1) Drainage of peatlands for forestry in Finland is releasing large amounts of soil carbon, with estimates of 9.1 teragrams (Tg) of carbon lost per year, equal to 33 million tonnes of CO2. 2) Studies of re-sampled boreal forest soil sites show average losses of 160 grams of carbon per square meter per year from drained peatlands. 3) Comparisons of adjacent natural and intensively managed boreal forest sites found average losses of 1.5 kilograms of organic matter per square meter from tilled forest soils more than 10 years post-harvest.

1. Alarming loss of soil
carbon stores in the
Boreal forest zone in
Finland
Heikki Simola
Finnish Association of Nature Conservation FANC
Univ Eastern Finland UEF, Dept Env & Biol Sciences
FAO, GSOC17 Rome, March 2017

2. Starting point: Finnish IPCC reporting of the forest sector
net
sink
of
forestry
reported
at
~30 Mt
CO2-eq
0
peat soils (histosols)
mineral soils (podsols)
Wood biomass

3. THIS PRESENTATION:
Direct observation / chronosequence approaches
to soil carbon dynamics under human impact::
1.Forestry-drained peatland soils (histosols)
2.Tilled clearcuts on mineral ground (podsols)

4. Carbon stores of Finland
Liski et al. 2006), Liski & Westman 1997, Turunen 2008, Laturi et al 2008
peatlands
~ 6000
mill. t C
timber
~ 800
mill. t C
forest floor
(on mineral soils)
~ 1300
mill. t C
sedimens
~ 650
milj. t C
(mill t = megaton = Tg = teragram)

5. Carbon stores of Finland
Lähteet: Liski et al. 2006), Liski ja Westman 1997, Turunen 2008, Laturi et al 2008
peatbogs
~ 6000
milj. t C
trees
~ 800
milj. t C
Forest soil
(mineral grounds)
~ 1300
milj. t C
Lake sediments
~ 650
milj. t C
Atmosphere
above Finland
< 500
milj. t C = 500 Tg
(milj t = megatonni = Tg = teragramma)

6. Finnish peatlands
as C stores
and effects of
forestry drainage on
them;
Two research
approaches

7. Original peatland coverage:
Red = Ditch-drained
Blue and green = in natural condition

8. RAHESUO IN ILOMANTSI
Case A. Partially drained eccentric bog:

9. Rahesuo, Ilomantsi
ojitettu
luonnontilainen

11. Rahesuo, Ilomantsi, aerial photo, and sample pairs
from the natural and drained sides

12. Matching of sample pairs from undrained (left) and drained sides

13. Case B. Comparison of old (1980s) peat inventories
with to-day’s situation on the same sites
• 49 sites investigated by the Geological Survey of Finland in the 1980s
• Represent the range of natural and common peatland types in each region
• Selection criteria for re-sampling sites:
- the precise original coring point possible to find again
- about 2 m peat layer on the site
- drainage ditching of the site done before the Geol
Survey study
New samples from precisely the original spot (GPS)
- volumetric coring
- entire profile analysed in 10-cm sections
..
.

14. Aumakankaansuo, old coring hole found by GPS!

15. Kaavi, Välisuo mire. Peat profile in 1982 (left), and at the same site in 2009 (right):
- compression of the peat layer: decreased thickness, increased bulk density
- considerable loss of total mass (166 kg m-2 in 1982; 125 kg m-2 in 2009)
Turpeen
massa:
166 kg/m
Kaavi, Välisuo (ptk); turvemassat v. 1982 ja 2009
turpeen massa g/dm 3
Turpeen
massa:
125 kg/m
2
2

16. Peat C balance in the 37 re-investigated mires
(loss = above, increase = below the 0-line);
shading =fertility class;
lower panel = surface subsidence
Average
LOSS
160 g C
m-2 yr-1
peat
subsidence
variable, but
related to C
loss

17. BOLDLY EXTRAPOLATING:
average loss 160 g C m-2 yr-1
equalling 590 g CO2 m-2 yr-1
from the forestry-drained 5,7 mill hectares
= total loss 9,1 Tg C yr-1
or 33 mill. tonnes CO2 per year

18. The natural C stores in Finland
Lähteet: Liski et al. 2006), Liski ja Westman 1997, Turunen 2008, Laturi et al 2008
peatbogs
~ 6000
milj. t C
trees
~ 800
milj. t C
Forest soil
(mineral grounds)
~ 1300
milj. t C
Lake sediments
~ 650
milj. t C
Atmosphere
above Finland
< 500
milj. t C = 500 Tg
(milj t = megatonni = Tg = teragramma)

19. Natural C reservoirs in Finland
Lähteet: Liski et al. 2006), Liski ja Westman 1997, Turunen 2008, Laturi et al 2008
suot
~ 6000
milj. t C
puusto
~ 800
milj. t C
metsämaa
(kivennäismailla)
~ 1300
milj. t C
järvisedimentit
~ 650
milj. t C
Atmosphere
above Finland
< 500
milj. t C = 500 Tg
(milj t = megatonni = Tg = teragramma)
emission
9 Tg/yr
= 2 % CO2
Per annum

20. Nature’s C stores in Finland
Lähteet: Liski et al. 2006), Liski ja Westman 1997, Turunen 2008, Laturi et al 2008
suot
~ 6000
milj. t C
puusto
~ 800
milj. t C
metsämaa
(kivennäismailla)
~ 1300
milj. t C
järvisedimentit
~ 650
milj. t C
Atmosphere
above Finland
< 500
milj. t C = 500 Tg
(milj t = megatonni = Tg = teragramma)
emission
9 Tg/v
= 2 % CO2
Per annuum
At an even rate the C
store of drained
peatlands (about 3000
Tg) would be totally
evaporated in 300 years ?

