Land Use, Land-Use Change and Forestry

Other reports in this collection Options for Reducing Discrepancies between Actual and Reported Carbon Stock Changes

Additional rules could be used to avert some of the type I and type II discrepancies described in Section, where actual and reported stock changes do not match. Two possible ways of doing this are as follows:

  • By limiting "reforestation lands" that fall under Article 3.3 through the use of additional time rules. For example, reforestation could exclude establishment of tree cover on land that was non-forest for less than a specified period of time (e.g., 10 years) after deforestation or land that was forest at a specific point in time (e.g., 1990). If a densely stocked forest with 200 t C ha-1 is deforested in 1991, for example, and reforested 5 years later, no carbon credits could be claimed in the commitment period. One problem, however, is shown by the following example: Assume deforestation of a stand with little carbon (e.g., 20 t C ha-1 in 1991) and reforestation 5 years later with vigorously growing trees, with stocks increasing to 50 t C ha-1 in 2012. Even though this activity reduces atmospheric CO2, it would be excluded by the use of a time rule. This approach addresses only the type I discrepancy.
  • By not limiting "reforestation lands" but limiting the amount of credits and debits for these lands. There are at least two ways to do this:
    • Credit for reforestation in areas deforested after 1990 or 1997, for example, could be excluded. With a stand of 200 t C ha-1 deforested after 1997, no credits would be possible for subsequent reforestation. In the foregoing example of an initial stand at 20 t C and the carbon stocks at 50 t C in the commitment period, no credits would be possible. This approach addresses only the type I discrepancy.
    • Credits for reforestation in areas deforested after 1990 could be limited; debits for afforestation and reforestation lands could be limited. This approach addresses both type I and type II discrepancies.
      • Avoiding the type I discrepancy. For land deforested between 1990 and 2007, carbon credits for reforestation could be awarded only for increased carbon stocks above the level of carbon stocks present on the land prior to deforestation (or in 1990) (D-R Rule). This approach would eliminate an incentive to deforest land then reforest it to claim carbon credits during the commitment period, thereby avoiding that type I discrepancy in b2 on the facing page (note that ARD land is assumed to be able to switch from the "deforestation" to the "reforestation" category). This approach entails a moderate increase in data requirements because information about the carbon stock prior to deforestation or in 1990 is needed. The first sentence of Article 3.4 asks for data on carbon stocks in 1990, but it is not clear whether these data have to be geo-referenced; thus, it is not clear whether such data are of use here.
      • Avoiding the type II discrepancy. Carbon debits in afforestation and reforestation could be limited to the amount of net credits (i.e., credits minus debits) received for carbon accumulating on the same land (A/R Debit Rule). This approach would avoid the type II discrepancy in b3 on the facing page, and it does not create additional data needs. The purpose is to cap debits for reforestation activities (that sequestered carbon between 1990 and 2008) followed by harvesting in the first few commitment periods. It ensures that activities that increase carbon stocks in the long term are not counted as debits under Article 3.3. Particularly in the first few commitment periods, there are carbon stocks on afforestation/reforestation lands that would not be credited because they accrue before 2008. Any harvest loss in a commitment period, however, would count to the extent that carbon is lost (see Section In the first commitment period, the A/R Debit Rule would disallow debits because no credits have been assigned previously and because the stocks are most likely higher than they were before the initiation of the afforestation/ reforestation activity. As subsequent commitment periods occur, an increasingly greater share of carbon sequestering on afforestation/ reforestation lands will have been credited, so the allowable debit for harvest also increases. In any event, the net credit (credit minus debit) over time for a unit of land would not be negative.
      • The FAO scenario with land-based approach I (stock changes over the full commitment period are accounted). With a harvest in 2009 and replanting in 2010, carbon losses from the harvest would be accounted through the 2008-2012 stock change. If the A/R Debit Rule were applied, however, there would be no debit in the first commitment period, even though stocks have decreased. In the FAO scenario with the land-based approach, the debits would be set to zero.

      The amount of land included in the "reforestation" category would not be affected by these two rules. Their main effect is on carbon stock changes, not all of which would necessarily count even if an area is "reforested since 1990."

The carbon discrepancies in items a1 and c1 could be avoided through the use of the Degradation/Aggradation definitional scenario or possibly the Biome scenario. The discrepancy in item a2 could be minimized through contiguous commitment periods. The problem outlined in b4 could be avoided by defining "reforestation" to include planting or regrowth of individual trees in an existing stand. Issue d1 could be addressed through the way a forest is defined.

Other reports in this collection

IPCC Homepage