Optimal Management Strategies to Maximize Carbon Capture in Forest Plantations: A Case Study with Pinus radiata D. Don
Round 1
Reviewer 1 Report
This study focused on seeking optimal management strategies in terms of reforestation, felling, thinning and fire prevention for forest plantations to achieve the maximum carbon accumulation rate. Among the three scenarios, the optimal one that assumes the prolonged rotation age, the decreased felling rate and higher reforestation rate produces the highest volume biomass. In my view such conclusion likes a common sense unless the authors present more quantitative remark. I have some minor comments as below:
The language of the manuscript needs to be polished. There are lots of grammar mistakes. Please ask a native speaker to fix them.
You may need to add another paragraph about the generality of this modeling framework to other tree species or other forest ecosystems.
You should also present a comparison of the amount of CO2 emission that can be offset among these three scenarios to highlight the advantage of the optimal strategy.
For intrinsic growth part, can you add the effect of climate factors? For example, the mean annual temperature and mean annual precipitation really matter in the biomass growth. These two parameters can also be added into the logistic form.
Besides the natural mortality rate, the tree mortality rate due to extreme events should also be considered although you can try a simpler way as well.
Line 32 Could you please confirm whether the abrupt changes in these climatic metrics matter or the gradual changes?
Line 34 negatively?
Line 38 by the end of this century?
Line 46 Please add references.
Line 49, 53 should be ‘was estimated to’
Line 72-73, 88 ‘determined’ should not be used here.
Line 172,173 Please confirm the consistency of the tense used.
Line 213-215 What did you mean by ‘two thousand times’?
Figure 2 You should also show a plot of accumulated carbon capture during 200 years.
Figure 2 Is the time mismatch among three scenarios shown here due to different rotation length?
Line 232, 251, 320-321: Please check the grammar.
Author Response
Dear editor,
We appreciate the detailed revision of our manuscript forests-2089293entitled " Optimal management strategies to maximize carbon capture in forest plantations: A case study with Pinus radiata". As you can check, we paid careful attention to the suggestions and made the corrections accordingly. We believe that the changes suggested by Reviewers have greatly improved the manuscript making important and positive changes. The point-by-point response are indicated below.
Minor changes
We write the full name of species mentioned in the manuscript.
Number of citations in the text have changed due to the inclusion of new paragraphs and their respective references. New references are included in the Reference list.
The words ‘Eq.’ and ‘Fig.’ were replaced by ‘Equation’ and ‘Figure’ throughout the text.
Reviewer 1#
The language of the manuscript needs to be polished. There are lots of grammar mistakes. Please ask a native speaker to fix them.
Answer: The language was double-checked.
You may need to add another paragraph about the generality of this modeling framework to other tree species or other forest ecosystems.
Answer: From Line 62 to 69, we have added a paragraph in the Introduction section for the planting species Elaaeis guinensis or oil palm.
You should also present a comparison of the amount of CO2 emission that can be offset among these three scenarios to highlight the advantage of the optimal strategy.
Answer: We appreciate the comment by the reviewer. This is an interesting comment that deserves to be considered, but we respectfully believe this goes beyond the scope of our paper. Our paper is aimed is to determine optimal rotation strategies that maximize carbon capture in forest plantations.
For intrinsic growth part, can you add the effect of climate factors? For example, the mean annual temperature and mean annual precipitation really matter in the biomass growth. These two parameters can also be added into the logistic form.
Answer: In Equation (2), the intrinsic growth dynamics parameter implicitly considers climatic factors. But we like the idea of considering mean annual temperature and mean precipitation explicitly, which we will consider for future work.
Besides the natural mortality rate, the tree mortality rate due to extreme events should also be considered although you can try a simpler way as well.
Answer: For our model we are disregarding extreme events. In this case, in Line 191 an additional assumption was added to the model.
Line 40 Could you please confirm whether the abrupt changes in these climatic metrics matter or the gradual changes?
Answer: To avoid confusion, we omitted the phrase ‘abrupt’.
Line 42 negatively?
Answer: We slightly modified the sentence. ‘concerns and’ was replaced by ‘could have’.
Line 46 by the end of this century?
Answer: We modified the sentence. ‘next century’ was replaced by ‘21st century’.
Line 54 Please add references.
Answer: In line 54, the references 12 and 13 have been included.
