3.1.4 Enhancement of forest carbon stocks (afforestation of land not previously forest, reforestation of land previously converted from forest to another land use)
In addition to enhancement within existing forests, forest carbon stocks can be enhanced by establishing forests on land which was not previously forest, or which had earlier been converted from forest to another land use. Forest establishment on such land will result in carbon accumulation in biomass, though initially the loss of soil carbon due to disturbance of carbon stocks in mineral soils may exceed the biomass accumulation; and if organic soil has been drained, this loss will continue as long as the drainage continues. Accumulation of biomass will follow a sigmoid curve, with rates varying with species, site growing conditions and age. Harvest will interrupt the sigmoid accumulation of biomass (with disturbance emissions) with growth resuming again after replanting. This produces the characteristic saw-tooth curve illustrated in Box 9. Harvesting with replanting is part of a forest management cycle and does not constitute deforestation, because the land use does not change. Neither is it degradation within forest land use if the average carbon stock is maintained in the long term (Section 3.1.2). Planted forests established for environmental values will not necessarily be harvested, and if they are not, the initial sigmoid will proceed to saturation at the carbon carrying capacity of forest on the land concerned, and there will be no saw-tooth pattern. Consistent with the GPG2003 and the 2006GL, emissions and removals on unmanaged(1) land are not included in GHG inventories so it is assumed that forest expansion on unmanaged land will not count towards this activity. Consistent with the agreed safeguards(2), REDD+ actions should not be used for conversion of natural forest.
Since this entails a conversion of another land use to forest it corresponds directly to section 3.2.2 of GPG2003 , Land Converted to Forest Land, corresponding to volume 4, section 4.3 of 2006GL . In applying the IPCC methodology countries should:
- Via the NFMS, collect information on forest establishment on lands not previously used as forest, or on lands which were once used as forest but have been converted to another land use. Information may be available from stakeholders, government departments or forestry authorities (all of whom should be represented on the NFMS) on tracking concessions and planting permits. Remote sensing may not always be a useful data source for this step, because forests in the early stage of growth are not easily distinguished by remote sensing. It may be possible to detect signs of preparation and planting work and this can be used as supporting information. The information sought should include type of forest established, planting date, and if possible a management plan.
- As the planted forest grows following establishment, use remotely sensed data to confirm the forest areas and timing of harvest activities and resolve any differences with the information obtained under 1). This will improve the accuracy of results.
- Utilize yield tables or growth curves in the generation of changes in carbon density through time on afforested/reforested lands. In the absence of such annual biomass estimates, averages may be used as an interim measure, however their use can introduce bias especially in early years of forest establishment or where actual growth rates are not representative of the average (i.e. where the percentage survival is known to be low). An assessment of such bias should be conducted and transparently reported. Priority improvements to reduce bias should also be identified.
- In making national estimates, emissions and removals associated with this activity should be included with those from sustainable management of forests, enhancement of forest carbon stocks (within an existing forest), and conservation of forest carbon stocks.
See section 1, GPG2003 for a discussion of forest definitions including managed and unmanaged forest.