Chapter 9: Other Land

CHAPTER 9

OTHER LAND

2006 IPCC Guidelines for National Greenhouse Gas Inventories

9.1

Volume 4: Agriculture, Forestry and Other Land Use

Authors
Jennifer C. Jenkins (USA), Hector D. Ginzo (Argentina), and Stephen Ogle (USA)9.2

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 9: Other Land

Contents
9

Other Land
9.1

Introduction ...........................................................................................................................................9.4

9.2

Other Land Remaining Other Land.......................................................................................................9.4

9.3

Land Converted to Other Land..............................................................................................................9.4

9.3.1

Biomass .........................................................................................................................................9.4

9.3.1.1

Choice of method.....................................................................................................................9.4

9.3.1.2

Choice of emission/removal factors.........................................................................................9.5

9.3.1.3

Choice of activity data .............................................................................................................9.5

9.3.1.4

Uncertainty assessment............................................................................................................9.6

9.3.2

Dead organic matter ......................................................................................................................9.6

9.3.3

Soil carbon.....................................................................................................................................9.7

9.4

9.3.3.1

Choice of method.....................................................................................................................9.7

9.3.3.2

Choice of stock change and emission factors ..........................................................................9.7

9.3.3.3

Choice of activity data .............................................................................................................9.8

9.3.3.4

Uncertainty assessment............................................................................................................9.8

Completeness, Time series, QA/QC, and Reporting .............................................................................9.9

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Volume 4: Agriculture, Forestry and Other Land Use

9 OTHER LAND
9.1

INTRODUCTION

Chapter 3 of this Volume defines Other Land to include bare soil, rock, ice, and all land areas that do not fall into
any of the other five land-use categories treated in Chapters 4 to 8. Other Land is often unmanaged, and in thatcase changes in carbon stocks and non-CO2 emissions and removals are not estimated. Guidance is provided forthe case of Land Converted to Other Land. This is because the conversion is associated with changes in carbon
stocks or non-CO2 emissions, most importantly those associated with conversions from Forest Land. Emissions
and removals from this land should continue to be estimated following the conversion, as described below.
Inclusion also enables checking the overall consistency of land area and tracking conversions to and from Other
Land.

9.2

OTHER LAND REMAINING OTHER LAND

Emissions and removals on Land Converted to Other Land class are estimated using the methods described
below, which also cover land remaining Other Land after conversion. All areas of Other Land Remaining Other
Land should be included in the land-use change matrix as described in Chapter 3 as a check on the overall area.
Emissions from land converted to bare soil as a result of development of settlements should of course be
included in the Settlements land-use category (See Chapter 8, Settlements).

9.3

LAND CONVERTED TO OTHER LANDThis section provides guidance on methods for estimating carbon stock changes for Land Converted to Other
Land. In general this is unlikely to be a key category, if it takes place at all, but land can be converted to Other
Land, e.g., as a result of deforestation with subsequent severe degradation, release of carbon stocks andassociated emissions. Figure 1.3 in Chapter 1 provides the decision tree which can be used to identify theappropriate tier-level for Land Converted to Other Land.
The fundamental equation for estimating change in carbon stocks associated with land-use conversions wasintroduced in Section 2.3.1.2 in Chapter 2. This basic method can be applied to estimate change in carbon stocks
in Forest Land, Cropland, Grassland, Wetlands, and Settlements converted to Other Land. Extensions to themethod are provided for the subsequent treatment of these land areas following the transition period to the Other
Land category.

9.3.1

Biomass

The method requires estimates of carbon in biomass stocks prior to conversion, based on estimates of the areasof land converted during the period between land-use surveys. As a result of conversion to Other Land, it isassumed that the dominant vegetation is removed entirely, resulting in no carbon remaining in biomass afterconversion. The difference between initial and final biomass carbon pools is used to calculate change in carbon
stocks due to land-use conversion. In subsequent years, accumulations and losses in living biomass in Other
Land is considered to be zero. Figure 2.2 provides the decision tree for identification of appropriate tier toestimate changes in carbon stocks in biomass.

