Soil carbon accumulation and nitrogen
retention traits of four tree species grown in
common gardens
Geshere A., Inger K., Gundersen P.
November, 2011
•
•
•
•
Introduction
Methods
Results and discussions
Conclusion
Introduction
• Forest ecosystems approximately 50% of the total terrestrial
ecosystems C pool, 2/3 of which resides in forest soils (Dixon et
al, 1994)
• Forest management affects soil C and N (Johnson & Curtis, 2001)
e.g tree species selection Economic consequences: productivity
 Ecological consequences: biodiversity conservation, gene-pools,
climate
 Biogeochemical consequences: affect inputs, turnover and losses
of organic matter (Augusto et al., 2002)
-C sequestration , nutrient recycling, water pollution
 Future afforestation? Climate scenario?
Introduction cont...
• Studies on tree species effects on C and N stocks by use of common
garden experiment are rare
Examples
• Vesterdal et al. (2002) -no difference between the two species on C
stock in mineral soil in 0-25 cm depth
• Finzi et al, (1998) -largest difference among the tree species in the
forest floor and top 7.5cm of the mineral soil
• Vesterdal et al., (2008) -significant effect of tree species on 15-30
cm mineral soil C stock
- tree species affect C distribution in soil
• Few species were compared-data is lacking for some species e.g.
larch
• Confounding factors: site properties, stand ages, data, different tree
species etc
Introduction cont....
Objective
• to identify the tree species that accumulate most soil C and at the
same time efficiently retain deposition N
Hypothesis
• Thicker organic layers or accumulation under coniferous species;
higher SOC storage in the mineral soil of broadleaved species
• Higher NO3-N concentration below root-zone under Norway
spruce species
• For the deciduous-conifer larch we expect NO3-N cycling to be
intermediate between Norway spruce and the broadleaved
species
Methods
• Studt areas
Ulborg, Hastrup, Lindet, Tisted Nørskov, Løvenholm,
Kragelund, Christianssæde, Frederiksborg
Methods cont...
• Table 1. Selected climate and soil properties at the study sites
•
• Tree species
 Oak, Beech, Larch, Norway Spruce
 One stand of each tree species on each site
Methods cont...
• Sampling and analysis
 Forest floor and mineral soil C and N
contents (Vasterdal et al., 2008)
Forest floor
 Mineral soil (70-90 cm)- NO3-N conc.
determination
• Statistics –one-way-ANOVA,
regression
Soil density
Mineral soil
Results and discussion
• Tree species effects on C and N stocks
80
tree species, P<0.001
tree type, P<0.001
30
a
Forest floor C (Mg/ha)
25
x
20
b
15
x
10
c
d
5
tree species, P<0.001
tree type, P<0.001
y
y
0
Mineral soil C (Mg/ha)
a)
tree species, P<0.001
tree type, P<0.001 a
70
ab
60
b
b
50
tree species, P>0.05
tree type, P>0.05
40
0
200
400
600
800
Forest floor N (kg/ha)
1000
2400
2900
3400
3900
Mineral soil N (kg/ha)
 Significant effect of tree spp/type on forest floor C and N, and
mineral soil C, but not N stocks
Result & discussion cont...
Total soil C (Mg/ha)
c)
100
tree species, P<0.001
tree type, P<0.001
90
a
a
80
xy
x
70
b
b
60
y
y
tree species, P<0.001
tree type, P<0.001
50
2500
3000
3500
4000
Total soil N (Kg/ha)
4500
5000
• The observed tree species/type effect on C and N stock was
attributed to:
 Difference in litterfall quantity and litter chemistry
 Turnover rates of organic matter
 Rooting system
 Interaction among these factors,
 ...and ofcourse site-related factors
Result & discussion cont...
Effect of site factors confounds the effects of tree species...
