Forest Carbon Estimation and management, techniques and tools.pdf

Estimation of Carbon sequestration in Forest.

1. Forest Carbon Estimation
and Management:
Techniques and Tools
Coeli M. Hoover
USDA Forest Service, Northern
Research Station
Pre-Conference Workshop, ACES 2010
Phoenix, AZ, 6 December 2010

2. Introductions
•I am an ecosystem ecologist,
with a background in soils
•Work primarily in the
Northeast US
•Research focused on forest
carbon sequestration
–Effects of forest management
practices
–Work mostly at the scale of
stands and forests
–Have worked on forest carbon
since 1999

3. Your turn…
•Please share your name, where you’re
from, and where you work
•Tell us a bit about what you do
–Any prior experience with forest inventory or
carbon inventory?
•Also, what do you hope to gain
from this class ?
–Are there specific things you
need to learn today ?
–Are you planning a project?

4. Course Objectives
•Understand the main concepts of the
forest carbon cycle and the principles of
forest carbon inventory
•Develop familiarity with methods of
forest carbon accounting as described by
the IPCC Good Practice Guidance
•Learn where to find tools, models, and
resources for forest carbon inventory and
accounting

5. Course Outline
•Basic principles of forest carbon
sequestration
–The forest carbon cycle
–Forest carbon pools
•Estimation approaches
–Effects of spatial scales
–Data requirements
–Walk through of calculations

6. Course Outline, II
•Calculating change through time
–Calculating change through time
–Assessing the C consequences of management
practices
•Tools and resources
–Overview of software tools and models from
various nations
–Where to find tools, databases, and
information
•Q & A, general discussion

7. Pleasestopme if…
You have a question related
to the topic we are
covering. If you have
questions relating to a
project you are planning,
or a specific situation, we
will have time to discuss
those at the end of the
workshop.

8. Basic Principles of Forest Carbon
Sequestration

9. Major Greenhouse Gases
•Carbon Dioxide (CO
2)
–Uptake by vegetation, emission from soils
•Methane (CH
4)
–Uptake by soils
•Nitrous Oxide (N
2O)
–Emission from soils
•Water vapor
–Transpiration
•Carbon monoxide (CO)
•Sulfur hexafluoride (SF
6)

10. Carbon Sequestration
•During photosynthesis, plants use carbon
dioxide (CO
2) from the atmosphere to
make sugars, wood, etc.
–Plant tissues are about 50% carbon (C)
•This carbon is temporarily sequestered –
removed from circulation in the
atmosphere
–This slows the rate of CO
2
accumulation
•Forests can serve as carbon sinks

11. What is a forest?
Note that different nations and entities
define forests in different ways. Here is
a generic international definition:
“Forest is the minimum area of land of [X]
hectares with tree crown cover (or equivalent stocking level) of more than
[X%] with trees with the potential to reach
a minimum height of [X m] at maturity.
Young stands which have yet to reach a
crown density of [X%] or tree height of [X
m] are included under forest, as are areas
normally forming part of the forest area
which are temporarily unstocked as a
result of human intervention such as
harvesting or natural causes but which are
expected to revert to forest.”

12. Forests Play an Important Role in
the Global Carbon Cycle !!

13. Forests and the Carbon Cycle
•Trees take up carbon dioxide and store it
as wood
•Carbon is also stored in the soil
–Decomposing roots
–Decomposing leaves, wood, etc.
•Soils also absorb methane, a gas that traps
more heat than CO
2
•Wood in products is also stored carbon !

14. Forest Emissions
•Forests also release
carbon to the
atmosphere
–Forest respiration
–Microbial respiration
–Decaying dead wood
and debris
•Forests can also emit
N
2O from soils in
some cases

15. The Forest Carbon Equation
•Any given forest can be a
carbon source OR a
carbon sink
•Outcome depends on
many variables:
–Age class distribution
–Forest health/
disturbance history
–Management practices
•Overall, US forests are
acting as a carbon sink

16. The forest carbon cycle
Growth
Removals
Litterfall,
Mortality
Treefall
Harvest
residue
Humification
Decomposition
SOIL
DOWN
DEAD
WOOD
FOREST
FLOOR
ATMOSPHERE
STANDING
DEAD
HARVESTED
CARBON
BIOMASS
Above and Below
Mortality
Decay
Source: L. Heath 2003

