Forestry in numbers

The forests cover 4.1 million ha, which is 37 % of the Bulgarian territory. Broadleaved forests account for 68% of the forest area, and conifers account for 32% of the area. The Bulgarian forests are relatively young forests with an average age of about 51 years. In 2008, 50% of the annual increment was harvested, of which ¾ have been used by the Bulgarian forest products industry and ¼ was used as fuel wood. ¾ of the Bulgarian forests are state owned, while the rest is owned by private individuals, companies, municipalities and institutions (1).

The GDP contribution of the sector is 2.5%. Approximately 150,000 people are directly employed in the sector, primarily in rural areas and there are thousands of local timber based manufacturers and small scaled industries, and a few big and international oriented pulp, paper and board producers. The forests give wide range of essential public products and services; such as water production, protection functions, erosion control, fire prevention, social timber supply, etc (1).

The large-scale afforestation activities from the middle of the last century resulted in a sudden increase in the area covered by coniferous forest. After 1990 the area of conifer forests started to decline and at the end of 2008 represented only 30.2% of the forest area. This trend is expected to continue into the future. The forest area managed mainly for the purpose of harvesting and environmental functions during 2008 was 68.1%; protective forests and forests for recreation represented 19.8% and the forests and lands in protected areas covered 8.2% of the forest fund of the country. Some 13.4% of Bulgarian forests have as a primary function the protection of the soil against erosion and water balance maintenance (1).

The importance of forestry

One of the most important ecological function of the forests at the moment is the prevention/reduction of climate changes through carbon absorption. Forests are also natural obstacles against degradation and soil erosion and its desertification and influence very much the water balance. During the last 50 years about 1.5 million ha forests have been forested for the purpose of increasing forest productivity and soil erosion control. Bulgarian forests provide about 85% of the water flow in the country or nearly 3.6 billion m3 of clear drinkable water. In the past 35 years over 1/3 of the country’s forests were re-established (1).

Another opportunity that needs to be considered in the forestry sector is the use of biomass in energy production. The use of local fuel-wood and wood waste (bark, shavings, etc.), industrial waste wood, or agricultural residues for heating, energy production, or combined heat and power plants could have a large potential in rural areas in Bulgaria. Improved forest management and thinning operations could increase the access to fuel-wood and wood waste. The benefits would potentially include lower fuel costs, reduced local air pollution, and access to locally-produced energy sources (1).

Changes in species composition

The coniferous forest vegetation, which was widely introduced during the last decades under 800 m a.s.l., i.e. out of its natural habitats, forms very unstable forest ecosystems. The main reason is the discrepancy between the ecological conditions (mainly rainfalls) and the requirements of the coniferous tree species. Due to this reason these forests are physiologically in a chronic water deficit and in drought periods like the one in 1983-1994 they begin to disintegrate. The above tendency subsequently encompasses the high fields of west Bulgaria, north Bulgaria, south Bulgaria, Black Sea Coast, and southern parts of the country. In this sequence the vulnerability of the forest vegetation to the adverse dry climate increases (1).

The changes are from “cool temperate moist forest” to “warm temperate dry forest” for north Bulgaria, and for south Bulgaria the “warm temperate dry forest” will remain typical. In the warmest country regions “subtropical dry forest” could be expected, which means drastic warming and droughts. Since 60.6% of forests are in the zone below 800 m, it is clear, that most of the Bulgarian forests would be vulnerable to the drastic climate change under the eventual doubling of carbon dioxide in the near future. The changes in the mountain regions of the country would pass from “cool temperate wet forest” to “warm temperate moist forest”. At an eventual climate warming a moving of the species composition from south to north could be expected. That means that it could be expected that the south Bulgarian border region area will be settled by typical Mediterranean vegetation, a part of which is to be seen there even at present (1).

South Bulgaria

In Western Rhodopes in South Bulgaria important timber species such as spruce, beech, Scots pine and fir are near the current southern edge of their distribution. The European spruce is the most susceptible native species to climate change, specifically at lower altitudes and less fertile sites (31). Similar results are reported for the lower altitudes in the Alps, where the proportion of Norway spruce is projected to decrease, and the importance of Spruce as a crop tree is expected to diminish (32). The loss of spruce is considered undesirable due to higher economic value of spruce timber.

In South Bulgaria a shift in forest composition is expected. At lower elevations (1000-1450 m above sea level) drought-sensitive species such as Norway spruce will probably be replaced by more drought-tolerant species such as Scots pine and black pine, and forest diversity will decrease. At higher elevations (1550-2100 m above sea level) a reduction in spruce growth is projected, and forest diversity will increase (30). The latter projection differs from conclusions of other studies for mountainous areas that show that at higher altitudes spruce benefits from warmer climatic conditions (33). At both elevations carbon storage potential is projected to decrease (30).

