Forested areas in Bulgaria occupy about one third of the country's territory and amount to 4 230 million ha, of which over 90% are forests. The stock of wood in Bulgaria's forests has almost tripled since the 1960s and now stands at around 680 million cubic metres.
Predictions of rising temperatures due to climate change, warmer winters and more summer droughts, along with the greater number and magnitude of extreme weather events such as heat and cold waves, severe storms, wet snow and ice accumulation, will degrade forest health and tree growth, increase attacks by pathogenic insects and fungi, including invasive species, and cause severe losses due to fire and storm damage. There is already evidence of the impact of these different climatic events on the forest sector in Bulgaria. In the future, they could contribute to very high economic losses, impair the ability of forests to fix carbon, and affect the quality of life in Bulgaria by reducing opportunities to deliver valuable ecosystem services.
According to one study, total forest growth could decrease by up to 3.5 million cubic metres per year (Kostov and Rafailova, 2009). This is equivalent to 42% of annual timber harvest and would have a devastating impact on primary forest product production and the rural economy. Impacts of a similar magnitude can also be expected on the ability of forests to maintain drinking water supply, mitigate the effects of extreme rainfall and flooding, stabilize vulnerable soils on steep slopes, meet the growing needs of the recreation and tourism sector, sequester and fix carbon, and conserve the rich resource of natural biodiversity.
The main vulnerabilities of forests to climate change are:
- Species-specific physiological responses to altered temperature and precipitation regimes and inability to respond to changing climatic conditions. Some species may lack the adaptability to cope with new climatic conditions and thus become locally or globally extinct, or suffer serious growth and health problems
- Uncertainties regarding the interaction between species. Related to species-specific responses are uncertainties about the interactions between species as competition for resources, which is one of the main processes influencing forest dynamics and composition in a changing climate. Some species are likely to lose their growth advantage compared to other species, which in turn could seriously alter forest composition and, in the long term, forest productivity and other related ecosystem services provided by certain forests
- Large areas of conifer plantations at too low altitudes and the associated potential risk of reduced growth and various health problems. This vulnerability is a consequence of large-scale afforestation in the 20th century. While plantations have generally fulfilled their primary purpose of helping to control erosion processes, recent decades have seen numerous waves of mortality due to the combined negative effects of drought, aging and lack of regular growing opportunities
- Increased likelihood of large fires and other disturbances such as damage from high winds, damage from wet snow and ice, insect attacks. This is potentially the most important factor for forests, given that natural disturbances often lead to significant changes in their structure and environment
- Improved conditions for invasive species with high potential for significant forest damage. Future climate change may provide improved opportunities for invasive species to migrate and spread, thereby damaging native species. This is a potentially very high risk for habitats that are rare and located in frontier locations
