the effect of fire on dry dipterocarp forest soil...
TRANSCRIPT
Karma DorjiKarma DorjiSchool of Biology, Institute of Science,
Suranaree University of Technology
THE EFFECT OF FIRE ON DRY DIPTEROCARP FOREST SOIL
SPIRATION AT SAKAERAT ENVIRONMENTAL RESEARCH
STATION, NAKHON RATCHASIMA
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� Soils are the largest carbon pool in terrestrial ecosystems and
soil respiration is the major pathway of carbon transfer from
soil to atmosphere
� Soil respiration releases about 11 times more CO2 than
current fossil fuel combustion (Peng et al., 2009)
Soil respirationSoil respiration
Root respirationRoot respiration
Microbial decomposition
(litter soil organic matter)
Microbial decomposition
(litter soil organic matter)
Fauna respirationFauna respiration
Temp. in
degree F
CO2
in parts
per
million
C0
2(p
pm
)te
mp
erat
ure
ch
ang
ed (
F)
(Manchester Knowledge Capital, 2009)
Carbon dioxide and global temperature since 1880
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4
What is the role
of forest fire on
DDF soil
respiration?
(Photography.nationalgeographic.com/photography)
Materials and method
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Sakaerat Environmental Research Station
(Sakaerat Environmental Research Station 2009) 6
SERS(79.6km2)
Longitude 101°50‘~102°00’
Latitude 14°25‘~14°35’
・The hillside around Korat Plateau
・Dominant Vetetation
Dry Evergreen Forest(DEF)
Dry Dipterocarp Forest(DDF)
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Forest types at SERS
DDF
Area (km²) %
Dry evergreen forest 46.82 59.96
Dry dipterocarp forest 14.51 18.58
Forest plantation 14.46 18.52
Grassland 0.93 1.19
Bamboo 1.12 1.43
Buildinng 0.25 0.32
78.08 100
(Sakaerat Environmental Research Station 2009)
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Fired area Fire protected area
Study sites (DDF, SERS)
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StudyStudy
Feild studyFeild study Laboratory incubation experimentsLaboratory incubation experiments
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�Field Soil Respiration measurement:
Line transect 100 m (at 10m interval)
EGM-4 (PP-systems)
�Soil moisture (Delta Probe type ML2x
(Delta-T Devices)
�Soil temperature (CT-430WP)
Field study
10m
100m
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1. 3 soil samples from 40m line transect (20 m apart)
2. Sieve through 2mm mesh
3. Incubation treatments:
� Temperature: 25 and 30°C
� Water : 75% WHC
4. Soil analysis (C, N, pH)
Incubation experiment
40m
20m
Soils sampling
Incubation procedures
SR measured using LI-820 CO2 Gas
Analyzer on day 1, 2, 3, 6, 9, 12.
SR measured using LI-820 CO2 Gas
Analyzer on day 1, 2, 3, 6, 9, 12.
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� Conical flasks (500ml)
� 50 g Soil samples
� Parafilm sheet
� Incubation chamberTemperature: 25, 30°C
Laboratory equipment set-up
LI-820 CO2 analyzer
�Water content:
75% WHC
Data analysis
� Pearson’s correlation coefficient: relationship between
the soil respirations and environmental factors.
� Statistical analysis :using SPSS 16.0 for windows
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� t-test: compare soil respiration between fired and no fire
soils of a DDF.
� ANOVA : compare soil respiration among temperature
different treatments
Results and Discussion
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Field results
Fired Fire protected p-value
Respiration rate
(µmol CO₂m¯² s¯²) 1.39 2.3 0.013
Water content (%) 0.9 1.92 0.000
Organic C (%) 2.43 1.83 0.005
Total N (%) 0.19 0.15 0.000
pH 5.2 5.3 0.742
soil temperature (°C) 28.4 27.8 0.100
Soil respiration rates and soil factors of fired and fire-protected areas at DDF
The last column shows the significance value of t-test
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Field results
The soil water content of soils were positively correlated with
soil respiration rates at p<0.01
The soil water content of soils were positively correlated with
soil respiration rates at p<0.01
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Mean soil respiration rates of fired and fire-protected
areas with response to different treatments (n=18)
ab
c
b
The letters a, b and c shows the results of post hoc Duncan tests
Laboratory incubation results
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Ecosystem Fire No fire p-value
Organic C (%) 2.291 2.142 0.000
Total N (%) 0.187 0.174 0.035
Table The mean values of soil respiration rates and other
controlling factors of fired and fire-protected soils (n=3)
The last column shows the significant value of t-test
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The mean soil respiration rates of two ecosystems at different
incubation days (N=3).
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� Field SR of fire protected soil was significantly higher than fired
areas with 2.299 and 1.792 µmol CO2 m-2 s-1 (significant higher
soil water content)
� On incubation (25°Cand 30°C and water content of 75% WHC)
fired area soils had significantly higher SR than non-fire soils
(p<0.05)
� Significantly higher soil organic carbon in fired soils might have
accelerated the SR
� Results suggest that forest fire in DDF could enhance SR if there
is a rainfall after the fire
Conclusion
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Recommendation
More detail study needed: The effect of fire on soil respiration
� SR measurements: before and after the fire.
� fire and non-fire site should be close to each
other.
�To fully understand the carbon (C) cycle impacts of forest
fires,
both C emissions during the fire and post-disturbance fluxes
need to be considered
THANK YOU FOR
YOUR
KIND ATTENTION
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