Climate Effect on Ponderosa Pine Radial Growth Varies with Tree Density and Shrub Removal
Round 1
Reviewer 1 Report
a) General comment :
The authors present a study to evaluate the long-term responses of radial growth to climate vary with tree density and shrub removal in a ponderosa pine plantation in California. From my understanding, the technical parts of this work were done carefully and correctly, following adequate approaches (statistical and dendroecological). I appreciate the effort the author put in the originality of this experience. Therefore, the research question is very interesting, the manuscript is very well structured, the objectives are clear. This study provides an important contribution in plantation management and climate change.
However, this article has some weaknesses that could be improved that I list below:
- The title is very long.
- The structure of method section must to be improved (see comments below). Also, it is too long.
- The introduction is too short and did not present all the important topics. Introduction doesn’t describe the international context. And also, there is some important references lacking.
- Some Figures should be improved. Many Figures
- In the discussion, doesn’t describes the international context. Also, in the discussion is lacking the management implication.
I have also provided the following specific suggestions that would help to improve the quality of this manuscript. At this stage, I propose the authors to consider these suggestions in a major revision, and request the editor not to accept the manuscript until and unless the authors make the changes. I encourage the author to incorporate these suggestions, and I want to say congratulations for this interesting and original research.
b) Specific comments
1. Tittle is very long.
2. Abstract :Nice.
3. Keywords: Keywords must to follow alphabetic order.. modify it, please. Also, you could add other keywords as thinning or sustainable forest management.
4. Introduction:
L35. I suggest to add a broad paragraph about climate change, plantation, thinning, sustainaile forest management in forest ecosystems (not only in California) providing an international scopus.
L42: add reference.
L46. Add reference.
L47-50: Please, add other studies with other species to provide an international approaches.
L51-52: Please, add this reference here about a new study that show how low harvest intensities reduce risk of mortality: Post-cutting mortality following experimental silvicultural treatments in unmanaged boreal forest stands. Frontiers in Forests and Global Change, 2, 4.
L60-61: Add a sentences before it to say the adventaces of dendrochronology as tool to evaluate the impact of forest disturbances: e.g. Tree-ring series provide more accurate estimations of radial growth than inventories data because they allow reconstruction at fine resolution of forests disturbances.
L.84: Could you provide a section for study area and another for sample collection, please?
Figure 1: could you provide the latitude and longitude in the map (Figure 1a).
Figure 1b: It is blurred. Could you improve the quality, please?
L99: No list. Please, re-writte it. Replace: trees per hectare by trees ha-1.
L101: No list. Please, re-writte it.
L105-106: No list. Please, re-writte it. Difficoult to read.
L112-114: No list. Please, re-writte it.
L124-125: Why? More details, please.
L128. How many cores? Add this information here.
Figure 2: Could you remove the title Figure? It was written in the caption. C = °C? replace it, please. Could you move mm to the top? 30.2 and 1.9: It is strange it…!!!
Figure 3: Please add a letter to each graph e.g. a, b,c. Please, remove the time scale on the first and second graph.
L152-153: Please add this reference here, because they used the same analyse: Radial Growth Response of Black Spruce Stands Ten Years after Experimental Shelterwoods and Seed-Tree Cuttings in Boreal Forest. Forests 2016, 7, 240.
L153: Add the version of SAS, please
L195-196: this information is not a result, it is part of the methodology. Move it please.
L201-205: this is not a result. This is discussion of result. Move it please.
L206-207: rewritte it please. Replace m3 by cubic meters (hiper-index).
Table 1: two or three decimals, not both.
Figure 4: Nice!
Figure 5: Please add a letter to each graph e.g. a, b,c. Please, remove the time scale on the first, second and third graph.
Figure 6b: 2 or 3 decimals? E.g. 0.54. Could you describe the number in the Figure caption.
Figure 7: Please remove: treatment resistance correlation for each graph (it is a systematic repetition).
342-243: please remove: Using the same… start your sentence with Johnson.
351-363: International context is lacking as well as comparission with other species.
