highly stand-specific carbon model, they are welcome to conduct precise chemical analyses—but who is actually willing to do that? Furthermore, any tool intended for this kind of application must remain simple and practical. We cannot rely on overly complex academic methods, especially when the final model is still, by nature, an estimate. We have addressed this point in the Conclusions section of the revised text.

 

Therefore, this research is not necessary because the results are predictable. This study has no scientific novelty and practical relevance.

Sorry but we do not think so.

 

Literature cited:

Penman et al., 2003. IPCC Report on good practice guidance for land use, land-use change and forestry. The Intergovernmental Panel on Climate Change (IPCC).

Hirata et al., 2012. Forestry and Forestry Product. Research Institute, REDD Research and Development Centre.

Thanks for the recommendation.

Reviewer 2 Report

Comments and Suggestions for Authors

The study investigates the actual issue how can forestry provide a way to regulate the consequences of climate change. Considering the potential possibility of forest plantations to contribute in this efforts, the authors apply a complex approach to evaluate productivity of the studied tree species. However, it seems that some imrportant factors were not taken into account, whereas their consideration can significantly change the obtained estimates and conclusion. First, considered was not the impact of tree density on biomass of stands of the comparable age (see the comment on lines 136-138 below). Second, 12 yrs seems to be too short span to evaluate the stand biomass accumulation (unless the spruce plantations are not created especially to obtain Christmas trees). Probably, the intensive self-thinning of stands will begin later (after 15-25 yrs of stand growth), and then the interspecific comparison can result in other conclusion on species-specific biomass accumulation. It is advisable to address this issue in the introduction or discussion of the article. As was rightly noted in lines 355-357, important is to take in account long-term processes in tree growth and forest formation.   

line 110 ("... stands which might arise from both natural and artificial regeneration") vs. line 111 ("we focused exclusively on young planted stands.") & line 120 ("All trees had to be planted, with none originating from natural regeneration"). To make the explanation on study objects clearer for a reader, it is not desirable to mention natural stands (in line 110) whereas the only artificial (planted) stands were really studied. 
line 136-138: "The spacing of planted trees varied between 1.0 m and 2.5 m (with an average of 1.7 m) in the beech plantations and between 1.1 m and 2.6 m (with an average of 1.9 m) in the Norway spruce plantations." Probably, the reported difference in tree spacing could impact the most on the revealed interspecific difference in, at least, radial growth (Figure 4, a), and consequent biomass accumulation. So, it is necessary to compare the two set of mono-species stands by the density of the planted trees, to check whether the results of the growth comparison of the two species were affected by the systematic difference in the planting density of each one. And the most correct way of the analysis would be to consider stand density like another predictor in the regression equations else.
line 167: "The stem diameter d₀ and tree height of each sampled tree were measured." Here, it would be worth to remind a reader that ages of the sampled trees were a priory known because they corresponded to the age of the planted stands studied.
line 222: "The carbon stock per hectare was calculated as 50% of the biomass". Desirable is to give a reference supporting such a ratio used in calculation.

Technical note:
Figure 6: To make clearer that the two different parameters (not two different species) are plotted on each diagram, advisable is to use the other line types unlike on Figures 2-5, 7.

Comments on the Quality of English Language

line 160-163: "we selected seven beech stands and seven spruce stands, representing a subset of those used for the annual measurements. Stands were ranked by size (based on mean height), and every other stand was selected in order of size." In this context, what does mean "other stands" (line 162)? Whether the stands selected for destructive sampling are implied?
line 218: "While leaf litter in beech equals the current year's needle stock". The phrase is not clear enough. Did you imply "leaf stock"?

Author Response

Comments 1:

The study investigates the actual issue how can forestry provide a way to regulate the consequences of climate change. Considering the potential possibility of forest plantations to contribute in this efforts, the authors apply a complex approach to evaluate productivity of the studied tree species. However, it seems that some important factors were not taken into account, whereas their consideration can significantly change the obtained estimates and conclusion. First, considered was not the impact of tree density on biomass of stands of the comparable age (see the comment on lines 136-138 below).

Response 1:

You’re right; however, it's important to note that the trees were still growing without mutual contact between their crowns—gaps between them were still present. As a result, the influence of stand density on biomass allocation was perhaps negligible at this stage. This factor will become more relevant once the canopy closes. Therefore, while stand density will be important in the future, we are uncertain whether our current experimental design allows for a detailed analysis of this effect, as it would require more replicates with varying tree spacing.

