Historical Fires Induced Deforestation in Relict Scots Pine Forests during the Late 19th Century
, Gabriel Sangüesa-Barreda 2, Cristina Montiel-Molina 3, Reyes Luelmo-Lautenschlaeger 4, Paula Ortega 5, Mar Génova 5 and José Antonio López-Sáez 4Round 1
Reviewer 1 Report
This is an interesting merging of historical and living vegetation data. My only comment for change is that the dates of the historical studies are so important for this paper that I think they should be briefly described here. Refereeing to other papers is fine and aids brevity, but some overlap is justified here.
Author Response
Comments and Suggestions for Authors
This is an interesting merging of historical and living vegetation data. My only comment for change is that the dates of the historical studies are so important for this paper that I think they should be briefly described here. Refereeing to other papers is fine and aids brevity, but some overlap is justified here.
> We added a reference to the dates commented by the reviewer in the revised title.
Reviewer 2 Report
I found this manuscript interesting and well constructed but have a few suggestions for its improvement.
General Comments
Please be explicit about human influences other than changes in fire regimes. In particular, were the pines harvested for timber?
Also clarify whether all the pines mentioned are fire-dependent, and, if so, in what ways.
I do not have a very clear picture of the vegetation in the study area. From the pictures it looks like sparse woodland on rocky slopes.
Abstract:
Line 3: “low post-fire resilience”---I know that resilience is a perfectly good term in English, but this reader (a native speaker) does not understand what it means in this context.
Second to last line: “livestock organization”---I am not sure what this means…is it in reference to a formal organization, like FAO?
Introduction:
2nd paragraph: forest “encroachment” into what?
3rd clarify that the human-caused fires occurred at a frequency higher than what would be “natural”. Also, Scots pine is fire sensitive? But how is it related to fire? Later it’s described as being “thick barked”?
Figure legend: what crosses?
Materials and Methods
Paragraph 1: reporting the extreme temperatures would be MUCH more useful. A mean temperature of 14.5 is very different if the range in temperatures is -5 to +45, then if the range is much smaller.
The soils are described as moderately deep, but the pictures show lots of rocks on the surface; this needs clarification.
Para 2: how did resin tapping favor the tapped pines?
Table 1: something wrong with the Dbh column/ And shouldn’t ranges be presented in both sizes and ages?
Section 2.3: Is it correct to italicize tribal names (Genisteae)? I presumed it was a genus. Readers unfamiliar with your flora won’t understand this reference.
Results 3.1
“deforestation process” is unclear, and again I wonder about logging, which is not mentioned—is the process anthropogenic and, if so, in what way?
Para 2: “shift from dense pine forests to scattered…” based on the pictures provided and the brief description of the area, it is hard for me to imagine dense forest on those steep rocky slopes.
Page 8, paragraph 3: dense pine forest? Is this gotten from the percentages of different pollen types? Some more explanation of the evidence is needed.
Para 4: cattle, sheep, goats? “caused new clearances”---this needs rephrasing and clarification.
Para 5: “crown fires”----given the pictured stand densities, this seems unlikely….again, it would help to know what sorts of fire kill each of the pines, and what fire regimes favor them.
Para 6: are plantations established on these steep rocky slopes?
I hope at least a few of these comments, questions, and suggestions help improve this interesting manuscript.
Author Response
Comments and Suggestions for Authors
I found this manuscript interesting and well constructed but have a few suggestions for its improvement.
> We thank you for the positive comments.
General Comments
Please be explicit about human influences other than changes in fire regimes. In particular, were the pines harvested for timber?
> According to local historical information including Historical Management Plans, no major timber harvest occurred during the 19th-century abrupt decline of the study Scots pine forests. In addition, the tree ring data do not show releases which would suggest a sharp reduction in competition due to tree removal. We have stated this in the revised Discussion.
Also clarify whether all the pines mentioned are fire-dependent, and, if so, in what ways.
> Scots pine is not considered a fire dependent species, but we clarified this issue in comparison with the other mentioned species (for instance, P. pinaster is better equipped to tolerate fire than P. nigra).
I do not have a very clear picture of the vegetation in the study area. From the pictures it looks like sparse woodland on rocky slopes.
> Yes, currently there are forests and also open stands (woodland) on rocky sites. Probably, they were more dense and extensive in the past. We added this info in the Material and Methods section.
Abstract:
Line 3: “low post-fire resilience”---I know that resilience is a perfectly good term in English, but this reader (a native speaker) does not understand what it means in this context.
> Thanks, we should have been more explicit and state the framework of the study (tree-ring data). We refer to “post-fire growth resilience” in the revised ms.
