| 27 Jun 2025
Forest disturbances and their impact on ground surface temperatures in permafrost-underlain forest in central Mongolia
Abstract. In the forest-steppe ecotone in central Mongolia, forest and permafrost exist close to their climatic limits and are co-located on north-facing slopes. The deciduous forest ecosystems and permafrost on these slopes are linked through interactions in the local energy and water balance. Furthermore, in this region the presence of such permafrost-forest systems provides essential services that supports local livelihoods and ecosystem function. However, forest disturbances that reduce or remove the forest canopies and lead to changes in surface cover could impact ground surface temperatures (GSTs) and potentially lead to permafrost degradation. In this study, we investigate the relationship between different forest states and GSTs at a site in the forest-steppe ecotone. We measured GSTs and surveyed vegetation density and surface cover over two years in an area that features both intact, dead and logged forest and dense stands of young regrowth. Overall, we find GSTs in summer and winter to vary substantially among the forest states, while differences in GST in spring and fall are small. Compared to the intact forest, the annual GST range is increased in the dead and logged forest while it is dampened in stands of young regrowth. Contrary to existing literature, we do not observe a general warming of the ground surface at disturbed sites, but instead find mean annual GSTs at disturbed sites to be 0.5 °C lower than at intact sites. We also find substantial floor vegetation in the dead and logged forest, which has implications for livestock grazing patterns and remote sensing of forest disturbances.
Competing interests: One of the co-authors is on the editorial board of The Cryosphere.
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.
Ground surface temperature (GST) is a crucial factor for permafrost research and predictive mapping. However, the current study requires substantial improvements in the following aspects:
Mechanistic Analysis
Permafrost Context
Line 40: Such disruptions? The above text does not mention such disruptions.
Lines 45-49: Many studies have also examined the changes in winter in the permafrost region.
For Introduction: It is essential to highlight the significance of ground surface temperatures (GSTs) research in the introduction, particularly in the context of permafrost. Studying GST can reveal its connection with permafrost, such as whether it can reflect the dynamic changes in permafrost conditions.
Line 101: What is A1?
Figures 1 and 2: The general title for all figures should be provided first, followed by individual captions for each subplot.
2.1 Site description: It is recommended to specify the permafrost classification characteristics and thermal regime parameters in the study area. For instance: Permafrost type: continuous/discontinuous/sporadic/isolated patches. Mean annual ground temperature (MAGT) range, active layer thickness, permafrost thickness.
Line 134: What are the start and end months of the hydrological year?
Line 185: December represents the early snow accumulation phase, while March marks the end of winter when snow begins to melt. An additional snow measurement should be conducted in February during the stable snow cover period.
Figure 3: The authors have two years of data, so seasonal and annual averages should be presented with error bars. These error bars could help reveal certain patterns in the data. The authors have not provided complete figure titles for any of the figures, only including subfigure captions.
Line 272: Table C2?
Lines 285-286: What’s the reason? Such a result seems counterintuitive.
Lines 291-296: This content has already been mentioned in the Introduction and Study Area sections, and its repetition here is redundant.
Lines 367-368: What is the reason? Why has summer disappeared?
Line 403: The interference may not necessarily lead to an increase in the MAGST, but it could still cause a significant rise in summer GST—it's just that the MAGST is offset by the decrease in winter GST.
Line 417: Why is that?
Lines 415-429: Different vegetation cover can lead to changes in wind speed, and does wind speed affect snow cover? I believe livestock trampling might have some impact, but it’s definitely not the main factor.
Line 433-434, Table C2: How do you determine whether livestock trampling is sparse or dense? By the number of hoofprints? But could there be cases where heavy trampling is later covered by snow?
Line 290：The authors should construct a relational diagram between all factors and GST (Ground Surface Temperature), calculate the contribution rate of each factor to GST, and then discuss which one is the dominant influencing factor. Otherwise, the discussion can only superficially address whether the factors affect GST and which one plays a major role. Due to the presence of anthropogenic factors such as livestock trampling, it is impossible to analyze GST differences caused solely by variations in vegetation cover.
Line 464: I believe such a conclusion is unreasonable. Livestock trampling compacts snow cover, reducing its thickness while increasing its density. However, this factor has not been quantified, nor has the influence of snow layers—another critical aspect—been quantitatively assessed.
Line 475: The understory vegetation in logged or dead forest plots is dense, resulting in a Plant Area Index (PAI) similar to that of intact forests. However, their effects on ground surface temperature (GST) still differ. Relying solely on PAI may fail to distinguish the varying impacts of different vegetation covers on GST.