A Disturbance Ecology Perspective on Silvicultural Site Preparation
Round 1
Reviewer 1 Report
Please see my latest comments on the revised version
This is a thorough and overall nicely presented review of common silvicuture approaches, used in the boreal forests, however I do not find that it presents any particularly novel or ground-breaking information. The two-dimensional disturbance severity framework seems over-simplistic to me, and the scoring system a bit arbitrary. The manuscript would be much improved if the approach was tested empirically in the field, supported by some real data, and put in the context of forest management more directly and clearly.
Response: Thank you for your review and comments. While we agree that empirically testing our disturbance ecology framework for site preparation would be great, we also feel that there is a need, and value, to present this perspective as a coherent conceptual framework. In this MS we aim to clearly and concisely outline how site preparation can be viewed through the lens of disturbance ecology, and provide a framework that can be used to evaluate site preparation going forward. While we feel it is beyond the scope of our current manuscript, we do strongly hope the ideas we present in the paper will be tested with empirical data in the future.
The new version of the manuscript flows better now and is clearer after the changes have been made. Please see responses below in bold, confirming the changes, and/or providing further explanations re: my original comments, or suggestions for minor changes.
Silvicultural approaches considered should be described more clearly in terms of how they are performed and what kind of equipment is used. (This could be summarized e.g. in an additional column in Table 1.). Figure 1 is not clear, with the inappropriate scale on the ‘x’ axis (see further comments below, under ‘specific comments’).
Response: We have addressed the request to provide more information of how the site preparations techniques are done in the “2. Silvicultural site preparation techniques” section, which was previously in the online appendix. This section describes the techniques in detail, including references. We feel that there is too much information to simply include this material as an additional column in table 1, and that in the current configuration this section is complimentary to the information in table 1 (Table 1 also links to figure 1, as it situates each technique within the x and y axis of the figure).
Re: new section on silvicultural methods: L92 reads: adapted to fire or to invades after fire…
Grammatically, it does not sound right, as is.
L107: add ) at the end of the sentence.
L124: Plowing consist of creating continuous…
L132: medium sites does not tell you explicitly that you are referring to soil moisture. Replace with “medium-dry” or “medium-moist” or “moderate moist” some other word that implies that it is of medium moisture (mesic?).
Move plowing section after mounding, since it is more similar to mounding than to disc trenching (i.e. as you say, sometimes referred to as continuous mounding). In addition, that way you introduced mounding already, so it makes more sense when you refer to it under the plowing section.
L147: also known as
L150: why ; after ‘of the site’?
L155: consider replacing ‘principally’ with ‘especially’ or ‘particularly’
L157: consider replacing ‘upside down’ with ‘over’
Furthermore, as discussed more in the ‘specific comments’ (L50), I have some reservations is seeing silvicuture as ‘anthropogenic disturbance’.
Response: We appreciate the Reviewer’s reservations in perceiving silviculture as disturbance, particularly in the context of forest regeneration. However, by focusing specifically on the processes of vegetation and soil disruption associated with pre-planting site preparation at microsite and stand-level scales, we argue that these operations constitute ecological disturbances. Indeed, we propose this to be the fundamental contribution of the paper. Authors such as Runkle (1985, p. 31) have referred to silvicultural systems as “artificial disturbance regimes,” and Reice (2001) devotes an entire chapter to “human-caused disturbance.” Mechanical site preparation, herbicide application, and prescribed fire all meet the classically accepted definition of ecological disturbance (White and Pickett 1985, p. 7): “A disturbance is any relatively discrete event in time that disrupts ecosystem, community, or population structure and changes resources, substrate availability, or the physical environment.”
Specific comments to the authors
Note: The required changes have been indicated by "Track Changes" function in Microsoft Word. Our references insertions are not highlighted with “Track changes function” because we used Zotero Software.
L 33: I think you should define silviculture in this sentence. It is a technical term not widely used outside of forestry and forest ecology.
Response: It is our expectation that all readers of the journal Forests will know what silviculture is. Nonetheless, we have modified this introductory sentence to clarify the purpose of silviculture and silvicultural site preparation. It now reads as follows: “Silvicultural site preparation techniques are planned anthropogenic disturbances designed to aid in the regeneration and establishment of a new stand of trees.”ok
L40: This seems like a big claim. Were these really the conclusions of the referenced study?
