Thank you for your review. We are pleased to see that other researchers can see the benefit of this work.

The SahulCHAR collection now provides a highly relevant harmonized compilation of newly digitized and author-provided datasets, and includes also some updated records already stored in globally available paleorecord compilations. Of the latter, most data derived from the Global Paleofire Database (GPD, formerly Global Charcoal Database, GCD), which is specifically dedicated to provide long-term access to paleofire data but lacks data curation. The authors acknowledged that the records stored there are of different quality, though more detailed information on what exactly has been changed for the GPD records that became part of the SahulCHAR collection is missing (e.g. in terms of x% of the records required coordinate updates, y% required correction of site descriptions or contained missing values in comparison to the original publication etc). This is a matter of ongoing debate.

Our response to this comment was largely addressed in the comments to Reviewer 1. We improved the clarity of the text surrounding the discussion of previous databases and how they were incorporated into the new SahulCHAR database. We have included the additional information requested by both reviewers regarding the transfer of datasets from GPD and how each individual site was incorporated into SahulCHAR. Very few sites were transferred verbatim and each record was critically appraised, with additional information or corrections added when necessary.

The manuscript also contributes to the debate on how to harmonize the high diversity of charcoal and black carbon measurement units in publications and existing databases (see Dietze et al., 2024: First steps towards integrating the Global Paleofire Database with Neotoma | PAGES Magazine 2024) – a crucial step before GPD datasets can be integrated into the Neotoma Paleoecological Database. Especially the separation of the measurement unit (e.g. counts or a concentration in cm³) from the charcoal size and to group measurements into classes of minimum and maximum size classes is highly attractive. Here it would be great to also learn how many of the individual measurements overall in the data collection would fall in which class, e.g. as an extension of Fig. 4. In addition, figure 4 that provides an overview of the characteristics of the data compilation, could also be extended to learn which time periods are covered by the compiled records – that would surely increase its attractivity for users.

This was a difficult issue we grappled with when incorporating the different reported metrics of charcoal counts. Whilst we can see there might be some users of the database that would like to know the number of individual measurements for each charcoal measure, this is a large amount of data that would be largely meaningless without knowing which individual records this data comes from. We believe the number of records that use the different charcoal measures is sufficient for this manuscript, primarily designed to provide an overview of the SahulCHAR database.

Including the age range of the different records is a good idea. We have modified the map figure to show the variety of ages of the different records in the database. We believe this is the best way to display this data without adding additional figures or panels.

The SahulCHAR collection is hosted by OCTUPUS, a database platform that is briefly described. To improve the understanding of the “why this platform” and of the overall structure illustrated in Fig. 1 that shadows out other Sahul-compilations, it would help the reader if the authors would briefly describe the purpose and framing of this platform. Also briefly, and more for non-database experts among the users, how data sets would SahulCHAR records be “fully integrated” to other Sahul partner collections (e.g. via sites or even samples)? Please, briefly describe the links in Fig. 1.

We have included some additional description of the OCTOPUS database and how the different collections will interact. We also refer the reviewer and other readers to the other papers published that describe the OCTOPUS database.

Following on that: the authors mention that it has some compatibility with the GPD by using similar categories of metadata and dataset categories, but the structure of OCTOPUS is different, also compared to Neotoma, to which it might contribute in the future, as a bit vaguely described in the “conclusion”. As this is a project-based compilation that encourages also for updates and future data submissions: How do the authors envision a (technical) connection between the versions of SahulCHAR and the GPD as a new Constituent Database in Neotoma, to avoid data loss and parallel datasets that may promote insecurity about data quality and originality as we are currently facing with the existing multiple open paleofire data compilations?

We have not determined how exactly the SahulCHAR database will become a constituent database in Neotoma, however several of the authors are working with the global Palaeofire community and Neotoma managers to determine how this will occur morning forward. The selection of size classes, data metrics and metadata kept the future integration with Neotoma in mind, with the hope to reduce any additional future workload in incorporating the data into Neotoma.

