AR: 7 25 44

-72^j
-65 -47 -28

n/a = Area of regeneration after harvest not available. In addition, regeneration after selective cutting, as is often used in tropics, is difficult to capture with the FAO Definitional Scenario.

^a Literature sources do not allow estimation of uncertainty levels of carbon stocks prior to deforestation or of areas deforested.
^b The values under the three accounting approaches of the FAO Definitional Scenario and in the IPCC Definitional Scenario were calculated with a spreadsheet that includes all relevant cohorts of the landscape subject to ARD activities, based on the following assumptions. (1) Trees grow according to a sigmoidal growth curve with a maximum mean annual increment at the time of harvest ("Average Uptake Rate" in the table). (2) The biomass stock (aboveground and below-ground biomass, but not soil carbon) just before harvest is twice the "D Average Stock" in boreal and temperate regions and 1.33 times in the tropical regions. This, in combination with the growth rates in the table, results in rotation cycles of 175, 88, and 58 years for the boreal region; 80, 40, and 27 years for the temperate region; and 40, 27, and 20 for the tropical region. (3) One-third of the biomass stock at harvest is assumed to be left on the site as slash, litter, and dead roots. This material is assumed to decay at a constant rate in 15 years (boreal), 10 years (temperate), and 5 years (tropical).
The IPCC Definitional Scenario includes transitions between forest and non-forest land uses under Article 3.3. The FAO Definitional Scenario includes the harvest/regeneration cycle, because regeneration is defined as reforestation. Within the FAO Definitional Scenario we distinguish three accounting approaches. Land-based I approach always accounts for stock changes over the full commitment period. Land-based II approach starts the accounting in 2008 or with the activity, whichever is later. Stock changes that do not result from reforestation (e.g., decay of post-harvest slash) are counted. The activity-based approach is the same as land-based II except that stock changes in decaying slash from a preceding harvest are excluded.
The results for R in FAO land-based I approach are negative because the stock changes due to harvest dominate the carbon balance. The stock-change values under FAO land-based II approach are negative in boreal Annex I Parties and range from negative to positive numbers for temperate Annex I Parties depending on how quickly stand growth increases after harvest to offset the loss of carbon from decaying materials. The large positive values shown for FAO activity-based accounting arise because none of the carbon-stock losses are accounted whereas the carbon gains from biomass growth are. In the IPCC Definitional Scenario no initial harvest occurs and therefore there is no difference between the accounting approaches-only one set of numbers is shown. Sigmoidal growth curves as used in the calculations provide lower uptake in the early and late stand development compared to linear growth curves, but higher uptake in between.
Stock changes from deforestation are calculated as the average stock multiplied by the recent annual rate of deforestation. For example, annual deforestation of 1.2 Mha in temperate region (with 60 t C ha^-1) results in annual emissions of 72 Mt C yr^-1.
^c FAO (1996) and Brown et al. (1996) estimate deforestation in developing countries between 1980 and 1990 at 16.3 Mha yr^-1 (15.4 Mha yr^-1 in the tropics). A critique of the methods and database sources with which these estimates were derived can be found at <http://www.fao.org/forestry/for/fra/FO124E/GEP15>. A more recent number for deforestation between 1990 and 1995 is lower at 13.7 Mha yr^-1 (FAO, 1999) and has been used here. The older number from FRA 1990 (FAO, 1996) is not comparable with this new number from FAO (1999) because: (i) The two data sets are completely different; (ii) the FRA data sets are updated for new data becoming available after an assessment; and (iii) the data set for the period 1990-1995 (FAO, 1999) still has some gaps (FAO, 2000). It is recommended that definitive conclusions be drawn based on the forthcoming new statistics from the Forest Resource Assessment 2000, which should become available during the year 2000 (FAO, 2000).
^d Uptake rates are intended to span the range within which the average value for each region is expected to be. These numbers were derived from the sources below, some of which (e.g., Nilsson and Schopfhauser, 1995) give country- or region-specific data, thus allowing to calculate a weighted mean. Uptake rates and carbon stocks given include aboveground and below-ground biomass, but not soil carbon or dead organic matter (DOC). "D Average Stock" is an average over the landscape, assuming that D will equally impact all age classes of the forest estate. All these values include total biomass but exclude carbon in wood products, DOC, and soil carbon (except FAO land-based II approach which factors in post-harvest slash). Average rate of uptake are from Dixon et al. (1994), Nabuurs and Mohren (1995), Nilsson and Schopfhauser (1995), Brown et al. (1996), and Yamagata and Alexandro (1999); average stock for boreal and temperate regions are from TBFRA 2000 (UN, 1999), for tropics from Dixon et al. (1994), supported by Table 1 in the SPM. The number for the tropics may be regarded to be a high estimate, but was used here in absence of additional literature sources.
^e Areas as given in Table 3-14. Extension of forest is used to approximate the area of afforestation and reforestation under the IPCC Definitional Scenario and the area of afforestation under the FAO Definitional Scenario. Regeneration is used to approximate the area of reforestation under the FAO Definitional Scenario. Loss to other uses is used to approximate the area of deforestation.
Recent AR area estimates for Annex I Parties are data from the TBFRA 2000 (UN, 1999), and D area estimates from FRA 1990 (UN-ECE/FAO, 1992). D for Russian Federation is from A. Shvidenko (pers. comm.). D for Canada is from Robinson et al. (1999). Data for Australia are based on NGGI (1999).
^f FAO (1995). This estimate should be regarded as an upper limit, because some countries may have reported plantations for 1990 but not for 1980, and because some of the plantations may not qualify as resulting from AR activities under the IPCC Definitional Scenario.
^g Boreal Annex I countries included: Canada, Finland, Iceland, Norway, Russian Federation, and Sweden. Temperate Annex I countries included: Australia, Austria, Belarus, Belgium, Bulgaria, Croatia, Czech Republic, Denmark, Estonia, France, Germany, Hungary, Ireland, Italy, Japan, Latvia, Liechtenstein, Lithuania, The Netherlands, New Zealand, Poland, Portugal, Slovakia, Slovenia, Switzerland, Turkey, Ukraine, United Kingdom, and United States of America. Data for Greece, Luxemburg, and Spain were not available.
^h Because of the average uptake rates and carbon stocks at harvest that were used in this table, stands planted or regenerated since 1990 are not harvested before the end of the commitment period in the calculations. However, there may be AR forests with a very short rotation that are harvested in the first commitment period. The accounting for such stands may require a deduction of the harvested stock from the reported stock change. See Section 3.3.2.2, item b3.
ⁱ The regeneration area for the United States of America in UN (1999) is 1.8 Mha yr^-1. However, this number is incorrect and has been replaced with a corrected number of 0.2 Mha yr^-1 (US Forest Service, 2000).
^j These results do not take into account the effect of the second sentence of Article 3.7 of the Kyoto Protocol.