Forests ability to provide soil stabilization is a key function of the studied landscapes as a result of the steep slopes and extreme weather events observed during recent years. Historically, the loss of forest cover caused by unregulated cutting and overgrazing has triggered mass erosion in many regions of South Bulgaria. Erosion risk has been partially mitigated by establishing extensive forest plantations on the eroded slopes during the beginning of nineteenth century. However, recently parts of these artificial forests have been destroyed by fires and pathogen outbreaks (34), which brought back most of the issues observed before the rehabilitation of these lands. 

Vulnerabilities - Overview

The increased vulnerability of forests (and people) with respect to climate change refers to several impacts (22,28):

• Forest cover: conversion of forests to non-woody energy plantations; accelerated deforestation and forest degradation; increased use of wood for domestic energy.
• Biodiversity: alteration of plant and animal distributions; loss of biodiversity; habitat invasions by non-native species; alteration of pollination systems; changes in plant dispersal and regeneration.
• Productivity: changes in forest growth and ecosystem biomass; changes in species/site relations; changes in ecosystem nitrogen dynamics.
• Health: increased mortality due to climate stresses; decreased health and vitality of forest ecosystems due to the cumulative impacts of multiple stressors; deteriorating health of forest-dependent peoples.
• Soils and water: changes in the seasonality and intensity of precipitation, altering the flow regimes of streams; changes in the salinity of coastal forest ecosystems; increased probability of severe droughts; increased terrain instability and soil erosion due to increased precipitation and melting of permafrost; more/earlier snow melt resulting in changes in the timing of peak flow and volume in streams. The capacity of the forest ecosystem to purify water is an important service, obviating the cost of expensive filtration plants.
• Carbon cycles: alteration of forest sinks and increased CO2 emissions from forested ecosystems due to changes in forest growth and productivity.
• Tangible benefits of forests for people: changes in tree cover; changes in socio-economic resilience; changes in availability of specific forest products (timber, non-timber wood products and fuel wood, wild foods, medicines, and other non-wood forest products).
• Intangible services provided by forests: changes in the incidence of conflicts between humans and wildlife; changes in the livelihoods of forest-dependent peoples (also a tangible benefit); changes in socio-economic resilience; changes in the cultural, religious and spiritual values associated with particular forests.

Productivity

Increasing CO2 concentration can affect tree growth through increased photosynthetic rates and through improved water-use efficiency. There will be complex interactions, however: forest growth rates may well be increased in some cases by rising levels of atmospheric CO2, but rising temperatures, higher evaporation rates and lower rainfall may lower growth rates in other cases (13).

Non-timber products

Increasingly there are concerns about the productivity of non-timber products such as medicines and foods. Relatively little information is available in the scientific literature about the sustainable management of such products, and even less is known about their vulnerability to climate change (22).

Vulnerabilities  - Fires, floods, storms and insects

The main natural disasters in Bulgaria are forest fires, floods, wind throws and disturbances by insects. Recently these have seriously damaged the Bulgarian forests (1).

During the last 5 years more than 500 thousands ha forests were damaged by forest fires. Most of them (about 80%) are not restored until now. These forest territories are with high capacity to be damaged further by insects and diseases and they contribute to soil erosion and floods. In addition private forest owners do not have enough financial resources to restore these forest areas (1).

Other natural disasters important for forests are wind throws. During the last 5 years more than 120 thousands m3 (250 thousands ha) have been damaged. Only 50% from these forests are restored. As a result huge damaged territory is still not restored like the areas damaged by forest fires, especially in small private and communal forest lands. These serious threats for Bulgarian forests lead to loss of capacity for CO2 absorption and production of forest products. Without financial funding from the rural Development Programme, forest areas will be further damaged and the damaged areas will not be restored (1).

A big part of the former agriculture lands in mountain and semi-mountain regions is still not used, which leads to big ecological, social and economic problems. In the mountain areas there is high level of land degradation and regressive succession. These areas lose soil as a result from wind and water erosion. Their opportunities to combat with natural disasters like floods, soil erosion and to improve the water quality are very small. Through increasing the forest cover (with native tree species) the water balance in the adjacent territories will be improved, which is important problem for the southeast countries (1).

Vulnerabilities – Temperate forests in Europe

Present situation

In parts of Europe with temperate forests, annual mean temperatures are below 17°C but above 6°C, and annual precipitation is at least 500 mm and there is a markedly cool winter period (2). Temperate forests are dominated by broad-leaf species with smaller amounts of evergreen broad-leaf and needle-leaf species (3). Common species include the oaks, eucalypts, acacias, beeches, pines, and birches.

Many of the major factors that influence these forests are due to human activities, including land-use and landscape fragmentation, pollution, soil nutrients and chemistry, fire suppression, alteration to herbivore populations, species loss, alien invasive species, and now climate change (4).