Site
Forest floor
Mineral soil
Total soil
C (Mg/ha)
N (kg/ha)
C (Mg/ha)
N (kg/ha)
C (Mg/ha)
N (kg/ha)
ULB
17.0(5.7)a
580.9(186.9)a
71.9(4.3)a
2435.9(53.3)cd
88.9(9.8)a
3016.8(226.5)cde
HAS
13.3(5.3)ab
488.3(170.8)ab
66.5(4.9)ab
2803.1(204.8)cd
79.8(9.1)a
3291.4(249.6)bcde
LIN
13.9(3.2)ab
511.5(104.6)ab
64.7(2.1)ab
2825.7(92.6)cd
78.6(4.7)a
3337.2(67.9)bcd
TIS
10.3(5.7)ab
320.2(188.4)ab
63.3(3.7)ab
3457.2(115.5)bc
73.5(7.4)ab
3777.4(272.5)bc
LOV
7.6(2.6)ab
233.8(78.8)ab
41.0(4.0)cd
2516.2(269.7)cd
48.7(4.1)c
2750.0(244.8)de
KRA
16.1(6.7)ab
517.1(217.7)ab
31.7(4.4)d
1818.2(278.8)d
47.7(8.6)c
2335.3(350.7)e
CHR
5.6(1.77)b
156.7(53.5)b
74.2(6.8)a
6042.2(336.1)a
79.8(8.6)a
6198.9(381.1)a
FRE
7.5(3.35)ab
229.4(98.0)ab
50.9(5.2)bc
3992.7(219.1)b
58.4(6.9)bc
4222.1(219.9)b
&
disc
ussi
• C and
N stocks are correlated, mostly in the forest floor
on
cont.
R =0.35
..
R =0.98
35.00
Conifers
Broadleaves
120.00
30.00
Broadleaves
2
100.00
2
25.00
Mineral soil C (Mg/ha)
Forest floor C (Mg/ha)
Conifers
20.00
15.00
10.00
5.00
60.00
40.00
20.00
0.00
0.00
80.00
200.00 400.00 600.00 800.00 1000.00 1200.00
Forest floor N (kg/ha)
0.00
0.00
2000.00
4000.00
6000.00
Mineral soil N (kg/ha)
8000.00
10000.00
Result & discussion cont...
Total soil
120.00
Norway spruce
Larch
Total soil C (Mg/ha)
100.00
Beech
Oak
80.00
60.00
R2=0.28
40.00
20.00
0.00
0.00
2000.00
4000.00
6000.00
Total soil N (kg/ha)
8000.00
10000.00
Result & discussion cont...
• Variation between sites in C and N stocks was attributed to:
 Site properties (Raulund-Rasmussen and Vejre (1995) e.g. soil
texture
 Site productivity (biomass production; organic matter
accumulation or litter fall)
 Land-use legacy; land-use history, past management activities
(Schulp & Verburg, 2009)
 Interaction among the the factors....
Result & discussion cont...
• NO3-N concentration
10
a
a)
NO3-N (mg/l)
6
ab
ab
4
b
2
12
P=0.018
b)
ab
8
ab
6
ab
ab
4
2
ab
ab
b
0
0
Oak
Beech
Larch
ULB HAS LIN
Spruce
Tree spp, P<0.001; tree type, P<0.001
25
20
a
c
bc
A
b
B
15
10
5
35
Mineral soil C/N
30
TIS LOV KRA CHR FRE
Sites
Tree species
Minera soil C/N
a
10
NO3-N (mg/l)
Tree species, P=0.045
Tree type, P=0.7
8
a
30
P<0.001
b
25
b
20
c
c
c
15
d
d
CHR
FRE
10
5
0
0
ULB
HAS
LIN
TIS
LOV
Sites
Tree species and tree type
KRA
Result & discussion cont...
25
25
20
20
NO3-N (Mg/l)
NO3-N (Mg/l)
• NO3-N concentration was not correlated with forest floor and mineral
soil C/N ratio
15
10
R² = 0.0241
5
15
10
5
R² = 0.1036
0
0
20
25
30
35
40
Forest floor C/N
25
45
-5
NO3-N (mg/l)
NO3-N (Mg/l)
20
10
R² = 0.0077
5
15
20
25
30
35
40
Mineral soil C/N
d)
15
10
10
8
6
R² = 0.65
4
2
0
0
0
10
20
Forest floor C (Mg/ha)
30
40
-2
8
18
28
38
Soil (clay +silt) content
• NO3-N concentration was correlated with soil texture i.e clay+silt
48
58
Differences in nitrate concentration among tree
spp/ tree type and sites
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•
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

Litter quality (C/N ratio, lignin/N ratio)
N deposition (Gundersen, 2008)
Soil microclimate
Light (canopy nature) (Ranger et al, 2004)
Composition of understory vegetation (Augusto et al, 2003)internal N cycling
 Soil temperature and moisture (rainfall interception and
evapotranspiration) (Barge & Edmond, 1999)
 Land-use legacy
 Interaction among these factors
Conclusion
After about four decades of the stand establishment:
• Forest floor C-larch>spruce>>beech>oak
• Total soil C- larch=spruce>>beech=oak
• Relatively more acidic and nutrient poor sites accumulate
more organic C and N in forest floor layer, but the difference
was not clear in mineral soil
• Larch …..high soil C and N accumulation and less nitrate
concentration below root-zone
End
• Thanks