9.3.1.1

C HOICE OF METHOD

The basic method (Equation 2.16 in Chapter 2) summarises how to estimate the change in carbon stocks inbiomass on Land Converted to Other Land. Average change in carbon stocks on a per area basis are estimated tobe equal to the change in carbon stocks due to the removal of living biomass from the initial land uses.
Tier 1
A Tier 1 method follows the approach in Equation 2.16 in Chapter 2 where the amount of above-ground biomass
that is removed is estimated by multiplying the area (e.g., forest area) converted annually to Other Land by theaverage carbon content of biomass in the land prior to conversion (BBEFORE). In this case, BAFTER in Equation

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2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 9: Other Land2.16 is set to zero by default. The default assumption for the Tier 1 calculation is that all carbon in biomass (lessharvested wood products removed from the area) is released to the atmosphere immediately (i.e., in the first year
after conversion) through decay processes either on- or off-site.
Tier 2
A Tier 2 method can be developed and used if country-specific data on carbon stocks before conversion to Other
Land (i.e., BBEFORE in Equation 2.16) are obtainable. BAFTER remains at zero. In addition, under Tier 2, carbon
losses can be apportioned to specific conversion processes, such as burning or harvesting. This allows for moreaccurate estimation of non-CO2 greenhouse gas emissions. A portion of biomass removed is sometimes used aswood products or as fuel wood. Chapter 2, Section 2.4 provides the basic method for estimating non-CO2
greenhouse gas emissions from biomass burning. Chapter 12 provides guidance for estimation techniques forcarbon stored in harvested wood products.
Tier 3
A Tier 3 method requires more detailed data/information than the Tier 2 approach, e.g.,:•

Geo-referenced disaggregated areas converted annually are used for each land use converted to Other Land;•

Carbon densities are based on locally specific information and; and•Biomass stock values are based on inventories and/or the model estimations.

•

Where data are available, Tier 3 methods may be used to track the dynamic behaviour of carbon stocks andgreenhouse gas emissions following conversion. Where the land remains in a vegetation-free state (due tosevere degradation), there will generally be a continuing decline in carbon stocks. If this is not the case,countries should consider whether the land should be classified under another land use, as indicated in
Chapter 3.

9.3.1.2

C HOICE OF EMISSION / REMOVAL FACTORS

Tier 1
Default parameters are provided for biomass stocks before conversion to enable countries with limited data
resources to estimate emissions and removals from this source. The method requires the estimation of carbon
stocks before conversion for the initial land use (BBEFORE) and assumes that the carbon stock after conversion(BAFTER) is zero. Tables provided in Chapters 4, 5, 6, 7 and 8 of this report, for average above-ground biomass
volume and below-ground to above-ground biomass ratio in different land uses, can be used to estimate carbon
stocks before conversion.
Tier 2The Tier 2 method requires country-specific information, which may be obtained, for example, throughsystematic studies of biomass carbon stocks in the various land-use categories. The default carbon stock values
mentioned above can be applied to some parameters in a Tier 2 approach. Default parameters for emissions frombiomass burning are provided in Chapter 2 Section 2.4. However, inventory compilers are encouraged to develop
country-specific coefficients to improve the accuracy of estimates. BAFTER is set to zero.
Tier 3
Under Tier 3, all model parameters should be country-specific and at a disaggregated level, and/or biomass
stocks derived from periodic inventories should be used.

9.3.1.3

C HOICE OF ACTIVITY DATA

All tiers require estimate of the area of land converted to Other Land over a time period that is consistent withland-use surveys and the period used for conversions in the land-use change matrix. Chapter 3 provides
guidance on the use of different types of data representing land so that they are applied as appropriately andconsistently as possible in inventory calculations. The same aggregate area estimates should be used for bothbiomass and soil in the calculations of change in carbon stocks on land converted to Other Land. As described
below, higher tiers require greater specificity of areas.
Tier 1
For a Tier 1 approach, activity data on areas of different land-use categories converted to Other Land are needed.
If countries do not have these data, partial samples may be extrapolated to the entire land base, or historic