Response: The referenced study found that in the boreal zone of B.C., the height growth of white spruce in the future period 2005-2035 could potentially increase by around 3% on average where vegetation control or mechanical site preparation is applied. Their main conclusions are white spruce growth in untreated stands (i.e. no site preparation or vegetation control) may suffer decreases in height of up to 10% due to increased drought stress. Vegetation control and mechanical site preparation appear to mitigate effects of climate change to some extent.
We modified the sentence and it t now reads as follows “Silvicultural site preparation has the potential to mitigate the effects of climate change on early plantation growth in boreal forests by promoting tree establishment and growth, as well as promoting microclimate conditions for vegetation establishment”. ok
L43: "Mapping a method on site condition, tree species etc. " seems like and awkward phrase. Sounds like you want to map a method on a tree species. Consider rephrasing.
Response: Thank-you for that observation. We have rephrased this to: “The efficacy of site preparation depends on appropriately aligning potential methods with the specific site conditions, tree species, competing vegetation, climate, and the desired silviculture objectives.” ok
L49: I’m not sure if “having no negative impacts” is really achievable. Rephrase to “minimize undesired impacts”.
Response: Good point; we rephrased it as suggested. ok
L50: Is silvicuture really perceived as an 'anthropogenic disturbance'? To me anthropogenic disturbance has a negative connotation, and is usually an undesired consequence or a byproduct of human actions performed for some other human gain, need or pleasure (e.g. natural resource extraction/acquisition, recreation, infrastructure development), with an overall negative impact on affected ecosystem and its integrity. Silviculture is a planned activity (not a byproduct of another activity), which is meant to have a positive impact on the ecosystem and increase the speed and/or effectiveness of ecosystem regeneration and restoration. Although I see where you are coming from, calling silvicuture a "disturbance" seems strange. To me it is more of a forest restoration and health maintenance management practice.
Response: Silviculture as a whole may not, in its net effects, be an ecological disturbance; but site preparation certainly is. See response to the third general comment, above. ok
L71: The way this is written seems like prescribed burning and herbicides are also MSP. Rephrase, i.e. make clear that these two methods belong to some other category.
Response: We rephrased it as you suggested. It now reads as follows: “We focus on eight types of site preparation treatments – prescribed burning and herbicides, plus six types of mechanical site preparation (MSP), namely mixing, plowing, disc trenching, mounding, patch scarification (scalping), and inverting - that are commonly used today in boreal mixedwood ecosystems.” ok
L72-76: This sentence makes the reader believe that this forest type and tree species will be the focus of your paper - you set it up here, in your objectives paragraph. However, you don't really mention it again later in the paper. This sentence also seems a bit inconsequential here, i.e. out of place.
Response: We used this sentence to add a bit more context in terms of mixedwood management, providing the rationale for site preparation in the management of this forest type. A focus on the practices in this region also provides the basis for which site preparation techniques to include in our comparison. In addition, many of the references and examples that we draw from are derived from this system. ok
L76: Preferred by whom and why? From ecological perspective P. tremuloides and P. glauca are equally valuable within their ecosystems.
Response: Preferred as crop tree species, as reflected in provincial government-sanctioned stocking standards and current sawmill feedstock. We rewrote the sentence accordingly. ok
L78: I suppose the whole paper is based on considering silvicuture as a human disturbance, but as I pointed out above, I'm not sure if I agree with that designation. If anything, it is meant as a counter-disturbance, i.e. with the goal of mitigating disturbances connected to timber harvest and other forestry-related disturbances.
Response: This may be true of reforestation and afforestation activities as a whole, but the particular processes and effects of site preparation can be disruptive to some components of the forest ecosystem, and meet the definition of ecological disturbances, as detailed above in our response to the third general comment. More generally the perception of disturbances as being intrinsically negative doesn’t always hold, and usually must be qualified by referring to specific objectives, locations, and time frames over which impacts are assessed. The questions the reviewer has raised here are valid, and we feel they actually highlight the value of asking, and challenging, foresters and ecologists to consider silvicultural site preparation through the lens of disturbance ecology. Ok
These are good arguments, so the authors may consider including some of them in the introduction, to make their approach clear to others who may potentially question it. (Also applicable to my general comment #3)
L82: These methods seem a bit arbitrary and subjective to me.
