ArticlePDF Available

Abstract and Figures

The historical development of afforestations in Bulgaria was investigated. Some of the more important decisions and events which determine the correct state policy in the field of afforestations are pointed out. The most significant achievements are in: erosion control, incl. water tank protection from silting up; increasing the tree volume and forest growth; protection of agriculture via forest protection belts; landscape improving. The social importance for more employment and improvement of means of livelihood is mentioned. Proved reasons for decreasing the afforested areas since 1980s are given. The main mistakes and problems are mentioned as well as the changes in the afforestation policy and future challenges.
Annual afforestation dynamics in Bulgaria. During the second half of XX century the afforestations done in Bulgaria can be classified as follows: new ones – 680,000 ha (25 %), reconstruction of low-value and low-production forests – 630 000 ha (37 %), in mature non-renewed plantations – 370,000 ha (26 %), filling rare forests – 350,000 ha (11 %), for two-storeyed stands – 32,700 ha (1 %), or total 2,060,000 ha. According to the character of the afforested objects and the aims of the plantations established, their composition was 70 % conifers and 30 % deciduous species. The mentioned large total area included several times afforestation of the same objects, where the felling was short as it is in poplar plantations and fillings, re-afforestations, etc. (Milev et al. 2015). The afforestations performed required sufficient seed supply and nursery production that were developed at rather good level but they will not be commented here. With decreasing of bare areas and detecting some discrepancies and problems related to the species chosen for afforestation, a decrease of conifer species share in favour of deciduous ones happened during the 1980s. Critiques to afforestation increased in the last decade of 20 th century. It was due mostly to misunderstanding and with the motive of conserving the autochthonous vegetation and if afforestation should be done at all, it should be using the local deciduous species. The expert opinions were based on the sites' conditions and where these conditions were secondary worsen, mainly by erosion, using of valuable oak and other sensitive deciduous species is groundless (Milev et al. 2015). During the long term of afforestation practice there were some mistakes and aberrations. Many of them were corrected with time and with experience gathered. The treatment of some species as Pubescent oak (Quercus pubescens Willd.), Oriental hornbeam (Carpinus orientalis Mill.), Manna ash (Fraxinus ornus L.), was changed;
… 
Content may be subject to copyright.
PERSONAL
REFORESTA (2017) 3:143-154 Milev et al.
Reforesta Scientific Society 143
Afforestation in Bulgaria
Milko Milev, Krasimira Petkova, Nasko Iliev
University of Forestry, Faculty of Forestry, Department of Forestry, 10 Kliment Ohridski blvd.,
1797 Sofia, Bulgaria
m_milev@abv.bg
Abstract
The historical development of afforestations in Bulgaria was investigated.
Some of the more important decisions and events which determine the correct state
policy in the field of afforestations are pointed out. The most significant achievements
are in: erosion control, incl. water tank protection from silting up; increasing the tree
volume and forest growth; protection of agriculture via forest protection belts;
landscape improving. The social importance for more employment and improvement
of means of livelihood is mentioned. Proved reasons for decreasing the afforested
areas since 1980s are given. The main mistakes and problems are mentioned as well
as the changes in the afforestation policy and future challenges.
Keywords
History of Afforestation; Forest Plantation; Erosion Control; Forest Facts; Main
Challenges
Contents
1 History and results o f a f f o r e s t a t i on i n Bu lgar ia 143
2 Importance and eff e cti v en e s s o f a ffore st a t i o n 148
3 Afforestation in rec ent t im e s 150
4 Contemporary probl e m s a n d p r osp e ct s f o r a ffor e stat ion 15 1
5 References 15 3
1 History and r e s ults of a fforestation in Bulgaria
Afforestations in Bulgaria have over 135 year of history. The first attempts for
artificial planting of forest vegetation were performed in 1880, when the Ministry of
Finances, to which Forest Service was affiliated at the time, issued orders for
establishment of new forests. In 18881889 the foresters from North Bulgaria were
given seeds of Black locust and instructions for afforestation via sowing on grounds
near the settlements. This way started the earliest period of afforestation
development lasting nearly 25 years from 1880 tо 1905 (Milev et al. 2015).
First plantings were mainly afforestation on free and uncultivated lands, as
well as for ornamental purposes around settlements. There were only beginnings of
reforestation in the forests. Forest plantations were established in the vicinities of
many towns but the best ones, even today, remain these around Sofia, Kyustendil,
Stara Zagora and Koprivshtitsa (Zahariev 1977).
ARTICLE INFO
Review Artic le
Citation:
Milev M, Petkova K, Iliev N (2017)
Afforestation in Bulgaria. Reforesta
3:143-154.
DOI: https://dx.doi.org/10.21750/R
EFOR.3.12.36
Editor: Vladan Ivetić, Serbia
Received: 2017-06-02
Accepted: 2017-06-29
Published: 2017-06-30
Copyright: © 2017 Milev Milko,
Petkova Krasimira, Iliev Nasko. This
work is licensed under a Creative
Commons Attribution 4.0
International Public License.
PERSONAL
REFORESTA (2017) 3:143-154 Milev et al.
Reforesta Scientific Society 144
Substantial part of the first afforestations were unsuccessful but the
difficulties did not discourage the public activists who were the main initiators of this
noble activity and the enthusiastsmodel found many new followers. During the
period 18851900 total 3,060 ha were afforested in the country, using 29,400 kg seeds
and 2.436 million saplings. Although not large in area, the afforestations of this period
were first attempts to cultivate forest vegetation (Vachovski and Dimitrov 2003).
The autumn of 1904 is accepted as the beginning of the state-organized
afforestations. It was marked by the launching otthe Bureau for reinforcement of
torrents and afforestation in Kazanluk. The Bureau itself was officially opened in 1905.
