disturbance, degradation, and recovery: forest dynamics and climate change mitigation

Department of Forest and Ecosystem Science

Disturbance, degradation, and recovery: forest

dynamics and climate change mitigation

Professor Rod Keenan

Acknowledgements to Colin Filer, Julian Fox, Cossey Yosi and the Australian Centre for International Agricultural Research


Fate of Anthropogenic CO2 Emissions (2000-2007)

Canadell et al. 2007, PNAS (updated)

1.5 Pg C y-1

+7.5 Pg C y-1

Atmosphere46%

4.2 Pg y-1

Land29%

2.6 Pg y-1

Oceans26%

2.3 Pg y-1

1 Petagram = 1000 Megatonnes

Global C cycle

Department of Forest and Ecosystem ScienceCanadell et al. 2007, PNAS (updated to 2007)

Human Perturbation of the Global Carbon BudgetHuman perturbation of the global carbon cycle


After Bali

Two parallel processes • AWGKP

– sets rules for post-2012 Kyoto Protocol

• AWGLCA – seeks global agreement for further co-

operative action, now and post-2012– engagement with ‘heavy hitters’ (US,

China, India)– includes REDD


Forests leading to Copenhagen

• Article 3.3 sinks – no real change• Article 3.4

– Differing positions – Australia remains conservative – Baseline a continuing challenge

• REDD+restoration


Nabuurs et al 2007 Forestry. in IPCC 4th Assessment report

Forest-based mitigation options


Garnaut potential estimates

Activity Potential CO2-e uptake/yr

Post-1990 plantations

50 Mt by 2020

Pre-1990 eucalypt forests (cease harvesting)

136 Mt CO2-e for 100 years

Carbon farming (plantations)

143 Mt CO2-e for 20 years Garnaut review 2007. Includes allowance for 100 GWPs)


Defining forest degradation

• Forest productivity• Genes, tree vigour and quality• Forest species composition

compared with a ‘natural’ state• Impacted soils, water, nutrients

or broader landscape features• Carbon stock


Forest degradationa proposed definition

‘A human-induced process that results in long-term reduction in forest carbon stocks’

• forest canopy cover is sufficient for the land to be defined as forest

• Challengesdefining ‘long-term’, extent of reduction in carbon stocks Forest area considered subject to

‘degradation’


Forest management carbon accounting principles

1. Determine the forest area subject to management

2. Identify human-induced activities 3. Assess change in carbon stock

associated with these activities4. Comprehensive accounting:

– include lands subject to past or present management

5. Balanced accounting – include all changes in carbon stocks


Balanced accounting

Emissions

• Harvest

Removal of wood products

Site preparation

Decay of residues

• Fire

• Disease

Uptake

• Regrowth

Accounting pools

• Above and below ground live biomass

• Dead organic matter

• Soil carbon


Case studies

AustraliaNative forest harvestingWildfirePapua New GuineaForest harvestingShifting cultivation


CO2 uptake in Australian Managed Native Forest

Forest type Net area(Mha)

WeightedNet growth(tC/ha/yr)

Total CO2 uptake

(Mt)

Rainforests 1.33 0.58 2.8

Tall Dense Eucalypt Forests

3.24 2.4028.5

Medium Dense Eucalypt Forests

6.71 0.9523.3

Medium Sparse Eucalypt Forests

2.03 0.181.3

Callitris Forests 0.30 0.25 0.3

Other Forests 1.29 0.24 1.1

TOTAL 14.89 1.03 57.3

2007 National Greenhouse Gas Inventory Appendix 7.B


Harvest emissions= Wood removals (m3) * C in roundwood

(0.35) * Slash Ratio (0.9)


CO2 losses due to harvest

0

5

10

15

20

25

30

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

Year

Mt

CO

2 /

ye

ar

Net uptake of 32 to 37 Mt CO2 per year


NF management options

• Further reduce removals?– Consider leakage, cost, social impacts

• Reduce ‘slash factor’– greater or less utilisation?– potential impacts on CWD or

regeneration success• Increase growth?

– Ensure fully stocked stands• Further benefits generally marginal


Wildfire

2007 Australian National Greenhouse Gas Inventory


Australian emissions 06 and 07

2007 National Greenhouse Gas Inventory


Biomass lost in wildfire assumed to recover in 5 years


Wildfire and carbon

• Wildfire human induced?• Frequency may increase

with climate change• This may change species

composition and C stock• Impacts can be

mitigated through education, effective suppression, prescribed burning

• Better quantify impacts on C stocks

• Factoring in long-term disturbance cycles


Fire-harvest interactions

Hurteau et al 2008 Carbon protection and fire risk reduction:toward a full accounting of forest carbon offsets. Frontiers in Ecology


PNG forests


PNG drivers of forest change

• Conversion to plantation agriculture– limited

• Fire– Extensive in

some regions but forest recovers

• Mining– Localised

impacts except along Fly River


Shifting cultivation

• 11 million hectares used by local farmers

• Fallow– 50% > 15 yrs– 43% 5-15 yrs– 7%

• Little conversion of primary forest

Allen et al. 2001. Food security for Papua New Guinea: Proceedings of the Papua New Guinea food and nutrition 2000 conference. Australian Centre for International Agricultural Research (Proceedings 99), Canberra, pp. 529-553


Timber harvesting• Last 20 years average of 1.75 M m3

logs exported• 120,000 ha/year harvest area • 3.2 M ha impacted• C stock reduction of 44.4 t/ha• 17 tCO2 per m3 wood removed


PNG harvest emissions

05

1015202530354045

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

Mt

CO

2


PNG regrowth uptake

-20

-10

0

10

20

30

40

501

97

8

19

80

19

82

19

84

19

86

19

88

19

90

19

92

19

94

19

96

19

98

20

00

20

02

20

04

20

06

20

08

Mt

CO

2


PNG net emissions

-20

-10

0

10

20

30

40

50

1978

1981

1984

1987

1990

1993

1996

1999

2002

2005

2008

Mt

CO

2


Baseline option – base year

0

510

1520

25

3035

40

1978

1981

1984

1987

1990

1993

1996

1999

2002

2005

2008

Mt

CO

2

Base year eg. 2000 7.6 Mt/yr


Baseline option – Base period

0

510

1520

25

3035

40

1978

1981

1984

1987

1990

1993

1996

1999

2002

2005

2008

Mt

CO

2

Base period eg. 1990’s 21Mt/yr


Baseline option - BAU

0

510

1520

25

3035

40

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

Mt

CO

2

?


Best options for PNG

• Reduce harvest rate – Long term sustainable

supply– Management capacity– Accessibility,

operability and market factors

• Reduce harvest impacts

• Support post-harvest regeneration and rehabilitation

• Encourage industry diversification


Degradation?

ACTIVITY

Native forest harvesting in Australia Wildfire ?Shifting cultivation in PNG Forest harvesting in PNG


Key points• Definition of forest degradation still

uncertain• Need to adopt balanced and

comprehensive accounting• Need improved monitoring

frameworks based on field measurement

• Baseline, leakage and economic and social impacts are important policy considerations

disturbance, degradation, and recovery: forest dynamics and climate change mitigation

Documents

carbon stocks forest

forest dynamics

forest area subject

global carbon cyclecanadell

harvest emissions

medium dense eucalypt

lands subject

longterm reduction