1.2 Materials and Methods
1.2.1 Spatial Dataset
Annual land cover maps in East Kalimantan from 2000 to 2016 from Landsat satellite images were used to estimate GHG emissions in each land cover map. The detailed data set and methodology used in this paper were explained in Kiswanto et al. 2018. These spatial datasets were used for calculating the total changed areas in each period using the transition matrix (Appendix 1.A) and multiplying with the carbon stock changes in each period.
1.2.2 Carbon Stock in Each Land Cover Class
The emission factor for land cover changes is defined as the stock difference in carbon between two land cover classes (Santosa et al. 2014). The reference for carbon stock estimation for each land cover class was required to calculate carbon stock differences and GHG emissions from the land‐based sector at a specific location. For each land cover class, the reference was generated from research related to above‐ground biomass for specific sites. For forest cover classes, data references were developed from the average of above‐ground biomass in the forest areas (Hairiah et al. 2011). For cropland and agricultural land covered with regular cycles of planting and harvesting, carbon stock references were developed from the time average of above‐ground biomass (Agus et al. 2013a).
The provincial and district are supported to develop the highest carbon stock estimation that accurately illustrated the circumstances. If reference data is available at the province level, the carbon stock in the various districts within the province can be used to represent the emission factor. If it is not available, data can be used from the national level (Santosa et al. 2014). Table 1.1 shows land cover classes and their carbon stocks for estimating GHG emissions that were used for devising the local action plan for REDD+ in East Kalimantan.
Table 1.1 Land cover classes and their carbon stocks for estimating carbon emissions from land‐based sectors.
| Land cover type | Carbon stock (tC ha–1) | Reference; remarks | ||
|---|---|---|---|---|
| Forest | Dryland | Primary | 195 | MoF 2008; Agus et al. 2013b |
| Secondary | 169 | |||
| Mangrove | Primary | 170 | MoF 2008; Agus et al. 2013b; Krisnawati et al. 2014 | |
| Secondary | 120 | |||
| Swamp | Primary | 196 | MoF 2008, Agus et al. 2013a,b | |
| Secondary | 155 | |||
| Artificial/Plantation forest | 64 | Agus et al. 2013b; MoF 2008; Verstegen et al. 2019 | ||
| Non‐forest | Agriculture | Pure dry | 8 | East Kalimantan 2013 |
| Mixed dry | 10 | East Kalimantan 2013 | ||
| Rice field | 5 | Rahayu et al. 2005; East Kalimantan 2013, | ||
| Estate cropland | 63 | Agus et al. 2013b; Verstegen et al. 2019 | ||
| Aquaculture | 0 | Agus et al. 2013b | ||
| Shrubland | Dry | 15 | Prasetyo and Saito 2000; East Kalimantan 2013 | |
| Wet | 15 | Prasetyo and Saito 2000; East Kalimantan 2013 | ||
| Savanna and grasses | 4.5 | Rahayu et al. 2005; Agus et al. 2013b | ||
| Open swamp | 0 | Agus et al. 2013b | ||
| Open water | 0 | East Kalimantan 2013 | ||
| Transmigration areas | 10 | Agus et al. 2013b – assuming 30% of the area was used for agriculture | ||
| Settlement areas | 1 | East Kalimantan 2013 –assuming less vegetation | ||
| Port and harbor | 5 | East Kalimantan 2013 | ||
| Mining areas | 0 | Agus et al. 2013b | ||
| Bare ground | 0 | Prasetyo and Saito 2000; East Kalimantan 2013 | ||
| Cloud | 0 | East Kalimantan 2013 | ||
1.2.3 Change in Carbon Stock and CO2 Emission
Based on the yearly land cover maps in the study area from 2000 to 2016 referred to in Kiswanto et al. 2018, the change in carbon stock for each period was estimated using the IPCC guideline for national GHG inventories (IPCC, 2006) for agriculture, forestry, and other land use (AFOLU) by calculating carbon stock difference before (B) and after (A), multiplying by the total changed area, and divided by interval year periods (Eq. (1.1)):
where:
ΔCBA= annual change in carbon stock from the change in the land cover, tC yr‐1
CB= carbon stock of the land cover class before (B) the change, tC ha‐1
CA= carbon stock of the land cover class after (A) the change, tC ha‐1
ƩA=total