Its first chief was the French inspector-forester Félix Louis-Marie Vogéli who arrived
with his assistant Jean-Christian Jagerschmidt. Thus the leading French experience for
afforestation of torrential slopes was introduced to Bulgaria (Zahariev et al. 1977;
Némoz-Rajot et al. 2015). At first seeds and saplings were imported from Central
Europe (mainly from Germany and Austria). The saplings arrived in bad conditions and
most of them were wasted. This was the reason since 1908 to leave the import and to
start local sapling production. Seeds and saplings of the following species were
delivered from abroad: Scots pine (Pinus sylvestris L.), Austrian pine (Pinus nigra Arn.),
Norway spruce (Picea abies (L.) Karst.), Eastern white pine (Pinus strobus L.), Douglas
fir (Pseudotsuga menziesii (Mirb.) Franco), Pinus banksiana Lamb., Grey alder (Alnus
incana (L.) Moench) and Black alder (Alnus glutinosa (L.) Gaetn.), European larch (Larix
decidua Mill.), oaks (Quercus spp., incl. Northern red oak Q. borealis Mich. F.),
European beech (Fagus sylvatica L.), Large-leaved Lime (Tilia platyphyllos Scop.), ashes
(Fraxinus sp.), Sycamore (Acer pseudoplatanus L.), Box elder (Acer negundo L.), Silver
birch (Betula pendula Roth.) (Milev et al. 2015).
The result of the activities of Bureau for reinforcement of torrents and
afforestation of Vogeli from 1905 to 1911 was 5 established nurseries with an area of
6.1 ha and annual production of 1 million saplings, afforested nearly 500 ha,
constructed 18 barrages and many other reinforcement equipment, and the most
important effect many torrents in the region of Kazanluk were turned into calm
water streams. Since 1911, following the model of Kazanluk, other sections on torrent
reinforcement and afforestation were opened in the country and their number
reached 38 to 1944. Significant work on inventory and précising of torrent catchments
named protection perimeters was done. The activity of the sections lasted until 1951,
when that they were closed and their functions taken by the state forest services
(Milev et al. 2015).
In 1904, after a competition, 5 Bulgarian youngsters were selected to go to
study in France on states expenses and they successfully graduated in French National
School of Forestry in Nancy. This school played an important role for the
reinforcement of afforestations and development of forestry science in Bulgaria
(Vachovski and Dimitrov 2003).
Noticeable impact on the development of forestry and in particular the
afforestation activities were given after the opening of a Forestry Department at the
Faculty of Agronomy and Forestry of Sofia University “St. Kliment Ohridski” in 1925
and the Forest Service in 1928. Special contribution to this progress had the Minister
of agriculture at the time Dimiter Hristov. At the beginning of his stay in the Office
192627 4,101.3 ha were afforested. He provided better finance and supported the
afforestation in a number of torrential catchments. Only in 1927 he organised 3
meetings dedicated to afforestations and insisted on their acceleration. The years of
PERSONAL
REFORESTA (2017) 3:143-154 Milev et al.
Reforesta Scientific Society 145
D. Hristov as a Minister were the peak in the annual afforestations for the period, the
maximum being in 1928 9,262.1 ha. The momentum of the intelligent management
of this notable statesman lasted no longer and in 1934 the afforested area decreased
4 times to 2,246.4 ha. During the next years 19351936 there was a new increase of
the afforestations and in 1943 they reached 8,996.3 ha (Milev et al. 2015).
After Second World War all branches in Bulgaria, incl. forestry and
afforestation developed on systematic base. It started with 2-year plan from 1947 and
during its implementation 41,400 ha bare and erosion terrains were afforested,
5,737 ha rare forests were completed, 34,721 ha sparsely forests were rejuvenated
and 100 km forest protection belts were established in the region of Dobrudzha. Main
part of the activities were realised with voluntary work (Vachovski and Dimitrov 2003).
The management was implemented with a number of governmental decisions
and decrees. The Governmental Decree (GD) N1171 in 1951 framed and developed
the first 10-year plan for afforestation (Vachovski and Dimitrov 2003). To the
established Management of Forestry to the Government were set 10 tasks in the field
of afforestation and erosion control. Among them were: afforestation of total 99,000
ha; production of 37,000 Mg seeds and 3.76 billion saplings; opening of new nurseries
on an area of 654 ha; organizing of preliminary soil cultivation and attention for the
plantations up to their 3rd year; establishment of two forest seed control stations in
Sofia and Plovdiv; development of forestry regions; preparing instruction for
afforestation; educating annually 100120 engineers in forestry and 200 specialists
with special secondary education in the forestry schools, etc. (Milev et al. 2015).
With Decrees from 1951, 1953 and 1954 work stared on the so called
technical projects for erosion control in the catchments of the building large dams.
Within the framework of such projects 153,000 ha new forests with anti-erosion
purpose were established. In order to synchronise the anti-erosion activities in forest
and agriculture territories, National programme for erosion control was developed in
1975. It was found that 54,200 ha (15 %) of forest territories were affected or
endangered by erosion. For the agricultural grounds the percent was over 80, having
in mind the wind erosion problem. Total of 2,294 torrents for technical and biological
reinforcement were detected (Milev et al. 2015).
Significant achievement of afforestation activity was the establishment of
protection belts system in North-east Bulgaria. During the period from 1951 tо 1958
belts with a total length 800 km and an area of 22,000 ha had been established
(Vachovski and Dimitrov 2003). Successfully were used the local oaks Pedunculate
oak (Quercus robur L.), Sessile oak (Q. petraea (Matt.) Liebl.), Turkey oak (Q. cerris L.),
European ash (Fraxinus excelsior L.), Honey locust (Gleditsia triacanthos L.), Black
locust (Robinia pseudoacacia L.), English walnut (Juglans regia L.), poplars (Populus
sp.), etc. To 1980 the belts reached 15 m height and accumulated volume of about
390,000 m3, playing as well an anti-erosion role, mitigating the microclimatic
conditions and favouring the agriculture production. Due to the belts agricultural
cropsproduction increased by 1535 %, especially in dry years (Milev et al. 2015;
Petkova et al. 2002).
An achievement of the foresters in Bulgaria is the system of sources of quality
reproductive materials and establishment of intensive forest plantations of fast
growing forest species, incl. development of poplar breeding. As a result of the started
in 1947 selection work in our country, more than 5,300 objects were established with
a total area of 52 thousand ha for the most valuable plantations of the main tree
PERSONAL
REFORESTA (2017) 3:143-154 Milev et al.