Response: This is why different site preparation methods are presented on an ordinal scale rather than being quantified on the basis of empirical data.
It flows better after you added the descriptions of the silvicuture methods in section 2 and described the methods of assigning the disturbance severity index and degree of biomass modification in section 4. (And put background into in section 3 before describing your methods).
L100: Table 1: Adding photographs, or at least diagrams presenting these methods, would add a lot of value and clarification to these descriptions. Also, could you add a column describing how the method is performed and what kind of equipment is used for it? What is the source of all these information? Observations in the field, literature, government guidelines?
Response: We have added a citation referring the reader to a government report, von der Gönna (1992), already cited as Reference #1, that outlines the range of surface areas disturbed by different mechanical site preparation techniques, and provides drawings of the different kinds of machines involved. Some area estimates have been adjusted based on our own observations; e.g., because mounding typically leaves a pit as well as a mound, it affects a greater area than inverting in place. For prescribed burning and herbicide use we assume broadcast applications with 100% coverage. ok
Table 1: Second column: Total area in what context? What are these percentage estimations based on? Literature, measurements taken in the field, government regulations? Or are they just arbitrary guesses?
Response: See response above. The % area biomass impacts are developed from the reports and trials referenced in section 2. A footnote has been added to the table to draw the reader’s attention to our main sources.
In the footnote, add ‘and’ in line 285 (between the two references).
Third column: Is that the main effects? I thought is was to reduce soil moisture and competition.
Response: We have modified the wording to “Principal effect”. The soil moisture and competition are the outcomes of the technique’s application that are not always achieved.
Last column: Overall, these scores seem a bit arbitrary to me, Can you explain more explicitly how this score is suppose to be applied in silvicuture management decision making? (I.e. the value and applicability of these scores). Can you support it by some empirical evidence, i.e. application of it in the field so see how reliable it is?
Response: The ordinal score approach allows us to roughly evaluate the biomass modification of each technique sufficiently enough to score them along one of the axes of our two-dimensional disturbance severity framework. The ordinal score was developed based on our literature review and our assessment of the mechanism by which each method alters the environment. The response variables reported in the various literature review papers differ, and the meaningful metrics also differ. Therefore, a unitless ordination score allows comparison across the techniques. Biomass modification was inferred from general principles and the few reports of percentage change. Our two-dimensional framework thereby allows a comparative evaluation of the overall disturbance severity of these techniques.
Depending on the forest management goal, foresters may opt to apply a site preparation technique with certain disturbance severity. As mentioned in new line numbers 56-59, “…a forester managing a forest for ecological restoration may opt to apply a site preparation technique with little area disturbed and/or little biomass modification..”.
L104: This section seems out of place. It seems like a literature review, without much connection to your scoring analysis described above. Perhaps section 4 should come before section 3.
Response: This section is now section 3; we changed the order to better connect current sections 4 and 5. ok
L116: Indicate where the H layer is within a soil profile, relatively to L and F.
Response: It now reads as follows: “the humus layer (H horizon, located beneath LF horizons) may remain cool on warm days as the litter and fermentation layers (LF horizons) act as insulation.” ok
L122-123: Can you provide a reference for this sentence?
Response: Two relevant references have been provided: Dobbs and McMinn 1973, Malik and Hu 1997.
L127-129: Again, this would be clearer, if description of silvicutural methods (i.e. how they are performed) was presented earlier, e.g. in Table 1.
Response: We moved suppl.material (description of silvicultural techniques) to the manuscript (section 2), which we hope makes this sentence more clear. ok
L136: Can facilitate and [can] enhance - parallel structure would sounds better.
Response: Modified as suggested. ok
L145-148: Reference for that?
Response: Reference to Gregory 1981 have been added (see new lines 218- 221). ok
L149-153: Why do you use element abbreviation in the first sentence of this paragraph, and full words for elements here? Be consistent. If anything, the whole word should be used first and abbreviations after.
Response: Proper technical writing does not employ abbreviations at the beginning of a sentence; retained as is.
I don’t understand your response above, since you did make the changes in the text to what I was looking for. That is, you changed the full words for elements in (new) lines 212-213 to abbreviated elements, which is now consistent with (new) lines 209 and 210. Maybe I wasn’t clear above – by ‘here’ I meant (new) lines 212 and 213, where originally you had full words for the elements (but abbreviations earlier, in (new) lines 209-210).