The discussion present some weakness as:
a) Study limitations and future recommendations:Authors must to do recommendations for future researches. Also, authors have analysed it using stand models. Authors did not consider the individual tree variability. I suggest that author said in the discussion: - For future researches, we recommended to explore the growth response using individual non-linear models to get a better resolution of growth. Reference: Understanding tree growth responses after partial cuttings: A new approach. PLoS ONE 12(2): e0172653. https://doi.org/10.1371/journal.pone.0172653
b) International context is lacking: A small paragraph to discuss other studies in other forest ecosystem could be great for the readers and to improve the Scopus of this paper. For examples. Author could give recommendations for future research in Canadian boreal forests. I suggest to indicate something as: Recently, new shelterwood silvicultural treatments has been developed in black spruce stands from Canadian boreal forest. These treatments showed a high growth response on residual trees, intermediate level of mortality for wind damages, as well as provided adequate level of natural regeneration. Based on the results obtained here, we recommended to study the climate and competition influence in the adaptation to climate change context.
Author Response
Please see the attachment for responses to specific comments.
Author Response File: 
Author Response.docx
Reviewer 2 Report
General comments:
Overall, the paper is of interest to readers. It is not publishable as it is now for the following reasons:
- English should be revised, not so much because of typos or spelling but because of sentence structure and clarity.
- Different parts are not clear and have to be re-written. I suggest review the writing and grammar throughout the document, it will improve the readability of the paper.
- Please see below specific comments, some are minor comments and some require a major re-definition of the paragraph.
Specific comments:
Material and methods
L96-L106: I recommend to clarify this paragraph. It is difficult to understand. I recommend also to use the international system units through the paper, is not necessary to use acres or feet it’s confusing.
L182: disturbance word is repeated. Correct it
L182: How have you selected the years considered as a disturbance? Which are these years? Can you explain in it?
Results
L212: “For 2005 QMD, comparing the combined densities between different shrub treatments showed significant differences between the three treatments with diameter increasing with treatment level.” I can’t see this in figure 5, please improve the figure.
Discussion
L329-331: I suggest rephrasing this sentence “We have also shown that decades later on poor quality sites, without substantial shrub removal efforts for young ponderosa pine plantations, the long-term growth and vigor of trees will have continued detrimental impacts”. It is difficult to understand.
L336-337: “Although temperature showed a significant correlation with radial growth, we believe that its effect on growth and resistance was through influencing soil moisture”. Clarify this statement, what do you mean with “we believe”? You need to refer to some data…
L364-365: “While the precipitation modelling (Figure 6b) showed similar trends in adjusted R2 values and positive springtime relationships to RWI as CMI (Figure 6c), the seasonal response for PPT was much shorter compared to both temperature (Figure 6a) and CMI.” I don’t understand what do you mean with …was much shorter… in this sentence, please clarify.
L381-382: “Previous research have found that ponderosa pine is typically more sensitive to moisture than by temperature alone over a wide geographic range [18, 23, 27, 54]”. Please correct and clarify this sentence.
L393-395: “The results also indicate that the higher the competition (i.e. highest shrub cover and highest tree density), CMI during the summer season is the primary variable to drive radial growth, while only secondary or non-significant for the more heavily treated groups affected by moisture availability after May (Figure 6c)”. I suggest to clarify this sentence.
L420:”However, the monthly delay (AMJ compared to MAM) for the seasonal relationship for 2200 (V0) group does stand out…”. I don’t know the meaning of AMJ and MAM…clarify please
Figures and tables
Figure 1: It is necessary to improve this figure. I will give some suggestions as,… use the same label in the legend and in the description of figure. I recommend using the density instead of the spacing between trees, as is a more understandable reference.
Figure 3: I cannot see the difference between dark and light vertical lines in this figure.
Figure 4: It is necessary to improve this figure. I will give some suggestions as change the X-Axis, put the year (1975 to 2005) not the stand age. In the results, you are referring to the years no to the stand age. Is there any difference between treatments? In which moment? I suggest to put a label (*) when it occurs.
Figure 6: It is necessary to improve this figure also. It is difficult to understand which R2 corresponds to which month. What is the meaning of the numbers (1, 2, 3, 4)? Why are some months plotted individually and in some cases we find it as a group? I recommend changing this figure and plotting all the correlation coefficients for all month with a color ramp from blue to red for example.
Figure 7: I recommend using a color ramp with the different correlation coefficients.
Author Response
Please see the attachment for responses to specific comments.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
At this stage, I request the editor to accept the manuscript in the current form.
Congratulations to the authors, they have realized a good job considering most of the reviewer suggestions.