Reforesta Scientific Society 146
species. About 6,000 plus trees and candidate-elite trees were selected and
registered. For the species used about 390 ha generative and 135 ha clonal seed
orchards were established. A collection of about 120 poplar cultivars was established
and maintained. It could be stated that Bulgaria has well-developed seed production
base but with a view to rich genetic diversity and differences of afforestation objects it
should be further developed and maintained. During the second half of 20th century
many provenance tests and short-rotation plantations were established using both
local and exotic species Douglas fir (Ps. menziesii ssp. menziesii), cedars (Cedrus sp.),
European larch (L. decidua), Eastern white pine (P. strobus), Willows (Salix sp.),
Northern red oak (Quercus rubra L.), Black locust (R. pseudoacacia), and some others.
The results concerning main conifers Scots pine (P. sylvestris), Austrian pine (P.
nigra) and Norway spruce (P. abies) showed that 50 % higher productivity was
achieved by using seeds from the best sources. Only poplar plantations reached an
area 34 250 ha, but during the last years there is retreat and the poplar breeding was
implemented only in about 20 thousand hа, of the available appropriate sites, which
are about 35,000 ha (Milev et al. 2015).
Since 1958 reconstruction management system was introduced, consisting of
replacement of the so-called low-value, rare coppice forests. Programmes for
establishment of plantations of fast growing (local and exotic) and fruit trees species
were set English walnut (J. regia), Sweet chestnut (Castanea sativa Mill.). Since
1966 afforestations aiming at two-storeyed stands have been introduced, and since
1977 for establishment of intensive (industrial) plantations. There was some bias to
quantitative indicators (forested area) instead of precise evaluation and identification
of appropriate sites. In many reconstructions conifers were settled on significantly dry
sites and in regions with critically low air humidity. The unrealistic goal for increasing
the timber production on such places led to drying and became a reason to cease the
action in 2007. Of the forest fruit plantations established from 1951 tо 1970 only
about 1/3 are in good status (Milev et al. 2015).
Interesting experiments were set in order to recover the alpine tree line in the
high mountains Rila, Pirin, Stara planina (Balkan range) and Osogovo. Nine tree
species and hybrids were examined as well as technological variants for afforestation.
These experiments are a source of useful information in case of anti-avalanche and
other melioration afforestations in high mountain zone (Dakov et al. 1980).
The most important question in case of afforestations is the choice of the
species. It is related to the sustainability and longevity of the plantations as well as the
economic and ecological results. Answer to this question is especially difficult in the
variable natural conditions and diverse floristic composition of Bulgaria. For years the
species choice was done based on observations, visual determination of
environmental conditions, imitating the nature and older successful plantations. A task
was set in 1951 to identify and prepare a classification of the main forest vegetation
regions in Bulgaria. Five teams of scientists and experts worked on this task starting
from 1974 and developed methods for identification and classification of forest sites
regarding their optimal species composition (Zahariev 1977; Zahariev et al. 1977). In
1978 ‘Instruction for identification and mapping of forest sites and optimizing the
trees composition’ was published and it was a base for the ‘Classification scheme of
forest site types, which was implemented in the forestry practice and served for
determining of the proper afforestation composition.
PERSONAL
REFORESTA (2017) 3:143-154 Milev et al.
Reforesta Scientific Society 147
Afforestations reached the highest rate during 1960s and 1970s an average
of 50,00060,000 ha year-1 (Fig. 1). At that time the annual afforestation areas were
larger than those in France, Italy, Great Britain, for example. For afforested area per
capita Bulgaria was at the leading places in the world (Milev et al. 2015). The
establishment of suburban forest parks was activated during this period and many
terrains destroyed by industrial activity were recultivated by afforestation (Vachovski
and Dimitrov 2003).
Figure 1. Annual afforestation dynamics in Bulgaria.
During the second half of XX century the afforestations done in Bulgaria can
be classified as follows: new ones 680,000 ha (25 %), reconstruction of low-value
and low-production forests 630 000 ha (37 %), in mature non-renewed plantations
370,000 ha (26 %), filling rare forests 350,000 ha (11 %), for two-storeyed stands
32,700 ha (1 %), or total 2,060,000 ha. According to the character of the afforested
objects and the aims of the plantations established, their composition was 70 %
conifers and 30 % deciduous species. The mentioned large total area included several
times afforestation of the same objects, where the felling was short as it is in poplar
plantations and fillings, re-afforestations, etc. (Milev et al. 2015). The afforestations
performed required sufficient seed supply and nursery production that were
developed at rather good level but they will not be commented here.
With decreasing of bare areas and detecting some discrepancies and problems
related to the species chosen for afforestation, a decrease of conifer species share in
favour of deciduous ones happened during the 1980s.
Critiques to afforestation increased in the last decade of 20th century. It was
due mostly to misunderstanding and with the motive of conserving the autochthonous
vegetation and if afforestation should be done at all, it should be using the local
deciduous species. The expert opinions were based on the sites’ conditions and where
these conditions were secondary worsen, mainly by erosion, using of valuable oak and
other sensitive deciduous species is groundless (Milev et al. 2015).
During the long term of afforestation practice there were some mistakes and
aberrations. Many of them were corrected with time and with experience gathered.
The treatment of some species as Pubescent oak (Quercus pubescens Willd.), Oriental
hornbeam (Carpinus orientalis Mill.), Manna ash (Fraxinus ornus L.), was changed;
PERSONAL
REFORESTA (2017) 3:143-154 Milev et al.
Reforesta Scientific Society 148
these species, although slow growing, are now not considered ‘low-value’. They
perform satisfactory their protective functions on very poor and dry sites and there is
no reason to be changed with economically more valuable ones (Milev et al. 2015).
For about 55 years the participation of coniferous species increased from 11.8
to 32 %. This fact is the base for increasing our forests production, to assure better
quality and demanded timber, the social functions were improved. Similar policy in
the afforestations have many countries. Coniferous species dominate in Belgium
(89 %), Spain (98 %), Greece (91 %), and France (89 %). Gradually, with mastering the
torrents and changes in the afforestation policy, the balance between conifers and
deciduous changed. The view for priority usage of deciduous species was supported by
the specialists yet in 1980s and since the 1990s it has become in practice (Fig. 2). The
percentage showed on Figure 2 is not due to the significant increase of afforestations
with deciduous but to the significant decrease of coniferous plantations establishment
(Milev et al. 2015).