Forest productivity has been increasing in western Europe (5). This is thought to be from increasing CO2 in the atmosphere (6), anthropogenic nitrogen deposition (7), warming temperatures (8), and associated longer growing seasons (9).

Trends

Most models predict continuing trends of modestly increasing forest productivity in Western Europe over this century (10). Projections for the time near the end of the next century generally suggest decreasing growth and a reduction in primary productivity enhancement as temperatures warm, CO2 saturation is reached for photosynthetic enhancement, and reduced summer precipitation all interact to decrease temperate zone primary productivity (11). The projected increased occurrence of pests, particularly in drought-stressed regions, also contributes to decreased long-term primary productivity in some regions of temperate forests  (12).

Sensitivity to increasing air pollution loads, particularly nitrogen deposition and tropospheric ozone, will impact large areas of the northern temperate forest over the next century. In the temperate domain, air pollution is expected to interact with climate change; while the fertilization effects from nitrogen deposition are still highly uncertain, pollutants such as ozone are known to diminish primary productivity (13).

Migration

The ranges of northern temperate forests are predicted to extend into the boreal forest range in the north and upward on mountains (14). The distribution of temperate broadleaved tree species is typically limited by low winter temperatures (15). Since the latter are projected to rise more rapidly than summer temperatures in Europe and North America, temperate broad-leaved tree species may profit and invade currently boreal areas more rapidly than other temperate species.

Carbon sinks/sources

Temperate forest regions in the highly productive forests of western Europe (16) are known to be robust carbon sinks, although increased temperature may reduce this effect through loss of carbon from soils (17). Weaker carbon sinks or even carbon losses are seen for temperate forests in areas prone to periodic drought, such as southern Europe (18).

Models suggest that the greatest climate change threat to temperate forest ecosystems is reduced summer precipitation, leading to increased frequency and severity of drought (19). This will probably be most prominent in temperate forest regions that have already been characterized as prone to drought stress, such as southern Europe. Drought-stricken forests are also more susceptible to opportunistic pests and fire (20). Together, these related effects can potentially change large areas of temperate forest ecosystems from carbon sinks to sources.

Benefits

Globally, based on both satellite and ground-based data, climatic changes seemed to have a generally positive impact on forest productivity since the middle of the 20th century, when water was not limiting (29).

Timber production in Europe

Climate change will probably increase timber production and reduce prices for wood products in Europe. For 2000–2050 a change of timber production in Europe is expected of -4 to +5%. For 2050–2100 an increase is expected of +2 to +13% (21).

Adaptation strategies – Improving sustainability

For the forests in the low parts of the country (under 800 m a.s.l.), where the most significant impact from climate change is expected, the strategic objective of the management must be adaptation towards drought and improving forest sustainability. For the forests in the higher parts of the country, i.e. those above 800 m a.s.l., where expected changes are not likely to be drastic, the objectives are preservation of biodiversity, ecosystem sustainability, multifunctional management, system of protected nature territories (1).

The natural and introduced forest wood and shrub species in Bulgaria have great potential for a good adaptation towards possible climate change in the present century. Through planned felling of young plantations, the vital space of the remaining woods is improved and so is their light and water regime. This is also an approach to improve the possibilities for adaptation of wood plantations, resulting in increased biomass (1).

Sustainability of forest plantations is achieved by an increase in the proportion of native broadleaved tree species, a decrease in the initial stocking rate of plantations, the establishment of mixed plantations and afforestation using forest tree and shrub species in their natural areas. Establishment operations are undertaken principally on state forest fund territories and particularly on areas destroyed by fire, stands and plantations damaged by drought, clearings and bare areas (1).

Afforestation of non-agricultural lands is promoted, aimed at (1):

• contributing to the climate change mitigation and increasing the biodiversity;
• reducing soil erosion and improving the protection of the lands from marginalization;
• improving the water balance.

Restoration of forest capacity and implementation of preventive activities are carried out, aimed at (1):

• restoration of the forests, damaged by forest fires or other natural disasters;
• reforestation of the affected forests, using native tree species;
• increasing the tree species diversity through transformation of the coniferous ecosystems in mixed forest or broadleaved ecosystems;
• improving the prevention activities for combat against forest fires.

Adaptation strategies - Forest management measures in general

Near-nature forest management and a move away from monocultures toward mixed forest types, in terms of both species and age classes, are advocated. In addition, natural or imitated natural regeneration is indicated as a method of maintaining genetic diversity, and subsequently reducing vulnerability. For management against extreme disturbances, improvements in fire detection and suppression techniques are recommended, as well as methods for combating pests and diseases. It is reported that through stricter quarantine and sanitary management, the impact of insects and diseases can be minimized. The establishment of migration corridors between forest reserves may aid in the autonomous colonization and migration of species in response to climate change (26).