Some minor suggestions:

• Consider to define at the beginning what is meant by “black carbon” (multiple methods are behind that may give different measurement units, which not only include classical “count” data as common for charcoal) and briefly state if or how black carbon records were added to a size-related field such as CHARSIZE_U

We have added a definition of charcoal and black carbon to the introduction and further refined the text that specifies the method of charcoal quantification.

“The structure of SahulCHAR differs from the GPD in its approach to char sizes and measurement units. SahulCHAR specifies the method of charcoal quantification (CHARMETHOD) for each record, with 11 methodologies for measuring charcoal and black carbon particles included.”:

I am aware that BASIN refers to the depocenter of the sedimentary archive, correct? If I understand right, it is the size of the polygon of the METASITE, yet I was a bit confused by the example in Tab 1 where the CATCHMENT is smaller than the BASIN. Also consider to add a note in the text on which basis the polygons were drawn (esp. year or months) as especially lake extents could vary seasonally and interannually.

Thank you for noticing this issue with the example in Table 1. The site used in the text was actually incorrectly reported in the original paper. This has been rectified in the database and now in the manuscript as well.

METASITE is a bounding box geometry around a semantic entity, in the case of SahulChar, a geographic feature such as a lake. Both BASIN and CATCHMENT classes and size values were taken from GDP. We did not calculate those values for the non-GPD sites; therefore we have n=294 ‘ND’ values for CATCHSIZE. Re small catchment, but large basin – indeed, those classes are binned differently (Parent table fields & values — OCTOPUS database documentation 1.0 documentation), meaning that a small CATCHMENT can fit into a large BASIN. These two classifications are not logically related, therefore there may be some odd variations.

• For all field in Tab 1-3 that refer to a list, consider to add a hyperlink to the respective list, as done for BIOME, for consistency and easier understanding.

We have updated the captions for Tables 1-3 and included a hyperlink to the pages with the table definitions.

Thank you for your positive and constructive comments on this manuscript. We hope that this update will be a useful contribution to the Australian and global palaeofire communities.

Response to general comments –

We acknowledge the ambiguity of the text in regards to propagation of previous Palaeofire databases. This was an omission of the correct references here on our part, which we have rectified in the text (detailed below). We have also tried to improve the clarity of the text surrounding the discussion of previous databases and how they were incorporated into the new SahulCHAR database.

We have included additional information in the Supplement that specifies the way each individual site was incorporated into SahulCHAR from the GPD. Very few sites were transferred verbatim and each record was critically appraised, with additional information or corrections added when necessary. 

Specific comments -

1. 3, line 70: “However, the last major compilation and synthesis of sedimentary charcoal records from Australasia was Mooney et al. (2011, 2012), containing 224 sedimentary charcoal records, primarily derived from the Global Paleofire Database (GPD, formerly known as the Global Charcoal Database; Power et al., 2010).”

We acknowledge we have used the incorrect citations here and have modified the text to make it clear that the data used by Mooney was subsequently included into GPD but this was not where it originated.

“However, the last major compilation and synthesis of sedimentary charcoal records from Australasia was Mooney et al. (2011, 2012), containing 224 sedimentary charcoal records. These records were primarily derived from the Global Charcoal Database version 2 (GPDv2, Daniau et al. 2012) and version 2.5 (GPDv2.5. Marlon et al., 2013, 2016). These records are now included in the Global Paleofire Database (GPDv4, Power et al., 2010)”

1. 3, line 82: “These records are replicated in the RPD [RPDv1b] …” “Replication” here might imply “copy”, which was not quite the case (Harrison et al., 2022). Many records were given new chronologies, and in some cases the GPD data were replaced by data obtained from original authors.

We have altered this text to read “These records are also contained in the RPD….” To reduce the suggestion that these records are identical in the RPD.

1. 3, line 86: “As noted by Harrison et al. (2022), current limitations of the GPD include potential duplicates of sites, missing metadata and age data, and necessary updates to incorporate newly published records.” In addition, the GPD lost precision in locational metadata and in key variables such as sample depth and charcoal values relative to the parent GCDv3 data.