Figure 2. Relationship between areas of afforestation with conifers and deciduous species.
2 Importance a n d effective ness of afforestation
Bulgaria has doubtless success which show significant possibilities of
afforestation for establishment of new multifunctional forests as well as to assure fast
and quality artificial restoration of forests. As to current value the established
1.2 million ha forest plantations are an investment for about 2.5 billion euro for the
afforestation only. Due to the implemented forest economy policy the share of forest
plantations reached about 1/3 of the total forest territory. Bulgaria got new image
with the newly established forests. The forest vegetation of the country at the
beginning of XXI century reached reasonable level 33.4 %. To a high rate the territory
has been protected from erosion, the torrent risk has decreased and the adjoined
agricultural areas, reservoirs and transport infrastructure were better protected. The
established plantation had a significant is the contribution of the plantations created
to increasing the timber volume within 60 years with 3.3 times (from 193 to
645 million m3), and of the annual growth with 2.3 times (from 6 to
13.97 million m3).
If the effect of afforestation is graded, it is at first place ecological, having in
mind that most of the plantations have erosion controlling functions, and with the
PERSONAL
REFORESTA (2017) 3:143-154 Milev et al.
Reforesta Scientific Society 149
scale it has significant environment formation function. On the next place is providing
raw material. Considering the multifunctional character of afforestations, it is
important to mention that they influenced positively many branches agriculture and
water industry, tourism, transport, power production and the entire life style of the
population. The results of torrent control, protection of reservoirs from silting, field
protection role of agricultural areas, increased productivity of forest and the
landscape of Bulgaria was refined beyond recognition. The best examples showing the
positive effect of afforestation are the parallel photos from the past and after the
plantations have grown (Fig. 3). This is the reason why the foresters feel proud of the
activities realized, which were of the most significant country achievements of 20th
century. In order to realize completely the timber production potential and to follow
the realization of their ecological functions, silvicultural activities are needed for
management of the plantations established a responsible task for contemporary
foresters.
Figure 3. Views from Stara planina slope above Shipka town from 1905 (left) and 2005 (right), (Archive Gora Journal).
Special attention was paid to the in time dam protection. Nowadays all large
dams in Bulgaria are surrounded by protective ‘green belts, which protect them from
silting and increase the exploitation terms to centuries (Fig. 4).
Figure 4. Views from dams Iskar (left) and Kamchiya (right).
PERSONAL
REFORESTA (2017) 3:143-154 Milev et al.
Reforesta Scientific Society 150
3 Afforestation in recent t i mes
Since the 1980 the afforestations in Bulgaria have decreased. This is expected
having in mind the large mastered areas for afforestation. There were additional
factors as well: development of silvicultural systems with natural regeneration priority;
chronic economic crises and lack of resources, etc. Similar processes are typical for
other countries in East Europe (Weber 2000). During 1990s the afforested areas per
year decreased under 10,000 ha year-1, and after 2009 under 5,000 ha year-1 (Fig. 1).
At the same time the possibilities for afforestations according the project calculations
reflecting the forest territories condition are about 15 tо 18 thousand ha annually.
Obviously the afforestation dynamics is under the power of social and economic
environment and the forest policy realized, and for the last 2025 years more
significantly influenced the market relations in the forest sector.
Looking at the afforestations from a multifunctional point of view, we could
state that they are not only a solid ecological and raw material investment, but have a
social importance as well. They are a carrier of a potential for work loan security and
stabilizing the population occupation. Good work loan has a reflection on the
decreasing the offenders in the forests. The afforestation marginalization hides a
significant risk to break the connection in the transmitting the rich experience in the
activity of seed production, nursery production, afforestation and plantation care.
The correct direction of afforestation policy needs analysis of the condition
and dynamics of forest territories. According to data from Executive Forest Agency
(EFA 2016) to 31.12.2016 forest territories in Republic of Bulgaria cover 4,230,825 ha
(increased toward 2015 with 7,951 ha) or 38 % of the country area. Of these, 91 % are
forests so they reach 34.7 %. The area of forest territories without forest vegetation is
365,860 ha. The average age of forests increased and reached 57 years. The total
growing stock is 680.5 million m3 and it increased with 4.2 % only after 2005. About
42 % of this stock is concentrated in the protected and recreational forests, and
protected territories. The average growing stock is 178 m3 ha-1. It is higher than that in
Europe (105 m3 ha-1) and higher than that for forests in the world (130 m3 ha-1). For
the first time decrease of the mean increment is reported, from 14.4 (2010) to
13.97 million m3 year-1. Use of the timber is about 8 million m3 year-1, which is 55 % of
the annual increment. The detected tendency for increasing the timber stock is better
expressed in coniferous forests. The average stock in these forests is 260 m3 ha-1. On
the other hand, significant decrease was registered in the average growing stock of
coppice forests to be turned into seed ones only 114 m3/ha. Coniferous forests
demonstrate the highest annual increment 6.2 m3 ha-1 year-1, followed by deciduous
high forests 3.7 m3 ha-1 year-1, and for coppice forest it is about 2.3 m3 ha-1 year-1. For
the distribution of forest territory according types of forests there is a trend to
decrease coniferous forests area (towards 2013 they are 1,145,781 ha or 21.6 %) and
coniferous plantations. The total area of established forest plantations during the last
three years is small but increases from 3862.4 ha (2013) to 5,694.2 ha (2015). As a
results, the total share of coniferous decreases to 20.9 %, mainly due to abiotic and
biotic damages. The deciduous forests cover 68.4 % of the total area of forest
territories and their share gradually increases. An important fact is that Bulgarian
forests are a reservoir of 229 million Mg carbon.
Significant influence on decreasing the afforestations has the active processes
of auto-afforestation of free forest territories and abandoned uncultivated areas out
PERSONAL
REFORESTA (2017) 3:143-154 Milev et al.
