assumptions used
The linkage between AR and the reporting based on land-use (sub-) categories for the Convention is as follows: • 5.A.2.1 Cropland converted to forest land – Forests
according to the Kyoto definition;
• 5.A.2.2 Grassland converted to forest land – Forests according to the Kyoto definition;
• 5.A.2.3 Wetland converted to forest land – Forests according to the Kyoto definition;
• 5.A.2.4 Settlement converted to forest land – Forests according to the Kyoto definition;
• 5.A.2.5 Other Land converted to forest land – Forests according to the Kyoto definition as well as the conversion from 5.1.1. (Trees outside forests) to Forests according to the Kyoto definition, included in 5.1.1. • The methodologies used to calculate carbon stock
changes in biomass due to AR activities are in accordance with those under the Convention as presented in sections 7.2 and 7.5. The carbon stock changes due to changes in biomass were attributed to above-ground or below-ground biomass using one average R value derived from the plots 0–20 years old (Arets et al., 2013). Carbon stock change due to changes in above-ground and below-ground biomass in land use conversions from Cropland and Grassland were calculated on the basis of Tier 1 default carbon stocks. Carbon stock changes in dead wood and litter are not reported (see section 11.3.1.2). Methods for carbon stock changes in mineral and organic soils are presented below. Results for carbon stock changes for all pools are given for the full-time series from 1990 on in Table 11.3. The linkage between D and the reporting based on
land-use (sub-)categories for the Convention is as follows: • 5.B.2.1 Forest Land – Forests according to the Kyoto
definition converted to Cropland;
• 5.C.2.1 Forest Land – Forests according to the Kyoto definition converted to Grassland;
• 5.D.2.1 Forest Land – Forests according to the Kyoto definition converted to Wetland;
• 5.E.2.1 Forest Land – Forests according to the Kyoto definition converted to Settlements;
• 5.F.2.1 Forest Land – Forests according to the Kyoto definition converted to ‘Other Land’ as well as the conversion from Forests according to the Kyoto definition to Trees outside forests, included in 5.1.1. The methodologies used to calculate carbon stock changes in biomass due to D activities are generally in accordance with those under the Convention as presented in section 7.5. The carbon stock changes due to changes in biomass were differentiated in above-ground or below-ground biomass using data available from the simple bookkeeping model used (Arets et al., 2014). Data from the newly available 6th Dutch Forest Inventory 2012-2013 in combination with the data from the previous National Forest Inventory (MFV) in 2000, allowed the calculation of actual carbon stock changes between in 2000 and 2012. Therefore emission factors involving living tree biomass were recalculated. As a consequence, emissions from Deforestation and from wildfires in forests needed to be recalculated for 2008-2011.
In the Netherlands, the definition of forest that was chosen for the Kyoto Protocol (Forest According the Kyoto Definition, FAD) does not include all land with woody cover. Wooded areas that comply with the FAD definition, except for their surface area (=< 0.5 ha or less than 30 m width), are included in a forest land category ‘Trees outside Forests’ (TOF). In terms of biomass and carbon stocks, these areas are similar to the forests that meet the Kyoto definition.
For both AR and D, therefore, a distinction is made between land-use conversions that imply a discontinuity in woody cover (i.e. conversions to cropland, grassland, wetland, settlement and other land uses, see above) and conversions that imply a discontinuity in land use but not in land cover (conversion to and from trees outside forest). FAD land may be converted to TOF if, for instance, part of a larger FAD area is converted to other non-woody land- uses. After such conversions, small units of lands with their original woody cover intact may remain separated from the larger area. If these areas don’t meet the area requirements for FAD any longer, then they are converted to TOF. Similarly, the previously larger FAD area may stop meeting the area requirements for FAD. It is part of its area and is converted to non-woody land uses.
This does not involve a discontinuity in land cover (i.e. living biomass) over time for the units of land with woody cover, though the loss of connection to a larger unit does involve a change in land use from Kyoto forests to Trees outside forest, which is reported under deforestation. Since the trees on these units of land still grow, this is reported as a carbon stock increase in biomass. Carbon stock losses on the units of land of the originally larger FAD area that were converted to non-woody land uses are reported under Deforestation of FAD to those land-use categories.
