Forest Owner Willingness to Accept Payment for Forest Carbon in the United States: A Meta-Analysis
Round 1
Reviewer 1 Report
I read with the interest the paper. Overall, I think the topic is important, and well tackled by the authors in terms of method and writing. The meta-analysis provides a comprehensive review of the research literature assessing forest owner preferences for carbon payment programs. The estimated willingness to accept (WTA) for carbon payment contracts for different categories of FFOs analyzed by the robust regression model and benefit transfer techniques. The findings show the different categories of forest owners (management objectives, contract length, number of forest acres, management plan requirement, and management restrictions) affect the forest owner's WTA. Some minor suggestions are provided as what followed for the authors’ consideration.
Comment 1: I'm confused by the independent variables used in the analysis. How many independent variables? 21? 17? 19?
L166-167: A total of 21 variables were considered useful for explaining important variation in WTA and were included as independent variables in the analysis.
Table 2: there are 17 variables.
L216-262: Five out of the 19 variables tested were significant in predicting variation in WTA and revealed the important influence of contract design on forest owner choices (Table 3).
Comment 2: Authors mention some limitations in this study (L466-473), please offer brief directions for future research in the conclusion.
Author Response
Comment: I read with the interest the paper. Overall, I think the topic is important, and well tackled by the authors in terms of method and writing. The meta-analysis provides a comprehensive review of the research literature assessing forest owner preferences for carbon payment programs. The estimated willingness to accept (WTA) for carbon payment contracts for different categories of FFOs analyzed by the robust regression model and benefit transfer techniques. The findings show the different categories of forest owners (management objectives, contract length, number of forest acres, management plan requirement, and management restrictions) affect the forest owner's WTA.
Response: Thank you for acknowledging our work, and for your kind words and appreciation.
Comment: Some minor suggestions are provided as what followed for the authors’ consideration.
Comment: I'm confused by the independent variables used in the analysis. How many independent variables? 21? 17? 19?
L166-167: A total of 21 variables were considered useful for explaining important variation in WTA and were included as independent variables in the analysis.
Table 2: there are 17 variables.
L216-262: Five out of the 19 variables tested were significant in predicting variation in WTA and revealed the important influence of contract design on forest owner choices (Table 3).
Response: We apologize for the confusion. We started by identifying a total of 21 potential variables, but several were removed at different points due to insufficient data. We have now modified this information in the places you indicated and reported that data for 17 variables were compiled and used for testing in the model throughout the text in the manuscript.
Comment: Authors mention some limitations in this study (L466-473), please offer brief directions for future research in the conclusion.
Response: Thank you for the suggestion. After the section on study limitations, we now offer recommendations for future research to help with meta-analysis studies in the future. Recommendations for other types of future research are also offered at the end of the conclusions section.
“To assist with these types of meta- analysis studies in the future it would be helpful for researchers to use consistent in formatting when describing socio-economic data and provide mean WTA estimates for 100% of the sample group. More research on landowners WTA for forest carbon is also needed in western states.”
Reviewer 2 Report
Based on my review, I have the following comments and suggestions:
1. The Meta-analysis is one of the main innovations of this manuscript. It is recommended that the authors describe in detail the principles of this method and the operational steps. Even add an appendix if necessary.
2. The authors should have included the maximum and minimum values in the descriptive statistics table in Table 2.
3. It is recommended that authors elaborate on the meaning and differences among the passive forest owner, the conservation-oriented forest owner and the timber production-oriented forest owner, when they first appear in the manuscript.
4. Please keep the formatting of formulas consistent throughout this manuscript.
5. The problem of subscripts for letters seems to have escaped the attention of the author, e.g. line 225.
6. For Table 3 in the results section, the authors needed to present the regression results for all 19 variables, not just the results for the five significant variables.
7. It would be useful for the authors to explain in detail the reasons for the differences in the results in Table 3.
Author Response
Based on my review, I have the following comments and suggestions:
Comment: 1. The Meta-analysis is one of the main innovations of this manuscript. It is recommended that the authors describe in detail the principles of this method and the operational steps. Even add an appendix if necessary.
Response: Specific principles and steps are now briefly discussed in Appendix A.
Comment: 2. The authors should have included the maximum and minimum values in the descriptive statistics table in Table 2.
Response: Max and min values have now been added to Table 2.
Comment: 3. It is recommended that authors elaborate on the meaning and differences among the passive forest owner, the conservation-oriented forest owner and the timber production-oriented forest owner, when they first appear in the manuscript.
Response: Thank you for the suggestion. We have now added in the methods and discussion sections a more complete explanation of the meanings of these categories of owners and how they differ. For example, the paragraph on line 215 now reads:
“The following benefit transfer procedure was used to assign values to carbon contracts expected to appeal to three categories of forest owners. These categories are intended to represent different forest owner archetypes and include the passive forest owner, the conservation-oriented forest owner and the timber production-oriented forest owner. These categories were based on the findings of a related study which linked willingness to pay/accept behaviors with different motivations and management objectives [44]. Those with conservation or social responsibility motives were less sensitive to financial losses compared to those with timber production motives. Other differences among these groups may also be related to how land use and expected benefits are prioritized.”