Reforesta Scientific Society 151
of forest territories. During the last years afforestation is done mainly in post-fire
areas, drying stands and plantations, cutting areas and only on small part of the rest
are bare non-forested territories. The decrease in afforestation is due to various
reasons. First, large part of the areas that need afforestation were used by the
programmes for wide scale establishment of forest plantations in the near past.
Second, the influence the social and economic factors as insufficient funding, low
labor cost, lack of workers., Also, along with the decreased funding of afforestation
activities, another important factor was the priority of the natural regeneration,
regulated in the Forest Act.
4 Contemporar y problems and prospects for afforestation
Bulgarian forests are characterised by extremely rich diversity of coniferous
and deciduous tree species. Forest territories included in the European Ecological
Network NATURA 2000 are 58 % of the total forest area. An essential fact is that 2/5 of
the forest stock is concentrated in protected and recreational forests and in protected
areas. This is related to increasing of use in other forests. As the mentioned above
increase of forest resources is mainly extensive so the establishment of intensive
plantations, where possible, turns to be an important reserve for providing the
necessary quantity of wood. In other words, the development of plantation silviculture
could contribute to close-to-nature management in predominant part of our forest
territories. There are recommendations for establishment of plantations aiming
mainly at timber production on 20,000 ha (1012 % from forest territories), which
should be managed following the principles of plantation silviculture (Vachovski 2009).
Despite of significant achievements in the erosion control not everything is
completed. Still 15 % ofrom the forest territories are endangered by torrents, and
80 % of the agricultural areas are threatened by erosion. The inclined terrains are
particularly susceptible. Even if cultivated, annually soil layer of up to 5 mm is
removed. About 250 thousand ha are desolated and unsuitable for agriculture. Their
afforestation is implemented in the National Action Plan on Climate Change and
should be realised within Bulgarian duties on UN Frame Convention. That is why in the
National strategy for development of forest sector 20132020 (MoAF 2013), as well as
in the Strategic plan for development of forest sector 20142023 (MoAF 2014) is
foreseen increasing of the forest area via afforestation of abandoned former
agricultural lands, bare, deforested, eroded and endangered by erosion territories.
Favourable opportunity for afforestation of neglected non-agriculture lands is
provided by the Programme for development of rural areas. Other important factors
are described In the mentioned strategic documents s as well: significant fire risk;
necessity of adapting the afforestations to climate changes; potential for carbon
accumulation and disturbances in the forests. In this connection actions for recovering
from forest fires, natural disasters and illegal action are foreseen (Milev et al. 2015).
Currently, we are facing the challenge of frequent forest fires. The annually
burnt area in 20th century upto 1980s ranged between 800 and 3,000 ha. During the
subsequent years the fires as a number became 6 times more and caused 35 times
larger damages measured as area. Total 133,700 ha were burnt from 1991 to 2001
which was about 3 % from the forest area of the country. Only 1200 ha were
afforested of about 78,000 ha burnt in 2000-2001. According to the statistical data the
PERSONAL
REFORESTA (2017) 3:143-154 Milev et al.
Reforesta Scientific Society 152
forest fires during the period 20032013 affected 91,127 ha forest territories, with an
average for the country 8,284 ha. Total 584 forest fires were registered in 2016, and
6,320 ha were affected, of which 5,331 ha in forests and 989 ha in unforested areas
(Batalov 2017). Burnt areas were about 40,000 ha.
Violations of rules and illegal activities in the forests in the initial period of the
development of Bulgarian forest economy as well as today are described as the main
problem of the system. There are users and offenders, and even owners, possessed by
rude commercialism, who during cutting harvest the valuable individuals, without
ensuring sufficient and quality renovation. Thus during the last 20 years when the
conceptions of close-to-nature management of the forests and biodiversity
conservation were implied, the expected good results are difficult to achieve in the
practice. The quality of many stands is destroyed. Their natural restoration, even if
achieved, will be a step back in the genetic sense. A clear example is one of the most
valuable local deciduous species the Pedunculate oak. There are practically no
valuable populations left. So it could be certainly said that there is groundless
underestimation of one very positive part of the afforestations the possibility to
maintain and improve the quality of forest stands in genetic and breeding sense. This
is especially valid for valuable local deciduous species to which the policy of
afforestation pays attention. Stopping the reconstructions should not limit the use of
good quality reproductive materials to help or totally restore in case of worsen
breeding structure. The highest potential in this direction is in turning the coppice
stands into seed ones, because along with their low quantity indicators, also negative
phenotypic selection took part many times there. The transition to seed origin is
important but it is only one and smaller step to improving the deciduous forests.
Promoting the restoration with use of appropriate seed origin could increase the
quality and value of the stands with 4050 %. Тhe negative changes should be also
taken into account due to the soil erosion. In such stands it is logical to look for
different species composition, which will correspond to the conditions available. The
balance shows that at least 15 % (410460 thousand ha) of the stands in forest
territories need improvement species composition, origin and quality.
Other important tasks are related to the recultivations of destroyed terrains
by means of afforestation, finishing the establishment and reconstruction of the forest
shelter belts system, and protecting the transport infrastructure by road protection
belts. Specific task related to the afforestations is how to manage the areas of forest
plantations damaged by biotic and abiotic factors. The cases are diverse and need
special differentiated measures. Bulgarian researchers work on this task and one
promising directions is the idea of ecosystem correspondence (Kostov 2014). The
evaluation should be based on the environmental conditions status evaluated via site
system (Raykov et al. 2011). It is important to evaluate to potential for natural
restoration and foresee which ecosystems would be stable and worth economically.
Significant challenge for the correct choice of species composition is the
problem of climate change. The afforestation policy should consider the direction and
speed of these changes. At this stage in Bulgaria and in the world dominates the
expectation of global warming. Different scenarios for local climate changes which
differ by the level of warming and drough were developed t (Raev and Alexandrov
2011; Raev et al. 2015). However, there are also other opinions and some of them
predict cooling rather than warming. There are even assumptions that according the
global cycles the world goes to next ice age (Yankov 2010; Hansen et al. 2013; Snyder
PERSONAL
REFORESTA (2017) 3:143-154 Milev et al.
Reforesta Scientific Society 153
2016; Viterito 2016; Nikolov and Zeller 2017). At this stage it is preferable not to relay
on a determined direction but run investigations on the adaptive possibilities of tree
species and their ecotypes.