Carbon stock change due to changes in above-ground and below-ground biomass in land-use conversions to Cropland and Grassland were calculated on the basis of Tier 1 default carbon stocks. All biomass emissions were attributed to the year of deforestation and no biomass emissions were reported for any other years. Carbon stock changes in mineral soils are reported using a 20-year transition period, while carbon stock changes in organic soils are reported for all organic soils under Article 3.3 activities. The methods are presented below.
Deforestation of reforested/afforested land involved an emission of all carbon stocks that had been calculated to have accumulated following the methodologies for reforestation/afforestation.
Method of estimating carbon stock change in ARD land in mineral soils
Carbon stock changes in mineral and organic soils are reported for all soils changing land use under Article 3.3. The carbon stock change in mineral soils was calculated from base data taken from the LSK survey (de Groot et al., 2005; Lesschen et al., 2012). The LSK database contains quantified soil properties, including soil organic matter, for approximately 1,400 locations at five depths. The soil types for each of the sample points were reclassified to 11 main soil types, which represent the main variation in carbon stocks within the Netherlands. Combined with the land use at the time of sampling, this led to a new soil/land use-based classification of all points.
The LSK dataset contains only data on soil carbon stocks for the land uses Grassland, Cropland and Forest. For the remaining land-use categories, separate estimates were made. For Settlements (about 25% of deforested land becomes settlements), the estimates make use of information in the IPCC 2006 guidelines. An average soil carbon stock under settlements that is 0.9 times the carbon stock of the previous land use is calculated on the basis of the following assumptions:
(i) 50% of the area classified as Settlements is paved and has a soil carbon stock of 0.8 times the corresponding carbon stock of the previous land use. Considering the high resolution of the land-use change maps in the Netherlands (25 m x 25 m grid cells), it can be assumed Table 11.3 Emissions (in Gg C) of re/afforestation activities during the commitment period.
Year CSC in AG biomass CSC in BG biomass CSC in litter CSC in DW CSC in mineral soil CSC in organic soil 2008 89.84 33.83 NE NE 11.18 -21.45 2009 95.65 34.24 NE NE 11.05 -21.87 2010 164.00 20.96 NE NE 10.32 -22.30 2011 167.60 21.72 NE NE 9.61 -22.72 2012 171.04 22.53 NE NE 8.90 -23.10
Table 11.4 Emissions (in Gg C) of deforestation activities during the commitment period.
Year CSC in AG biomass CSC in BG biomass CSC in litter CSC in DW CSC in mineral soil CSC in organic soil 2008 -117.32 -20.19 -52.72 -2.40 -0.31 -14.05 2009 -143.63 -23.12 -81.57 -3.84 -0.26 -15.27 2010 -147.00 -24.54 -81.57 -3.97 -0.23 -16.49 2011 -152.97 -25.37 -81.57 -4.10 -0.22 -17.71 2012 -158.96 -33.28 -81.57 -4.23 -0.23 -18.93
CSC : carbon stock change AR : afforestation and reforestation AG : above ground
D : deforestation BG : below ground
that, in reality, a large portion of that grid cell is indeed paved.
(ii) The remaining 50% consists mainly of Grassland and wooded land, for which the reference soil carbon stock from the previous land use, i.e. Forest, is assumed. For the land-use categories Wetland and Trees outside forests (TOF), no change in carbon stocks in mineral soils is assumed upon conversion to or from Forest. For the category ‘Other land’, a carbon stock of zero is assumed. This is a conservative estimate, yet in many cases very realistic (‘Other land’ in the Netherlands comprises sandy beaches and inland (drifting) sandy areas).
The estimated annual C flux associated with reforestation/ afforestation or deforestation is then estimated from the difference between land-use classes divided by 20 years (IPCC default):
E
min_ xy=
C
yiTC
xiA
min_ xyi 1i
E
min_ xy annual emission for land converted fromland-use x to land-use y on soil-type i (Gg C yr-1)
A
min_ xy area of land converted from land-use x toland-use y on soil-type i in years more recent than the length of the transition period (= less than 20 years ago) (ha)
C
yi,C
xi carbon stocks of land-use x or y on soil-type i (Gg C.ha-1)T
length of transition period (= 20 years)For units of land subject to land-use change during the transition period (e.g. changing from Forest to Grassland and then to Cropland), the estimated carbon stock at time of land-use change was calculated thus:
C
yit=C
xi+t C
yi