I am not sure which beginning of a sentence you are referring to above.
L158: Where is the support for this sentence?
Response: Reference to Löf 2012 has been added (see new lines 231). ok
L160: The sentence: “The risk of soil erosion…” - Isn't exposure of mineral soil one of the main goals of MSP? Here you make it sound like an undesired side effect.
Response: Yes, erosion can be an undesired side effect, especially when not carefully implemented for a specific site. We included a short sentence to make this clear (see new lines 232-233). While exposure of mineral soil can be beneficial there can be concomitant increase in the risk of detrimental soil erosion, so the challenge is to find the right balance of beneficial and undesired effects on a site by site basis.
I think you meant lines 219-220, not 232-233.
L180: I'm not sure what the rules are for the journal, but you already used the full scientific name in the introduction, and now you are using the common name and follow it again by the full scientific name, Usually you mention the full scientific name the first time, and then you can use the shortened scientific names (P. glauca), or the common name.
Response: It is now common name with scientific name in brackets the first time, after which we used the common name. We applied that format to all plant names throughout the manuscript. ok
L190: Pinus banksiana should be in Italics.
Response: It is now in italics. ok
L191-194: Seems like a pretty obvious and general statement - nothing ground-breaking about this conclusion.
Response: These sentences provide background (not conclusions), indicating the emphasis on crop tree performance, with little or no work done on the overall ecology of cutblocks modified by silvicultural site preparation.
Now that this whole section has been moved, this sentence makes more sense, because it is presented before your analysis, so it is obviously background information. In the original version it was in a section after your analysis, where I was expecting a ‘discussion’ of your results, and I interpreted this sentence as interpretation/conclusion you made based on your results.
L194: Intolerant to flooding. Otherwise it seems like the species is just intolerant in general.
Response: Simplified as suggested (see new line 270). ok
L194-195: Why no authorities here with the scientific names? Plus the lack of use of common names here is inconsistent with the earlier text, where they were used. Please follow the journal guidelines for plant naming and stay consistent throughout the manuscript!
Response: Plant naming is now consistent throughout the manuscript. ok
L196-197: Isn’t the whole point of mounding to form an elevated spot and plant the trees on it? (To reduce soil moisture?). Why would someone want to use mounding technique and then plant the seedling in the pit??
Response: Mounding is also used in some dry climates (such as southern British Columbia and the inland Pacific Northwest of the USA) in order to concentrate moisture in the pit, which can be the preferred planting spot in such situations. ok
Figure 1: This figure needs a better description. What do the two red points represent, and what does the broken line between them represent? Also notice that the scale on ‘x’ Axis is not proper: the distance between 4 and 5 is twice as long as between any other two units, e.g. 3 and 4.
Response: As described in the caption of Figure1, the vertical axis is the percentage of the total area disturbed and horizontal axis is the degree of biomass modification obtained from Table 1. We agree that rank scores should have uniform spacing, and the position of Herbicide has been altered accordingly. Further clarification and explanation has been added to the caption. ok
L244: I find the two-dimensional frameworks overall not very convicting and over-simplistic. Figure 1 is not clear. This all seems pretty obvious and would be considered in management decisions re: application of appropriate silvicuture methods anyways, without assigning an arbitrary number on a scale from 1 to 6.
Response: See response to the first general comment, above. ok
L252: Would be much stronger if it was supported by some empirical evidence from the field, or actual data complied from other studies, and not just and arbitrary and over-simplistic scoring.
Response: See first response. ok
L271: Nothing ground breaking about these conclusions - seem pretty obvious.
Response: We are unclear as to the nature of this comment, as Line 271 is not yet in the Conclusions section, but is merely describing the trends inferred from our analysis, as derived from Table 1 and Figure 1.
I was referring to the sentence:
“A preliminary conceptual assessment indicates that broadcast burning appears to have the highest severity, followed in order by herbicide, mixing, disc trenching, mounding, scalping and inverting, but other perspectives and statistical analyses are also possible.”
In the original manuscript version I was given, this sentence was under section 5: Conclusions, in lines 269-272. It was the second last sentence of your manuscript, which I would presume, should be a conclusion.
Author Response
Response to Reviewer#1 Comments
The new version of the manuscript flows better now and is clearer after the changes have been made. Please see responses below in bold, confirming the changes, and/or providing further explanations re: my original comments, or suggestions for minor changes.