 

Comments 2:

Second, 12 yrs seems to be too short span to evaluate the stand biomass accumulation (unless the spruce plantations are not created especially to obtain Christmas trees). Probably, the intensive self-thinning of stands will begin later (after 15-25 yrs of stand growth), and then the interspecific comparison can result in other conclusion on species-specific biomass accumulation. It is advisable to address this issue in the introduction or discussion of the article. As was rightly noted in lines 355-357, important is to take in account long-term processes in tree growth and forest formation.

Response 2:

You’re absolutely right, but this aspect can only be studied in the context of a long-term study. We will see whether these measurements can continue, depending on the success of our project proposals to scientific funding schemes. It would be fascinating to study the development of canopy closure, especially regarding tree competition and the resulting mortality.

Comments 3:

line 110 ("... stands which might arise from both natural and artificial regeneration") vs. line 111 ("we focused exclusively on young planted stands.") & line 120 ("All trees had to be planted, with none originating from natural regeneration"). To make the explanation on study objects clearer for a reader, it is not desirable to mention natural stands (in line 110) whereas the only artificial (planted) stands were really studied. 

Response 3: Right, we removed a part of the unnecessary text.

Comments 4:

line 136-138: "The spacing of planted trees varied between 1.0 m and 2.5 m (with an average of 1.7 m) in the beech plantations and between 1.1 m and 2.6 m (with an average of 1.9 m) in the Norway spruce plantations." Probably, the reported difference in tree spacing could impact the most on the revealed interspecific difference in, at least, radial growth (Figure 4, a), and consequent biomass accumulation. So, it is necessary to compare the two set of mono-species stands by the density of the planted trees, to check whether the results of the growth comparison of the two species were affected by the systematic difference in the planting density of each one. And the most correct way of the analysis would be to consider stand density like another predictor in the regression equations else.

Response 4:

You’re right; however, it's important to note that the trees were still growing without mutual contact between their crowns—gaps between them were still present. As a result, the influence of stand density on biomass allocation was negligible at this stage. This factor will become more relevant once the canopy closes.

Comments 5:

line 167: "The stem diameter d₀ and tree height of each sampled tree were measured." Here, it would be worth to remind a reader that ages of the sampled trees were a priory known because they corresponded to the age of the planted stands studied.

Response 5: Okay, the information has been added.

 

Comments 6:

line 222: "The carbon stock per hectare was calculated as 50% of the biomass". Desirable is to give a reference supporting such a ratio used in calculation.

Response 6: Citation has been added, specifically: Brown, S. (2002). Measuring carbon in forests: current status and future challenges. Environ. Pollut., 116, 363−372.

 

Technical note:
Figure 6: To make clearer that the two different parameters (not two different species) are plotted on each diagram, advisable is to use the other line types unlike on Figures 2-5, 7.

Ok, thanks. The Figure 6 was modified (carbon amount was excluded).

 

Comments on the Quality of English Language

line 160-163: "we selected seven beech stands and seven spruce stands, representing a subset of those used for the annual measurements. Stands were ranked by size (based on mean height), and every other stand was selected in order of size." In this context, what does mean "other stands" (line 162)? Whether the stands selected for destructive sampling are implied?
line 218: "While leaf litter in beech equals the current year's needle stock". The phrase is not clear enough. Did you imply "leaf stock"?

We modified these sentences. Thanks a lot

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript (MS) deals with a comparison of European beech and Norway spruce in terms of biomass growth in younger ages, as well as with comparing of the species perspectives in regard to carbon market. Overall, the MS is well structured, clearly presented, and written with fine English. It can find its readership within the scope of afforestation/reforestation and carbon sequestration. There are, however, a few issues to raise, attention to which should improve the MS.

General comments

I. l. 79-80 -> The authors enumerate a few internal factors influencing the biomass allocation. Surprisingly, no attention has been paid to such factor as planting density that dramatically changes the proportions of the biomass allocation.

II. l. 258 stand age may be a more reliable predictor -> This may well be, but if one speaks of younger even-aged stands the planting of which is well-documented. Old-growth stands will provide problems with the age parameter. In my view, the authors should point out to that they speak only about young even-aged stands.

