Shifts in Climatic Influences on Radial Growth of Scots Pine in the Central Scandinavian Mountains with an Evident Transition in the 1970s
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript analyzes the effect of temperature, precipitation and snow depth on the radial growth of Scots Pine in the Scandinavian Mountains. The way the work is approached seems very appropriate to me through the use of dynamic moving window heat map analysis. The dendrochronological study allowed us to determine the transition in the change of trend and the role of temperature in radial growth. The way the results are presented in tables and figures seems appropriate to me, so I have no additional comments. The only comment on the methodology is in the Handölan TWR chronology in which they should point out the reason why they had 40 to 50 trees for most of the data, except for the period from 1999 to 2002 with only approximately 20. The authors point out the limitations of the work, but emphasize the importance of the main results obtained and pointed them out in the discussion.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsDear authors,
I have reviewed the manuscript entitled “Shifts in Climatic Influences on Radial Growth of Scots Pine in the Central Scandinavian Mountains with an Evident Transition in the 1970s” submitted by Ulrika Gomm and collaborators for publication in Climate.
The manuscript evaluates the climate-growth relationship of a previously developed Scots pine chronology in the central Scandinavian mountains using a moving windows approach in order to identify possible changes in the relationship. This type of study is relevant to account for the decoupling between climate variables and tree growth in several forest types in the northern hemisphere as a consequence of climate warming.
Major Comments:
The manuscript is well written and address the study objective. However, it needs improvement to achieve the level of an original article.
The research question underlies the introduction, but it is not well defined as the objective of the study. The reader could not capture it by reading lines 61 to 70. The last paragraph of the introduction should contain the objective of the study and not the main conclusions. Please take care of this part as it is the main part of the introduction where the reader finds the need of this study.
The manuscript presents only three moving climate (temperature, precipitation, snow)-growth relationship of one tree-ring chronology as an original data, and dedicate several figures to climatic data available for the study site. I believe the authors could make better use of the data set, not only tree-ring data but also climate data. For example, the authors could compare the response of growth to past and recent climatic events, defining events considering months that showed changing influences. Another improvement source could be analyzing the individual variability in the climate-growth relationship (standard and moving) and comparing it with the mean chronology behavior. It is known that averaging individual response to build mean chronology could mask interesting variability at population level. Authors could run dcc_function at individual level and then plot (jitter) the response with the mean response at population level (chronology). By doing this analysis, authors could discuss the behavior at tree- to population level by considering other potential factors limiting growth. I believe that focusing the manuscript only on the temporal evolution of the climate-growth relationship misses the potential of the study.
The methodology is fairly straightforward, but more details are needed, particularly on the detrending method. Considering that the authors only use the final part of an extended chronology, I have doubts about the use of the negative exponential curve. Also, the authors do not mention if they pre-whitened the chronology. The readers need the age of the trees, and/or a chronology statistics table in order to know more about the chronology and the selection of the detrending method.
In addition to the aforementioned potential analyses that would give more scope to the manuscript, I would suggest reanalyzing the snow data. As the main change in the region is the extension of the growing season with concurrent shifts in the timing of snow events (start / end days Figure5), a daily approach could give other direction to the analysis. A daily approach, such as those using dendroTools or climwin (see Rubio-Cuadrado et al. 2022. Dendrochronologia, 71, 125916; or Camarero et al. 2020. Forests, 11(12), 1250), using daily snow and tree ring data could be quite interesting in providing evidence on the shift in climatic variables.
In addition, considering the lack of weather stations (or their short duration), the authors could consult the CRUTS v4.05 dataset (temperature and precipitation in 0.5° × 0.5° latitude-longitude grid cells) to compare the results obtained. These climate data are less local, but are useful when weather stations are scarce or incomplete.
In relation to the lack of in-depth analysis of the data, the Results and Discussion section does not explore the totality of the evidence of shift in the Scots pine climate-growth relationship.
Finally, figures and tables are generally clear and informative. However, several figures could be unified or re-plotted to enhance the clarity of the manuscript. I recommend to join Fig 1 and 2. Plot Temperature and Precipitation together (two plots in one figure) and used the same format (anomalies) as the authors used with Temperature. Plot together Fig 4b and 5 (or left only Fig 5 and put Fig 4b in an appendix). Figure 6 needs horizontal line at y=1, add sample depth as right y-axes, and change the y-axes name to Tree-ring index or Std chronology. Figure 7,8,9: please delete X3 to each y-tick names, authors can extract the values obtained by treeclim package and plot with ggplot in order to set the axes ticks names.
Based on the above comments, I recommend the manuscript for considerable improvement before it can be considered for publication. The study is significant and provides valuable insights, but the aforementioned revisions will improve its clarity and impact.
Minor comments
Please avoid mentioning RStudio in the manuscript (line 63 and 126). RStudio is only the interface to use the R packages.
Do not use spatio-temporal, as the manuscript does not inspect changes at spatial scale
Line 143: The approach used in the manuscript is not innovative. This type of analysis is used all over the world.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsDear authors,
Thank you for your answers, I sincerely believe that further analysis of the results would have been interesting. However, the study answers the original question.
