Young Silver Birch Grows Faster and Allocates Higher Portion of Biomass into Stem Than Norway Spruce, a Case Study from a Post-Disturbance Forest

Round 1

Reviewer 1 Report

The authors must describe the equipment used in the paper.

The authors must add 5 bibliographic references, from 2020 year, in the field of the paper. 

The paper analyzes aspect of wood biomass. This topic is current. The text is clear and easy to follow.   In conclusion the authors must  make a comparative study with value obtain on the woody species (silver bich and Norway spruce).

Author Response

We are very grateful for helpful comments from both reviewers! Thank you so much!

The authors must describe the equipment used in the paper.

We added the equipment description in the “Research site and transects” section.

The authors must add 5 bibliographic references, from 2020 year, in the field of the paper. 

We have added some papers published in 2020 and 2021.

The paper analyzes aspect of wood biomass. This topic is current. The text is clear and easy to follow.   In conclusion the authors must make a comparative study with value obtain on the woody species (silver bich and Norway spruce).

We have added values to compare the tree species (for diameter increment and wood density) in the Conclusions sections.   

Moreover, we made linguistic revision of the text.

Reviewer 2 Report

In this paper, young silver birch (B. pendula Roth.) are compared with Norway spruce (Picea abies L. Karst) growing on the same site with respect to the contribution of tree components to aboveground biomass stock, wood density, radial increment and aboveground biomass production. Species were considered in ecological and productive contexts. The authors conducted their research in the Tatra National Park (TANAP), northern Slovakia on post-disturbance area. The results showed that birch has 40% greater diameter increment and 30% denser stemwood than spruce.
Overall, the work does not show a high degree of novelty. It is well known that birch is a pioneer and fast-growing tree species. This fact has already been described in many publications and forest ecology books. However, the study may have important implications for forest management due to climate change and more frequent extreme events such as storm events. As a pioneer and fast-growing species, Birch can provide rapid forest regeneration after disturbance and ensure faster forest succession. This may be particularly important in mountainous areas where forests fulfill many protective functions (e.g. soil protection). 
I am not entirely convinced that the results of the study in National Park should include important conclusions based on species productivity. Such a statement should include the suggestion that the study can be considered in a broader context, i.e. that results may have significant implications for managed forests - where productive functions are more likely to be considered - than in a national park where protective functions predominate. This should be highlighted in the introduction and discussion.
The methodology was properly planned and the results were presented in a way that does not give rise to major comments.
The weakest part of the manuscript is the discussion section, where both species' potential should be discussed in an ecological and productive context instead of focusing mainly on birch. "Ecological aspects" largely reduces this part of the manuscript to a repetition of the results. The authors should mention and better describe the ecological benefits of foliage mass in both species. Leaf litter is the link between the tree canopy and the soils beneath, adding the nutrients accumulated from its biomass, influencing forest productivity and tree growth. This was only addressed in one sentence in the manuscript. It would also be beneficial if the authors better addressed other ecological factors, allowing them to draw more profound conclusions, especially from an ecological perspective. "Wood production aspects" addresses the main points and does not require significant changes.
Minor and editorial comments:
l. 57. change "light tolerant" to light-demanding;
l. 102, 524 remove one dot;
l. 269, 272 and elsewhere - please correct superscripts through the manuscript; 
l. 503, 504 please put the names of the authors before the reference number.

Author Response

We are very grateful for helpful comments from both reviewers! Thank you so much!

In this paper, young silver birch (B. pendula Roth.) are compared with Norway spruce (Picea abies L. Karst) growing on the same site with respect to the contribution of tree components to aboveground biomass stock, wood density, radial increment and aboveground biomass production. Species were considered in ecological and productive contexts. The authors conducted their research in the Tatra National Park (TANAP), northern Slovakia on post-disturbance area. The results showed that birch has 40% greater diameter increment and 30% denser stem wood than spruce.
Overall, the work does not show a high degree of novelty. It is well known that birch is a pioneer and fast-growing tree species. This fact has already been described in many publications and forest ecology books. However, the study may have important implications for forest management due to climate change and more frequent extreme events such as storm events. As a pioneer and fast-growing species, Birch can provide rapid forest regeneration after disturbance and ensure faster forest succession. This may be particularly important in mountainous areas where forests fulfill many protective functions (e.g. soil protection). 

I am not entirely convinced that the results of the study in National Park should include important conclusions based on species productivity. Such a statement should include the suggestion that the study can be considered in a broader context, i.e. that results may have significant implications for managed forests - where productive functions are more likely to be considered - than in a national park where protective functions predominate. This should be highlighted in the introduction and discussion.

Thank you for the comment. In fact, forest management at the research site (although it is a part of the Tatra National Park) is rather close to that in commercial forests. Thus, our results could be useful besides other purposes also for wood production in mixed spruce-birch stands.

To make the real situation clear to a reader, we have added this information in the Material and Methods section:

Actually, entire forest management, i.e. from forest regeneration to harvest, in this area is very close to “ordinary” forestry approaches promoting both wood production and other ecosystem services. On the other hand, forest management is limited or fully excluded only in the core of the Tatra National Park (not our case), specifically in high altitudes with alpine vegetation and in deep valleys with old-growth forests. 

The methodology was properly planned and the results were presented in a way that does not give rise to major comments.

The weakest part of the manuscript is the discussion section, where both species' potential should be discussed in an ecological and productive context instead of focusing mainly on birch. "Ecological aspects" largely reduces this part of the manuscript to a repetition of the results. The authors should mention and better describe the ecological benefits of foliage mass in both species. Leaf litter is the link between the tree canopy and the soils beneath, adding the nutrients accumulated from its biomass, influencing forest productivity and tree growth. This was only addressed in one sentence in the manuscript. It would also be beneficial if the authors better addressed other ecological factors, allowing them to draw more profound conclusions, especially from an ecological perspective.

Yes, we fully agree! Thus, we have extended the text of the “Ecological aspects” section. We explained more about characteristics of foliage litter in both birch and spruce as well as litter effects on soil properties.   

"Wood production aspects" addresses the main points and does not require significant changes.

Minor and editorial comments:
l. 57. change "light tolerant" to light-demanding;
l. 102, 524 remove one dot;
l. 269, 272 and elsewhere - please correct superscripts through the manuscript; 
l. 503, 504 please put the names of the authors before the reference number.

We corrected the mistakes all over the text.

Round 2

Reviewer 2 Report

Thank you that the authors have corrected the manuscript according to my suggestions. In particular, I think the passage added in the discussion was necessary. Although I still think that this study is not innovative, the appropriately designed research and the analyses carried out quite well lead me to accept the article in its present form.