17. Forest Carbon Pools

18. Forest Carbon Pools
Down dead
wood
Aboveground biomass = Live
trees + understory
Standing
dead trees
Soil organic
matter (1m)
Litter (Forest floor)
Belowgroundbiomass
Source: J. Smith

19. IPCC Pool Definitions
Living
Biomass
Aboveground
biomass
Belowground
biomass All living biomass above the soil,
including stem, stump, branches,
seeds, foliage
All living biomass of fine roots. Roots
<2mm diameter often excluded
Dead
Organic
Matter
Dead wood
Litter All non-living woody biomass not
contained in litter. May be standing,
lying on surface, or buried in soil.
Usually > or = to 10 cm dbh.
All non-living woody biomass above
the soil, generally <10 cm dbh; may
include live fine roots
Soils
Soil organic
matter Organic C in mineral and organic
soils to a specified depth; live fine
roots may be included
IPCC Good Practice Guidance for LULUCF, Table 3.1.2

20. Definitions may vary!
•The definitions just given are the IPCC
definitions, used for reporting at the
international level
•Definitions used by the US for the 1605b
Voluntary GHG reporting program vary
slightly
•Definitions for other US reporting systems
also may vary
–Usually litter and down dead wood

21. Aboveground Live Biomass
•Data availability
–On a statewide or multi- county level, FIA data
may be used
–For stand-level or project work, data will
generally need to be collected
–Understory data usually scarce
•Data collection
–Standardized methods are available
–Time consuming and can be expensive, but not
technically difficult
•Need to meet targeted error levels; may require
many plots

22. Understory
•Herbaceous layer is
generally a small
component and often
excluded; data generally
scarce
•Shrub layer often omitted,
but may be important in
some systems
•Shrub data generally not
available, but inventory
methods exist; can be
expensive (person-hours)

23. Belowground Biomass
•Live roots are often estimated using
established allometric relationships
•Sometimes estimated as 20% of
aboveground biomass
•Data are generally not available, except
for site-specific studies
•Measured by excavation –time consuming
method, creates extensive disturbance

24. Dead Wood and Litter
•Includes standing dead trees, harvest
debris and stumps
•May be on the soil surface or buried
•Sometimes data are collected during the
forest inventory; harvest debris can be
estimated if data on harvest volumes are
available
•Litter data are not routinely collected,
but may exist from individual research
studies

25. Soil Organic Matter
•Data may be available
from FIA, NRCS
–Ag or forest profile?
•Published research
studies can also provide
data
•May be collected –
standard methods exist,
but data collection is
costly
–High spatial variability

26. The forest carbon cycle
Growth
Removals
Litterfall,
Mortality
Treefall
Harvest
residue
Humification
Decomposition
SOIL
DOWN
DEAD
WOOD
FOREST
FLOOR
ATMOSPHERE
STANDING
DEAD
HARVESTED
CARBONBIOMASS
Above and Below
LANDFILLS
ENERGY
Imports/ Exports
PRODUCTS
Mortality
Recycling
decay
processing
burning
disposal burning
burning
Decay
decay
Source: L. Heath 2003

27. The Role of Wood Products
•Harvested C is turned into
product, but some waste is
landfilledor burned for
energy
•Products go different
places over time –pulp
often to a landfill,
sawtimberinto longer
lived products
•Products play a role in
sequestering carbon

28. Harvests and Wood Products
•Accounting for harvested carbon can be difficult
–Markets change quickly
–Often hard to quantify how much wood goes into each
type of product
–Dealing with imports and exports
•IPCC Good Practice Guidance allows for
reporting of harvested wood pools if it can be
documented that stocks of forest products are
increasing
•We will not consider products today

29. Estimation Approaches

30. C Estimation Techniques
•There are two main approaches to
measuring carbon in forests:
–Stock approach: measuring the amount of C
in different pools at a point in time
–Flux approach: measuring C exchanges
between pools in forests and between the
forest and the atmosphere “as they happen”
•Both methods are used and complement
each other

31. Flux Measurements
•Technically challenging
•Requires specialized equipment and
trained personnel
•Towers are costly to install (~60-80K) ;
terrain requirements limit useable sites
•Good for quantifying short term dynamics
of small homogenous areas. Examples:
AmeriFlux, CarboEurope, AsiaFlux