There are real risks for the sustainability of forest plantations and these risk
are related to their health conditions. Most frequent damages by abiotic causes are
snow breaks and snowfalls, windbreaks and wind throws, ice glass (ice breaks), fires
and other natural disasters. Droughts expressed in the low air humidity lead to
physiological weakness and occurrence of calamities. During the last years the
strongest attacks were on coniferous species, especially P. sylvestris, attacked by
Engraver beetle (Ips acuminatus Gyllenhal, 1827). Another important problem is
caused by the fungus Sphaeropsis blight (Sphaeropsis sapinea (Fr.) Dyko & B. Sutton.),
which attacks Austrian pine plantations.
Bulgarian foresters and researchers are in a complex situation due to the high
diversity of environmental conditions and rich floristic composition. On the other hand
this provides wide spectrum of opportunities to choose from. Тhe total number of
indigenous and introduced forest tree species used in Bulgaria (without shrubs) is
about 160, of which 120 are broadleaved and 40 coniferous. We are aware that with
the rich experience in the afforestations and scientifically based problem solving,
forest plantations will contribute to the sustainable development of forest resources
and better economic results in the forest sector in the country.
5 References
Batalov D (2017) Control, protection and defense from fires of forest territories in 2016. Forest (Gora) 3:
1418. (in Bulgarian).
Dakov M, Dobrinov I, Iliev A, Donov V, Dimitrov S (1980) Increasing forest upper limit. Zemizdat, Sofia,
218 (in Bulgarian).
Executive Forests Agency (EFA) (2016) Annual report of Executive Forest Agency for 2015. МAF, EFA,
Sofia, 71 p. (in Bulgarian).
Hansen J, Sato M, Russell G, Kharecha P (2013) Climate sensitivity, sea level and atmospheric carbon
dioxide. Philosophical Transactions of the Royal Society A, 371.
https://doi.org/10.1098/rsta.2012.0294
Kostov G (2014) An idea for classification of P. sylvestris and P. nigra plantations according the level of
ecosystem correspondence. Gora 9: 1921. (in Bulgarian).
Milev М, Petkova К, Iliev N. (2015) Forest plantations Forest seed production. Publishing house of
University of Forestry, Sofia, 288 p. (in Bulgarian).
MoAF (Ministry of Agriculture and Food) (2013) National Strategy for the Development of Forest Sector
in the Republic of Bulgaria 2013-2020. Available at:
http://www.strategy.bg/StrategicDocuments/View.aspx?lang=bg-BG&Id=875
MoAF (Ministry of Agriculture and Food) (2014) Strategic Plan for the Development of the Forest Sector
2014 2023. Available at:
http://www.iag.bg/data/docs/strategicheski_plan_za_razvitie_na_gsektor.pdf
Némoz-Rajot H, Petrakieva A, Gospodinov B (2015) La Restauration des Terrains en Montagne en
Bulgarie: Une greffe française réussie. In: Forêst et Montagne. Paris, L’Harmattan: 257–270.
Nikolov N, Zeller K (2017) New Insights on the Physical Nature of the Atmospheric Greenhouse Effect
Deduced from an Empirical Planetary Temperature Model. Environment Pollution and Climate
Change 1(2): 112. Available at: https://www.omicsonline.org/open-access/New-Insights-on-
the-Physical-Nature-of-the-Atmospheric-Greenhouse-Effect-Deduced-from-an-Empirical-
Planetary-Temperature-Model.pdf
Petkova K, Milev M, Bencheva S, Iliev N, Stancheva J, Kalmukov K (2002) Protection belts a base for
agroforestry system. Gora 6: 2022. (in Bulgarian).
PERSONAL
REFORESTA (2017) 3:143-154 Milev et al.
Reforesta Scientific Society 154
Raev I, Alexandrov V (2011) Chapter III. Determination of the main vulnerability zones of the forests
ecosystems in terms of climate changes. In: Raev I, Zhelev P, Grozeva M, Georgiev G,
Alexandrov V, Zhiyanski M, Markoff I, Velichkov I, Miteva S. Programme of measures for
adaptation of the forests in Republic of Bulgaria and mitigation the negative effect of climate
change on them. EU, Interreg IV C, Executive Forestry Agency, Sofia: 7383. (in Bulgarian).
Raev I, Alexandrov V, Tinchev G (2015) Assessment of drought related climate change impacts on forests
in Bulgaria. Silva Balcanica 16(1): 124.
Raykov R, Stefanov А, Milev М, Petrova R, Petkova К, Dobrichov I, Poryazov Ya, Yakimov М, Kalmukov К,
Broshtilov К, Nalbantov G, Terziyski Т, Stoykov S (2011) Classification scheme of forest site
types in Bulgaria. Executive Forest Agency, MAF, 104 p. (in Bulgarian).
Snyder C.W. (2016) Evolution of global temperature over the past two million years. Nature 538: 226
228. https://doi.org/10.1038/nature19798
Vachovski H (2009) To sustainable and economically effective forest economy. Farago, Sofia, 114
Bulgarian).
Vachovski H, Dimitrov S (2003) Forest and forest economy of Bulgaria in ХХ century. Aprokom Ltd, Sofia,
349 p. (in Bulgarian).
Viterito A (2016) The Correlation of Seismic Activity and Recent Global Warming. J. Earth Sci. Clim.
Change 7: 345. https://doi.org/10.4172/2157-7617.1000345
Weber N (ed.) (2000). NEWFOR New Forest for Europe: Afforistation at the Turn of the Century.
Proceedings of the Scientific Symposium. February 16th17th, Freiburg, Germany. European
Forest Institut Proceedings No 35, 248 p. Available at:
http://www.efi.int/files/attachments/publications/proc35_net.pdf
Yankov J (2010) The Global Lying. E-knigi, Sofia. 100 p. (in Bulgarian). Available at: http://www.bulgari-
istoria-2010.com/booksBG/J_Jankov_Globalnata_luzha.pdf
Zahariev B (1977) Forest plantations. Zemizdat, Sofia. 484 p. (in Bulgarian).
