title: Boreal Forest Cover Delays Thermokarst Onset in Central Siberia's Yedoma Deposits
Creators: name: Stuenzi, S. M.
name: Boike, J.
name: Westermann, S.
name: Langer, M.
Publisher: name: Humboldt-Universität zu Berlin
Year: 2025
Subjects: subject: boreal forest
subject: permafrost
subject: thermokarst
subject: climate change
subject: 550 Geowissenschaften

description: Boreal forests, covering more than half of the world's permafrost, are essential for maintaining permafrost stability. However, climate change and forest shifts are threatening the delicate balance in the thermal equilibrium between the atmosphere, vegetation, and permafrost. We focus on Central Yakutia's ice‐rich boreal regions, specifically two sites located in Spasskaya‐Pad and Churapcha, to investigate the interplay of hydrothermal and climatic conditions that induce thermokarst. We employ a numerical permafrost model (CryoGrid), with a canopy model, and features for excess ground ice, lateral water flow and lake formation, to simulate the underlying physical processes under two forcing scenarios until 2060. The results reveal that forest delays the onset of thermokarst and ground ice melting by 3–18 years, depending on ice depth, climate forcing, and local conditions. Our simulations additionally reveal that a canopy slows excess ice melt by up to 7 years compared to bare ground simulations. Furthermore, in exceptionally warm and wet years, thermokarst initiation occurred rapidly in the bare ground simulations. In contrast, the canopy buffered against these conditions, suggesting that canopies might mitigate the impacts of small temperature and precipitation anomalies. This research highlights the critical role of forests in shaping the trajectory of thermokarst‐related landscape transformations in ice‐rich boreal permafrost regions. With the study region warming faster than average, forest cover transformations could significantly alter the hydrological balance. By integrating thermodynamics, hydrology, and ecology, our findings underscore the importance of forests in delaying thermokarst initiation and slowing ground ice melt, ultimately stabilizing permafrost ecosystems.
description: Boreal forests play a crucial role in maintaining the stability of permafrost, which is ground that remains frozen year‐round. However, climate change and shifts in forest cover are threatening this balance, potentially leading to the melting of ground ice and ground subsidence, known as thermokarst. To understand how these changes might affect permafrost, we studied two ice‐rich boreal regions in Central Yakutia, Russia. Using a model that simulates permafrost and its interactions with the forest canopy, we examined how different climate conditions could influence boreal permafrost until 2060. Our results show that forests can delay the onset of thermokarst and ground ice melting by 3–18 years, depending on factors such as ice depth, climate, and local conditions. The forest canopy, can slow the melting of excess ice by up to 7 years compared to areas without tree cover. In extremely warm and wet years, areas without forests experienced rapid thermokarst formation, while forested areas were more resilient, suggesting that forests can buffer against small temperature and precipitation changes. This research highlights the importance of boreal forests in stabilizing permafrost. As the study area is warming faster than average, changes in forest cover could significantly impact this.
description: Forests delay thermokarst and excess ice melt by 3–18 years, depending on excess ice depth, climate scenarios, and site conditions. Canopies buffer fast initial thermokarst formation during climate anomalies, pointing toward a mitigating impact. Ongoing forest cover changes in rapidly warming Central Yakutia could alter the thermo‐hydrological permafrost conditions