Vulnerability of Ukrainian Forests to Climate Change

Ukraine is a country of the Mid-Latitude ecotone-a transition zone between forest zone and forestless dry lands. Availability of water defines distribution of the country's forests and decreases their productivity towards the south. Climate change generates a particular threat for Ukrainian forests and stability of agroforestry landscapes. This paper considers the impacts of expected climate change on vulnerability of Ukrainian forests using ensembles of global and regional climatic models (RCM) based on Scenarios B1, A2, A1B of the Intergovernmental Panel for Climate Change, and a "dry and warm" scenario A1B+T-P (increasing temperature and decreasing precipitation). The spatially explicit assessment was provided by RCM for the WMO standard period (1961-1990), "recent" (1991-2010) and three future periods: 2011-2030, 2031-2050 and 2081-2100. Forest-climate model by Vorobjov and model of amplitude of flora's tolerance to climate change by Didukh, as well as a number of specialized climatic indicators, were used in the assessment. Different approaches lead to rather consistent conclusions. Water stress is the major limitation factor of distribution and resilience of flatland Ukrainian forests. Within Scenario A1B, the area with unsuitable growth conditions for major forest forming species will substantially increase by end of the century occupying major part of Ukraine. Scenario A1B+T-P projects even a more dramatic decline of the country's forests. It is expected that the boundary of conditions that are favorable for forests will shift to north and northwest, and forests of the xeric belt will be the most vulnerable. Consistent policies of adaptation and mitigation might reduce climate-induced risks for Ukrainian forests.