Stratigraphic data on gross peat components, plant macrofossils, polle
n, ash after ignition, and radiocarbon ages are used to reconstruct th
e developmental history of the north unit of Caribou Bog in central Ma
ine, which presently consists of a sparsely wooded, ombrotrophic (rais
ed), center surrounded by extensive wooded fen. A lake existed from 12
500 to 8500 BP, when terrestrialization led to peatland initiation th
roughout the basin within similar to 500 years. Near the center of the
present peatland, limnic sedge fen developed to sedge fen at 8000 BP,
and to Larix laricina wooded fen at 7000 BP. At 5500 BP the wooded fe
n became Sphagnum dominated and sparsely wooded, a condition that has
persisted at the peatland center. Only two early transitions are clear
ly related to climate forcing. An abrupt shift from silt-clay to organ
ic lake sediment similar to 10 400 BP is typical of basins throughout
the region. This shift correlates with rapid changes in local and regi
onal vegetation, and likely reflects increased biological productivity
caused by a rapid warming of climate. Peatland initiation 8500-8000 B
P coincides with a drop of water level, probably associated with a rap
id shift to drier climate. We estimate that the water level around the
peatland was at least 0.4 m above the present level at and before 850
0 BP, dropped at least 1.7 m (min. 1.4 m with correction for peat comp
action) in the next 500 years, and rose to the present level around 70
00 BP or later. Major hydroseral changes after 8000 BP are asynchronou
s at several coring sites and are not consistently correlated with reg
ional paleoclimatic events. These changes were probably induced by aut
ogenic hydrological processes associated with peat accumulation.