To transport the cotton produced on 
the fertile southern plantations, 
steamboats plied the Mississippi. 
Plantations not situated directly 
along the waterway delivered their 
cotton to the river by railroad. 
Lithograph by Currier and Ives of William Walker's 1883 Cotton Plantation. The Histone New Orleans Collection 
On average, between 1750 and 1950 
the southeastern United States re- 
leased 0.13 petagrams (1 petagram 
= 1 0 15 grams) of carbon each year. Dur- 
ing this period, the area lost a total 
of 28.2 petagrams of carbon from the 
oxidation of vegetation and soil carbon. 
Replenishment of carbon reserves 
did not begin until the mid-1900s, 
when conservation and forest-manage- 
ment practices started to take effect. 
The U.S. Forest Service, created in 
1928, conducts intensive inventory 
and management of remaining forest 
resources. Virgin forests currently oc- 
cupy less than one percent of their 
former area in the Southeast, persist- 
ing only in small, isolated stands. Up- 
land old-field succession and inten- 
sively managed, commercial forest 
holdings, however, have continued to 
add to the amount of biomass in the 
vegetation. In the Piedmont area, 
where the boll weevil epidemic of the 
1920s led to the abandonment of much 
farmland, regeneration of the pine for- 
ests has been particularly extensive. 
Today, about 95 percent of all forest 
tracts in the Southeast are categorized 
as commercial forest and are under 
direct Forest Service supervision. For- 
est Service practices of restocking and 
selected harvesting, which make pos- 
sible the control of species composition 
and stand density, have resulted in 
a net gain in biomass and carbon on 
these lands since the 1950s. Conse- 
quently, as its forests capture carbon 
dioxide and convert it to wood, the 
Southeast today serves as a net sink 
for carbon. This region, representing 
15 percent of the world's temperate 
forest area, illustrates the potential for 
counterbalancing the effects of con- 
tinued deforestation elsewhere. 
Proper forest management, with an 
eye to approaching the upper limits 
of forest growth and hence maximum 
carbon gain, also necessitates vigilance 
against disease. For example, when 
the American chestnut ( Castanea 
dentata), a dominant canopy species 
in the southern Appalachians at the 
turn of the century, succumbed to 
blight in the 1920s, the result was 
a major change in forest composition 
and biomass. Originally distributed 
along the Appalachian mountain chain 
from Massachusetts to northern Geor- 
gia, chestnut trees once attained a 
height of up to 1 1 5 feet and a diameter 
at breast height of 8.5 feet. Reaching 
largest size and greatest abundance 
in the mountains of eastern Tennessee 
and western North Carolina, this spe- 
cies once occupied up to 60 percent 
of the forest canopy. Tragically, a fun- 
gal parasite (Endothia parasitica ) ac- 
cidentally introduced from Asia in the 
early 1900s in a shipment of nursery 
stock was responsible for widespread 
die-off of mature chestnut trees. By 
1925, this blight had spread into the 
southern Appalachians, and today, 
only stump sprouts of chestnut persist, 
rarely reaching reproductive maturity. 
The oaks and other hardwoods that 
have replaced chestnut in the Appa- 
lachians are smaller in stature than 
their predecessors. Recovery and re- 
growth of forest stands after major 
alterations, such as logging and blight, 
is a slow process. Decades of protec- 
tion from continued lumbering would 
be required for the regeneration of 
a forest of giant oaks, yellow poplar, 
and other hardwoods comparable in 
biomass to the massive chestnut trees. 
The balance between carbon source 
and carbon sink is clearly sensitive 
to changes in forest composition and 
land use. If the current gains in carbon 
storage in the Southeast are to be 
sustained, the area of managed, com- 
mercial forests and their high produc- 
tivity must be stabilized or even in- 
creased. An economic policy that 
maintained greater net growth than 
harvest would further enhance the ca- 
pability of southeastern forests to gain 
carbon. 
This capability is currently threat- 
ened, however, by active deforestation 
of the southern bottomland forests. 
The Mississippi Valley, once densely 
forested with tupelo gum ( Nyssa 
aquatica) and bald cypress ( Taxo - 
dium distichum), is one of the largest 
regions in the Southeast with great 
potential for accumulating biomass 
and carbon through forest regenera- 
tion. The fertile bottomlands along the 
Mississippi and other river systems in 
the Southeast, however, are now being 
rapidly converted to crop production, 
particularly of soybeans. The Forest 
Service estimates that at current rates 
of conversion, most of the remaining 
