Potential Carbon Sequestration and Economic Value Assessment of the Relict Plant Ginkgo biloba L. Based on the Maximum Entropy Model
Round 1
Reviewer 1 Report
This is the first study to explore the potential distribution of ginkgo in China under a range of climate scenarios and to explore potential carbon sequestration potential using well-known models. The findings will be useful in future planning for regreening of China. It was surprising to see the concentration of most suitable sites along the east coast of China and the lack of site suitability in much of Yunnan. The manuscript is well written but should be carefully checked to remove errors in style.
Section 2.1: Mention that the majority of the ginkgo in China are planted hence the current distribution is not mostly influenced by humans and is therefore not a natural range of the species. In Figure 1 indicate with a different symbol the distribution records of natural stands of the species.
Section 2.6: Does the carbon sink estimation include both the below and above ground C stock?
Figures and tables: Some of the figures and tables can be transferred to supplementary information.
Comment on the importance or not of altitude in informing the suitability of an area for ginkgo particularly under climate change scenarios of global warming.
Whilst simulations of potential distributions and calculations of potential carbon sinks are interesting, in reality much of the highly suitable areas for ginkgo coincide with dense human populations and land set aside for food production. Therefore, the discussion should include some reasonable estimates of the opportunities for C sequestration by existing and new urban and peri-urban plantings.
Also, three are a large number of other tree species in China that have been extensively used in green belt programs, regreening of cities and transport corridors, in addition to the enormous afforestation/reforestation program undertaken through the SFA, CAF. How important is ginkgo likely to be in the future given the extent of the value of other tree species in street and other scapes?
How do the estimates for carbon sequestration for ginkgo compare to the other estimates published for a range of urban tree species and forests in China? The authors should provide evidence for their statement ‘carbon sequestration capacity and carbon sink value of G. biloba are high’ by comparison with some other tree species in urban settings across China.
Also, of the 2017 data on the carbon sink of vegetation in urban China of 1.19×107-t, can the authors estimate the contribution that ginkgo might be contributing at the present time? If no information is available, perhaps comment on the extent of ginkgo plantings in some urban environments – are there avenues of trees, single trees in mixed plantings, trees in temple grounds, trees cultivated and being managed for medicinal and other products.
Minor edits desirable
Author Response
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Reviewer 2 Report
Dear authors,
Congratulations to your team on a well-written manuscript that contains valuable information. Additionally, I recommend you that focus on the discussion.
It should be noted that please include high-res images. It was difficult to see the details in your images!
Best regards,
M
It is suggested to make minor revisions to enhance the readability of the English language.
Author Response
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Reviewer 3 Report
General comments:
The manuscript addresses a relevant topic for one of China´s more important tree species, G. biloba. Following the MaxEnt modelling approach and based on data from several platforms, the authors estimated trends in the species distribution and changes in potential carbon sequestration and sink values under eight climate change scenarios.
The following lines include specific comments aimed to help improving the manuscript.
Introduction
This section focusses on the relevance of the species as a valuable tree species in carbon sequestration, enhancing its role in urban areas.
Line 155- pleased define AUC the first time it is mentioned.
Methods
Of all variables used in the modeling process, those related to social aspects deserve some more detailed description (lines 215-217). Especially because one of them (Hf) turned out to be highly important in explaining current and future distribution of the species. In addition, because the author seems to draw more attention on urban areas, where social roles are more direct and relevant for species occurrence.
Estimating prices or values for future services, (carbon sink) or products might require a different economic approach, one that accounts for future values, but as far as I understand this is out of the scope of this study.
Lines 230-231- please define ROC and AIC the first time they are mentioned
Line 269- ¿which “second class” it is referring to?
Results
Maps legends quality could be improved.
Please review Table 8, it includes duplicated information.
Discussion
The resulting values of carbon sequestration and carbon sink values under projected scenarios deserve some more discussion, considering the findings that future suitable areas for G. biloba will be larger than current area of distribution.
Although this section is in general well addressed, the authors failed to properly contrast their results with some cited literature, i.e. are there similar, or different results in other regions or species?. Additionally, despite some brief comments throughout the manuscript, two important points are missing in this section: no information on the species interaction (competition, synergies, etc.) is discussed; and there are no mentions on the species genetic plasticity to adapt in new areas, or remains in unsuitable areas, under climate change scenarios. These two points plays important roles in determining where a species regenerate and grows. This would enrich the discussion section, unless the authors want to focuses their results solely on urban areas, where those aspects might not be relevant.
Finally, is there any procedure (or data) to account for possible changes in carbon sequestration rates of G. biloba under different climatic scenarios?
Please review writing in lines 243, 434, 502…, and writing style throughout the manuscript.
In some paragraphs following the main ideas is hard due to redundant use of words, i.e. "...the area of suitable or higly suitable area is..." there should be a different way of rephrasing those sentences.
Author Response
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Round 2
Reviewer 1 Report
The amendments have improved the quality of the manuscript
Line 723 check spelling
Line 718 join the two sentences
Author Response
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