Response: We really appreciate your feedback.
Re: new section on silvicultural methods: L92 reads: adapted to fire or to invades after fire…
Response: It now reads as follows: “...and may intensify competition problems when undesired or invasive vegetation is adapted to fire or invades after fire [14,15]”.
Grammatically, it does not sound right, as is.
L107: add ) at the end of the sentence.
Response: Added.
L124: Plowing consist of creating continuous…
Response: Changed (new lines 139).
L132: medium sites does not tell you explicitly that you are referring to soil moisture. Replace with “medium-dry” or “medium-moist” or “moderate moist” some other word that implies that it is of medium moisture (mesic?).
Response: Replaced to “medium-moist”. It now reads as follows: “…trench position for dry sites, hinge position for medium-moist sites, and berm position for moist sites.” (new line 124)
Move plowing section after mounding, since it is more similar to mounding than to disc trenching (i.e. as you say, sometimes referred to as continuous mounding). In addition, that way you introduced mounding already, so it makes more sense when you refer to it under the plowing section.
Response: Moved as suggested.
L147: also known as
Response: Replaced. It now reads as follows: “Scalping, also known as patch scarification…”
L150: why ; after ‘of the site’?
Response: Deleted.
L155: consider replacing ‘principally’ with ‘especially’ or ‘particularly’
Response: Replaced to “especially”. It now reads as follows: “If scalping is too deep, the planting spot may become waterlogged, especially on a wet site or during wet periods”.
L157: consider replacing ‘upside down’ with ‘over’
Response: Replaced. It now reads as follows: “Inverting consists of turning the surface organic layer over; the inverted…”
Specific comments to the authors
These are good arguments, so the authors may consider including some of them in the introduction, to make their approach clear to others who may potentially question it. (Also applicable to my general comment #3)
Response: Thank you very much for your feedback. We really appreciate your suggestion, but we decided to not include these arguments in the introduction. The framing of the paper is made very clear in the third paragraph of the introduction (L51-54) and we don’t think this needs to be qualified (flow would be damaged).
It flows better after you added the descriptions of the silvicuture methods in section 2 and described the methods of assigning the disturbance severity index and degree of biomass modification in section 4. (And put background into in section 3 before describing your methods).
Response: Thanks for the feedback.
In the footnote, add ‘and’ in line 285 (between the two references).
Response: Added. It now reads as follows: “For drawings of the different MSP techniques and machines involved, refer to Von der Gönna [1] and McMinn and Hedin [23].”
I don’t understand your response above, since you did make the changes in the text to what I was looking for. That is, you changed the full words for elements in (new) lines 212-213 to abbreviated elements, which is now consistent with (new) lines 209 and 210. Maybe I wasn’t clear above – by ‘here’ I meant (new) lines 212 and 213, where originally you had full words for the elements (but abbreviations earlier, in (new) lines 209-210).
I am not sure which beginning of a sentence you are referring to above.
Response: Thanks for clarifying. We first thought you were referring to abbreviate the word “Mechanical site preparation” at the beginning of the sentence, but then we realized we misread your comment and made the changes suggested but forgot to mention that in our response (sorry for that).
I think you meant lines 219-220, not 232-233.
Response: Yes, thanks.
Now that this whole section has been moved, this sentence makes more sense, because it is presented before your analysis, so it is obviously background information. In the original version it was in a section after your analysis, where I was expecting a ‘discussion’ of your results, and I interpreted this sentence as interpretation/conclusion you made based on your results.
Response: Thanks for the feedback.
I was referring to the sentence:
“A preliminary conceptual assessment indicates that broadcast burning appears to have the highest severity, followed in order by herbicide, mixing, disc trenching, mounding, scalping and inverting, but other perspectives and statistical analyses are also possible.”
In the original manuscript version I was given, this sentence was under section 5: Conclusions, in lines 269-272. It was the second last sentence of your manuscript, which I would presume, should be a conclusion.
Response: Thanks for the clarification.
