Settlements

3.6

SETTLEMENTS

This land-use category is described in Chapter 2 as including all developed land, including transportation
infrastructure and human settlements of any size, unless they are already included under other land-use
categories. In this chapter, the focus of settlements is on the terrestrial components of developed land that aremanaged and may influence CO2 fluxes between the atmosphere and terrestrial carbon pools. In this context, theland-use category “Settlements” includes all classes of urban tree formations, namely: trees grown along streets,in public and private gardens, and in different kinds of parks, provided such trees are functionally or
administratively associated to cities, villages, etc. While dead organic matter and soil carbon pools may also be
sources or sinks of CO2 in settlements and CH4 and N2O emissions may result from urban land management
practices, little is known about the role and magnitude of these pools in overall greenhouse gas fluxes. Therefore,
the focus of the methodological discussions is on the subcategory of change in carbon stocks in living biomass,
where some research has been conducted (Nowak 1996, 2002).
Change in carbon stocks in living biomass in “Settlements” can be estimated in two parts: “Settlements
Remaining Settlements (SS)” and “Land Converted to Settlements (LS)”. The latter part may be an importantcomponent of national estimates of deforestation (or other nationally important land-use conversions). Therefore,
brief guidance is provided below on estimating change in carbon stocks due to conversion of forest land tosettlements. Only living biomass is addressed in this section.

3.6.1

Settlements Remaining Settlements

A basic method for estimating CO2 emissions and removals in settlements remaining settlements is provided inAppendix 3a.4 because the methods and available default data for this land-use conversion are preliminary.
Countries with data on dead wood, soil carbon, and non-CO2 gases in settlements are encouraged to report thisinformation as well.

3.6.2

Land Converted to Settlements

The fundamental equation for estimating change in carbon stocks associated with land-use conversions has been
explained in other sections of this chapter, namely Sections 3.2.2, 3.3.2 and 3.4.2 with regard to land converted
to forest land, cropland and grassland, respectively. The same decision tree (see Figure 3.1.2) and the same basic
method can be applied to estimate change in carbon stocks in forest land converted to settlements, following
Equation 3.6.1.
EQUATION 3.6.1
ANNUAL CHANGE IN CARBON STOCKS IN LIVING BIOMASSIN FOREST LAND CONVERTED TO SETTLEMENTS (FS)∆CFSLB = A ● (CAfter – CBefore)
Where:∆CFSLB = annual change in carbon stocks in living biomass due to conversion of forest land to settlements,
tonnes C yr-1A = area of land converted annually from forest land to settlements, ha yr-1
CAfter = carbon stocks in living biomass immediately following conversion to settlements, tonnes C ha-1
CBefore = carbon stocks in living biomass in forest land immediately before conversion to settlements,tonnes C ha-1
This method follows the approach in the IPCC Guidelines (Section 5.2.3, Forest and Grassland Conversion) where
the amount of living aboveground biomass that is cleared for expanding settlements is estimated by multiplying theforest area converted annually to settlements by the difference in carbon stocks between biomass in the forest prior
to conversion (CBefore) and that in the settlements after conversion (CAfter). The tiered approaches for estimatingchange in carbon stocks in living biomass outlined in Sections 3.2.2, 3.3.2 and 3.4.2 apply here as well. A Tier 1
estimate is developed using default assumptions and default values for carbon stocks. At Tier 2, country-specific

IPCC Good Practice Guidance for LULUCF

3.143

Chapter 3: LUCF Sector Good Practice Guidancecarbon stocks are applied to activity data disaggregated to appropriate scales. At Tier 3, countries use advanced
estimation methods that may involve complex models and highly disaggregated activity data.
The default assumptions for a Tier 1 estimate of change in carbon stocks in living biomass in land converted tosettlements are that all living biomass present before conversion to settlements will be lost in the same year as
the conversion takes place, and that carbon stocks in living biomass following conversion (CAfter) are equal tozero. Countries should estimate the area of forest land converted to settlements, by major forest types, and use
default carbon stock values in Tables 3A.1.2 and 3A.1.3 to develop estimates of carbon stocks in living biomass
before conversion (CBefore) for each initial forest type.
In cases where fires are used to clear vegetation, emissions of non-CO2 gases, i.e. CH4 and N2O, will also occur.
Countries may choose to estimate non-CO2 emissions from burning when fires are used to clear vegetation fordevelopment of settlements. The basic method for estimating non-CO2 emissions from fires can be found inSection 3.2.1.4.

3.144

IPCC Good Practice Guidance for LULUCF