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Volume 4: Agriculture, Forestry and Other Land Use

estimates of conversions may be extrapolated over time based on expert judgment. Forest areas converted to
Other Land are particularly important.
Tier 2
Under Tier 2, inventory compilers should use actual area estimates for transitions from various land-use
categories to Other Land. Full coverage of land areas can be accomplished either through analysis of periodic
remotely sensed images of land-use and land cover patterns, through periodic ground-based sampling of land-use
patterns, or hybrid inventory systems (Chapter 3, Annex 3A.3 provides guidance on sampling).
Tier 3
The activity data used should allow full accounting of all land-use category transitions to Other Land and should
be disaggregated to account for different conditions within a country. Disaggregation can occur along politicalboundaries (county, province, etc.), biome, climate, or on a combination of these parameters. In many cases,
information on multi-year trends in land conversion may be available (from periodic sample-based or remotelysensed inventories of land use and land cover).

9.3.1.4

U NCERTAINTY ASSESSMENT

Tier 1
Under Tier 1, the sources of uncertainty are the use of global or national averages for biomass carbon stocks in
Forest Land or Other Land uses before conversion, and coarse estimates of areas converted to Other Land. Areas
should be estimated using the methods outlined in Chapter 3. Carbon stocks will have the uncertainties
associated with their estimation in the relevant section of the Guidelines. In the absence of other estimates, adefault uncertainty level of +75% of the estimated mean CO2 emission may be assumed.
Tier 2
Actual area estimates for Land Converted to Other Land will enable more transparent accounting and allow
experts to identify gaps and double counting of land areas. The Tier 2 method uses at least some country-specificvalues, which will improve the accuracy of estimates, provided they better represent conditions relevant to thecountry. When country-specific values are developed, inventory compilers should use sufficient sample sizes andtechniques to minimize standard errors. Probability density functions (i.e., providing mean and varianceestimates) can be derived for all country-parameters. Such data can be used in more advanced uncertainty
analyses such as Monte Carlo simulations. Volume 1, Chapter 3 of this report can be referred for guidance on
developing such analyses. At a minimum, Tier 2 approaches should provide error ranges for each countryspecific parameter.
Tier 3
Activity data should provide a basis to assign estimates of uncertainty to areas associated with land conversion.
Combining emission/removal factors and activity data and their associated uncertainties can be done using
Monte Carlo procedures to estimate means and confidence intervals for the overall inventory.

9.3.2

Dead organic matter

Tiers 1 and 2
For Tiers 1 and 2, it is assumed that no carbon remains in biomass or dead organic matter after conversion to
Other Land. All biomass carbon stocks are assumed to be emitted in the year of conversion, thus there is no
accumulation of DOM stocks. Under Tier 1, DOM in the various land-use categories are not estimated and thus
there are no emissions or removals by sinks related to DOM to be estimated with conversions to Other Land.
Under Tier 2, if countries estimate DOM stocks for land-use categories that are subject to conversion to Other
Land, then (as for biomass) all DOM is assumed to be emitted in the year of conversion to Other Land.
Tier 3
At Tier 3, estimates should incorporate country-specific data on DOM.

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2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 9: Other Land

9.3.3

Soil carbon

For Land Converted to Other Land, inventory compilers should estimate the change in carbon stocks in mineralsoils under the initial land use relative to Other Land. Conversion of land to Other Land will result in a release oforganic carbon previously held in soil if the conversion is to impervious surfaces such as bare rock.
General information and guidance on estimating changes in soil C stocks are provided in Chapter 2, Section
2.3.3 (including equations), and needs to be reviewed before proceeding with a consideration of specificguidelines below. The total change in soil C stocks for land converted to Grassland is estimated using Equation
2.24 for the change in soil organic C stocks for mineral soils and organic soils; and stock changes associatedwith soil inorganic C pools (Tier 3 only). This section provides specific guidance for estimating mineral soilorganic C stock changes. It is assumed that the stock changes in organic soils are minimal because drainage isunlikely in “Other Lands” However, methods are provided in Section 2.3.3 (Chapter 2) to estimate stockchanges for organic soils in addition to soil inorganic C.

