Influence of Planting Scheme on Some Physical Properties of Norway Spruce (Picea abies (L.) H. Karst) Wood

Round 1

Reviewer 1 Report

There are no conclusions in the article; there are only observations. Please try to explain the causes of the measured dependencies between physical properties. I propose to answer the following research issues:

• Faster-growing trees (in less dense planting variants) have a lover wood density in the same DBH class. Can it be concluded from the results of the authors' research (can this be seen in Fig. 2)? I think not. Why? (Or maybe it is visible for average DBHs, e.g. not greater than 30 cm)
• A lower wood density has lower physical properties (lower micro-drill resistance). Depending on DBH, the variation in wood density is smaller in dense plantings (which is visible in Fig. 4). In my opinion, this is the explanation of the author's final observations (in line 466 "The significance test results indicated generally that are meaningful interactions between studied parameters regarding some physical wood properties (wood density, resistance towards micro-drilling, sound speed) of the standing trees between a variant with a low number of trees per hectare (eg, 2500, 3330) compared to those with a large number of trees per hectare (eg, 7510). "). Maybe it is a conclusion?
• Fig. 5 is the key. In my opinion, it can be seen that the differentiation in density is the greatest for sparse plantings (small R-factor). This suggests a more homogeneous wood volumetric density in dense plantings variants and more similar physical properties (correlated with density). Maybe it is a conclusion?

Some detailed comments

1. Line 11: instead “with four planting variants (2500; 3330; 5000; 7510 seedlings·ha-1 )” better “with four initial planting density variants(2500; 3330; 5000; 7510 trees per·hectar)” – “trees per·hectar” as in line 21.
2. Line 18-21: instead, “Correlation analysis showed that DBH had a significant impact to the studied physical properties. The significance test results indicated generally that are meaningful interactions between studied parameters between the variants with a low number of trees per hectare (e.g., 2500, 3330) compared to those with a large number of trees per hectare (e.g., 7510).” better “These results show a relationship between DBH values and studied physical properties. This relationship is more evident for variants with a low planting density (e.g., 2500, 3330 trees/ha) than dense planting variants (e.g., 7510 trees/ha). The explanation for this observation may be that the growth of trees in dense plantings is slower – in less dense plantings variants, the increase in wood is greater, and as a result, the wood volumetric density dependence on the DBH value is greater.”
3. Please standardize the important wording on "micro-drill resistance". It appears in the article as: "micro-drilling resistance", "micro-drilling wood resistance", "micro-drill wood resistance", "wood’s micro-drill resistance", "wood resistance towards micro-drilling". 
4. Line 260: “minim”?
5. Line 275: Instead „Relationship between diameter and micro-drill wood resistance” better „Relationship between the diameter of the trunk and wood resistance to micro-drilling
6. Line 277: Instead,“If we consider the presented results, the carriage of average curves regarding microdrill wood resistance in relation with diameter and plantation variant indicate the superiority of V3 over all other variants, up to the 22 cm diameter.” Better “The relationship between the resistance in Micro-Drill Resistance Test and the diameter of the trunk in combination with plantation variant shows the superiority of V3 over all other variants, up to the 22 cm diameter.”
7. Line 288: Instead, “A two-way t test result indicated that no significant correlation was detected between V1 and V2, V1 and V4, and V2 and V4 variants, (…)” better “A two-way t-test indicated that there is no significant correlation between V1 and V2, V1 and V4, and V2 and V4 variants, (…)”

sincerelly,

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

I fully recommend checking of the language by a native English speaker. There are still some sentences with language mistakes (in the abstract, in the conclusions, especially in the added sentences). I am not a native speaker so I am not able to correct those sentences myself.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The effects of the four various planting schemes (between 2500 to 7510 seedlings/ha) on the density, microdrilling resistance and sound speed in Norway spruce wood were studied. These structural properties are important factors considering the wood quality. The number of samples studied is high (326 trees). In addition, the relations between the stem diameter and the density,  the density and microdrilling resistance, and the density and sound speed were statistically determined.    Thus, the results of the study can be considered interesting and valuable for the readers interested in the wood quality and planting schemes.   However, I would like to suggest the following possible improvements and corrections for the paper:   1) Lines 19-22: the last sentence of the abstract (related to the main results of the study) could be expressed more clearly: instead of expressions as 'some' and 'several', it should be stated more clearly what is the main observation of this study: in which parameters were detected statistically relevant differences and/or correlations? Similarly, also the final sentences of the conclusions (Lines 446-453) could be clarified: it could be stated clearly which were the main observations, regarding the parameters in question.   3) Lines 132-133: could it be also mentioned, how these 90 trees were selected among the trees of the four schemes?   6) there are some repetition considering the lines 149-150, 157-159, 160-161. This section could be improved by removing this repetition.   4) Lines 223-224: Could there be added any references (and/or discussion) on the used power regression model (wood density as a function of the diameter)? Are the values of the fitted parameters 'a' and 'b' similar as previously found in the literature (and why both the parameters are slightly different between these four schemes?)   5) Line 246: the same question could consider also the exponential regression equation: could some reference be given here and/or some previous literature examples/values be given in the discussion considering the parameters?   6) Lines 257-258 and 288-289: please check the number of given decimals here (only a reasonable accuracy should be announced)   7) line 430-431: why reaction wood is mentioned here? Could it be explained further?   I am not a native speaker of English, but I think, that the text could be proof-read, for example the following small notes could be made:   line 265: 'plating' -> planting line 282: 'interaction' -> correlation? lines 286-287: please check the sentence here (used two times 'an experimental plot') line 407-408: please check the sentence here: some words might be missing (e.g. the number (1) is missing?)