III. l. 312-314 and throughout the text. The findings demonstrate that, at the individual tree level, beech exhibited greater height than spruce for the same stem diameter, indicating species-specific growth patterns that influence overall biomass production. -> It is a surprise that the authors do not use the term 'form factor/form quotient'. From the European forestry literature, the concept of stem form factor has been known since long ago. Also, it is well known that the form factor of beech is larger than that of spruce---that is, beeches are closer to a cylindric shape. Therefore, the authors' results just repeat the old results of previous generations. I believe, this should be somehow corrected. The Discussion section may be the right place for this.

IV. Conclusion. In my view, what is written in lines 386-406 is a simple repeating of results, which is unnecessary in Conclusion. Instead, the authors could give some key points highlighting the place of the research in a broader context, which is partly done. However, the authors could express their opinion regarding the perspectives of the carbon market. Beeches and spruces will grow under a human supervision or totally freely. But carbon market is a result of a political decision, so the presented results regarding the carbon sequestration are only sensible as long as the countries observe the decision.

Minor comments

l. 142-143 stands likely originating from artificial regeneration -> Does 'likely' mean that the planting activity 10 yr ago is not known for sure?

l. 218 needle stock -> leaf stock? Because the authors speak about beech.

Figs. 1-7 -> It's a good tradition to place equations on figures with approximation results, together with R2 values.

l. 333 height vulnerability -> high vulnerability?

 

 

Author Response

The manuscript (MS) deals with a comparison of European beech and Norway spruce in terms of biomass growth in younger ages, as well as with comparing of the species perspectives in regard to carbon market. Overall, the MS is well structured, clearly presented, and written with fine English. It can find its readership within the scope of afforestation/reforestation and carbon sequestration. There are, however, a few issues to raise, attention to which should improve the MS.

General comments

1. l. 79-80 -> The authors enumerate a few internal factors influencing the biomass allocation. Surprisingly, no attention has been paid to such factor as planting density that dramatically changes the proportions of the biomass allocation.

Response: You’re right; however, it's important to note that the trees were still growing without mutual contact between their crowns—gaps between them were still present. As a result, the influence of stand density on biomass allocation was negligible at this stage. This factor will become more relevant once the canopy closes. Therefore, while stand density will be important in the future, we are uncertain whether our current experimental design allows for a detailed analysis of this effect, as it would require more replicates with varying tree spacing.

 

Comments 2: 

1. l. 258 stand age may be a more reliable predictor -> This may well be, but if one speaks of younger even-aged stands the planting of which is well-documented. Old-growth stands will provide problems with the age parameter. In my view, the authors should point out to that they speak only about young even-aged stands.

Response 2: We agree – the information was added.

 

Comments 3:

III. l. 312-314 and throughout the text. The findings demonstrate that, at the individual tree level, beech exhibited greater height than spruce for the same stem diameter, indicating species-specific growth patterns that influence overall biomass production. -> It is a surprise that the authors do not use the term 'form factor/form quotient'. From the European forestry literature, the concept of stem form factor has been known since long ago. Also, it is well known that the form factor of beech is larger than that of spruce---that is, beeches are closer to a cylindric shape. Therefore, the authors' results just repeat the old results of previous generations. I believe, this should be somehow corrected. The Discussion section may be the right place for this.

Response 3: Yes, but the slenderness ratio is also used quite frequently, especially in Central European works.

 

Comments 4:

Conclusion. In my view, what is written in lines 386-406 is a simple repeating of results, which is unnecessary in Conclusion. Instead, the authors could give some key points highlighting the place of the research in a broader context, which is partly done. However, the authors could express their opinion regarding the perspectives of the carbon market. Beeches and spruces will grow under a human supervision or totally freely. But carbon market is a result of a political decision, so the presented results regarding the carbon sequestration are only sensible as long as the countries observe the decision.

Response 4: You are right; therefore, the text was extensively revised.

 

Minor comments

1. 142-143 stands likely originating from artificial regeneration -> Does 'likely' mean that the planting activity 10 yr ago is not known for sure?

We acknowledge that the expression in Lines 141–143 was incorrect. The use of the word “likely” was a mistake. All stands included in the study are of exclusively man-made origin. We apologize for this oversight and have corrected the text accordingly.

