estimating the potential carbon supply from changes in land use: afforestation of grazing lands in...

Estimating the potential carbon supply from changes in land use: afforestation of grazing lands in the US as a case study

Sandra BrownWinrock International

[email protected]

Third USDA Symposium onGreenhouse Gases & C Sequestration in

Agriculture and ForestryBaltimore, March 2005

2©Winrock International 2004

A key question …..

What amount of carbon is available and where from changing land use and management practices at what price?• Goes beyond just technical potential—

also includes economic potential


AcknowledgementsWinrock Team:

Timothy PearsonDavid ShochBrent SohngenJohn KadyszewskiJonathan Winsten

California Dept. Forestry:Mark RosenbergDoug Wickizer

SupportAmerican Electric PowerOgelthorpeCA Energy Commission/PIERElectric Power Research InstituteUS DOE


Overall Methodology

Identify and locate land classes suitable for increasing carbon stocks

Estimate rates of carbon accumulation for each major potential class of project activity for each land class

Assign costs to each contributing cost factor

Estimate carbon supply


Regional analyses of carbon supply

•California-WESTCARB partnership•Southern region-SSEB partnership

Details of analyses are in reports atwww.winrock.org/what/ecosystem_pubs.cfm

California-WESTCARB Afforestation of rangelands


Identify and locate land suitable for increasing carbon stocks

• Determine which rangelands could support forests—suitability analysis• Land-use suitability

analysis based on • Biophysical factor-

dependent suitability for forest habitats


Identify rangelands suitable for conversion to forests

Analyze the relationship between existing forests and several biophysical factors using GEOMOD =“suitability for forest map”

Cross-reference suitability map to areas of current rangelands to select areas with afforestation potential. Product = map of rangeland areas suitable to support forests


Inputs toGEOMODConverted to forest probability maps based on existing extent in each class

Prepare factor maps

Mean annual temperature

Slope


0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

0 2 4 6 8 10

12

14

16

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FOREST SUITABILITY SCORE

NU

MB

ER

OF

CE

LL

S (

HE

CT

AR

ES

)

FOREST

RANGELANDS

Overlap of rangeland classes in areas that have the same biophysical characteristics as current forests ~ 9.3 million ha

Area of existing rangelands suitable for forest growth

Montane chaparral


Map of populated places, montane chaparral areas, and selected populated places with names that refer to forests or forestry—e.g. Pine Grove, Pine Valley, Pinehurst, Redwoods, Sequoia, Seven Oaks, Sherwood Forest, Stallion Oaks, Sugarpine, Tall

Timber Camp


Map of rangeland areas (in yellow) suitable for afforestation •Represent about 9.3 million ha or 23% of State area

Areas where forest crown cover high, suggesting not suitable


Afforestation of grazing lands:

-Estimate rates of C accumulation and costs

C a rb on S up p ly C u rves$ p er ton @ 20 ye a rs

S T A T S G O

W oo d la ndD a tab a se

P re do m in a n tT re e S p e c ies

F o re st T ype

S ite Ind ex

A va ila b leF ie ld D a ta

A llo m e tricG ro w th E q ua tion

C a rb on Y ie ld

P ro d u ctiv ity o fra n ge lan ds

A U M b a sedo n p ro d uc tiv ity

P ro fit p era n im a l

O p p ortu n ityC o s t

F o re st T ype

L andC la ss if ica tion

P la n tingC o s ts

C o n ve rs ionC o s t

F o re st T ype

T re a tm e n tsT yp e

F re qu e ncy o fT re a tm e nt

M a in te na n ceC o s t

P ro je ctD u ra tion

A ccu racy a ndP re c is ion

M & MC o s t

E co no m ic Inp u ts



A ffo re s ta tion

Step 1Step 2


Step 1 Generate carbon sequestration curves

from establishing forests on grazing lands from integration of many data bases


Potential carbon accumulation in conifer and hardwood forests (no harvest)

0

50

100

150

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300

0 20 40 60 80

years since initiation

t C

/ha

redwood

red fir

ponderosa pine

lodgepole pine

pinyon-juniper

0

20

40

60

80

100

120

140

160

180

200

0 20 40 60 80years since initiation

t C

/ha

aspen

m ontane riparian hardwoods

blue oak woodland

valley foothill riparian

Select species for afforestation based on incidence of existing forests with same suitability score/bioregion


Net carbon accumulation applied to potential woody-species distributions over three time periods


Step 2 Economic analyses


Cost of carbon sequestration Opportunity costs:

• Using the same biophysical factors, a multivariate model was used to extrapolate STATSGO forage productivity data samples to a state-wide coverage.Product = map forage production

• Economic analysis of forage value derived from national databases and field interviews

• Mean annual profit/cow ($68/cow)• Number of cows supported based strongly on forage

production (1 animal unit month for CA = 791 lbs)• Net present value analysis of total costs using 4%

discount rateProduct = map total cost


Estimated forage productivity across rangeland classes

This map used to estimate number of cows per acre based on AUM and opportunity cost based on profitability per cow

lbs per acre per year

Combine quantities of carbon accumulation with

cost data to generate C supply in $/t C


Cost of carbon sequestration through afforestation of California rangelands


Carbon supply curves for afforestation activities for 20, 40 and 80 years

94 million tC 823 million tC 1,501 million tC

0

10

20

30

40

50

60

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80

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0 200 400 600 800 1,000 1,200 1,400 1,600 1,800

Millionscumulative tC available

Un

it c

arb

on

co

st (

$ /

tC)

20 years

40 years

80 years


Take home messages

Depending on the price, afforestation of grazing lands can provide substantial quantity of carbon offsets in the US• Little to no new technology needed, can be adopted

quickly, and provide other environmental benefits Protocols and registries for implementing

carbon sequestration activities in advanced state (e.g. CCAR) and markets developing

Incentive for adoption likely to be driven by states rather than feds

estimating the potential carbon supply from changes in land use: afforestation of grazing lands in...

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