Comment: 4. Please keep the formatting of formulas consistent throughout this manuscript.
Response: The formatting of formulas has been made consistent throughout the manuscript, as suggested.
Comment: 5. The problem of subscripts for letters seems to have escaped the attention of the author, e.g. line 225.
Response: The formatting issues for equations 4 to 6 have been corrected.
Comment 6. For Table 3 in the results section, the authors needed to present the regression results for all 19 variables, not just the results for the five significant variables.
Response: We apologize for the confusions regarding the number of variables tested and the number included in the model. Using a systematic process, we were able to compile data for 17 variables to testing in the model (Table 2). Out of these 17 a total of 5 were significant in predicting WTA in the model (Table 3). Other reviewers for this paper point out the need for more discussion regarding the non-significant variables. This has now been added starting on line 359.
Comment 7. It would be useful for the authors to explain in detail the reasons for the differences in the results in Table 3.
Response: A more complete discussion of apparent differences among variables is now given in the results and discussion sections.
Line 283: “Regarding the magnitude of significant coefficients, MR had the greatest influence on the model indicating that delaying harvest underpinned much of the opportunity costs associated with a carbon program compared to other variables. Region in which the study occurred, and the requirement of a management plan also had a large impact on acceptable prices. Comparatively, size of ownership (acres) and number of contract years had a more modest impact on price.”
Line 386: “Contract length, however, had the least impact on WTA compared to other significant variables, such as delay in harvest. This may be due to the abstract nature of future values and the uncertainty of how a carbon contract may impact those values.”
Line 418: “Developing a forest management plan is important for attaining sustainability goals but can be time consuming and accrue some costs since it is often done in conjunction with a professional forester.”
Line 432: “Harvesting trees is an important economic benefit of owning forest land, so a delay in harvest could be seen as a more tangible or meaningful loss.”
Reviewer 3 Report
I congratulate the authors on a scientifically sound meta-analysis that can help improve US carbon storage programs. I have no fundamental comments, because the study is very well done from a methodological point of view. The only disturbing moment of the study is when using BT, which in connection with the categories of forest owners has a lot of assumptions, but they are logical. However, it would be better to deal with variables that were not significant in the overall model in the results, because they could become significant for individual ownership categories. The sample size can then be a problem for some categories.
Small suggestions for changes:
Lines 263 – 264: I would state the abbreviations of the explanatory variables.
Table 3: I would explain the abbreviations.
Figure 1: Clarify in the picture, but also in the text, to which category the value 20 and the value 50 belong.
Lines 458-466: Some words have misplaced word dividers.
Author Response
Comment: I congratulate the authors on a scientifically sound meta-analysis that can help improve US carbon storage programs. I have no fundamental comments, because the study is very well done from a methodological point of view.
Response: Thank you for acknowledging our work, and for your kind words and appreciation.
Comment: The only disturbing moment of the study is when using BT, which in connection with the categories of forest owners has a lot of assumptions, but they are logical. However, it would be better to deal with variables that were not significant in the overall model in the results, because they could become significant for individual ownership categories. The sample size can then be a problem for some categories.
Response: We appreciate your interest in understanding why some variables were not significant. Yes, the small sample size did provide limitations for exploring why some variables did not become significant. We now offer some discussion on this point starting on line 363.
“Twelve of the variables tested were not significant in the model, however, study features such as survey design and socio-demographic characteristics may still be important. Moreover, early withdrawal penalties and additionality requirements not significant in this analysis have been found to influence choice in other analyses [35]. Low sample size may have obscured evidence of systematic variation within some of the data, and also prevented the use of filtering techniques.”
Comment: Small suggestions for changes: Lines 263 – 264: I would state the abbreviations of the explanatory variables.
Response: It has been changed as follows. The variable coefficients in order of magnitude include YRS, Acres_Ln, MP, MR, and Region.
Comment: Table 3: I would explain the abbreviations.
Response: A new column has been added to the Table 3 to explain the abbreviations used for the variables.
Comment: Figure 1: Clarify in the picture, but also in the text, to which category the value 20 and the value 50 belong.
Response: It is unclear to us what the reviewer is referring to. Could more clarification be provided please?
Comment: Lines 458-466: Some words have misplaced word dividers.
Response: Inappropriate hyphens have been removed from this section and elsewhere in the paper.
Round 2
Reviewer 2 Report
The manuscript “Forest Owner Willingness to Accept Payment for Forest Carbon 2 in the United States: A Meta-analysis” has been considerably improved. It is better structured and the language is clear. My comments have been adequately addressed. I recommend the paper for publication.