32. Flux Measurement Towers

33. Stock Measurements
•Technically straightforward
•Most measurements do not require highly
specialized equipment
•Data for some pools may already be
collected
•Less expensive than flux measurement
•Good for longer-term view of changes
•Cannot detect short term changes and
dynamics

34. We will focus on stocks
•Technically easier approach
•Data may be available
•More appropriate for reporting and
estimation purposes
•Flexibility in choosing pools to consider
–Some pools may be considered to remain
relatively constant

35. According to the IPCC
guidelines: “….the flux of CO
2
to or from the atmosphere is
assumed to be equal to changes
in carbon stocks in existing
biomass and soils…..”

36. •Easiest to measure or
estimate
–Data may be available
•Pool where large
changescan happen
fairly quickly
•Pool that can be the
most influenced by
management
Today, we’ll focus on the live
biomass carbon pool…

37. Two major approaches
•Volume based approach
–Uses data on merchantable volumes to
estimate total volume, then convert to C
–Underestimates the amount of carbon in
smaller stems
•Biomass based approach
–Calculate biomass in each stem using
allometric equations, then convert to C
–May be more accurate (especially with
smaller trees), but requires individual tree
measurements

38. Volume based approach
•Requires less data
–Merchantable or total volume in m
3
or ft
3
•Aggregated approach –use when individual
tree data are not available
•Underestimates carbon when there are
many small trees
•Easy to apply to large areas of land

39. Biomass Approach
•Requires diameter measurements for
individual trees
•More accurate for small stems
•Equations generally exist to compute
biomass in roots, leaves, stem, etc.
•Published allometry available for many
species, can also develop equations
•Time consuming for large regions-more
computations than volume method

40. Calculations
•Volume based calculations can sometimes
be done using a calculator
–When doing estimates for many stands or
areas, spreadsheets should be used
•Biomass based computations are best
done using a spreadsheet
•No specialized computer software is
required for either method
•We’ll walk through the calculations for
both approaches

41. General Notes
•Data should be cubic meters or feet of volume
–If data are total volume, no scaling is needed
–If data are merchantable volume, then a
scaling factor is needed to account for small
stems, branches, foliage, etc.
•Data may be either volume over a specified area,
or on a per area basis
–Computations are the same
–Remember to multiply by appropriate area to
get total stocks if using per area data

42. A word about units....
•There are a LOT of units
in use –triple check!
•Traditionally, C is
reported in metric
tons/ha
(may be tonnes or t)
•Tons/ac also used
•AND –metric tons/ac
•CO
2equivalents are also
used (44/12 = 3.67)
Note: mt(or MT) and Mg
are the same!

43. Volume based approach
1.Take value for volume (m3 or ft3)
2.Scale to total volume if necessary
3.Locate specific gravity in IPCC GPG
handbook, Wood Handbook, etc.
4.Multiply total volume (wet weight) by specific gravity to get dry
biomass
5.Multiply by % C to get mass of C
•Note: 50% is commonly used, though the number
can vary somewhat by species

44. Total and Merchantable
Volumes
•In many countries, forest volume statistics
may be reported in volume
•In the US, merchantable volume is most
commonly reported
–Does not include stumps and tops
•Merch to total volume scale factors exist
•Method of Smith et al. 2002
–Forest Volume-to-Biomass Models
–GTR NE-298

45. Smith et al. 2002 Volume to
Biomass Models
•Compiled from FIA data
•Coefficients for aboveground live tree,
total live tree, aboveground standing
dead, and total standing dead trees
–All species, hardwoods, softwoods
–By geographic region and forest type
•
Inputs: Merchvolume in cubic m/ha
•Mg/ha = F * (G + (1-e
(-volume/H)
))
–F, G, and H are coefficients

46. For a stand of Prunus, Acer, and Betula
Starting with 245 m
3
/ha of maple/beech/birch type,
aboveground live biomass is calculated:
1.Mg biomass/ha = F* (G+ (1- e
(-volume/H)
))
2.Mg/ha = 627.6 * (0.0236+ (1- e
(-245/541.8)
))
3.Mg/ha = 627.6 * (0.0236+ (1- 0.636))
4.Mg/ha = 627.6 * (0.0236+ 0.364)
5.Mg/ha = 627.6 * 0.387
6.Mg/ha = 243.1
7.MgC/ha = MtC/ha = (243.1 * 0.5) = 121.6

47. More general notes…
•This is one method; others are available
–Local scaling factors for merchantable to total
volume
•The publication provides many sets of
coefficients
–Forest type, region, hardwood/softwood species,
aboveground, total, and sometimes ownership group
•What about board feet?
–Must convert volumes to cubic meters!

