Transcript Forests, Carbon and Climate

Carbon Stocks and Fluxes in
Forests Ecosystems
Ken Byrne,
Forest Ecosystem Research Group,
Department of Environmental Resource Management,
University College Dublin.
Greenhouse Gas Balances of Biomass and Bioenergy Systems,
Sustainable Energy Ireland, 20th November 2003
Content
• Forests and Carbon
• UNFCCC and Kyoto Protocol
• Carbon sequestration in Irish forests
• Conclusions
Forests and the global carbon cycle
• Carbon pools:
– Oceans:
39,120 Gt Carbon
– Atmosphere:
750 Gt Carbon
– Land vegetation:
550 Gt Carbon
(65% in forests)
– Soil and organic matter:
1500 Gt Carbon
(53% in forests)
1 Gt = 109 t C
Background
• UNFCCC
– GHG inventories
– Conservation and enhancement of sinks
• Kyoto Protocol
–
–
–
–
Agreed GHG reduction targets
Ireland, limit emissions to 1990 + 13% by 2008-2012
‘Kyoto forests’
Article 3.3: C stock changes due to afforestation, reforestation
and deforestation since 1990
– Article 3.4: Forest Management
Background cont.
• Marrakesh Accords
– ‘Kyoto forests’
– Article 3.3: no limit, fully credited
– Article 3.4: Forest Management: 50,000t C/year
• Para. 21 “Each Party included in Annex I shall account for all changes
in the following carbon pools: above-ground biomass, below-ground
biomass, litter, dead wood, and soil organic carbon. A Party may
choose not to account for a given pool in a commitment period, if
transparent and verifiable information is provided that the pool is not
a source.”
Net ecosystem exchange (GPP - total respiration)
CO2 sinks
CO2 sources
Respiration
Photosynthesis
(GPP)
Forest growth
Respiration
Litterfall
Decomposition
soils
Carbon stocks/pools
•
Above-ground biomass
–
–
–
–
•
Below-ground biomass
–
–
–
•
•
•
Stemwood
Branchwood
Bark
Foliage
Coarse roots
Fine roots
Stumps
Litter
Coarse woody debris
Soil organic carbon
Carbon Stock Dynamics in Forest
Ecosystems
Managed as a carbon sink
a. Establishment
b. Full vigour
c. Mature Phase
d. Longterm equilibrium
Managed as commercial forest
Periodic felling indicated by arrows
Over several rotations carbon
stocks neither incrase of decrease
Accumulation balanced by removals
for wood products, bioenergy etc
Irish Forests and Carbon: Information Needs
• How does the forest C balance
function ?
National
level
• What is the C Stock ?
• How is it changing ?
• How will it change in the future ?
Upscaling
• What are the factors controlling it ?
• Soil, species, management etc.
Plot level
State and Private Afforestation
1900-2002
20000
18000
16000
State
Private
14000
Ha
12000
10000
8000
6000
4000
2000
0
1900
1920
1940
1960
Year
1980
2000
Pools and fluxes represented in
the C-Flow model
product decay
atmospheric
CO2
carbon fixation
wood
products
thinning
harvesting
woody
biomass
non-woody
biomass
mortality, thinning &
harvest residues
woody
litter
non-woody
litter
Transfer of
residues to soil
Byrne & Milne (in prep.)
Litter & soil
soil organic
matter
decomposition
Inputs to the Model
• Afforestation data 1906-2002.
• Extrapolated to 2012 using average annual rate
during 1988-2000.
• 100, 75, 50 and 25% achievement of forest strategy
• Areas reduced by 15% to allow for roads etc.
• Species categories and Yield Classes:
–
Sitka spruce
pre 1990 YC 16
post 1990 YC 20
– Other conifers
Lodgepole pine YC 8
– Broadleaves
Beech YC 6
Cumulative C sequestration in Irish
forests 1906 - 2002
1.6
Trees
Products
Litter
Soil
Total
1.4
1.2
Mt C
1.0
0.8
0.6
0.4
0.2
0.0
1900
1920
1940
1960
Year
1980
2000
C stocks and sequestration in Irish forests
2002
C stock (M t)
Trees
Soil
Products
Litter
Total
C sequestration (M t)
19.1
13.9
3.3
1.4
37.7
Trees
Soil
Products
Litter
Total
0.7
0.06
0.12
0.51
1.39
Cumulative C sequestration in
Article 3.3 forests
2008
2012
1.2
1.0
Mt C
0.8
TreesTrees
Products
LitterProducts
Soil
Litter
Total
0.95 M t C yr-1
Soil
Total
0.6
0.4
0.2
0.0
1990
1995
2000
2005
Year
2010
2015
Cumulative C sequestration in Article 3.3
forests: effect of afforestation rate
2008
2012
1.2
BAU
100%
75%
50%
25%
1.0
Mt C
0.8
0.6
0.4
0.2
0.0
1990
1995
2000
2005
Year
2010
2015
Average amount of C sequestered per year
during 2008-2012 in Article 3.3 forests
Scenario
Mt C
Mt CO2
BAU
0.95
3.48
100%
1.01
3.7
75%
0.93
3.41
50%
0.85
3.12
25%
0.78
2.86
Irelands Kyoto target
1990 emissions
53.74 mt CO2 equiv.
+ 13%
60.74 mt CO2 equiv.
BAU (+ 37.3%)
73.79 mt CO2 equiv.
Need to reduce emissions by 13.05 mt CO2 equiv. yr-1
Contribution of Article 3.3 forests to
meeting Irelands Kyoto target
Scenario
BAU
100%
75%
50%
25%
% contribution
27
28
26
24
22
Conclusions
• Forests can play an important role in reducing GHG
emissions.
• This is only part of the solution, fossil fuel emissions
need to be tackled.
• National Forest Inventory is vital.
• Need for national data on C cycling in forests.
• CH4 and N2O ?
• Forest residues can provide an indigenous energy
source and help to reduce GHG emissions.
Thank you !