Zahariev B, Duhovnikov Y, Iliev A, Biolchev A, Enchev E, Vlasev V, Zashev B, Donov V, Ganchev G,
Kalinkov V, Kitin B, Iliev S, Tsanova P, Damyanov A (1977) Afforestation work in Bulgaria.
Zemizdat, Sofia, 151 p. (in Bulgarian).
... In the 20th century large areas with coniferous plantations were created at very low altitudes. While coniferous plantations have usually served their primary purpose of helping to control erosion, numerous waves of mortality have been observed in recent decades due to the combined negative effects of drought, aging and lack of opportunities for regular thinnings (Milev et al. 2017, MoEW 2019. ...
Article
Full-text available
The results from survey of forestry equipment in 2019 show 1371 units in Bulgarian logging industry. Expectedly, the largest share is in the farm tractors adapted for timber skidding. The rate of cable skidders is more than three times lower. Cable skidders and yarders should prevail, given that most of the forests in Bulgaria are situated on steep terrains with complex forms. A fundamental problem in logging industry in Bulgaria is the huge predominance of old equipment (in operation over 10 years), and their lower production rates and higher maintenance and repair costs. A major renewal of the logging machinery is expected, due to its physical wear and lack of manpower in the logging industry as well as in the industry as a whole, which is becoming increasingly tangible. The retrofit must be done with new high-performance equipment that, while more expensive, will ensure efficiency and lower unit costs. Facilitating access to EU programs will encourage the purchase of modern logging equipment. The density of the forest road network is insufficient and investment is needed to build new forest roads to reduce the average skidding distance and unit costs, and to rise the productivity of primary transport. Increasing the maximum allowable felling intensity will lead to the possibility of mechanized logging. The increasing the intensity of cutting will expand the use of harvesters and forwarders in coniferous forests. Another driver for the rapid introduction of new logging equipment are the long-term contracts of companies for better predictability and sustainability of investments. Barriers are the oncoming recession in the demand for timber and the supply of large volumes of cheap timber damaged by natural disasters from other European countries.
Article
Full-text available
A comparative analysis of the rate of return on investments in a fast-growing poplar plantation in South Bulgaria and in two-room residential apartments in Sofia (average area 68 sq.m.) (including a room and a bedroom), differentiated by districts has been made. The investigation is based on the concept accepted in the normative basis, which determined these kinds of estates as real. It is motivated by the necessity to reveal suitable and perspective variants for investments , according to the utilities and abilities of a wide range of potential investors. Both static and dynamic methods have been applied for assessment of the rate of return on investments in a medium-period perspective. As a result of the carried out investigations it is determined that the rate of return is 4.01 % and it is expected to raise along with raising of the demand of poplar wood material. The advantage of this kind of investment is that it does not require a large amount of capital; it is ecological and allows using lands in rural areas. The rate of return of investment in residential real estates varies from 6.27 % to 15.26 % depending on the location and the result is always positive.
Chapter
The chapter presents information about the legal instruments and institutions concerning the conservation of genetic resources of forest tree species in Bulgaria. Due to the specific circumstances, the vast majority of the Bulgarian forests are state-owned. Therefore, the main regulation documents concerning management of state forests are relevant in the context of tree genetic resources sustainable use and conservation . A brief survey of the most important regulation documents determining the legislation framework for conservation of genetic resources of forest trees is presented.
Article
Full-text available
A recent study has revealed that the Earth’s natural atmospheric greenhouse effect is around 90 K or about 2.7 times stronger than assumed for the past 40 years. A thermal enhancement of such a magnitude cannot be explained with the observed amount of outgoing infrared long-wave radiation absorbed by the atmosphere (i.e. ≈ 158 W m-2), thus requiring a re-examination of the underlying Greenhouse theory. We present here a new investigation into the physical nature of the atmospheric thermal effect using a novel empirical approach toward predicting the Global Mean Annual near-surface equilibrium Temperature (GMAT) of rocky planets with diverse atmospheres. Our method utilizes Dimensional Analysis (DA) applied to a vetted set of observed data from six celestial bodies representing a broad range of physical environments in our Solar System, i.e. Venus, Earth, the Moon, Mars, Titan (a moon of Saturn), and Triton (a moon of Neptune). Twelve relationships (models) suggested by DA are explored via non-linear regression analyses that involve dimensionless products comprised of solar irradiance, greenhouse-gas partial pressure/density and total atmospheric pressure/density as forcing variables, and two temperature ratios as dependent variables. One non-linear regression model is found to statistically outperform the rest by a wide margin. Our analysis revealed that GMATs of rocky planets with tangible atmospheres and a negligible geothermal surface heating can accurately be predicted over a broad range of conditions using only two forcing variables: top-of-the-atmosphere solar irradiance and total surface atmospheric pressure. The hereto discovered interplanetary pressure-temperature relationship is shown to be statistically robust while describing a smooth physical continuum without climatic tipping points. This continuum fully explains the recently discovered 90 K thermal effect of Earth’s atmosphere. The new model displays characteristics of an emergent macro-level thermodynamic relationship heretofore unbeknown to science that has important theoretical implications. A key entailment from the model is that the atmospheric ‘greenhouse effect’ currently viewed as a radiative phenomenon is in fact an adiabatic (pressure-induced) thermal enhancement analogous to compression heating and independent of atmospheric composition. Consequently, the global down-welling long-wave ux presently assumed to drive Earth’s surface warming appears to be a product of the air temperature set by solar heating and atmospheric pressure. In other words, the so-called ‘greenhouse back radiation’ is globally a result of the atmospheric thermal effect rather than a cause for it. Our empirical model has also fundamental implications for the role of oceans, water vapour, and planetary albedo in global climate. Since produced by a rigorous attempt to describe planetary temperatures in the context of a cosmic continuum using an objective analysis of vetted observations from across the Solar System, these ndings call for a paradigm shift in our understanding of the atmospheric ‘greenhouse effect’ as a fundamental property of climate.
