This manuscript describes a six-year time series of permafrost temperature observations at four sets of paired burned/unburned sites in northeastern China. In addition, the data set includes analyses of gravimetric moisture content as well as soil nutrients derived from incremental soil/permafrost cores collected when the boreholes were installed. This is a relatively straight forward data set - similar to others I have seen published directly at data repositories without an accompanying data publication. Overall this is a useful and informative data set for understanding the influences of fire on permafrost temperature. Before the manuscript can be considered further for publication a number of clarifying improvements are necessary. 

While the introduction is useful, I find it a little broad, and think it would be helpful to have more focused contextual information. For example, is this an undersampled location compared to areas within the northern permafrost zone? Are there similar sites nearby in the GTN-P? It would be nice to know a little about the permafrost conditions of the region earlier in the manuscript. Is this ice rich permafrost? Similarly, basic information on the fire regime and any recent changes would be helpful (from the literature). One of the sites shows active layer recovery after fire, without context it is difficult to tell if this is an anomaly, or something to be expected more broadly. Some of this information is provided, but it is scattered throughout the manuscript. 

The following comments point to specific issues as well as more minor editorial areas for improvement. 

L24: typo - succession

L58: It would probably be good to specify the “soil organic layer”

L65-75: This is all accurate, however it is probably worth noting that the depth of the seasonally thawed active layer has been observed to decline with ecosystem recovery after fire (e.g. Rocha et al 2012). 

Rocha, A. V., Loranty, M. M., Higuera, P. E., Mack, M. C., Hu, F. S., Jones, B. M., et al. (2012). The footprint of Alaskan tundra fires during the past half-century: implications for surface properties and radiative forcing. Environmental Research Letters, 7(4), 044039. https://doi.org/10.1088/1748-9326/7/4/044039

L86-87: Is this assertion for ecosystem protected permafrost, or all cases of permafrost under the impacts of wildfire? I would suspect the former. Ice content is probably also important as well. 

L94: How can permafrost be prone to wildfire? 

L110: Are soil nutrient contents being continually observed? 

L115: Should this be section 2? 

L138: It would be good to describe the fire severity sampling before this point. I found myself wondering if and how severity was incorporated in site selection. 

L141: What are the units hm^2? 

L201-203: Are these values appropriate for this forest type? 

L204-205: This is a curious statement, why would damage/device malfunction be more prevalent in moderate burned relative to severe and unburned? 

L211: Isn’t it just burned and unburned? 

L222: In looking at the data it seems like three times per month is maximum - and one or two times per month is more common. Line 262 indicates collection occurred 1-2 times/month after the COVID-19 pandemic

L235: Table 2 is a  little unclear - it seems that soil moisture and nutrients are one-time observations, and the only thing being monitored over time is temperature. This distinction should be made clearly - I’m not sure that this table is warranted. 

L253: How was SE calculated? Were there multiple sub-samples analyzed from each depth? 

L254: How is time quantified? This data set seems somewhat small given that there are two different ecosystem type. 

L259: Should be pandemic, since it was not restricted to a specific geographical region. 

L341: In figure 7 it might be easier to compare burned and unburned for each site if they were side by side (i.e. a single row), rather than above/below each other. 

This paper presents 6 years of data in four areas of Northeast China at paired burned and unburned sites, including ground temperature, soil moisture, and soil nutrients. The four areas represent a chronosequence of time since fire, allowing for interpretation of the impacts of fire on permafrost over time. 

The dataset is not new or unique (there is similar data from Canada and Alaska), but the location is new as there is little previous work on the impacts of fire on permafrost in China. The methods are not new, most are standard for permafrost science. I am surprised that the authors did not use a temperature logger that stored hourly measurements (e.g. Onset HOBO U23 Pro v2 Temperature/RH Data Loggers) as that would've eliminated the need for weekly visits to the sites and would've allowed them to collect much more data with fewer gaps.

The dataset is complete, and I was able to access and download it from the given identifier. It is useable in it's current format and size. I do feel that the data could be useful in the future, particularly for those conducting modelling studies or as a baseline for future changes in permafrost conditions. There is one inconsistency within the data, see my major comment below, so I’d like the authors to provide an explanation for that. I do not feel that the meta data is sufficient unless accompanied by the current manuscript under review. I would like to see more information about the sites and the data collected in the metadata, as well as an explanation for the data gaps.

The article length was appropriate and it was well structured. There were some grammatical errors throughout, but especially in the conclusion. The figures and tables were good but overall not enough detail in the captions (see minor comments below for specific places).