Adaptive management

The terms adaptation and adaptive management are often incorrectly used interchangeably. The former involves making adjustments in response to or in anticipation of climate change whereas the latter describes a management system that may be considered, in itself, to be an adaptation tactic (23). Adaptive management is a systematic process for continually improving management policies and practices by learning from the outcomes of operational programmes (24). It involves recognizing uncertainty and establishing methodologies to test hypotheses concerning those uncertainties; it uses management as a tool not only to change the system but to learn about the system (25).

Both the climate and forest ecosystems are constantly changing, and managers will need to adapt their strategies as the climate evolves over the long term. An option that might be appropriate today given expected changes over the next 20 years may no longer be appropriate in 20 years’ time. This will require a continuous programme of actions, monitoring and evaluation – the adaptive management approach described above (22).

There is a widespread assumption that the forest currently at a site is adapted to the current conditions, but this ignores the extent to which the climate has changed over the past 200–300 years, and the lag effects that occur in forests. As a result, replacement of a forest by one of the same composition may no longer be a suitable strategy (22).

Adaptation to climate change has started to be incorporated into all levels of governance, from forest management to international forest policy. Often these policies are not adopted solely in response to climate, and may occur in the absence of knowledge about longer-term climate change. They often serve more than one purpose, including food and fuel provision, shelter and minimizing erosion, as well as adapting to changing climatic conditions (26).

Socio-economic and political conditions have significant influences on vulnerability and adaptive capacity. Climate change projections are perceived by many forest managers as too uncertain to support long-term and potentially costly decisions that may be difficult to reverse. Similarly, uncertainty over future policy developments may also constrain action. Finance is a further barrier to implementing adaptation actions in the forest sector (27).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Bulgaria.

1. Ministry of Environment and Water (2010)
2. Walter (1979), in: Fischlin (ed.) (2009)
3. Melillo et al. (1993), in: Fischlin (ed.) (2009)
4. Reich and Frelich (2002), in: Fischlin (ed.) (2009)
5. Carrer and Urbinati (2006), in: Fischlin (ed.) (2009)
6. Field et al. (2007b), in: Fischlin (ed.) (2009)
7. Hyvönen et al. (2007); Magnani et al. (2007), both in: Fischlin (ed.) (2009)
8. Marshall et al. (2008), in: Fischlin (ed.) (2009)
9. Chmielewski and Rötzer (2001); Parmesan (2006), both in: Fischlin (ed.) (2009)
10. Alcamo et al. (2007); Field et al. (2007b); Alo and Wang (2008), all in: Fischlin (ed.) (2009)
11. Lucht et al. (2006); Scholze et al. (2006); Alo and Wang (2008), all in: Fischlin (ed.) (2009)
12. Williams et al. (2000); Williams and Liebhold (2002); Logan and Powell (2001); Tran et al. (2007); Friedenberg et al. (2008), all in: Fischlin (ed.) (2009)
13. Fischlin (ed.) (2009)
14. Iverson and Prasad (2001); Ohlemüller et al. (2006); Fischlin et al. (2007); Golubyatnikov and Denisenko (2007), all in: Fischlin (ed.) (2009)
15. Perry et al. (2008), in: Fischlin (ed.) (2009)
16. Liski et al. (2002), in: Fischlin (ed.) (2009)
17. Piao et al. (2008), in: Fischlin (ed.) (2009)
18. Morales et al. (2007), in: Fischlin (ed.) (2009)
19. Christensen et al. (2007); Fischlin et al. (2007); Meehl et al. (2007); Schneider et al. (2007), all in: Fischlin (ed.) (2009)
20. Hanson and Weltzin (2000), in: Fischlin (ed.) (2009)
21. Karjalainen et al. (2003); Nabuurs et al. (2002); Perez-Garcia et al. (2002); Sohngen et al. (2001), in: Osman-Elasha and Parrotta (2009)
22. Innes (ed.) (2009)
23. Ogden and Innes (2007), in: Innes (ed.) (2009)
24. BCMOF (2006a), in: Innes (ed.) (2009)
25. Holling (1978); Lee (1993, 2001), all in: Innes (ed.) (2009)
26. Roberts (ed.) (2009)
27. Keskitalo (2008), in: Roberts (ed.) (2009)
28. Kirilenko and Sedjo (2007)
29. Boisvenue et al. (2006)
30. Zlatanov et al. (2017)
31. Zang et al. (2011), in: Zlatanov et al. (2017)
32. Jolly et al. (2005); Seidl et al. (2011); Elkin et al. (2013), all in: Zlatanov et al. (2017)
33. Hartl-Meier et al. (2014), in: Zlatanov et al. (2017)
34. Aleksandrov et al. (2009), in: Zlatanov et al. (2017)