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On the recent developments in the
restoration of extracted milled peatlands
in Estonia
Edgar Karofeld & Kai Vellak
University of Tartu, Estonia
The International WorkshopBEST EXPERIENCES IN CONSERVATION AND
RESTORATION OF HABITATS IN RAISED BOGS AND MIRES
EXCHANGE OF KNOWLEDGE TRANSFER TO AUKSTUMALA
11–13 June 2014, Šilutė, Lithuania
In Estonia peatlands in
different conditions cover
~22 % of the territory and
therefore we also do have a
lot of peat and long history
of peat extraction.
Evaluated exploitable peat
resources (775 milj. t) allow to
continue at current level (0,8-1,2
milj. t yr-1) for several hundred
years.
Mechanized peat cutting in Estonia started already in 1861, but
until the 1950-s peat was mostly extracted manually in bog
margins without deep drainage.
The impact on environment was small and localized, and
these areas re-vegetated spontaneously.
The situation changed drastically from the mid 1950-s when
milling and vacuum mining techniques were introduced ─
the number and especially the area of peat extraction sites with
deep drainage and removal of bog vegetation increased
dramatically.
The area of some bigger peat extraction areas is ca 1500 ha.
Peat production Extracted SUM
Estonia 18-19 000 ha 9400 ha 27 400 ha
During and shortly after the collapse of the Soviet system,
peat extraction was discontinued at many sites without any
restoration.
Extracted peatland in Viru bog (Lahemaa NP!),
... <25 yrs after the end of peat extraction
Abandoned extracted
(milled) peatlands stay
almost plantless for long
time and natural re-start of
mire initiation is unlikely, if
not possible.
Estonia’s legislation enact that all abandoned mining sites
must be re-cultivated. However, almost no full scale
restoration has been done on extracted peatlands.
In 2005 National Audit Office focused on this problem, but the
response has been minimal:
Important step toward the after-use of extracted peatlands in
Estonia was their revision carried out by the Estonian Geo-
logical Survey, published in 2005-2008.
This Revision:
• estimates the area and the state of extracted peatlands,
• gave the overview of their current plant cover,
• evaluate the remaining peat resources,
• based on remaining peat layer, current state, local
environment etc gave the recommendations for further peat
extraction or restoration.
Guide book „Extracted
peatlands, their
exploitation and
restoration” (2011) gives
the overview of the peat
extraction, spontaneous
re-vegetation and different
options for after use and
restoration.
In last years restoration was carried out on Viru and Hara
extracted milled peatlands in Lahemaa NP.
Unfortunately in Hara work was done only to raise water level.
In Viru on some areas also plant fragments from donor site
were spread. However, results were not so good, partly
because the work was done by the hired company without
knowledge and peatland expert supervision.
The abandoned extracted peatland on the eastern edge of Tässi peatfield
~ 30 years after the end of mining before the restoration (April 2012).
Restoration experiment on Tässi extracted peatland using
“Moss layer transfer technique” (“Canadian method”)
The topmost oxidized peat layer (10-20 cm) has been removed, surface
leveled and some ditches blocked (late April 2012).
Cutting and collecting plant fragments from nearby donor site (under the
preparation for widening of the current peat extraction area).
Spreading plant fragments (area ratio with donor site 1/10 to 1/15) and covering
them by straw. Finally drainage ditches were blocked.
May 2012
Since the end of 1970-s
September 2013
Total plant cover (%) on restored Tässi peatland, Sept. 2013
Treatment
Tota
l cover,
%
Total plant cover and number of species increased from spring to autumn 2013.
Total plant cover (%) on restored Tässi peatland, Sept. 2013
Treatment
Tota
l cover,
%
WTD or spreading density of plant fragments
did not have significant effect on total cover
Total plant cover (%) on restored Tässi peatland, Sept. 2013
Treatment
Tota
l cover,
%
WTD or spreading density of plant fragments
did not have significant effect on total cover
Total cover remains lowest with areas
without spreading of plant fragments
The similarity of species composition of mosses (acc. to
Czekanowski-Sørenseni similarity coeficent) between donor
site in Soosaare bog and restored sites in Tässi varied
depending from treatment from 0,67 to 0,78 (not restored 0,2).
19,515,612,69,2S. rubellum
2613,316,910,2S. magellanicum
343126,529,8S. fuscum
90,764,562,451Total moss cover
Spring 2014Autumn 2013Spring 2013
SoosaareTässi
Total mean moss cover and coverage of the main
Sphagnum species (%)
The similarity of species composition of mosses (acc. to
Czekanowski-Sørenseni similarity coeficent) between donor
site in Soosaare bog and restored sites in Tässi varied
depending from treatment from 0,67 to 0,78 (not restored 0,2).
The success of mire restoration depends not only from the right method but
also from it,s right application supervised by the experts on Sphagnum and
mire ecology and very much from unpredictable weather conditions.
Tässi bog, restored in spring 2012 Viru bog, restored in autumn 2012
What have caused the difference?
• In Tässi restoration was done in the
beginning of vegetation season 2012
followed by the rainy summer.
• The “Moss layer transfer method”
was followed using our expertize in
peatland studies.
• Water level depth during vegetation
periods is mostly within 20-30 cm
Tässi Viru
• In Viru restoration was done in late
autumn 2012 followed by the dry and
warm summer 2013.
• The surface layer was not peeled.
•The species of collected Sphagnum
mosses from donor site is unknown.
• Plant fragments and straw were
spread unevenelly and often too sparse
or too dense.
• Water level depth is highly fluctuating
from floods to -50 to -60 cm.
• Restoration was done by the hired
company without knowledge and
peatland expert supervision.
0
5
10
15
20
25
30
35
40
45
50
15.V
2013
4.VI2
013
19.V
I201
3
22.V
III20
13
11.IX
2013
17.IX
2013
4.X20
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18.X
2013
28.II
I 201
4
9. IV
201
4
28.IV
2014
27.V
2014
5.VI2
014
Date
WT
D,
cm
Fluctuation of water table depth in Tässi restoration area
In spring 2014 following the winter with minimal snow cover
and during longer dry periods it is difficult to rise and keep
water table in desirable depth (ca 20 cm) and without
frequent rain events plants will suffer from draughts.
The restoration of > 2000 ha of extracted
peatlands starts now in Estonia with the
help of EU support (10,9 milj Euros in
2014-2020) to reduce the mineralization of
residual peat, emission of GHG-s and to
create near-natural self regulating
ecosystems.
The priority is given for extracted peatlands:
• located on or bordering with protected areas and
• where extraction of residual peat layer is not reasonable.
The preliminary criteria for the selection of sites, recommen-
dations for the direction of the restoration (mostly
paludification or creating shallow water bodies) and
principles for monitoring have been worked out.
Thank you!
