Long-Term Growth Trends of 18 Native and Non-Native Tree Species Based on Data from Experimental Plots Since 1878 in Brandenburg, Germany

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This work investigates growth trends in both native and non-native forest species through the analysis of experimental plots spanning from the late 19th century to the present. It highlights the impact of environmental changes, especially recurrent droughts in last decades, on standing volumes and tree height increments. The findings reveal significant long-term growth increases for species like Scots pine (Pinus sylvestris) and Sessile oak (Quercus petraea), while documenting recent declines, post-2000, for 16 out of the 18 studied species due to intensified droughts driven by climate change.

In this context, I am delighted to learn of the complexity of forest species responses to environmental pressures, demonstrating significant inter-species variability with no clear distinction between native and non-native species. This underlines the importance of forest management strategies focusing on genetic diversity, resilience and adaptability to local conditions, through approaches based on assisted migration and gene flow to enhance the potential for intra-species adaptation.

The introduction correctly contextualizes the major issues related to tree growth dynamics in European forests in the face of climate change and the issue of assisted migration and provides a clear overview of the subject of the study, with bibliographical references that are generally well chosen. The methodology provides detailed descriptions of the data collection, modeling processes, and analytical frameworks used to understand how tree species in Brandenburg, respond to long-term environmental changes. However, I have some suggestions to further improve the manuscript:

·       The abstract would be improved by adding a sentence on the practical implications of this work.

·       L50-70: part of this section of the introduction is reserved for methodological aspects. Although these details are interesting, they could be partially moved to the Methodology section to refocus the introduction on the problem, the state of the art and the objectives.

·       In the method section and for the analysis of the results, it would have been more interesting to:

o   test other modeling approaches to integrate uncertainties and complex interactions between factors in a more rigorous way;

o   prospect other tests to judge model quality (BIC for example);

o   Monitor local climatic variations in greater detail to assess their direct impact on species; and

o   Investigate how individual species respond to environmental gradients, notably precipitation and temperature.

·       In the Discussion section:

o   Improve the section addressing the implications of the findings, and consider isolating this section to enhance clarity.

o   Present and discuss the practical implications of the results for managers and policy-makers.

o   Better present and discuss the limitations of the study and suggest specific future research perspectives (e.g. Set up a continuous monitoring network to detect signs of stress or species decline at an early stage; Test other modeling approaches; Simulate growth under future climate scenarios to understand how these changes might affect these species...)

Author Response

Please see the attachement!

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The article discusses the unique results of observations of the growth of 18 tree species in Germany, some of which are almost 150 years old. It shows a decrease in growth rates for almost all tree species over the past 20 years, which is alarming. It is noted that climate change leads to the spread of some tree species and the suppression of the spread of others. The article is very interesting and can be published, but there are questions and recommendations for the manuscript.

1. The work considers factors affecting growth, such as temperature and precipitation. But will forest density, i.e. shading, affect tree growth?

2. In the Materials and Methods section, the authors proposed a model for assessing tree growth. How did the authors verify the proposed model?

3. The authors assume uniform tree growth in the model. However, if you look at the rings on the cut of the trunks, they are not always uniform. How is this taken into account in the model?

4. Section 2.4. Why were three unequal periods of time taken for the study?

5. Why didn’t the authors construct correlations between tree growth and temperature, precipitation, the amount of carbon in the atmosphere, and soil fertility?

Author Response

Please see the attachment!

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The current version has been substantially improved and has addressed all the previous remarks. The revised manuscript is much more comprehensive and robust. The efforts in incorporating the suggested changes have significantly enhanced the quality of the paper.

Reviewer 2 Report

Comments and Suggestions for Authors

The authors significantly revised the manuscript, corrected all the reviewer’s comments or gave a substantiated answer to why the study was conducted in such a design. I think that the article has improved significantly and may be approved for publication.