1. 218 needle stock -> leaf stock? Because the authors speak about beech.

Corrected.

Figs. 1-7 -> It's a good tradition to place equations on figures with approximation results, together with R2 values.

We added comments to the figure captions to provide information about the specific formulas and statistical characteristics.

1. 333 height vulnerability -> high vulnerability?

Corrected.

Reviewer 4 Report

Comments and Suggestions for Authors

This is my first time to review this manuscript. However, there are many revision patterns in the paper and it is marked as "Revised version review" in the submission system. Nevertheless, I couldn't find the revision instructions. I read the manuscript and put forward some suggestions for revision:

     1.Why are the two plants, European Beech and Norway Spruce compared?

2. What are the key scientific questions in this paper? What research goals are aimed at achieving?
3. I think a table of sample plots can be provided, which is beneficial for comparing the similarities and differences between the two.
4. In the results, secondary titles can be added to present them hierarchically. Currently, the structure seems rather complex.
5. In the discussion, it seems rather unclear what the authors' writing logic is. In addition, it is suggested to add secondary headings.
6. Is the conclusion written too long?

Author Response

Comments 1. This is my first time to review this manuscript. However, there are many revision patterns in the paper and it is marked as "Revised version review" in the submission system. Nevertheless, I couldn't find the revision instructions. I read the manuscript and put forward some suggestions for revision:

Why are the two plants, European Beech and Norway Spruce compared?

Response 1: We have written this explanation, which we hope is sufficiently descriptive:

 

“Considering the European temperate climate zone, European beech (Fagus sylvatica L.) and Norway spruce (Picea abies [L.] Karst.) are among the most common and economically important tree species in a significant portion of European temperate forests. Beech and spruce differ in their growth characteristics, ecological requirements, and responses to ongoing climate change [22]. In the context of climate change, beech is generally considered more resilient than spruce (e.g., [23]). However, at the regional level, their performance depends on various environmental factors. The Carpathians boast highly productive mixed forests with dominance of beech and spruce, highlighting the species' suitability for the region. Future projections indicate that beech may further expand its presence in the area, potentially outcompeting tree species that are more vulnerable to climate change, such as spruce [24-26]. Nevertheless, both tree species play a crucial role in European temperate forests and contribute significantly to carbon sequestration and climate sustainability at both the European and global levels [27-28].”

 

…and also:

 

“We focused exclusively on young planted stands. When comparing the two species—beech and spruce—with respect to their differing leaf retention strategies, we hypothesized that they would exhibit contrasting carbon dynamics. Specifically, the deciduous beech to lose more carbon annually (transferring it from biomass to necromass via litterfall) than evergreen spruce might be expected.”

Comments 2: What are the key scientific questions in this paper? What research goals are aimed at achieving?

Response 2: We believe that we have clearly stated our goals:

“The objectives of this work, focusing on pure European beech and Norway spruce plantations, are as follows:

- to model tree biomass components (foliage, branches, stem, and roots) at the individual tree level using tree height and/or stem diameter as predictors.

- to model stand biomass stock, including all above- and below-ground tree components, using mean stand height, stem diameter, and age as predictive variables.

- to estimate the amount of carbon fixed in young stands and discuss the price of carbon (potentially calculated via carbon dioxide), which could theoretically be implemented within the carbon credit market.

- to make interspecific comparisons of all the above-mentioned dependent variables.”

 

…and moreover this:

 

“We focused exclusively on young planted stands. When comparing the two species—beech and spruce—with respect to their differing leaf retention strategies, we hypothesized that they would exhibit contrasting carbon dynamics. Specifically, the deciduous beech to lose more carbon annually (transferring it from biomass to necromass via litterfall) than evergreen spruce might be expected.”

Comments 3: I think a table of sample plots can be provided, which is beneficial for comparing the similarities and differences between the two.

Response 3: Initially, we intended to present such a table. However, the table may be too complex. Specifically, we have 15 + 15 plots, each with 3 subplots, and we conducted measurements over four years (2000–2003). We hope that the table is not necessary for the primary objectives of the manuscript.

Comments 4: In the results, secondary titles can be added to present them hierarchically. Currently, the structure seems rather complex.

Response 4: Yes, we added secondary titles to clarify the structure of the Results section.