Second to last line: “livestock organization”---I am not sure what this means…is it in reference to a formal organization, like FAO?
> It was a “formal” organization but could be considered also an association (we used this second term in the revised ms.). See https://en.wikipedia.org/wiki/Mesta.
Introduction:
2nd paragraph: forest “encroachment” into what?
> We rephrased the sentence and wrote it as “forest expansion”.
3rd clarify that the human-caused fires occurred at a frequency higher than what would be “natural”. Also, Scots pine is fire sensitive? But how is it related to fire? Later it’s described as being “thick barked”?
>We revised this paragraph following your comments. Scots pine is less tolerant to mid-severity fires than other Mediterranean pine species such as P. pinaster. We have changed its description to “thin-barked” in comparison with more tolerant pine species.
Figure legend: what crosses?
>We changed crosses to “dots” in the legend (they were crosses in the original figure but the reduction of the image “converted” them into dots).
Materials and Methods
Paragraph 1: reporting the extreme temperatures would be MUCH more useful. A mean temperature of 14.5 is very different if the range in temperatures is -5 to +45, then if the range is much smaller.
>We report maximum and minimum temperatures.
The soils are described as moderately deep, but the pictures show lots of rocks on the surface; this needs clarification.
>We clarified this issue since in the sample stands soils tend to be rocky and thin.
Para 2: how did resin tapping favor the tapped pines?
>The tapped species (Pinus pinaster) was historically favored and planted at low to mid elevations. We rephrased the sentence.
Table 1: something wrong with the Dbh column/ And shouldn’t ranges be presented in both sizes and ages?
>We added Dbh and age ranges as requested. The Dbh column is OK because we lacked Dbh and age data for the two ITRDB sites.
Section 2.3: Is it correct to italicize tribal names (Genisteae)? I presumed it was a genus. Readers unfamiliar with your flora won’t understand this reference.
>It is a tribe, we removed the italics.
Results 3.1
“deforestation process” is unclear, and again I wonder about logging, which is not mentioned—is the process anthropogenic and, if so, in what way?
>We are not aware of any logging during that time and tree-ring data do not indicate such logging occurred. We consider the decline of pine forests was caused by the increase in fire frequency. We have rephrased this section.
Para 2: “shift from dense pine forests to scattered…” based on the pictures provided and the brief description of the area, it is hard for me to imagine dense forest on those steep rocky slopes.
>We rephrased the sentence. We mean Scots pine forests probably occupied a wider area in the past.
Page 8, paragraph 3: dense pine forest? Is this gotten from the percentages of different pollen types? Some more explanation of the evidence is needed.
>We rephrased the sentence. We mean Scots pine forests probably occupied a wider area in the past as indicated pollen percentage.
Para 4: cattle, sheep, goats? “caused new clearances”---this needs rephrasing and clarification.
>We rephrased and clarified the paragraph.
Para 5: “crown fires”----given the pictured stand densities, this seems unlikely….again, it would help to know what sorts of fire kill each of the pines, and what fire regimes favor them.
>Note that the pictures show the current stand structure, but those forests were probably denser in the past. We revised the paragraph as you suggested and indicated the kind of fire regime tolerated by Scots pine, the study species.
Para 6: are plantations established on these steep rocky slopes?
>No.
I hope at least a few of these comments, questions, and suggestions help improve this interesting manuscript.
>Thanks a lot for your insightful comments.
Reviewer 3 Report
General comments:
The manuscript entitled ‘Historical fires induced deforestation in relict Scots pine forests’, aims at assessing fire regime during the past 300 years in a mountainous region in central Spain and relate it with the current status of relict Scots pine forests. In my opinion this manuscript deals with an interesting topic, and in general it is well written, though some parts need clarification.
Below I include specific comments and suggestions that in my opinion should be addressed by the authors in order to improve the manuscript.
Specific comments:
The fact that there are no line numbers in the manuscript makes the task of marking the different comments much more complicated. This should be changed in the future.
Page 1, beginning of second paragraph: Please clarify what you mean by historical resilience and specify to which book Chapter you are referring to.
Page 1, end of second paragraph: References are needed after “warming and aridification”.
Figure 1a: Need to include the source/reference for the distribution map. I suggest including a zoomed map of the Iberian Peninsula, because the situation in the study area cannot be seen in the current figure.
Page 3, second paragraph: Indicate the elevation range of scots pine stands.
Page 3, third paragraph: Indicate in detail how were the scots pine stands selected for this study, and how were the trees selected for core extraction.
Table 1: Indicate if Dbh values are averages.
Page 4, end of second paragraph: “We also considered (…)”; Considered for what? How?
