General comments:

This paper elucidated the relationship between climate and the phylogenetic and morphological divergence of global spruces (Picea) in the Northern Hemisphere. The authors found that temperature parameters and precipitation parameters tended to be the main driving factors for the primary divergence of spruce phylogeny and morphology, respectively. The primary divergence of morphology and phylogeny among the investigated spruces at 3388 sites tended to be driven by different selective pressures.
I think this paper is scientifically significant. The subject of the paper fall within the scope of the BG special issue (Ecosystem processes and functioning across current and future dryness gradients in arid and semi-arid lands). It is concise, well structured, and well written. The manuscript has a merit for publication in the SI (Ecosystem processes and functioning across current and future dryness gradients in arid and semi-arid lands). However, the manuscript can potentially be improved largely on the basis of referees’ comments and authors responses to the comments.

Therefore, I decide a major revision.

My specific comments:
1. Please simplify and specify abstract.
2. Add climatic zone distribution of climatic zone distribution to the methods section.
3. Add a statement of significance of the findings in this paper in relation to climate change to abstract. Discuss significance and implications of the findings of this research in relation to future climate change.

General comments:

The authors of the manuscript (bg-2016-465) addressed the reviewers’ issues clearly and answered our questions well. The manuscript has been largely improved and reaches the standard of BG. Therefore, I decide a minor revision. However, although authors clearly showed point-by-point revisions on the basis of reviewers’ and my comments by a marked-up copy of the revised manuscript, I would request authors to provide a point-by-point response list to each reviewer’s and my comments, showing how and where the revisions are in the revised manuscript. In addition, I have more minor comments as listed below for authors to respond.

Specific comments:

1. Line 13-14, what do you mean by ’at 31 nodes’ and ‘at 32 nodes’?
2. L16, add complete name of Dmax because it is mentioned first time.
3. Please add some new references published in year 2015 and 2016 in introduction and discussion.
4. Line 158-159, why you use P value less than 0.0016? I suggest a consistent significant level of 0.05 or 0.01 throughout text. Besides, I would like to have P value when you talk about statistical significance.
5. Line 160, rewrite ‘α=0.05/31 or 32≈0.0016’.
6. L220-222, move this statement to discussion.
7. L225, use specific p value.
8. L228-248, keep verb tense consistent throughout text. Similarly, check the tense throughout text.
9. L297, associated with
10. L299, what is the first hypothesis? You may underscore in the introduction or brief it here. Authors did not test the so-called second hypothesis that authors mentioned in the introduction. Please test the second hypothesis.
11. L432, please specify the statement ‘Our hypotheses are largely verified……’. Which hypothesis you specifically referred to?

Dear editor of BG,
I checked the revised manusript (bg-2016-465 ) carefully . The authors satisfacorilly answered all referees' and my questions and solved issues accordingly. I think the manusript now reached the BG level. Therefore, I would like to recommend the paper for final publication in BG Special Issue ( Ecosystem processes and functioning across current and future dryness gradients in arid and semi-arid lands).
Kind regards,
Tianshan Zha