Major comments:

1. The introduction is quite general. For example, I don’t feel that it is relevant to mention tundra fires as your data is for the hemiboreal environment. Your focus is on hydrothermal regimes and nutrients, but you didn’t give any background on post-fire permafrost soil moisture literature or any nutrients other than carbon.
2. You’re using a chronosequence, but I find it hard to know which sites are where in the sequence. Maybe a schematic showing time since fire and then the names of the sites would help. It will help the reader be able to interpret the results better, especially as time since fire is extremely important to infer post-fire impacts on permafrost. For example, Figure 3 is interesting to me, particularly because 3 of the areas show differences in MAGT between the burned and unburned sites at depths of 20m, except for MG. I’m wondering if this is because MG is the end of the chronosequence, decades after fire, and things have returned to pre-fire conditions, but I had to scroll around and find it on page 8. I think in general more attention needs to be paid to this in the paper. All the results should be interpreted with this in mind, which is currently lacking in the paper. 

Minor comments:

Abstract

Line 31: I wouldn’t consider a 6-year dataset to be long-term.

Introduction

Line 78: There are many other references about wildfire, permafrost and carbon. Some examples:

• O'Donnell JA, Harden JW, McGuire AD, Kanevskiys MZ, Jorgenson MT, Xu X. The effect of fire and permafrost interactions on soil carbon accumulation in an upland black spruce ecosystem of interior Alaska: implications for post-thaw carbon loss. Glob Chang Biol. 2011;17:1461-1474.
• Genet H, McGuire AD, Barrett K, Breen A, et al. Modeling the effects of fire severity and climate on active layer thickness and soil carbon storage of black spruce forests across the landscape in interior Alaska. Environ Res Lett. 2013;8(4):045016.
• O'Donnell JA, Harden JW, McGuire AD, Romanovsky VE. Exploring the sensitivity of soil carbon dynamics to climate change, fire disturbance and permafrost thaw in a black spruce ecosystem. Biogeosciences. 2011a;8:1367-1382.
• Dieleman C.M., Day N.J., Holloway J.E., Baltzer J., Douglas T.A., Turetsky M.R. 2022. Carbon and nitrogen cycling dynamics following permafrost thaw in the Northwest Territories, Canada. Science of the Total Environment, 845(1), 157288. https://doi.org/10.1016/j.scitotenv.2022.157288

Line 82: What about permafrost that is not ecosystem-protected? What about low ice-content sites that don’t experience thermokarst or “abrupt thaw”? Much of the boreal forest that is of this type and would still release carbon post-fire. I think it’s important to not focus only on ecosystem-protected or sites prone to thermokarst (unless your data applies only to those settings, then I think much more detail would be required in this introduction).

Line 104: Often complex how?

Section 2

Line 138: How was fire severity classified? What does “severely burned” indicate (i.e., a proportion of the organic layer lost, entire destruction of the canopy, etc.)?

Figure 1: It’s unclear to me where the permafrost region is in (a). More description is needed in the figure caption. Are the pink areas in the Landsat images burned areas?

Line 161: Why were these locations selected in particular?

Line 172: How do you know the pre-fire organic layer thickness? Organic layers vary substantially over short distances, I’m surprised the window for the site is only 5cm pre-fire, unless it was only measured in one spot.

Table 1: A relatively large amount of organic layer remains after the fires at all of the site (minimum 20cm). I think it’s important to note this somewhere in the paper, as this minimizes post-fire changes (less active layer thickening and ground temperature increase) than if, for example, less than 5cm remains.

Line 189: Why do you provide less details for the GL sites than the other sites? How far apart were they, when did measurements commence and how long after fire?

Line 201-203: Why were these thresholds chosen?

Table 1: I’m finding this table hard to interpret. For the last three columns, upon first glance, it looks like they only apply to site AL-S and GL-U. I was wondering why no ground temperature measurements were taken for all the other sites. But I think it is just the way the table is organized. Can you rethink this to make it more clear?

Line 238: What are complex changes? Please describe.

Line 271: How were they quality controlled?

Figure 3: Why do all the areas except MG show a large difference between burned and unburned sites?

Line 296: What dates were annual averages (e.g. MAGT) taken over? Calendar year?

Table 3: Similar to Figure 3, it’s curious that the unburned MAGT at 0.5 m depth for MG was warmer than the burned. Any explanation for this? This is also shown on Figure 4a and Figure 7a.

Line 350: Any ideas why it decreased only at MH-S?

Figure 9: I’d like to see these results described in terms of the chronosequence and how time since fire impacts soil moisture. Soil moisture varies over short temporal and spatial distances, so it would help add depth to your one off soil moisture measurements.

Figure 10: Same as above, it would be great if these results were described in terms of the chronosequence.

Line 425: Here you say SMC is decreasing, but you only have one measurement in time. How can you say it is decreasing? You haven’t described the chronosequence at all in the results, so I don’t think it’s fair to conclude this.