Large-scale forest conversion in Brazil, primarily to cattle pasture,
contributes significantly to the global anthropogenic emission of CO2
into the atmosphere. An alternative land-use, namely extractive reserv
es for forest residents, may serve as one means of using Amazonian for
ests sustainably and of maintaining carbon in living matter rather tha
n adding it to that in the atmosphere. In the Seringal (former rubber
estate) Porongaba (6,800 ha) of the Chico Mendes Extractive Reserve, A
cre, Brazil, primary forest still covers more than 90% of the area. To
tal biomass in primary forest is estimated at 426 tons per ha, equival
ent to 213 t C per ha. Rubber tappers effectively maintain about 60,00
0 tons of carbon per household (family unit) in forest biomass and thu
s out of the atmosphere. Deforestation of primary forest was less than
0.6% per yr - much less than rates of natural disturbances for other
neotropical forests. Slash-and-burn agriculture in the Seringal Porong
aba releases carbon at a gross rate of some 200 t C per yr per househo
ld. Net releases are much less, as regrowth forests absorb carbon at r
ates of about 9 t C per ha per yr. The net areal flux of carbon to the
atmosphere from land-use in Seringal is much less than one ton of car
bon per ha per yr, which is equivalent to less than 0.3% per yr of the
carbon stock in forest biomass. If Seringal Porongaba is typical of t
he three million hectares in extractive reserves in Brazilian Amazonia
, then these reserves are calculated to retain 0.6 Gigatons of carbon
in the terrestrial biota. Adverse changes in income patterns for rubbe
r tappers could lead to abandonment of extractive reserves or increase
d deforestation within them. Diversification and improvement of income
from non-timber forest products are needed to maintain rubber tappers
in extractive reserves. Most beneficiaries of carbon storage in these
and other reserves live outside Brazil; devising means of recompensat
ion for these benefits is a challenge for the global society.