We recognise that some data contained in the GPD is not without issues and we believe this comment is largely due to a lack of clarity in the text that suggested we accepted data from GPD uncritically. We have since included additional information to this manuscript and supplement that specifies which sites were copied verbatim (after assessment) from GPD and which sites included additional information either from original or subsequent publications and directly from authors.

“To avoid replicating potential errors contained in the GPD, all data from the GPD were carefully screened during data entry for SahulCHAR. Published sources – including but not limited to sources listed in GPD records – were used to modify and add to metadata and charcoal data captured in the GPD wherever possible, as part of a greater literature review to identify charcoal records in the region.”

Tables 1-3: It would be good at some point to point out that the tables are for discussion here, and are not constituent tables in the database.

We have changed captions for these tables to indicate that these table are the information that is recorded and available to view/sort for each site in the database. “Table representation of SahulCHAR attributes vs corresponding GDP fields, where applicable. For full description of database tables refer to Munack et al. 2023”

p.9, line 173: “Char data were last accessed from PANGAEA…” The R code unique(sahulchar_sf$DATASOURCE) applied to the sahulchar sf/data.frame returns “ "Author",  NA,  "Digitised",  "Paleofire database" ”. Are the PANGAEA data folded into one of those categories?

All Neotoma and PANGAEA data were entered with the source as 'author' because those databases explicitly show that those records were submitted directly by the authors. Please see line 175 for the intext explanation -

"Original char data from any source are classified in SahulCHAR as CHARSOURCE = ‘author’. Data sourced from another database either from digitization data or unknown origins are classified as ‘paleofire database’, and data digitized from published diagrams for SahulCHAR are classified as ‘digitized’”

1. 9, line 173: “While the RPD contains Australasian char data, these records are derived from the GPD and therefore the RPD was not used for 175 SahulCHAR data compilation.” But RPDv1b does contain alternative chronologies relative to those originally published (as well as other fixups), and so the RPDv1b data are not a simple mirror of the GPD data.

We have made it more clear that the records within these two databases are not simply replica’s and have also specified why we have not included updated chronologies for these records.

“While the RPD contains Australasian char data, these records were derived from the GPD. The methodology applied here involved assessing individual records from GPD and modifying, updating or correcting records where necessary based on local knowledge or discussion with original authors. Therefore, even though the RPD includes alternate chronologies and other modifications from GPD, this was not used for SahulCHAR data compilation. Due to constantly evolving and updated chronological modelling and calibration techniques we have not included new chronologies for individual records and recommend re-calibration of age-depth models using the most appropriate up to date methods for records included in SahulCHAR at time of use.”

Table 3: “CHARCOUNTS” Inspection of the data (and the example in the table) shows that the values in this field are not always counts (which should be integer values), but include influx and concentration values, ratios, etc. To avoid future misapprehensions of what the database contains, I suggest renaming this to “CHARVALUES” or something (but not just “CHAR” which could be ambiguously interpreted as “charcoal accumulation rate”).

This is a good point. We will change the name of the CHARCOUNTS to CHARVALUES to include the different charcoal measures included.

Figs. 3 and 4: Pie charts are denigrated for the kind of application here.

We have not changed the pie charts here as they are reflecting a subset of the data, so we believe the proportional data representation is ok in this instance.

Fig. 4d: Why the strange class intervals?

We have adjusted the class intervals.

I was not able to open the collection, getting the error message

This was likely an issue with the code due to unclear instructions in the documentation. It was not made clear that the required typename= "be10-denude:sahulchar" to get the charcoal data.

Unfortunately the ‘messiness’ of the data is difficult to help with the shear amount of data and necessary information required. Ideally the data is designed to work within a coding environment rather than excel. We aim to write some additional code that will enable uses to extact the data into its different constituent parts (eg. Ages, data) to run new ages depth models and plot data using newly developed models. This code will be included in a subsequent publication utilising the records for continental palaeofire compilation.

We have included code in the Supplement that is designed purely for SahulCHAR and can be used to access the data.