By Fred Jacobsen
500 years ago when Spanish explorer Hernando de
Soto moved up through west central Florida his chroniclers described
passing various landmarks, including mountains. This seems very odd to
us today as there are no mountains there. This has also puzzled
historians trying to rediscover and document the de Soto trail.
The Spanish word for mountain can also refer to
any forested rise. The most likely explanation for the sighting of
mountains was ancient cypress domes.
These occur in regions of depression within the
marsh which results in a longer hydroperiod than surrounding marsh
areas. The principle constituent of these are Cypress trees, of which
two species can be found here, the bald cypress and the pond cypress.
These cypress may have been 600 years old at the time and as much as 200
feet tall in the center..The term, “cypress dome” or cypress head refers
to the phenomenon that the larger cypress grow in the middle of the
dome, and then get progressively smaller as one goes out from the
center. The conditions for growth are much better in the center as
opposed to the edges.
These areas are nearly circular, and often
surrounded by marl prairies or herbaceous marsh community with few
trees. Near the centers of the domes, the soils are usually composed of
a thick layer of organic material, subtended by a sandy mineral layer or
sometimes by fractured limestone. The central parts of cypress domes
often contain standing water year-round. Closer to the edges of the
solution holes, the organic mantle on the soil surfaces is thinner and
more likely to be subtended by sands with some limestone or fragmented
limestone. Hydroperiods in these areas are also long, but they are not
likely to be submerged during the dry season.
In the margins of cypress
domes, the community becomes transitional with the surrounding marl
prairies, so that nutrient-rich organic material is not common in the
soils, and the soils often become desiccated during the dry season.
Limestone usually occurs near the substrate surface, so trees are often
unable to establish root systems beneath this layer of rock. This
substrate is marginal for cypress trees, so that the trees that survive
in this area are usually less robust and attain a smaller stature than
those near the wetter central part of the dome. Also, since the trees in
this marginal area are scattered and do not form a complete canopy,
sufficient sunlight reaches the ground to support a substantial grass
community, similar to that found in the adjacent prairies.
Dry season fires are
common in prairie communities and they are carried into the cypress
ecotone by the grassy ground cover. These fires ordinarily don’t kill
the cypress trees, but can damage them enough to slow their growth.
Thus, a difference in habitat conditions occurs, from a moist,
nutrient-rich substrate with almost no fires near the center of the dome
to a seasonally dry, nutrient-poor substrate with frequent fires at the
periphery. The result is a community that supports tall, vigorous trees
near the center of the dome with progressively shorter, less vigorous
trees toward the margins.
cypress domes would have appeared to these early explorers as small
trees growing up the side of a hill or small mountain.
Extensive logging of
cypress stands during the late 19th and early 20th centuries nearly
wiped cypress domes from the landscape. For those cypress domes that
survived, the oldest standing trees are usually less than 100 years old
and much smaller than historically.
More research needs to be done
to locate the cypress domes that would have marked the de Soto trail.