21. Effects of soil tilling on the carbon store
of boreal podsol soils –
Nature reserves and adjacent
intensive forestry sites as test fields

22. Fig. 1. Flow diagram of the Yasso07 model and the relative magnitudes of each mass flow between labile compund groups of
organic carbon and more calcitrant humus; acid hydrolysables (A), water solubles (W), ethanol solubles (E), and compounds neither
soluble n...
M. Tuomi, J. Rasinmäki, A. Repo, P. Vanhala, J. Liski
Soil carbon model Yasso07 graphical user interface ☆
Environmental Modelling & Software, Volume 26, Issue 11, 2011, 1358–1362
http://dx.doi.org/10.1016/j.envsoft.2011.05.009
Finnish IPCC accounting of forest soil (podsol) C balance is modelled and
calculated according to Yasso07-model

23. 4.1. Input and output information
The Yasso07-UI works with input information that is easily accessible in
practice. This information consists of: 1) the initial state of the soil in terms of
the amount of ash free organic carbon in the soil and its chemical quality in
terms of AWEN fractions; 2) the climatic conditions as monthly or annual
precipitation and mean monthly or annual temperature; and 3) the estimated
ash free organic carbon input into the soil in non-woody and woody
litter, including the estimated size distribution of the woody litter – again in
terms of the AWEN chemical fractions.
…
The lack of accurate information on the initial state of the simulated soils
is not limiting because given some constant litter input to the soil, the
software can be used calculate the long-term stationary state of the soil to be
used as the initial state.
…
… making the assumption that the litter input to the soils in terms of amount of
carbon is equal to the output

24. Critical question:
What is the real carbon balance of intensely managed
forestry land soils?

25. Critical question:
What is the real carbon balance of intensely managed
forest land podsol soils?
Research project:
Comparison of C stores of adjacent natural and managed
forest sites

26. The Finnish experimantal settings:
1.”National park loggings”–nature reserve margins

27. Syöte National park …

29. 2. Strip-felling forestry in Lapland

30. SOIL TREATMENT METHODS:
Deep ploughing
Harrowing/Disc trenching
Scarification
Stump removal

31. Fieldwork:
Sampling of the moor humus
layer with a 10 cm2 cylindrical
soil corer;
20 samples from the old-growth
forest, and
20 samples from the adjacent
logging;
notification of: forest type,
logging age, soil treatment,
regeneration (seeded/planted),
dominant species, fertilization,
mineral soil, charcoal in soil,
sloping of ground (N, S)

32. 20 samples/40
m
20 samples/40 m

33. NB
MB
SB
HB
Forest zones of Finland:
NB = northern boreal
MB = middle boreal
SB = southen boreal
HB = hemiboreal
Sampling sites

34. 60
65
70
0100200300400
MB and NB sites
HB and SB siteselevation,m
60
65
70
0 100 200 300 400
M
HB
elevation, m
Nlatitude
Latitude range: 59o 57’ – 68o 25’
Elevation range: 2 – 390 m a.s.l.

35. OM mass change, MB and NB sites
0 20 40 60
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
tilled
non-tilled
age, yr
OMchange,kgm-2
-1.52 kg OM m-2
= Average loss of
organic material
at tilled sites >10 yr
old
Middle and Northern Boreal sites

36. -4 -2 0 2 4
-4 -2 0 2 4
OM change, kg m-2
-6 -4 -2 0 2
-6 -4 -2 0 2
OM change, kg m-2
68
66
64
62
60
Soil OM change according to latitude
no soil treatment Tilled sites

37. All zones, treatments > 10 yrs
non-tilling
harrow
ed
ploughed
-2.0
-1.5
-1.0
-0.5
0.0OMchange,kgm-2
n = 27 24 24

38. South and North Finland,
natural (old) vs. tilled forest soils
South,old
forestsoil
South,tilled
forestsoil
N
orth,old
forestsoil
N
orth,tilled
forestsoil
0
2
4
6
8
10
OMinsoil,kgm-2
losses:
0.8 kg OM m-2 1.5 kg OM m-2

39. Concluding and critical
remarks:

40. Proposed correction for Finnish IPCC reporting
claimed
net
sink
of
forestry
0
peat soils
mineral soils (podsols)
Wood biomass

41. Proposed correction
claimed
net
sink
of
forestry
0
peat soils
mineral soils (podsols)
Wood biomass
podsol, 4Tg
+
histosol
33 Tg
CO2-eq

42. Proposed correction
claimed
net
sink
of
forestry
0
peat soils
mineral soils (podsols)
Wood biomass
podsol+4Tg
Histosol
+33 Tg

43. Critical conclusion
The boreal ecosystems are naturally C-neutral or
slowly C sequestering systems.
The Finnish forestry management has converted
our forest and mire ecosystems into a considerable
net source of C into the atmosphere for at least a
period of several decades.