Article
Full-text available
Cenozoic temperature, sea level and CO2 covariations provide insights into climate sensitivity to external forcings and sea-level sensitivity to climate change. Climate sensitivity depends on the initial climate state, but potentially can be accurately inferred from precise palaeoclimate data. Pleistocene climate oscillations yield a fast-feedback climate sensitivity of 3±1(°)C for a 4 W m(-2) CO2 forcing if Holocene warming relative to the Last Glacial Maximum (LGM) is used as calibration, but the error (uncertainty) is substantial and partly subjective because of poorly defined LGM global temperature and possible human influences in the Holocene. Glacial-to-interglacial climate change leading to the prior (Eemian) interglacial is less ambiguous and implies a sensitivity in the upper part of the above range, i.e. 3-4(°)C for a 4 W m(-2) CO2 forcing. Slow feedbacks, especially change of ice sheet size and atmospheric CO2, amplify the total Earth system sensitivity by an amount that depends on the time scale considered. Ice sheet response time is poorly defined, but we show that the slow response and hysteresis in prevailing ice sheet models are exaggerated. We use a global model, simplified to essential processes, to investigate state dependence of climate sensitivity, finding an increased sensitivity towards warmer climates, as low cloud cover is diminished and increased water vapour elevates the tropopause. Burning all fossil fuels, we conclude, would make most of the planet uninhabitable by humans, thus calling into question strategies that emphasize adaptation to climate change.
Article
Reconstructions of Earth's past climate strongly influence our understanding of the dynamics and sensitivity of the climate system. Yet global temperature has been reconstructed for only a few isolated windows of time, and continuous reconstructions across glacial cycles remain elusive. Here I present a spatially weighted proxy reconstruction of global temperature over the past 2 million years estimated from a multi-proxy database of over 20,000 sea surface temperature point reconstructions. Global temperature gradually cooled until roughly 1.2 million years ago and cooling then stalled until the present. The cooling trend probably stalled before the beginning of the mid-Pleistocene transition, and pre-dated the increase in the maximum size of ice sheets around 0.9 million years ago. Thus, global cooling may have been a pre-condition for, but probably is not the sole causal mechanism of, the shift to quasi-100,000-year glacial cycles at the mid-Pleistocene transition. Over the past 800,000 years, polar amplification (the amplification of temperature change at the poles relative to global temperature change) has been stable over time, and global temperature and atmospheric greenhouse gas concentrations have been closely coupled across glacial cycles. A comparison of the new temperature reconstruction with radiative forcing from greenhouse gases estimates an Earth system sensitivity of 9 degrees Celsius (range 7 to 13 degrees Celsius, 95 per cent credible interval) change in global average surface temperature per doubling of atmospheric carbon dioxide over millennium timescales. This result suggests that stabilization at today's greenhouse gas levels may already commit Earth to an eventual total warming of 5 degrees Celsius (range 3 to 7 degrees Celsius, 95 per cent credible interval) over the next few millennia as ice sheets, vegetation and atmospheric dust continue to respond to global warming.
Article
The latest report from the Intergovernmental Panel on Climate Change states with high confidence that the warming of global temperatures since 1901 has been driven by increased radiative forcing. The gases responsible for this enhanced forcing are greenhouse gases of anthropogenic origin, and include carbon dioxide, methane, and halocarbons. The Nongovernmental International Panel on Climate Change has challenged these findings and concludes that the forcing from greenhouse gases is minimal and diminishing. They add that modelling attempts of past and future climate states are inaccurate and do not incorporate important solar inputs, such as magnetic strength and total irradiance. One geophysical variable that has been overlooked by both groups is geothermal flux. This study will show that increasing seismic activity for the globe’s high geothermal flux areas (HGFA), an indicator of increasing geothermal forcing, is highly correlated with average global temperatures from 1979 to 2015 (r = 0.785). By comparison, the correlation between carbon dioxide loading and global temperatures for the same period is lower (r = 0.739). Multiple regression indicates that HGFA seismicity is a significant predictor of global temperatures (P < 0.05), but carbon dioxide concentrations do not significantly improve the explained variance (P > 0.1). A compelling case for geothermal forcing lies in the fact that 1) geothermal heat can trigger thermobaric convection and strengthen oceanic overturning, important mechanisms for transferring ocean heat to the overlying atmosphere, and 2) seismic activity is the leading indicator, while global temperature is the laggard.
Article
The paper presents projections for change of air temperature and precipitation during the period 1951-2000, for 2050 and 2070 based on analysis of climate elements in the forests of Bulgaria in XX century, and application of global circulation models, WorldClim data and scenarios of IPCC Fifth Assessment Report (2014). Considerable increasing of air temperature is expected, together with decreasing of precipitation during the vegetation season. The vulnerability zones of forest ecosystems are delineated and particularly vulnerable of them will be the forests within the range from 0 to 800-900 m a. s. l., mainly in the Continental-Mediterranean climatic zone of the country. Problems are expected for more sensitive representatives of genus Quercus, for beech foothills ecosystems and particularly, for coniferous plantations out of their natural area of distribution. The need for implementation of already established special programs for adaptation of forest ecosystems of Bulgaria to future climate change, including the new systems of close-to-nature silviculture, increases.
Control, protection and defense from fires of forest territories in 2016
  • D Batalov
Batalov D (2017) Control, protection and defense from fires of forest territories in 2016. Forest (Gora) 3: 14-18. (in Bulgarian).
Increasing forest upper limit
  • M Dakov
  • I Dobrinov
  • A Iliev
  • V Donov
  • S Dimitrov
Dakov M, Dobrinov I, Iliev A, Donov V, Dimitrov S (1980) Increasing forest upper limit. Zemizdat, Sofia, 218 (in Bulgarian).
Annual report of Executive Forest Agency for 2015
Executive Forests Agency (EFA) (2016) Annual report of Executive Forest Agency for 2015. МAF, EFA, Sofia, 71 p. (in Bulgarian).
An idea for classification of P. sylvestris and P. nigra plantations according the level of ecosystem correspondence
  • G Kostov
Kostov G (2014) An idea for classification of P. sylvestris and P. nigra plantations according the level of ecosystem correspondence. Gora 9: 19-21. (in Bulgarian).
Forest plantations -Forest seed production
  • М Milev
  • К Petkova
  • N Iliev
Milev М, Petkova К, Iliev N. (2015) Forest plantations -Forest seed production. Publishing house of University of Forestry, Sofia, 288 p. (in Bulgarian).