Effectiveness of Silvicultural Options in Renewal of Trembling Aspen–Jack Pine Mixedwood Stands, 21 Years After Treatment
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe paper focuses on post-harvest reforestation. This topic is relevant as the intensity of deforestation is increasing worldwide. The paper is fully in line with the theme and scientific level of the journal Forests. The authors have carried out a very well thought-out study using an appropriate scientific approach and methodology. I don't have any major comments. All parts of the work are written quite well. The text is clear and interesting to read. The paper is well designed. But here I can advise you to present the design of the study in the form of a visual diagram. This will make the paper easier to understand. This is necessary because the research is quite complex and multifaceted. Therefore, the diagram here will be very useful.
A more detailed analysis of the dynamics of the species composition of all forest layers and an assessment of the transformation of the forest type in different reforestation options under study may also be a good complement. The Braun-Blanquet approach can be used here (Global Overview of the Application of the Braun-Blanquet Approach in Research. Forests 2024, 15, 937. https://doi.org/10.3390/f15060937). This approach focuses on the analysis of species composition and its shifts. In addition, it is extremely important to emphasise more clearly the forest typology used as a basis and the forest type for which the research was carried out. For example: Pojar, J.; Klinka, K.; Meidinger, D.V. Biogeoclimatic ecosystem classification in British Columbia. For. Ecol. Manag. 1987, 22, 119–154. This is important because forest management all over the world is based on forest typology. Without a forest typology, it is difficult to apply the research results in practice, as it may be unclear to which forests certain patterns apply.
In the discussion it is important to make recommendations both for reforestation and for the conservation of forest biodiversity and forest health. At the same time, it is necessary to clearly state the limitations of the application of the research results on a forest typological basis and the unresolved problems to which further research will be devoted. I also propose to strengthen the abstract with a more detailed description of the research results.
Author Response
The paper focuses on post-harvest reforestation. This topic is relevant as the intensity of deforestation is increasing worldwide. The paper is fully in line with the theme and scientific level of the journal Forests. The authors have carried out a very well thought-out study using an appropriate scientific approach and methodology. I don't have any major comments. All parts of the work are written quite well. The text is clear and interesting to read. The paper is well designed. But here I can advise you to present the design of the study in the form of a visual diagram. This will make the paper easier to understand. This is necessary because the research is quite complex and multifaceted. Therefore, the diagram here will be very useful.
Author responses: The study design is simply a randomized complete block design with 5 treatments and 3 blocks and has been reported several times in previous publications. The time of re-assessments is shown in Figure 1.
A more detailed analysis of the dynamics of the species composition of all forest layers and an assessment of the transformation of the forest type in different reforestation options under study may also be a good complement. The Braun-Blanquet approach can be used here (Global Overview of the Application of the Braun-Blanquet Approach in Research. Forests 2024, 15, 937. https://doi.org/10.3390/f15060937). This approach focuses on the analysis of species composition and its shifts.
Author responses: Only regeneration layer has been assessed multiple times postharvest. Because of temporal dynamics of growth rates and densities of different species, the species composition at regeneration stage is not indicative of regeneration success or stand composition at crown closure. Also, early results of regeneration assessments are mostly reported and presented in Figure 1 for comparison and discussion.
In addition, it is extremely important to emphasise more clearly the forest typology used as a basis and the forest type for which the research was carried out. For example: Pojar, J.; Klinka, K.; Meidinger, D.V. Biogeoclimatic ecosystem classification in British Columbia. For. Ecol. Manag. 1987, 22, 119–154. This is important because forest management all over the world is based on forest typology. Without a forest typology, it is difficult to apply the research results in practice, as it may be unclear to which forests certain patterns apply.
Author responses: ecosite types have been added as suggested at lines 84-87.
In the discussion it is important to make recommendations both for reforestation and for the conservation of forest biodiversity and forest health. At the same time, it is necessary to clearly state the limitations of the application of the research results on a forest typological basis and the unresolved problems to which further research will be devoted.
Author responses: recommendations/conclusion and limitations are added at line 377-393.
I also propose to strengthen the abstract with a more detailed description of the research results.