Line 56, 61 should be ‘was estimated to’
Answer: The words ‘in’ and ‘at’ were replaced by the word ‘to’.
Line 87, 103 ‘determined’ should not be used here.
Answer: The sentence ‘They determined that’ was omitted in Line 87. In Line 103 the word ‘determined’ was replaced by ‘showed’.
Line 269, Please confirm the consistency of the tense used.
Answer: In Line 269 ‘perform’ was replaced by ‘performed’. The tense for ‘approximate’ is correct.
Line 321-322 What did you mean by ‘two thousand times’?
Answer: We slightly changed the sentence in Lines 321-322.
Figure 2 You should also show a plot of accumulated carbon capture during 200 years.
Answer: We have added a new Figure 3 related to the cumulative annual carbon capture for 200 years, and a brief commentary has been added in Lines 379-382.
Figure 2 Is the time mismatch among three scenarios shown here due to different rotation length?
Answer: We appreciate this comment by the reviewer, but the mismatch among the three scenarios is given by the parameters considered in each scenario (Tables 3 and 4) and not by a predetermined rotation age.
Line 340, 360, 442: Please check the grammar.
Answer: Line 340, the word ‘is’ was omitted. To avoid confusion, the sentence ‘since for the burned area to exist, biomass must first exist’ was omitted in Line 360. Similarly, in Line 442 the sentence ‘to avoid CO2 emissions caused by fires’ was omitted.
Sincerely yours
Dr. Sergio Espinoza
Corresponding author
Author Response File: 
Author Response.docx
Reviewer 2 Report
The optimal management strategies are important to guide the management of forest plantations to achieve the maximum carbon capture rate. Altamirano-Fernández et al. determined optimal management strategies that maximize carbon capture in fast-growing forest plantations using the optimal control theory. The model effectively simulates the optimal dynamics of live biomass, intrinsic growth, and burned area, considering four strategies such as reforestation, felling, fire prevention, and thinning. The manuscript is well written and pleasant to read. Here are some minor suggestions for the authors to further improve the manuscript.
First, the term “carbon capture” should be clarified. Does it mean carbon sequestration both in soil and wood or only in wood?
Second, how do you model the mean intrinsic biomass growth? Du and Tang (2022) have proposed a log-normal model for growth of larch plantations. You may consider it in your model.
Third, the current model doesn’t consider the role of nutrient. A recent assessment has revealed the global patterns of terrestrial nitrogen and phosphorus limitation (Du et al., 2020). The role of nutrient limitation should be considered here if possible and at least discussed. In plantations, nutrient limitation is likely to be strengthened after rotations due to biomass removal. Although nutrient can greatly affect the rates of forest productivity, it doesn’t likely affect the C use efficiency (NEP/GPP) (Du, 2016). Good to discuss it then.
Author Response
Reviewer 2#
First, the term “carbon capture” should be clarified. Does it mean carbon sequestration both in soil and wood or only in wood?
Answer: We appreciate this comment by the reviewer. To clarify with this comment, we considered carbon capture only in wood. As mentioned in Line 126, we considered above- and below ground biomass i.e., shoot and roots.
Second, how do you model the mean intrinsic biomass growth? Du and Tang (2022) have proposed a log-normal model for growth of larch plantations. You may consider it in your model.
Answer: The description of how we modelled intrinsic biomass growth was stated in Equation 2. However, we found interesting the work by Du and Tang and made a reference in Line 149 (reference number 36). Since, the represents the maximum growth under ideal conditions.
Third, the current model doesn’t consider the role of nutrient. A recent assessment has revealed the global patterns of terrestrial nitrogen and phosphorus limitation (Du et al., 2020). The role of nutrient limitation should be considered here if possible and at least discussed. In plantations, nutrient limitation is likely to be strengthened after rotations due to biomass removal. Although nutrient can greatly affect the rates of forest productivity, it doesn’t likely affect the C use efficiency (NEP/GPP) (Du, 2016). Good to discuss it then.
Answer: We appreciate this comment the reviewer, but for simplicity and to propose a parsimonious model, we assumed no fertilization (Line 343). However, we discuss the works by Du et al., (2020) and Du (2016) in Lines 341-343.
Sincerely yours
Dr. Sergio Espinoza
Corresponding author
Author Response File: Author Response.docx