Comments 5: In the discussion, it seems rather unclear what the authors' writing logic is. In addition, it is suggested to add secondary headings.

Response 5: Ok, so we added secondary titles to make the structure of the Discussion section more transparent.

Comments 6: Is the conclusion written too long?

Response 6: The Conclusion section was quite long due to requirements from other reviewers. However, we have excluded some sentences to make it more concise.

Reviewer 5 Report

Comments and Suggestions for Authors

Understanding the biospheric role of forests makes the study of forest bioproductivity an urgent issue. At the same time, the study of forest bioproductivity is very time-consuming. Therefore, qualitative research in this scientific field is highly valued by researchers. The paper looks good. The authors have carried out a thorough study. The research results obtained are novel and of practical importance. Two approaches were used to analyze young forest trees and stands: destructive tree sampling and repetitive tree measurements. At the same time, the authors used methods appropriate to the tasks set. This allows us to consider the choices made to be justified. I have no big comments. However, I can advise you to present the design of the study in the form of a visual figure. This will make the research easier to understand. I also have an idea that there may be room for improvement in the discussion. It is imperative to underscore in the discourse that forestry on a global scale is predicated on forest typology. It is evident that the practical recommendations and all efforts are directed towards specific types of forests. In my opinion, the authors did not adequately address this aspect in the study. Theoretical conclusions and practical recommendations become important only when the forest typological features of forest growth and development are taken into account. In order to achieve this objective, it is imperative to depend on a reliable ecological classification of forests. It is imperative that this aspect is reflected in the methodology and discussion. A synopsis of forest typologies might prove advantageous to the authors: Ivanova, N.; Fomin, V.; Kusbach, A. Experience of Forest Ecological Classification in Assessment of Vegetation Dynamics. Sustainability 2022, 14, 3384. https://doi.org/10.3390/su14063384.

Author Response

Comments 1: Understanding the biospheric role of forests makes the study of forest bioproductivity an urgent issue. At the same time, the study of forest bioproductivity is very time-consuming. Therefore, qualitative research in this scientific field is highly valued by researchers. The paper looks good. The authors have carried out a thorough study. The research results obtained are novel and of practical importance. Two approaches were used to analyze young forest trees and stands: destructive tree sampling and repetitive tree measurements. At the same time, the authors used methods appropriate to the tasks set. This allows us to consider the choices made to be justified. I have no big comments. However, I can advise you to present the design of the study in the form of a visual figure. This will make the research easier to understand. I also have an idea that there may be room for improvement in the discussion. It is imperative to underscore in the discourse that forestry on a global scale is predicated on forest typology. It is evident that the practical recommendations and all efforts are directed towards specific types of forests. In my opinion, the authors did not adequately address this aspect in the study. Theoretical conclusions and practical recommendations become important only when the forest typological features of forest growth and development are taken into account. In order to achieve this objective, it is imperative to depend on a reliable ecological classification of forests. It is imperative that this aspect is reflected in the methodology and discussion. A synopsis of forest typologies might prove advantageous to the authors: Ivanova, N.; Fomin, V.; Kusbach, A. Experience of Forest Ecological Classification in Assessment of Vegetation Dynamics. Sustainability 2022, 14, 3384. https://doi.org/10.3390/su14063384.

Response 1: Thank you for your comments. While we cannot significantly alter the philosophy and structure of the work to fully align with your suggestion (the incorporation of the typological principle throughout the paper), we have added a brief comment and included the recommended citation at the end of the Discussion section to partially address your request, specifically:

“It is important to note that, in the case of forest lands, the selection of tree species for plantations should be based on traditional knowledge derived from forest typology, in order to respect the optimal ecological conditions for growth [46]. On the other hand, these principles have limited applicability on former agricultural lands.”

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The reviewer's opinion is not overly critical, but rather objective, as it is based on a thorough examination of the research materials. After reading the authors' responses to the review, my viewpoint remains unchanged.

For a long time, researchers have investigated how biomass accumulates with age and how biomass varies with tree diameter and height of these species. As well as biomass modelling for other tree species. Nothing new was obtained in this study.

Existing studies on biomass in mature trees rarely include the root system. But it is common for young trees to include the biomass of the root system in the calculations. Because determining the biomass of young tree root systems using destructive methods is significantly simpler than conducting equivalent experiments on mature trees.