48. Biomass approach
1.Obtain data that provides records of individual
trees and their diameter at breast height
2.Locate appropriate allometric equations for
your species of interest (equations may also be
developed)
3.Apply the equations to each individual stem,
then sum totals. Be sure to calculate DRY
biomass.
4.Multiply by % C to convert from dry biomass to
carbon. Watch the units in the allometric
equation to be sure of your end product
(e. g.
kg, tonnes)
. Be sure to use correct input units!

49. Example of a biomass equation
(Jenkins et al. 2003)
Biomass = e (β
0+ β
1 lndbh)
The appropriate coefficients for use in this equation
are :
β
0= -2.4800 and β
1 = 2.4835
So, for a Prunusstem with a dbh of 20.50 cm , the
calculation looks like this:
Biomass = e (-2.48+ 2.4835* ln20.50)
Biomass = e (-2.48 + (2.4835* 3.02)
Biomass = e (-2.48 + 7.501)
Biomass = e (5.02096)
Biomass = 151.56 kg

50. Notes on biomass equations
•Equations are for individual stems
–Calculate stem by stem, then sum
–May be for aboveground or total biomass
•Equations can take many forms
–Some are simple, some complex
–Some will require height as well as dbh
•Equations are species and often
regionally specific

52. Calculating Changes Through Time

53. How much C is the forest storing?
•Instead of measuring fluxes, we can
measure the carbon in the forest at two
points in time, and then take the
difference of the two (stock change)
•Values can be expressed in absolute terms
or on a per area basis
–Metric tons of C for an entire stand/ forest/
county/etc
–Metric tons of C/ hectare for a specified area

54. And so…
Carbon sequestered =
Amount of carbon at time 2 –Amount of
carbon at time 1
This tells you change over that period of
time. How can you compare different stands,
forests, or provinces if the amount of carbon
in them is very different at Time 1? And
what about comparing stands of different
ages?

55. Average Annual Change
•This is a quantity like a timber yield
•Average annual change =
(tonnes C at Time 2 – tonnes C at Time 1) /
number of years between Time 2 and Time 1
(38.4 tC/ha -19.5 tC/ha) / 32 = 0.59 tC/ha/yr
•Usually expressed on a per area basis:
–tonnes C/hectare/year or tons/ac/yr
•
This provides the rateof change

56. Now we can compare the rate of
change in these stands…

57. Standing Stocks vs. Changes
C Stocks in 2000
0
10
20
30
40
50
60
70
Below Above Control
tons c/ac
Products
Debris
Deadwood
Biomass
•Stocks give a
snapshot in time
–Carbon in the
“bank”
•Can be expressed
per acre or for total
land area
•If areas had
different initial
conditions, this
won’t be reflected

58. Standing Stocks vs. Changes
Avg. Annual Change
1975-2000
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Below Above Control
tons C/ac/yr
•Annual stock changes
show change over
time
–“Interest” earned on
C in the bank
•Useful for comparing
two areas that may
have different
starting points
–Comparing ratesof
change, not total
changes

59. Both quantities are used…
•Stocks and total changes in stocks are
used:
–When you want to know how much carbon is
in a forest
–When you want to know change in the total
amount of carbon stored in the forest
•Average annual change in C is used:
–
To compare the rateof carbon change
between forest types, age classes,
management types, etc.