9.3.3.1

C HOICE OF METHOD

Inventories can be developed using a Tier 1, 2 or 3 approach, with each successive tier requiring more detail andresources than the previous one. Decision trees are provided for mineral soils (Figure 2.4, in Chapter 2) to assist
inventory compilers with selection of the appropriate tier. The approach at Tier 1 is that soil carbon stocks will
decline to zero after conversion. If this is not the case, then the land should probably be classified under one of
the Other Land uses. For Tier 2, country-specific estimates for C stocks on land that has been converted to Other
Land should be used or the dynamics of carbon stocks in soils can be tracked at Tier 3 using country-specific
data.

Mineral soils
Tier 1
Using Equation 2.25 in Chapter 2, the change in soil organic C stocks are estimated for mineral soils accounting
for the impact of land-use conversion to Other Land. Annual rates of emissions (source) or removals (sink) are
estimated based on the difference in stocks (over time) for the initial and last year divided by the timedependence of the stock change factors (D, default is 20 years).
Tier 2The Tier 2 method for mineral soils also uses Equation 2.25, but involves country- or region-specific reference C
stocks and/or stock change factors and more disaggregated land-use activity and environmental data.
Tier 3Tier 3 methods will involve more detailed and country-specific models and/or measurement-based approaches
along with highly disaggregated land-use and management data. It is good practice that Tier 3 approaches
estimating soil C change from land-use conversions to Other Land, employ models, data sets and/or monitoring
networks that are capable of representing transitions over time from other land uses, including Forest Land,
Grassland, Cropland, and possibly Settlements. Tier 3 methods should, where possible, be integrated withestimates of biomass removal and the post-clearance treatment of plant residues (including woody debris andlitter), as variation in the removal and treatment of residues (e.g., burning, site preparation) will affect C inputs tosoil organic matter formation and C losses through decomposition and combustion.

9.3.3.2

C HOICE OF STOCK CHANGE AND EMISSION FACTORS

Mineral soils
Tier 1
The initial (pre-conversion) soil organic C stock (SOC(0-T)) is computed from the default reference soil organic C
stock (SOCREF) and stock change factor for land-use systems (FLU). The reference C stock at the end of the 20
year default transition period is assumed to be zero. See the appropriate section for specific information
regarding the derivation of pre-conversion stock change factors for other land-use sectors (Forest Land in
Section 4.2.3.2, Cropland in 5.2.3.2, Grassland in 6.2.3.2, and Settlements in 8.2.3.2).

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Tier 2
A Tier 2 approach can be implemented in which country-specific data are used to derive reference C stock andstock change factors (SOC(0-T), FLU, FMG, FI) that better represent conditions in different types of Other Land.
Country-specific reference stocks at the end of the 20 year period can also be applied. Subsequently, emissions
and removals are set to zero. See the appropriate section for specific information regarding the derivation of preconversion stock change factors for other land-use sectors (Forest Land in Section 4.2.3.2, Cropland in 5.2.3.2,
Grassland in 6.2.3.2, and Settlements in 8.2.3.2).
Reference values should be consistent across land-use sectors (i.e., Forest Land, Cropland, Grassland,
Settlements, and Other Land), which requires coordination among the various teams conducting soil C
inventories for AFOLU.
Tier 3Model parameters will be determined using country-specific data or soil stocks measures; using soil inventories
with representative sampling as set out in Chapter 3.

