General comments

How are the results relevant for simulation models of tree growth and competition (that is, for projections of climate change effects on forests at landscape and broader scales) especially for those models that account for physiological species traits such as temperature and drought tolerance?

I assumed that the methodology is sound (not my expertise) and concluded that the study is sound and the results useful.  I found the study interesting, well-presented, and I think it would make a great addition to the forestry literature.

In general, the English is understandable and quite passable, but it could be improved.  I have made some suggestions below, but others could be made.  However, the English is very adequate given that English is not likely the native language of any of the authors. 

Specific comments

First paragraph.  The phrase “at stake” as used here is probably not the best because it is somewhat ambiguous.  “At risk” or “threatened” would be more accurate.

L 52.  Warming may also affect disturbance rates and intensity, also impacting mortality.  See https://doi.org/10.1016/j.scitotenv.2024.177043.

L 93.  What is the expected mechanism driving the prediction about species responses in H3?  Such mechanisms are important to convey the a priori nature of your hypotheses.

L 102.  Is this describing the design of the inventory or your study?  Or both?  Not clear.

L 109.  Give the rationale for excluding these trees.  Also provide the rationale for the method described in L 100.

L 112.  Reword to: “value magnitudes higher than”

L 115.  Define acronym (COFECHA).

L 123.  What time period do the climate data represent?

L 138.  Reword to: “could not end until after September 1^st.”

L 143.  Run-on words.

L 144.  Is “mean soil moisture values” the wetness probability described in the prior sentence?  Unclear.

L 184.  Re: “while precipitation and SPEI…” – should this read “reduced precipitation”?

L 188.  Re: “The growth response to precipitation and SPEI became increasingly positive with increasing MAT (Fig. A2; Table 1). Has the SPEI acronym been defined?  I think the index itself should be defined to ensure that readers are aware that it goes quite negative with severe drought.

Results presentations (especially graphs) are excellent!  The results data are difficult to interpret, but the presentation helps some and the text descriptions of the meaning of the results help a LOT.

L 260.  Here and throughout, you might consider using “relative MAT” given that in Sweden, your MAT is relatively low compared to elsewhere on the globe.  You might somewhere in the discussion discuss the generality of your results in the context of the globe.

L 277.  I would have liked some speculation about the mechanism for this result.  Is permafrost involved?  Is some precipitation in the form of snow that is lost before the growing season?

L 299.  Didn’t you exclude plots on wet sites?

L 321.  I would like to see more exploration of this discrepancy with other results.  Did this cause you to question your results?  On what basis do you trust these results?

L 328.  “indicators for” seems to be the wrong phrase here.  “drivers of?”

L 337.  Other studies have suggested that long periods of stress are required to actually kill trees because even one good year can rebuild reserves.  For example, see DOI: 10.1002/ecs2.1253.

Tree growth is a fundamental and widely used term in plant science and ecology. The current study aimed to explore and explain tree ring width response to temperature and precipitation gradient over almost 2000 plots across a gradient of climatic conditions in the boreal forests of Sweden. The analysis revealed that in cold environments tree growth responds positively to an increase in the ambient temperature, while in “warm” environments, trees reduce growth due to an increase in ambient temperature. Additionally, soil moisture can mitigate reduction in tree growth in areas of high MAT. Overall, the analysis is well done and has an important value. However, as a whole, this study needs to strength and clarify the main message. I found some descriptions are too detailed, whereas some important steps were either ignored or provided with very little information. Therefore, I recommend this to be gone through a major revision. I explain my concerns in more detail below.

Major comments:

1. The ideas in introduction are leaping through one to another without a proper flow. Also, different terms were not consistent across the document, which makes this document very confusing. It begins with a description of the economic implications of tree growth, which is not the central focus of the study. Additionally, there is excessive use of the term “climate change” and occasional use of “global warming.” I recommend define the scope of what aspect of climate change is being investigated. This needs to be clearly defined, as “climate change” on its own is too vague.
   
   Terms like “high temperature” and “high/low soil moisture” are also imprecise and need to be quantified or clearly contextualized—what temperature or soil moisture levels are considered “high”? use the actual value or range of values. That will allow a more application result in other areas. Overall, this section failed to answer/ satisfy "why" it is important? Then, need more specific information about "why" this particular species?
2. The tree species (the core subject of the paper) are barely introduced. The introduction does not explain why these two species are meaningful. The introduction should describe their geographical distribution, ecological characteristics, and the typical range of temperature, VPD, and soil moisture conditions in which they thrive. It should also reference recent studies related to their responses to environmental stressors that are investigated here.
3. All the hypotheses refer to specific regions that are not even mentioned in the introduction, despite playing a central role in the study.
4. There is a clear lack of background on previous research on the physiological responses of conifer trees to temperature and soil moisture. Key studies in the field—such as those by Wagner et al., 2021; Zweifel et al., 2006, Zweifel et al., 2021; Klein et al., 2014; Novick et al., 2024 —are notably absent and should be incorporated to establish the scientific context on trees physiological response to soil and atmospheric conditions.
5. H4 needs to be rewritten and detailed- how each species will respond to an increase/ decrease in ambient temperature? How will each species respond to an increase/decrease in soil moisture? And add a paragraph in the introduction that explains why you hypothesize for each species.
6. In the method section, a brief sites descriptions was missing, more details, such as what the dominant tree species are, their approximate age, and overall environmental conditions. Snow? Solar radiation?
7. In Figure 1B, the comparison between high and low soil moisture needs to be clearly defined. What thresholds or criteria were used to distinguish “high” from “low” soil moisture? And why not give the actual values of soil moisture (v/v %)?
8. Regarding the calculation of the Standardized Precipitation-Evaporation Index (SPEI), the authors mention using net solar radiation based on latitude. However, cloud cover, which can significantly affect incoming radiation, is not addressed. Was this factor considered or accounted for in the calculations?
9. In the results section, I suggest adding a short description of the number of extreme events experienced by the trees during the study period. Were high-temperature extremes or low-precipitation events more frequent? Additionally, it would strengthen the results to quantify the reduction in RWI associated with extreme increases in temperature and extreme reductions in precipitation.
10. I recommend expanding the discussion on the threshold between atmospheric demand (VPD) and soil moisture availability. This would provide valuable ecological insight into species-specific sensitivities under climatic stress.