60. Which pools to include?
Forest
Carbon Sink
Forest Floor
Woody debris
Products
Biomass
Soils

61. It depends on the system and the
activity….
•Living biomass –stems and coarse roots
–Forest understory may be omitted in some cases
•Dead wood/litter –may not change much,
depending on activity
–Varies according to program type
–May be negotiated between buyer and seller
•Harvested C –often omitted

62. More on C pools…
•Soils –mineral and organic soils to a
specified depth, generally 1 meter
–Note: current knowledge holds that when
forested land remains in forest, soil carbon
changes are generally minimal. You may not
need to measure this pool
•Requirements vary by registry and
program type
–May be negotiated between buyer/seller
–Hard to detect/verify change -variability

63. Things to consider when choosing
C pools to include
•Do you want to establish a monitoring
program?
–Consider measuring as many pools as possible
to start, then choosing longer intervals for
slower pools, e. g. soil
•Are you conducting a project?
–Afforestation: consider soils and forest floor
–Harvesting : consider dead wood, products
•
Cost of measurement vs. benefit of data

64. •Decide which pools you want to consider
•Decide the time period of interest
•This is a very important decision! Short term
and long term results can be verydifferent
•Calculate the average annual change for
each treatment or stand
•The treatment with the highest average
annual change sequesters the most carbon
(over that time period)
How do you assess which practice
stores the most C?

65. Tools and Resources

66. IPCC GHG Site
•Source of internationally accepted
guidance on greenhouse gas accounting
and reporting methods for all sectors
•The Good Practice Guidance for Land
Use, Land Use Change, and Forestry is a
primary reference
•Provides a good background in carbon
accounting at large spatial scales

68. Canada
•Canadian Forest Service has the lead for
Canada’s Forest Carbon Monitoring,
Accounting, and Reporting System
•Uses data from Canada’s National Forest
Inventory
•Also uses the CBM-CFS2 model to simulate
and project forest carbon dynamics

70. United States
•US Environmental Protection Agency has
overall responsibility for greenhouse gas
inventory and reporting
•US Forest Service compiles the carbon
inventory for the forest sector
•A variety of estimation tools are available
–May serve as models
–Rely heavily on forest inventory data

71. Tools with consistent output at
various scales
•Forest Stand
•Landscape
•County
•State
•Region or ecoregion
•National
FVS-C
GTR-343
COLE
CCT
FORCARB2
All tools except FVS-C based on FIA data

72. •Phase 2 -forest mensuration
•1 plot per 2,429 ha (6000 ac)
•visit plot every 5 years
•
Phase 3 –forest health
•each 16
th
Phase 2 plot
•soils, forest floor, down woody nationally
•1 plot per 38,866 ha (96,000 ac)
•soils sampled every 2
nd
visit
•
Phase 1 –remote sensing
•reduce variance through stratification
FIA Program Overview

73. FIA data and tools at
http://fia.fs.fed.us
•FIDO–graphical interface, the next
generation web tool with maps
•Forest health data–access from “other
data” link on the “data and tools” page
•Evalidator-Produces estimates and their
sampling errors for user designated areas
•Carbon variables are included

74. The Forest Vegetation Simulator
(FVS)
•Stand-level growth and yield model
•Uses standard inventory data
–Not a process model, not spatially explicit
•Simulates nearly any type of management
•22 geographic variants… so far
•Under continuous development
•Widely used by managers

75. Carbon Reports with FVS
•Carbon pools reported:
–Live biomass, above- and-belowground, shrub
and herb
(shrubs and herbs are estimates)
–Standing dead trees
–Down dead wood
–Forest floor
•Also reports carbon in harvested wood
products
•Can be used to assess the C outcomes of
management options

76. Standard Tables (GTR 343)
•Forest carbon and carbon in
harvested wood from tabular
summaries or simple default
calculations
•Intended for low cost or limited
information applications
•Represent regional averages for
common forest types
•Simple and transparent
•Developed to support US 1605b
Voluntary GHG Reporting Program

77. COLE: Carbon OnLine Estimator
•Works with the
FIA database
•Can produce a
variety of maps
and tables
•County, state,
and multi-state
areas
•New-GCOLE

78. Carbon Calculation Tool (CCT)
•Annual carbon pools and change from
1990 to present
•Comes with FIA data for conterminous US
•Can download and use new data
•Produces annualized estimates
•State-level output

79. FORCARB2
•Produces estimates of C stocks and stock
changes at 5 year intervals
•Includes forest products
•Estimates are at the regional level
•Written in FORTRAN
•Used to provide estimates for policy
related needs, including US GHG estimates
•Best for expert users

80. Carbon Estimation Resources
http://nrs.fs.fed.us/carbon/tools
Your one-stop shop on the web for forest
carbon inventory information –links to
tools and publications

82. Your turn....Q & A