Author responses: more results have been included in the abstract.
Reviewer 2 Report
Comments and Suggestions for AuthorsPlease see my attached comments.
Comments for author File: 
Comments.pdf
Author Response
Thank you very much.
Reviewer 3 Report
Comments and Suggestions for AuthorsMan - Effectiveness of Herbicide Alternatives in Renewal of Trembling Aspen-Jack Pine Mixedwood Stands 21 Years After Harvest
Overall, this paper reports on a longterm study that looks at several different strategies to establish jack pine stand in an Ontario mixedwood forest. The data appear to be carefully collected, and the analyses appear to be correct. It also reports somewhat on previous measurements of this experiment. In my reading of the paper, I was often confused about the main objectives of the paper. In terms of tree growth, it shows that postharvest spraying resulted in the most and largest trees of jack pine (although we must remember that this treatment also had the higher planting density). In terms of growing a successful mixture of jack pine with some healthy overstory aspen, the preharvest spray was quite successful. The partial harvest was not successful at promoting the shade intolerant jack pine (no surprise here). This treatment, however, was very good at supporting the establishment and growth of the tolerant red maple. Based upon the Abstract, such a line of reasoning also seems to be what the author thinks. The way that the paper is presented, however, does not readily build a coherent story to support these ideas. Results and Discussion should be reorganized to start with the information on the development of the overstory – while understory trees have some relevance, this is a secondary line of information. Furthermore, if data from the earlier remeasurement times is relevant to this main story, please ensure that it is presented so that we can understand it.
Title The title is somewhat confusing as to when the treatments were applied. How about ‘Effectiveness of Herbicide Alternatives in Renewal of Trembling Aspen-Jack Pine Mixedwood Stands, 21 Years later’. Indeed, given that only partial harvest was tested as an alternative to herbicide and clearcut with planting and no vegetation control was not included in the treatments, this study certainly does not test many alternatives to herbicides. I suggest that ‘alternatives to herbicides’ should not be a focus in the title.
L117 Was a tree >4 m tall defined as an overstory tree in all later analyses. If so, state this clearly here.
L137-141 This is a long and very confusing sentence. I suggest breaking it up into multiple sentences with the goal of clarifying what was rare and what was combined into what categories. This threshold likely is not suitable for the control plot.
L196-97 ‘The Shannon species diversity on percent cover of understory woody species (trees and shrubs) did not differ significantly among treatments, despite a higher level in the preharvest spray (Table 1).’ What exactly are you saying here? It looks like no difference at all.
Fig. 1 This represents only understory trees. Perhaps there would be some difficulty in converting the different plot sizes over time, but I would like to have some information on the density of either the overstory trees or the density of both understory and overstory trees over time. This is important in estimating the mortality of the shade intolerant species such as pine and poplar – such a graph would be important.
L278 How do we assess change in overstory density between year 11 and 21 when year 11 data were not presented?
L291-293 ‘Preharvest overstory trees aged about 80 years for jack pine, trembling aspen, and white birch in the main canopy, nearly 20 years older than black spruce, white spruce, and balsam fir in the subcanopy [20].’ I am completely confused by this sentence.
Start you Discussion with the most important finding of this study and stick with the important finding of this study in the rest of the Discussion, i.e., shorten it!
Comments on the Quality of English LanguagePlease make sure that it is carefully reviewed with fresh eyes.
Author Response
Overall, this paper reports on a longterm study that looks at several different strategies to establish jack pine stand in an Ontario mixedwood forest. The data appear to be carefully collected, and the analyses appear to be correct. It also reports somewhat on previous measurements of this experiment. In my reading of the paper, I was often confused about the main objectives of the paper. In terms of tree growth, it shows that postharvest spraying resulted in the most and largest trees of jack pine (although we must remember that this treatment also had the higher planting density).
Author responses: The title has been modified to better reflect objectives of the paper. Yes, planting density was highest in the postharvest broadcast spray, a conventional option for comparison with other alternative treatments. Because of natural ingress, however, jack pine density was highest in preharvest spray and partial spray–sprayed corridors at year 6 postharvest.