Reviewer 2 Report
The Authors considered my comments on the previous paper version and applied most of them in the resubmitted article. Thus, I have only 2 minor reservations regarding the present manuscript version:
- As suggested, the Authors included “ploughing” as an evaluated site preparation technique. However, they refer to the option in which trees are planted on ridges (l. 125), while in many European countries (e.g. in Germany, Poland, Lithuania, Finland) trees are planted not on ridges but in furrows. Furthermore, in European forestry the total area disturbed when ploughing is used for site preparation is much higher than proposed by the Authors 30-65% (Table 1). In many clear cuts in which a plough is used the total (100%) topsoil is disturbed: the topsoil is removed from furrows and placed on ridges covering the original soil. Please see the attached photo showing as extensive areas prepared with a plough look like in European woodlands. Consequently, the issue of “ploughing” should be rethought by the Authors. If they aim their paper would refer to global forestry, they cannot ignore the different management regarding this site preparation method in the paper. Otherwise, they should reconsider my previous suggestion to modify the paper’s title by inserting e.g. “lessons from Canadian forests” at the title’s end.
- l. 176, 177: L and H refer to two soil subhorizons, hence “LF” should be replaced with “L and H”.
Comments for author File: 
Comments.docx
Author Response
The Authors considered my comments on the previous paper version and applied most of them in the resubmitted article. Thus, I have only 2 minor reservations regarding the present manuscript version:
Response: Thank you very much for your feedback.
- As suggested, the Authors included “ploughing” as an evaluated site preparation technique. However, they refer to the option in which trees are planted on ridges (l. 125), while in many European countries (e.g. in Germany, Poland, Lithuania, Finland) trees are planted not on ridges but in furrows. Furthermore, in European forestry the total area disturbed when ploughing is used for site preparation is much higher than proposed by the Authors 30-65% (Table 1). In many clear cuts in which a plough is used the total (100%) topsoil is disturbed: the topsoil is removed from furrows and placed on ridges covering the original soil. Please see the attached photo showing as extensive areas prepared with a plough look like in European woodlands. Consequently, the issue of “ploughing” should be rethought by the Authors. If they aim their paper would refer to global forestry, they cannot ignore the different management regarding this site preparation method in the paper. Otherwise, they should reconsider my previous suggestion to modify the paper’s title by inserting e.g. “lessons from Canadian forests” at the title’s end.
Response: Thank you for your thoughtful comments. We appreciate that there are regional nuances with regard to how the various site preparation techniques are implemented and planted, particularly with regard to the use of ploughing. We have modifier our description of ploughing to account for this: “Plowing consist of creating continuous elevated berms [1,2]. In some regions it is listed as continuous mounding because it creates elevated planting spots on ridges [2], while in other regions planting is done in the furrows.”
Our reporting of area disturbed through ploughing is taken from Von der Gonna 1992, but again, we appreciate that the area disturbed can exceed these amounts depending on how ploughing is used. In our description of the “area disturbed” (section 4) we state that the listed % disturbed areas are based on “typical application”, but we don’t imply that the full range of potential disturbance is included in our estimate. While this is a simplification, we feel it is necessary in order to generally characterize the methods.
We believe that our work speaks to the global value of evaluating site preparation techniques through the framework of “disturbance ecology”. In our abstract and introduction we do explicitly identify that the case study examples that we draw from are primarily from boreal mixedwood ecosystem. As such, we feel it is appropriate to retain our current title.
- l. 176, 177: L and H refer to two soil subhorizons, hence “LF” should be replaced with “L and H”.
Response: Do you mean replaced with “L and F”? If so, we replaced. It now reads: “the humus layer (H horizon, located beneath L and F horizons) may remain cool on warm days as the litter and fermentation layers (L and F horizons) act as insulation [27]”
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
General comments to the authors
This is a thorough and overall nicely presented review of common silvicuture approaches, used in the boreal forests, however I do not find that it presents any particularly novel or ground-breaking information. The two-dimensional disturbance severity framework seems over-simplistic to me, and the scoring system a bit arbitrary. The manuscript would be much improved if the approach was tested empirically in the field, supported by some real data, and put in the context of forest management more directly and clearly.
Silvicultural approaches considered should be described more clearly in terms of how they are performed and what kind of equipment is used. (This could be summarized e.g. in an additional column in Table 1.). Figure 1 is not clear, with the inappropriate scale on the ‘x’ axis (see further comments below, under ‘specific comments’).
Furthermore, as discussed more in the ‘specific comments’ (L50), I have some reservations is seeing silvicuture as ‘anthropogenic disturbance’.
Specific comments to the authors
L 33: I think you should define silviculture in this sentence. It is a technical term not widely used outside of forestry and forest ecology.