Page 4, third paragraph: “after fire”, “post-fire” or “following fire” is used often. Explain how did you establish that there was a fire? Growth suppression can have other causes (e.g. pests and diseases).
Page 4, fifth paragraph: The authors should include an explanation of this process, at least as Supplementary material, for those readers wanting to know more about it; it is not appropriate to mention 8 references and leave the work to the reader.
Page 5, first paragraph: Please focus only on Gredos Mountains and not all the Spanish central system. How many records and which period?
Page 5, end of first paragraph: More detail needed. Also check “see 1”.
Page 5, forth paragraph: Not much accurate statements. Indeed, after 1886 there were several fires in the Arroyo, but the trend in pine pollen shows that pine forests were basically increasing until 2000. This also needs to be discussed.
Figure 4: How was the number of fires assessed? Also clarify if this number refer to two sites. Additionally, the number of fires should not be represented as a line (these are numbers in 20-year periods).
Figure 5: Please use different colours for the two lines.
Author Response
Comments and Suggestions for Authors
General comments:
The manuscript entitled ‘Historical fires induced deforestation in relict Scots pine forests’, aims at assessing fire regime during the past 300 years in a mountainous region in central Spain and relate it with the current status of relict Scots pine forests. In my opinion this manuscript deals with an interesting topic, and in general it is well written, though some parts need clarification.
Below I include specific comments and suggestions that in my opinion should be addressed by the authors in order to improve the manuscript.
>We thank you for your positive comments.
Specific comments:
The fact that there are no line numbers in the manuscript makes the task of marking the different comments much more complicated. This should be changed in the future.
>We are sorry about that. We follow the journal guidelines and used their template.
Page 1, beginning of second paragraph: Please clarify what you mean by historical resilience and specify to which book Chapter you are referring to.
>Done, we rephrased the sentence and indicated the chapter.
Page 1, end of second paragraph: References are needed after “warming and aridification”.
>Done, we added a reference.
Figure 1a: Need to include the source/reference for the distribution map. I suggest including a zoomed map of the Iberian Peninsula, because the situation in the study area cannot be seen in the current figure.
>Done, we added a reference. We included an inset in the Fig.1b where the Iberian Peninsula is clearly identified.
Page 3, second paragraph: Indicate the elevation range of scots pine stands.
>Done, we indicated it.
Page 3, third paragraph: Indicate in detail how were the scots pine stands selected for this study, and how were the trees selected for core extraction.
>Done, we indicated it. As stated in section “2.2. Field sampling of Scot pine forests and dendroecology” we selected relict Scots pine stands situated near sites with paleoecological records but subjected to different climate conditions. We selected and cored trees with Dbh > 10 cm.
Table 1: Indicate if Dbh values are averages.
>Done, we also included the ranges.
Page 4, end of second paragraph: “We also considered (…)”; Considered for what? How?
> They were used to check our cross-dating. This is stated in the revised ms.
Page 4, third paragraph: “after fire”, “post-fire” or “following fire” is used often. Explain how did you establish that there was a fire? Growth suppression can have other causes (e.g. pests and diseases).
> We already used this approach (ref. 14) and discarded other possible drivers of growth suppression such as pests or diseases (e.g., pine processionary moth, bark beetles), which produce different signals or do not affect all trees within a stand. We better explained our approach in the revised ms. According to climate reconstructions, the late 19th-century growth drop was not related to severe droughts or other extreme climate events. In addition, we usually selected stands in areas which were historically burnt as demonstrated the existence of charcoal records.
Page 4, fifth paragraph: The authors should include an explanation of this process, at least as Supplementary material, for those readers wanting to know more about it; it is not appropriate to mention 8 references and leave the work to the reader.
> We better explained this part as Supplementary Material.
Page 5, first paragraph: Please focus only on Gredos Mountains and not all the Spanish central system. How many records and which period?
> We focused on Gredos mountains and indicated the number of records (1094 records).
Page 5, end of first paragraph: More detail needed. Also check “see 1”.
> We added more detail on the extraction of historical fire records.
Page 5, forth paragraph: Not much accurate statements. Indeed, after 1886 there were several fires in the Arroyo, but the trend in pine pollen shows that pine forests were basically increasing until 2000. This also needs to be discussed.
> We discussed this pattern as suggested.
Figure 4: How was the number of fires assessed? Also clarify if this number refers to two sites. Additionally, the number of fires should not be represented as a line (these are numbers in 20-year periods).
> The number of fires corresponded to historical records of fire events in the Gredos mountains study area since they were not always accurate enough to be assigned top each study forest. We also modified the figure as suggested.
Figure 5: Please use different colours for the two lines.
> We modified the figure as suggested.