In terms of growing a successful mixture of jack pine with some healthy overstory aspen, the preharvest spray was quite successful. The partial harvest was not successful at promoting the shade intolerant jack pine (no surprise here). This treatment, however, was very good at supporting the establishment and growth of the tolerant red maple. Based upon the Abstract, such a line of reasoning also seems to be what the author thinks. The way that the paper is presented, however, does not readily build a coherent story to support these ideas. Results and Discussion should be reorganized to start with the information on the development of the overstory – while understory trees have some relevance, this is a secondary line of information.
Author responses: there is really no overstory until year 21 postharvest, except for partial cut-leave corridors and uncut. The result and discussion have been shortened/modified.
Furthermore, if data from the earlier remeasurement times is relevant to this main story, please ensure that it is presented so that we can understand it.
Author responses: earlier regeneration assessments are relevant and already presented in Figure 1 to show dynamics of regeneration densities.
Title The title is somewhat confusing as to when the treatments were applied. How about ‘Effectiveness of Herbicide Alternatives in Renewal of Trembling Aspen-Jack Pine Mixedwood Stands, 21 Years later’. Indeed, given that only partial harvest was tested as an alternative to herbicide and clearcut with planting and no vegetation control was not included in the treatments, this study certainly does not test many alternatives to herbicides. I suggest that ‘alternatives to herbicides’ should not be a focus in the title.
Author responses: The title has been changed to “Effectiveness of Silvicultural Options in Renewal of Trembling Aspen–Jack Pine Mixedwood Stands, 21 Years after treatment’.
L117 Was a tree >4 m tall defined as an overstory tree in all later analyses. If so, state this clearly here.
Author responses: changes are made as suggested.
L137-141 This is a long and very confusing sentence. I suggest breaking it up into multiple sentences with the goal of clarifying what was rare and what was combined into what categories. This threshold likely is not suitable for the control plot.
Author responses: The sentence is shortened to “Some species were low in overstory composition and combined into species groups, poplar (trembling aspen), birch (white birch), maple (red maple, red ash, and black ash), pine (jack pine and white pine), spruce (black spruce and white spruce), and fir (balsam fir).”
L196-97 ‘The Shannon species diversity on percent cover of understory woody species (trees and shrubs) did not differ significantly among treatments, despite a higher level in the preharvest spray (Table 1).’ What exactly are you saying here? It looks like no difference at all.
Author responses: “despite a higher level in the preharvest spray” is removed.
Fig. 1 This represents only understory trees. Perhaps there would be some difficulty in converting the different plot sizes over time, but I would like to have some information on the density of either the overstory trees or the density of both understory and overstory trees over time. This is important in estimating the mortality of the shade intolerant species such as pine and poplar – such a graph would be important.
Author responses: Among the four harvest treatments, preharvest spray, partial spray and broadcast spray were clearcut and did not have overstory (>4 m tall) until after year 11. Partial cut-leave strips and uncut have intact overstory that showed substantial decline at 21-year assessment from preharvest levels.
L278 How do we assess change in overstory density between year 11 and 21 when year 11 data were not presented?
Author responses: the sentence is changed to “from year 11 regeneration to year 21 overstory canopy”. I am trying to link year 11 regeneration assessment to year 21 overstory at crown closure, not comparing overstory density change. As described in previous responses, trees were generally < 4 m at year 11.
L291-293 ‘Preharvest overstory trees aged about 80 years for jack pine, trembling aspen, and white birch in the main canopy, nearly 20 years older than black spruce, white spruce, and balsam fir in the subcanopy [20].’ I am completely confused by this sentence.
Author responses: The sentence is changed to “At time of harvest, trembling aspen, jack pine, and white birch aged about 80 years [18] and showed signs of dying branches and crown, indicating a canopy transition to gap dynamics [41].”
Start you Discussion with the most important finding of this study and stick with the important finding of this study in the rest of the Discussion, i.e., shorten it!
Author responses: The discussion section has been shortened/modified at various places (highlighted).
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors responded to all my comments and improved the paper. I have no additional comments.
Reviewer 3 Report
Comments and Suggestions for AuthorsIt is much improved. Ready to go.