L40: This seems like a big claim. Were these really the conclusions of the referenced study?
L43: "Mapping a method on site condition, tree species etc. " seems like and awkward phrase. Sounds like you want to map a method on a tree species. Consider rephrasing.
L49: I’m not sure if “having no negative impacts” is really achievable. Rephrase to “minimize undesired impacts”.
L50: Is silvicuture really perceived as an 'anthropogenic disturbance'? To me anthropogenic disturbance has a negative connotation, and is usually an undesired consequence or a byproduct of human actions performed for some other human gain, need or pleasure (e.g. natural resource extraction/acquisition, recreation, infrastructure development), with an overall negative impact on affected ecosystem and its integrity. Silviculture is a planned activity (not a byproduct of another activity), which is meant to have a positive impact on the ecosystem and increase the speed and/or effectiveness of ecosystem regeneration and restoration. Although I see where you are coming from, calling silvicuture a "disturbance" seems strange. To me it is more of a forest restoration and health maintenance management practice.
L71: The way this is written seems like prescribed burning and herbicides are also MSP. Rephrase, i.e. make clear that these two methods belong to some other category.
L72-76: This sentence makes the reader believe that this forest type and tree species will be the focus of your paper - you set it up here, in your objectives paragraph. However, you don't really mention it again later in the paper. This sentence also seems a bit inconsequential here, i.e. out of place.
L76: Preferred by whom and why? From ecological perspective P. tremuloides and P. glauca are equally valuable within their ecosystems.
L78: I suppose the whole paper is based on considering silvicuture as a human disturbance, but as I pointed out above, I'm not sure if I agree with that designation. If anything, it is meant as a counter-disturbance, i.e. with the goal of mitigating disturbances connected to timber harvest and other forestry-related disturbances.
L82: These methods seem a bit arbitrary and subjective to me.
L100: Table 1: Adding photographs, or at least diagrams presenting these methods, would add a lot of value and clarification to these descriptions. Also, could you add a column describing how the method is performed and what kind of equipment is used for it? What is the source of all these information? Observations in the field, literature, government guidelines?
Table 1: Second column: Total area in what context? What are these percentage estimations based on? Literature, measurements taken in the field, government regulations? Or are they just arbitrary guesses?
Third column: Is that the main effects? I thought is was to reduce soil moisture and competition.
Last column: Overall, these scores seem a bit arbitrary to me, Can you explain more explicitly how this score is suppose to be applied in silvicuture management decision making? (I.e. the value and applicability of these scores). Can you support it by some empirical evidence, i.e. application of it in the field so see how reliable it is?
L104: This section seems out of place. It seems like a literature review, without much connection to your scoring analysis described above. Perhaps section 4 should come before section 3.
L116: Indicate where the H layer is within a soil profile, relatively to L and F.
L122-123: Can you provide a reference for this sentence?
L127-129: Again, this would be clearer, if description of silvicutural methods (i.e. how they are performed) was presented earlier, e.g. in Table 1.
L136: Can facilitate and [can] enhance - parallel structure would sounds better.
L145-148: Reference for that?
L149-153: Why do you use element abbreviation in the first sentence of this paragraph, and full words for elements here? Be consistent. If anything, the whole word should be used first and abbreviations after.
L158: Where is the support for this sentence?
L160: The sentence: “The risk of soil erosion…” - Isn't exposure of mineral soil one of the main goals of MSP? Here you make it sound like an undesired side effect.
L180: I'm not sure what the rules are for the journal, but you already used the full scientific name in the introduction, and now you are using the common name and follow it again by the full scientific name, Usually you mention the full scientific name the first time, and then you can use the shortened scientific names (P. glauca), or the common name.
L190: Pinus banksiana should be in Italics.
L191-194: Seems like a pretty obvious and general statement - nothing ground-breaking about this conclusion.
L194: Intolerant to flooding. Otherwise it seems like the species is just intolerant in general.
L194-195: Why no authorities here with the scientific names? Plus the lack of use of common names here is inconsistent with the earlier text, where they were used. Please follow the journal guidelines for plant naming and stay consistent throughout the manuscript!
L196-197: Isn’t the whole point of mounding to form an elevated spot and plant the trees on it? (To reduce soil moisture?). Why would someone want to use mounding technique and then plant the seedling in the pit??