9.3.3.3

C HOICE OF ACTIVITY DATA

Mineral soils
Tiers 1 and 2
For purposes of estimating soil carbon stock change, area estimates of land-use conversions to Other Landshould be stratified according to major climate regions and soil types. If such information has not already been
compiled, an initial approach would be to overlay available land cover/land-use maps (of national origin or fromglobal datasets such as IGBP_DIS) with soil and climate maps of national origin or global sources, such as the
FAO Soils Map of the World and climate data from the United Nations Environmental Program. Detailed
descriptions of the default climate and soil classification schemes are provided in Chapter 3. Soil types areclassified based on taxonomic description and textural data, and climate regions are based on mean annual
temperatures and precipitation, elevation and potential evapotranspiration. See corresponding sections dealing
with each land-use category for sector-specific information on activity data (Forest Land in Section 4.2.3.3,
Cropland in 5.2.3.3, Grassland in 6.2.3.3, and Settlements in 8.2.3.3).
Activity data gathered using Approach 2 or 3 (see Chapter 3) provide the underlying basis for determining theprevious land use for Land Converted to Other Land, but in its basic form at least, aggregate data (Approach 1)
do not reveal specific transitions. In this case, conversions to Other Land will be reported with the Other Land
Remaining Other Land and in effect transitions become step changes across the landscape. This makes it
particularly important to achieve coordination among categories of land use to ensure consistency over time.
Tier 3For application of dynamic models and/or a direct measurement-based inventory in Tier 3, similar or moredetailed data on the combinations of climate, soil, topographic and management data are needed, relative to Tier
1 or 2 methods, but the exact requirements will be dependent on the model or measurement design.

9.3.3.4

U NCERTAINTY ASSESSMENT

Uncertainties in estimating soil C stock changes in Land Converted to Other Land are due to: (i) uncertainties inland-use and management activity prior to conversion; (ii) uncertainties in reference soil C stocks if using a Tier
1 or 2 approach for mineral soils only; and (iii) uncertainties in the stock change/emission factors for Tier 1 or 2
approaches (or equivalently for Tier 3, uncertainties due to model structure or parameter values, or inmeasurements with sample-based inventories). Uncertainties may be large at Tier 1 where global or nationally
aggregated statistics on land conversion are used, and because of reliance on default reference carbon stocks.
Table 3.7 in Chapter 3 provides default uncertainties ranges associated with the different approaches to area
estimation, and the uncertainty in carbon stock estimation could exceed +50% at Tier 1.

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Chapter 9: Other Land

9.4

COMPLETENESS, TIME SERIES, QA/QC, AND
REPORTINGCOMPLETENESS
The total area of Other Land covered by the inventory methodology is the sum of Other Land Remaining Other
Land and Land Converted to Other Land during the time period. Inventory compilers are encouraged to track
through time the total area of land classified as Other Land within country boundaries, keeping transparent
records on which portions are used to estimate change in carbon stocks. All land area in a country should be
included in the reporting even if an inventory of emissions and removals has not been compiled for a portion of
the land base, such as Other Land.

DEVELOPING A CONSISTENT TIME SERIESTo maintain a consistent time series, it is good practice for countries to apply the same inventory methods overthe entire reporting time period, including definitions for land uses, area included in a C inventory, andcalculation method. It is good practice to keep transparent records of any changes, and then re-calculate the C
stock changes over the entire inventory time period. Guidance on re-calculation under these circumstances isgiven in Volume 1, Chapter 5. Consistent estimation and reporting of “Other Lands” also requires common
definitions of climate and soil types across the entire time series for the period of the inventory.

INVENTORY QUALITY ASSURANCE/QUALITY CONTROL (QA/QC)
It is good practice to implement quality control checks and external expert review of inventory estimates anddata. Specific attention should be paid to country-specific estimates of stock change factors and emission factors
to ensure that they are based on high quality data and verifiable expert opinion.

REPORTING AND DOCUMENTATION
It is good practice to maintain and archive all information used to produce national inventory estimates.
Metadata and data sources for information used to estimate country-specific parameters should be documented,
and both mean and variance estimates provided. Actual databases and procedures used to process the data (e.g.,
statistical programs) to estimate country-specific factors should be archived. Activity data and definitions used tocategorise or aggregate the activity data should be documented and archived.

REPORTING TABLES AND WORKSHEETS
The categories described in this section can be reported using the reporting tables in Volume1, Chapter 8. The
estimates for carbon dioxide emissions and removals from soils resulting from Land Converted to Other Landare reported in IPCC Reporting Category 5D, changes in soil carbon. Worksheets are provided in Annex 1 forcalculating emissions and removals of CO2 from Land Converted to Other Land.

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