Seasonal, Monthly, Daily, and Diel Growth, and Water Status Dynamics of Balsam Fir in a Cold and Humid Boreal Environment

Round 1

Reviewer 1 Report

Comments for author File: Comments.pdf

Author Response

Reviewer 1
The main strength of this study is a 3.1 million stem radius measurements made over
a period of more than a decade. It is extremely valuable dataset that can provide knew
insight into various physiological processes in balsam fir growing in a cold and humid
boreal environment.
• Thank you
Overall, the manuscript is quite well organized and written, however there are some
important issues that need to be addressed.
Objectives/hypothesis
I strongly recommend re-thinking on what is the main goal of this study. Currently there
is several objectives, aims and expected results presented in the text and not all are
appropriately addressed in results (e.q. aim (2) and (3) of secondary objectives).
According to presented results authors achieved primary objective and aim (1) of
secondary objective. Aims (2) and (3) should be statistically tested (corelations,
ANOVA, …). From the last sentence in Conclusions (396-398) it can be concluded
that these kind of analysis are planned in further work. It is a reasonable plan,
however, then objectives need to be edited to fit the results. Also, first two sentences
in Abstract (14-18) are a bit misleading as with results of this study authors do not
elucidate the variations in tree growth in response to variations in environmental
factors, but only bring data on the growth variation.
• We removed secondary objectives 2 and 3, which were exploratory in nature
and were addressed to the Reviewer's satisfaction.
• We also modified the first two sentences of the abstract to emphasize the lack
of understanding of tree phenology rather than the missing information on the
growth response to variations in environmental factors.
“Zero growth” concept and decomposition of signal
Concept should be explained in more detail earlier in the Introduction, and not only
under aims.
• The concept is now explained in more detail earlier in the introduction.
Furthermore, M&M should include detail description on how the decomposition of
signal was performed. Figure 1 is not good figure under M&M as it does not explain
the procedure of signal separation to growth, dehydration and rehydration. A
scheme/decision tree/protocol should be presented to explain the reader the
calculation process.
• The calculation process is now mathematically formulated, and Figure 1 has
been moved to the results section.
Figures
Overall, too bad quality. Good practice is to avoid colours (as it is not useful in B-W
printing) and use different marker/line/pattern types.
• Although we do not totally agree with the Reviewer's comments concerning the
poor quality of the figures, these were modified to try to meet most of his/her
expectations, including switching to black and white figures.
Figure 1 – not for M&M, but for Results. Only first two graphs are important. VPD, Rad
and Ta - too much information whit no clear use in the paper. First graph can be all in
black, as differentiation between growth, dehydration and rehydration is not visible.
For second graph, the colours on the legend do not differ in B-W print. Recommend
to write rehydration/growth on y-axis above 0 and dehydration on y-axis below 0.
• As mentioned above, Figure 1 has been moved to the results section. However,
we think it is relevant to keep the climate data panels because they allow us to
discuss patterns observed in individual time series that are not discernible from
the average patterns presented in Figure 2. We do not agree with the
Reviewer’s proposal to not distinguish between growth, dehydration, and
rehydration in the first panel of Figure 1, but we have sharpened the contrast
between shades of gray to better distinguish the three parameters in the first
two panels. We also followed the recommendation to add information on the yaxis. We hope this compromise will satisfy the Reviewer.
Figure 2 - left column all in one colour as you have only one line in each graph.
Suggestion is to try to combine rehydration and dehydration as one graph with above
0 and below 0 data. Or et leat swap the position to be more intuitive for the reader.
Legend for line (daily averages) and dot (monthly averages) is missing.
- right column use different line types instead of colours. Shaded area is not visible
enough, should be darker.
• Based on the Reviewer's comment, the figure has been changed to black and
white, with line types used to differentiate the curves of the right column panels.
We combined rehydration and dehydration in one graph. We added a legend
for lines and dots in the left column and darkened shaded areas.
Results, Discussion
Should be harmonized with new objectives. Statements that some variables are
synchronized (line 234, 267, 366…) should be avoided unless they are tested with
statistics.
• Note that we already express moderate and thus reasonable statements about
the relationships between stem radius variations and climate variables.
However, some statements, such as the one about synchrony between
maximum average growth and maximum day length, are based on
observations and do not, in our opinion, require statistical testing.
Maximum day length is mentioning but there is no data on it in Figure 2. ?
• It is well known that the summer solstice (June 20-21) is the day with the
longest duration of daylight in the northern hemisphere. We do not consider it
relevant to illustrate this variable in the figure.
Line 191 – add “left column” after “Figure 2.”
• Corrected.
Line 201 – Autumn instead of fall
• Corrected.
Line 204 – add “average” before “seasonal”
• We prefer not to add the word “average” before “seasonal” in the figure caption
because it is already mentioned in the caption that the patterns presented are
“for all monitored trees (averaged)”.
Line 225 – delete “changes”
• Corrected.
Line 226 – add “right column” after “Figure 2.”
• Corrected.
Line 244 – delete “changes”
• Corrected.
Line 245 – delete changes in”
• Corrected.
Line 257 – delete “First,”
• Corrected.
Line 278-303 – Too much discussion on soil water which is not the topic of this study.
This paragraph can be excluded and only 1-2 sentences with references can cover
this issue.
• The paragraph has been significantly reduced. We retained the essential
information to discuss the influence of snowmelt and air temperature on the
risk of drought in these cold and wet environments.
Line 304 – focus on dehydration by adding “associated with dehydration” after
“variations”. Otherwise it is misleading and it sounds like during growing season there
is no growth.
• We added “associated with changes in tree water status (dehydration and
rehydration)” since both mechanisms are involved.
Line 329-330, 334 – which individual patterns do you mean?
• We added "of radial stem variations" after “individual patterns” and now refer
to Figure 1.
Line 360-361 – replace the sentence with “Unlike for growth, that shows variation only
in the summer, diel dynamics in tree water status (dehydration and rehydration) differ
widely in all seasons (Figure 2).
• Corrected.
Line 375-380 – move to Results
• Corrected.
Line 382 – what “new analytical methods” you mean?
• We added “for signal decomposition” to avoid confusion.
Conclusions
Should be rewritten, without repeating the results or discussion. Conclusion should
present the meaning of the things you discovered in the research
• We have not completely rewritten the conclusion, but we have lightened it by not
repeating the results. We also tried to clarify the meaning of the key elements
discovered during the research.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript (MS) presents a well grounded, consise research that reports interesting observations. The research is certainly can be recommended for publication in Forests. There are however a couple of points that may be useful to improve the MS.