Figure 1: This figure needs a better description. What do the two red points represent, and what does the broken line between them represent? Also notice that the scale on ‘x’ Axis is not proper: the distance between 4 and 5 is twice as long as between any other two units, e.g. 3 and 4.
L244: I find the two-dimensional frameworks overall not very convicting and over-simplistic. Figure 1 is not clear. This all seems pretty obvious and would be considered in management decisions re: application of appropriate silvicuture methods anyways, without assigning an arbitrary number on a scale from 1 to 6.
L252: Would be much stronger if it was supported by some empirical evidence from the field, or actual data complied from other studies, and not just and arbitrary and over-simplistic scoring.
L271: Nothing ground breaking about these conclusions - seem pretty obvious.
Reviewer 2 Report
The study concerns site preparation preceding reestablishment of a new forest generation, which is one of the fundamental issues for silviculture and sustainable forestry. Consequently, the issue has been extensively discussed in literature. The Authors in the paper present a thorough overview of the most common site preparation techniques used in Canadian forests as well as environmental effects of the techniques. The paper is well designed and written, and I am sure this review article would raise interest of readers (practical foresters; scientists; policy makers etc.) from many countries. The manuscript was carefully prepared also regarding the technical quality – for example, while the accurate review of the paper I found only very few typo errors. Thus, taking into account all the above, I recommend publishing this interesting paper in Forests. However, before the possible publication the Authors should consider the following points:
- The paper refers to boreal forests based on results gained in Canada, mainly. Thus, in my opinion the title is too wide. For example, it should be inserted at the title’s end “lessons from Canadian/boreal forests”; however, I think the Authors could probably come up with a better idea. The paper does not refer to other site preparation techniques which are commonly used in other countries/climatic zones, as e.g. manual planting or ploughing. For example, the latter technique has been commonly used in central and northern Europe (see e.g. Makitalo, 1999, Scand. J. For. Res. 14: 512–525). Besides, in my research plots in Central Europe the share of disturbed soil after mixing (a forest mill was used) is much lower (ca. 30% of the total area; please se the attached photos) than referred by the Authors in the paper (50-75%, Table 1). Thus, in my opinion, the paper’s title should be completed with the reference to Canadian/boreal conditions.
- The description of the examined site preparation techniques in supplementary file is a very good idea. However, for full clarity, I strongly recommend the Authors to complete the file with photos showing the plots in which particular techniques were applied.
- 70/71: the reference to suppl. material should be given somewhere here.
- 71: double ”-“
- 82: the title of the chapter 2 could be better adjusted to its content.
- Table 1: the order of the presented site preparation techniques should be changed. It should be adjusted with the order in l. 70/71.
- Table 1: The scores of biomass modification were arbitrarily ordered to particular site preparation technique. If I understand well, it was done based on Canadian cited documents [1, 12] (l. 87), which could be not accessible for all the interested readers in internet. Thus, I suggest inserting some more explanation on the methodology of ordering scores to the techniques in the text.
- 104: I suggest introducing the word “techniques” into the chapter’s title (then, it would be “Effects of silvicultural site preparation techniques on soil conditions and seedling performance”).
- 118/119: It is of course true. I could assume that the magnitude of this temperature increase would be primarily related to topsoil color. However, we found that the much darker material occurring in belts prepared with a forest mill warms weaker than bright material occurring in trenches prepared with a plough. We explained this apparent inconsistency by the higher moisture of topsoil in belts than in trenches, and subsequent different losses of thermal energy for evaporation (Sewerniak, Stelter, 2016; https://doi.org/10.26202/sylwan.2016085). I do not refer to this article suggesting citing it in the paper, but just because I found the results interesting.
- 148: I think this sentence could be finished with the reference.
- 155/157: “few…planting.” – these statements seem to be contradictory.
- 165: please specify what kind of “effects” do you mean here.
- 239: “then” – do you mean “than” here?
- I am aware that it could be under discussion if the issue is within the scope of this paper; however, I encourage the Authors to consider introducing in Discussion/Conclusions some words suggesting the need to the wide approach when the assessment of site preparation technique is done. I mean that the full evaluation should include also the differences in energy consumption (petrol etc.) which, in my opinion, is given too little consideration. I stay the potential application of this comment in the paper absolutely freely for the Authors.
Comments for author File: Comments.docx
