Standing out conspicuously on the glades landscape are tall, domelike
tree islands of baldcypress. Unlike hammocks, which occupy elevations,
cypress heads, or domes, occupy depressions in the limestone
bedrock—areas that remain as ponds or wet places during seasons when the
glades dry up. Water-loving cypresses need only a thin accumulation of
peat and soil to begin their growth in these depressions or in smaller
solution holes in the limestone.
[Illustration: Cypress head]
BALDCYPRESS
ALLIGATOR HOLE (often in middle of cypress head)
SAWGRASS
[Illustration: TURKEY VULTURE]
Though most conifers retain their needles all year, baldcypresses shed
their foliage in winter. The fallen needles decay, forming acids that
dissolve the limestone further; thus these trees tend to enlarge their
own ponds. Since the pond is deeper in the middle, and the accumulation
of peat is greater there, the taller trees grow in the center of the
head, with the smaller ones toward the edge. Hence the characteristic
dome-shaped profile.
Usually when fire sweeps the glades, the baldcypresses, occupying low,
wet spots, are not injured. But with extended drought, the water
disappears and the peat may burn for months, killing all the
baldcypresses.
The cypress heads sometimes serve as alligator holes, where the big
reptiles and other aquatic animals are able to survive dry periods. As
you drive along the park road, stop and examine these tree islands
through your binoculars; they are favored haunts of many of the park’s
larger wading birds. Look for herons, egrets, wood storks, and white
ibis, which visit these swampy habitats to feed on the abundant aquatic
life.
Bald eagles find the tops of the tallest cypresses advantageous perches
from which to scan the marsh. And at night certain of the cypress heads
are “buzzard roosts”—resting areas for gatherings of hundreds of turkey
vultures.