Effects of artificial drought on the ground vegetation, crown condition and litterfall
Effects of artificial drought on the
ground vegetation, crown condition and
litterfall in Scots pine stands:
The results of the roof experiment in Lithuania
Remigijus Ozolinčius, Vidas Stakėnas,
Rasa Buožytė, Brigita Serafinavičiūtė
LIETUVOS MIŠKŲ INSTITUTAS
Lithuanian Forest Research Institute
Ecology Department
Girionys, Kaunas distr.
Lithuania
LIETUVOS MIŠKŲ INSTITUTAS
LITHUANIAN FOREST RESEARCH INSTITUTE
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
Study site
• Central Lithuania (54°55' N, 23°43'E )
• 60-year old Scots pine
(Pinus sylvestris L.) stand
• Sandy soil (Arenosol)
• Pinetum vacciniosum forest type
The annual mean temperature
is 6.5°C, and the annual mean
precipitation is 686 mm.
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
Design of the experiment
• Start in spring/summer 2003
• The roofs were removed in
autumn 2005
Transparent roofs were
constructed below the canopy,
1-3 m above the ground
Control
Drougth
1m
3m
Roof made of
polypropylene
Litter traps
on the roof
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
Design of the experiment
Crown
condition
assessment
15 m
0.25 m2
1m
1m
2m
(25-33 trees
per plot;
mean stem
diameter at
breast height 20-21 cm)
1m
Litter traps
(every 2 months and
once in winter)
20 m
Ground vegetation assessment quadrats
(the cover of moss and vascular plants)
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LITHUANIAN FOREST RESEARCH INSTITUTE
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
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LITHUANIAN FOREST RESEARCH INSTITUTE
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
Meteorological conditions
Year
Mean JulyMean annual
August
temperature
temperature
Mean annual
precipitation
Mean
July-August
precipitation
2002
8.1°C
20.5°C
653 mm
35 mm
2003
6.9°C
18.6°C
574 mm
86 mm
2004
6.9°C
17.3°C
638 mm
88 mm
2005
7.0°C
17.9°C
641 mm
90 mm
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
Results. Ground vegetation cover
Vascular plants
No
1
Species
Calluna vaulgaris L.
2
Convallaria majalis L.
3
Festuca ovina L.
4
Hieracium umbellatum L.
5
Solidago virgaurea L.
6
Vaccinium myrtillus L.
7
Vaccinium vitis-idea L.
Mosses
No
Species
1
Hylocomium splendens (Hedw.) Schimp.
2
Pleurozium schreberi (Brid.) Mitt.
3
Ptilium crista-castrensis (Hedw.) De Not.
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
Results. Ground vegetation cover
Mean cover, %
Mosses
100
89,1 88,5
90,4
90,5
90,9
90,4
90,4
80
60
40
20
3,6
0,5
3,0
0,4
11,2
0
2003
2004
2005
Control
2006
2007
2008
Drought
Mean cover, %
Vascular plants
100
80
60
40
49,3
42,7
41,5
48,0
38,0
37,3
17,5
20
3,8
1,6
0
2003
2004
2005
Control
1,1
0,6
1,3
2006
2007
2008
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Drought
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
Results. Ground vegetation cover
Shannon-Weaner diversity index
Shannon-Weaner index
3,0
2,5
2,4
2,5 2,6
2,6
2,5
2,3
2,2
1,8
2,0
2,3
2,3 2,2
1,7
1,5
1,0
0,5
0,0
2003
2004
2005
Control
2006
2007
2008
Drought
Shannon-Weaner diversity index was non-significantly lower in the
second year of experiment and significant in the third year, after the roofs
were removed.
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
Results. Ground vegetation cover
Control
Drought
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
Results. Crown condition
Defoliation, %
50
41,8
40
32,6
31,9
28,7
30
22,5
24,3
22,8
25,1
20,9 24,2
20,0 19,9
20
10
0
2003
2004
Control
2005
2006
2007
2008
Drougth
Soil drought significantly increased mean crown defoliation of Scots pine
trees, and this parameter has been continually increasing.
The next year after the removal of the roofs the start of the recovery process
was detected.
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
Mean annual mortality, %
Mean tree mortality during 2003-2008 in soil drought
treatment was higher comparing to the control trees.
3,61
5
4
2,46
3
2
1
0
Control
Drought
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
Results. Litterfall
Litterfall, t/ha per year
5,0
3,97
4,07
4,0
4,05
4,00
3,49
3,63
3,33
3,27
3,0
1,67
2,0
1,45
*
1,0
0,0
2004
2005
2006
Control
2007
2008
Drought
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
Experimental
plot
Number of
trees
Diameter,
cm
Basal area,
m2/ha
Control (1)
25
21.4
29.9
Control (2)
32
19.8
32.8
Control (3)
30
21.9
37.5
Mean
29.0
21.0±0.6
33.4±2.2
Drought (1)
31
22.2
29.6
Drought (2)
31
20.7
34.7
Drought (3)
33
20.2
28.9
Mean
31.7
20.0±0.6
31.1±1.8
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
Conclusions
¾
The cover of mosses under soil drought conditions decreased more
sharply comparing to the cover of vascular plants. However, mosses
tended to recover more fast than the vascular plants.
¾
The Shannon-Weaner diversity index showed the complete recovery
of the ground vegetation diversity in 1 year after the removal of the roofs,
however the ground vegetation cover didn’t recover completely even in 3
years.
¾
The mean crown defoliation of Scots pine trees increased significantly
due to soil drought, but this effect disappeared in 1 year after the removal
of the stressor.
¾
The recovery of Scots pine assimilation mass leaded to the increase of
litterfall.
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
Prof. Remigijus
Ozolinčius
Dr. Vidas
Stakėnas
Rasa
Buožytė
Dr. Brigita
Serafinavičiūtė
Thank You !
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Effects of artificial drought on the ground vegetation, crown condition and litterfall
Moisture, %
Moisture of mineral soil 0-100 cm layer in 2004 (n=3)
9
8
7
6
5
4
3
2
1
0
Control
Artificial drought
7,7
6,1
4,3
0-5
5,9
4,0
5-10
6,0
5,8
5,3
3,6
3,7
3,6
10-20
20-40
40-60
4,3
3,2
60-80
3,0
80-100
Depth, cm
The significant decrease (p<0.05) of soil moisture was determined 2
years after start of the artificial drought in the organic and mineral soil
layers.
The drought influence was found up to 1 meter depth.
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