General comments

(I) It would be important if the authors shared with the readership not only the clear results but also uncertainties that they encoutered. Every sofisticated research technique is able to produce artifacts. For a researcher, it's unpleasant to think of it. He/she wants to be sure regarding the methods applied. But the reality may be different.

For example, l. 196-199, after the words 'results reveal' the reader expects an explanation of the 'growth pulses' but no real explanation follows. Are these 'growth pulses' candidates to simple artifacts of the method?

(II) In Figure 1, the reader sees a linear trend in which a point is declared to be an onset of the growing season. Formally, the authors use the fact that the stem radius achieved the maximal value from the previous growing season. However, this is just a formal approach. The linear trend doesn't have here a knee or other peculiarity. The growing season starts when the cells begin to divide. The authors should indicate that the exact onset day of the growing season is really not known as it's not known whether the cells started to divide. 

Minor comments

l. 17 -> 'Improvements require' or 'Improvement requires'.

l. 21 -> It's a standard to provide author's names at the first appearance of Latin names.

l. 145, 160, 164, 266 -> It's better to refer to cited author's names that to naked square brackets.

Figure 1. -> Please, be consistent with citing panels. Only panel a) and b) are given in the figure caption.

Author Response

Reviewer 2
The manuscript (MS) presents a well grounded, concise research that reports
interesting observations. The research is certainly can be recommended for
publication in Forests. There are however a couple of points that may be useful to
improve the MS.
• Thank you
General comments
(I) It would be important if the authors shared with the readership not only the clear
results but also uncertainties that they encountered. Every sofisticated research
technique is able to produce artifacts. For a researcher, it's unpleasant to think of
it. He/she wants to be sure regarding the methods applied. But the reality may be
different.
For example, l. 196-199, after the words 'results reveal' the reader expects an
explanation of the 'growth pulses' but no real explanation follows. Are these 'growth
pulses' candidates to simple artifacts of the method?
• Although the low-amplitude growth pulses referred to by the Reviewer do
not strike us as an anomaly or the result of an artifact, we understand the
point made by the Reviewer. We now discuss this possibility, which seems
more likely for occasional variations of very large amplitude associated with
freeze/thaw events during the non-growing season.
(II) In Figure 1, the reader sees a linear trend in which a point is declared to be an
onset of the growing season. Formally, the authors use the fact that the stem radius
achieved the maximal value from the previous growing season. However, this is
just a formal approach. The linear trend doesn't have here a knee or other
peculiarity. The growing season starts when the cells begin to divide. The authors
should indicate that the exact onset day of the growing season is really not known
as it's not known whether the cells started to divide.
• In addition to moving Figure 1 from the M&M section to the results section
following Reviewer 1's suggestion, we added a caveat about better
identifying the start and end dates of the growing season from dendrometer
signals.
Minor comments
l. 17 -> 'Improvements require' or 'Improvement requires'.
• This sentence was removed from the summary based on the suggestion of
Reviewer 1.
l. 21 -> It's a standard to provide author's names at the first appearance of Latin
names.
• Corrected.
l. 145, 160, 164, 266 -> It's better to refer to cited author's names that to naked
square brackets.
• We have reworded to avoid citing names and comply with the journal
format.
Figure 1. -> Please, be consistent with citing panels. Only panel a) and b) are given
in the figure caption.
• Corrected.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Authors adressed all the raised issues and manuscript is significantly improved.

Aim is much more clear and focused, MM contain important description of the signal partitioning and conclusions are rewritten.

I am glad that authors accepted majority of the suggestions and hope they found them usefull.