Reviewer 2 Report

The article is interesting, methodically correct. However, it needs to be improved.

Please detail the “Abstract”

1. Line 15. Instead of saying "determined by classical methods and indirectly using modern equipment”, please name these two methods.

 

2. Line 17. In the sentence "relationships between diameter and (...)" please add "Diameter at breast height, or DBH".

 

3. The conclusions in the “Abstract” are so general as to be worthless to the reader: "The results obtained regarding the influence of the planting scheme on some physical-mechanical properties of the Norway spruce wood showed that forest management, as expressed by the planting scheme, influences the diversity of the stands, in this case in several physical-mechanical wood properties. " There should be numbers here, not only truisms. It is obvious that "planting scheme" affects the "physical-mechanical properties" and that "forest management" includes "planting scheme" and, "the diversity" (i.e. Silviculture). The phrase "physical-mechanical properties" is terrible. First, mechanical properties are also physical properties. "Physical" is not in opposition to "mechanical". In my opinion, the authors investigated the physical properties. Susceptibility to drilling is not a mechanical property, but a technological one.

 

“Introduction”

4. Line 26. Someone forgot to write about the length of the log, in addition to the diameter and shape - this is a key parameter in wood industry.

 

“M&M”

5. Line 140. "DBH" is missing (as comment 2)
6. Line 160. Is "microdrilling" "non-destructive methods"? Is there a "semidestructive" method?

 

“Conclusions”

7. The conclusions are too general. Numbers and explanations are missing. I believe that interesting information about "density" should be summarized here with some conclusions or conclusions. For example, in article, "wood density" is related to seedlings (the largest seedlings ha − 1 planted give the largest value for the density - information in lines 265 and 360). In my opinion, there should be three groups of conclusions: (a) an explanation of changes in wood density, (b) an explanation of the relationship between DBH diameter, micro-drill wood resistance and planting variant; (c) the relationship between sound speed, DBH and planting variant. For a section of an article to be called "Conclusions", it has to be a content: “we measured this and that, something interesting follows from it”.

 

8. Line 312 and 315 "sound velocity" in m / s?

 

General comments.

9. I am not an English language specialist, but the text is poorly written. It gives the impression of being machine translated. Very often the word order in sentences is rearranged. Please redact the text (and "Pass on what you have learned." - Yoda "Return of the Jedi (final words)).
10. Please think about replacing the overused word "determinine" with "measure". Two examples: Line 14: "wood density determined by classical methods". Line 53 "volumetric method was used as a method for determining density". This density is already "determined" before being measured by the method. The method does not "determine" anything. The method "measures" the size.
11. Not always synonyms in a text are good. Consistency is a value in scientific articles. The article contains an important statement in several variants: "planting version" (mostly), "plantation version" (line 296, 302), "plantation schemes" (line 103, 120, 122, 285, 287, 442), "Experimental version" "in table 3," work version" in line 263. If I wrote this, I would write "plantation variant "(as in line 283). The "versions" imply that plant scheme is really one.

Please consider my comments or use them as an invitation to discussion.

Yours sincerely

Reviewer 3 Report

In the opinion of the reviewer, it is worth writing down the Latin name of the species of wood in at least one place. In such works, the botanical name means a lot.

In all graphs, change the decimal point to a period.

Were all the trees the same age? Did the trees come from a 40-year-old forest?

Line 140: please add Pressler drill diameter.

Lines 141-142: Drying samples to a dry state seems risky. Because what does dry state mean? It is not oven dry state and the wood is not completely dry. What was the final moisture content of the samples? Was the moisture content the same for all samples?

In the wood science, the following terms can be used alternately: sound speed=sound velocity.

Table 1: please explain why it was decided to give the density with such high accuracy. Why is the standard deviation given with less accuracy to 3 decimal places ??

Line 225: what do three zeros mean with the correlation coefficient? to the power of 0?

Line 222: why was this feature chosen? What made you decide? Highest R²-Factor?

Figure 2: Were the trees one age? A very large range of diameters of 10-40 cm.

Why does drawing 2c, 5c, 7c have a different x scale?

Figure 4 and lines 247-248: the x-axis is density, you wrote the reverse.

Line 246: why was this particular function chosen y = ae^bx? What was behind the choice?

Figure 6: a strange y-axis scale was chosen. Why is this one?

Figures 5, 6 and table 4 they seem to be too low. This is already a subsection about speed.

Line 340: what does it mean young and old wood? Is it juvenile and mature wood or something else?

Lines 342-344: what wood is affected by this high variability (350-850)?

Line 345: confusing to mix units in one paragraph. You used g / cm³ from the beginning, so use consistently throughout this paragraph.

Lines 334-363: written quite chaotically. The main problem with reading is that the vague term "young and old wood" is used. When reading this paragraph, two possible ways of explaining this may come to mind. It can be juwenile and mature wood or early and latewood.

In whole discussion chapter: moisture not humidity.

Line 377: Sylvester pine or Scots pine?

Lines 365-382: as for the subsection named discussion, information that can almost be found in the introduction is provided here. It is not typical for the discussion to compare the obtained results with other data, or to indicate potential causes of the phenomena.

Line 407-409: the first sentence of this section is spelled chaotically.

Lines 407-436: Why does this fragment refer to rot, since there was no signal that rot was present in the analyzed material? This is also mostly information that could be found in the introduction to the work.