The fact that the tree species analysed are common or dominant in Europe does not negate the predictability of the results. Different plant species that have diverged throughout evolution have different biomass and carbon accumulation rates.

Your research would be much more valuable if you were to compare the biomass accumulation of two species of deciduous trees or two species of conifers.

“By the way, what would we have gained if we had performed our own chemical analyses on the sampled biomass in the measured stands?” Sorry, but with this approach it is best not to conduct any research at all.

p.s. Positive aspects should be highlighted in spite of all the critical issues addressed in this study. Banal statements on the dependence of biomass of woody plants on age, diameter and height of trees were eliminated from the Conclusions section following the article revision.

Author Response

Comments 1:

The reviewer's opinion is not overly critical, but rather objective, as it is based on a thorough examination of the research materials. After reading the authors' responses to the review, my viewpoint remains unchanged.

Response 1: Sorry that your opinion hasn't changed. I think you're too skeptical about the significance of your work. Maybe this bit of wisdom will help shift your perspective: 'There are three kinds of truth—yours, mine, and the real one…'

Comments 2: For a long time, researchers have investigated how biomass accumulates with age and how biomass varies with tree diameter and height of these species. As well as biomass modelling for other tree species. Nothing new was obtained in this study.

Response 2: OK, but this type of research is still ongoing, and models of biomass, growth, and production have yet to be developed for all situations and conditions—especially during the early growth stages. We have been conducting this kind of research for two decades and are well-acquainted with the existing literature. As a result, we can clearly distinguish between what is already known and what remains unexplored. We do not conduct or publish findings that are already well established.

Comments 3: Existing studies on biomass in mature trees rarely include the root system. But it is common for young trees to include the biomass of the root system in the calculations. Because determining the biomass of young tree root systems using destructive methods is significantly simpler than conducting equivalent experiments on mature trees.

Response 3: Biomass models that include root components are mostly available for seedlings, and are rarely developed for larger trees. In our study, we did not measure seedlings, but trees up to approximately 5 meters in height—which are still challenging to excavate, even at that size. For context, one should refer to Annighöfer et al. (2016), “Species-specific and generic biomass equations for seedlings and saplings of European tree species” (European Journal of Forest Research). Meta-analyses in this work have focused on aboveground biomass, as data for root biomass remain sparse.

Comments 4: The fact that the tree species analysed are common or dominant in Europe does not negate the predictability of the results. Different plant species that have diverged throughout evolution have different biomass and carbon accumulation rates. Your research would be much more valuable if you were to compare the biomass accumulation of two species of deciduous trees or two species of conifers.

Response 4: We compared two tree species due to their differing foliage retention strategies, with the expectation that beech would produce more litter than spruce. However, the results were surprising—our findings revealed a novel outcome that contradicted this assumption.

Comments 5: “By the way, what would we have gained if we had performed our own chemical analyses on the sampled biomass in the measured stands?” Sorry, but with this approach it is best not to conduct any research at all.

Response 5: This is not a strong argument. You prefer carbon content research over biomass research, but it's well-established that carbon content values are generally more consistent (falling within a narrow range), whereas biomass values show high variability. This is widely accepted.

Comments 6: p.s. Positive aspects should be highlighted in spite of all the critical issues addressed in this study. Banal statements on the dependence of biomass of woody plants on age, diameter and height of trees were eliminated from the Conclusions section following the article revision.

Response 6: Thank you for the positive comment. Once again, we're very sorry to hear that you're not satisfied with our work.

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for the answers given and text processing. I have no more remarks on the article.

Author Response

Thank you for the answers given and text processing. I have no more remarks on the article.

Reviewer 3 Report

Comments and Suggestions for Authors

I have read the responses of the authors and find they as well as the corrections done to be quite satisfactory. I do not have any further issues to raise.

Author Response

I have read the responses of the authors and find they as well as the corrections done to be quite satisfactory. I do not have any further issues to raise.

Reviewer 5 Report

Comments and Suggestions for Authors

The authors have responded to my comments and improved the paper. I have no further comments.

Round 3

Reviewer 1 Report

Comments and Suggestions for Authors

All the responses made by the authors are clear, thoughtful, and satisfactory. Everything ok. Thanks to the authors for their work.