Deciduous larch is a weak competitor when growing in mixed stands with evergreen taxa but is dominant in many boreal forest areas of Eastern Siberia. However, it is hypothesized that certain factors such as a shallow active layer thickness and high fire frequency favor larch dominance. Our aim is to understand how thermohydrological interactions between vegetation, permafrost, and atmosphere stabilize the larch forests and the underlying permafrost in Eastern Siberia. A tailored version of a one-dimensional land surface model (CryoGrid) is adapted for the application in vegetated areas and used to reproduce the energy transfer and thermal regime of permafrost ground in typical boreal larch stands. In order to simulate the responds of Arctic trees to local climate and permafrost conditions we have implemented a multilayer canopy parameterization originally developed for the Community Land Model (CLM-ml_v0). The coupled model is capable of calculating the full energy balance above, within and below the canopy including the radiation budget, the turbulent fluxes and the heat budget of the permafrost ground under several forcing scenarios. We will present first results of simulations performed for different study sites in larch-dominated forests of Eastern Siberia and Mongolia under current and future climate conditions. Model performance is thoroughly evaluated based on comprehensive in-situ soil temperature and radiation measurements at our study sites.