Cecropia peltata L.
CECROPIA, GUARUMO
Abundant evergreen tree (10-15 m) notable for its very large,
deeply lobed leaves, hollow trunk ringed with leaf scars, and
appeal to wildlife. Cecropia is a pioneer species and is thus
one of the first trees to appear in a disturbed habitat, growing
rapidly and providing the ground cover necessary for the survival
of less-hardy plant species.
Description: Cecropia seeds
germinate most readily in soil that is warmed by a sudden influx
of sunlight - perhaps caused by a treefall or some other disturbance
that serves to break the otherwise continuous shade produced by
an intact, primary forest canopy. A sun-loving species, Cecropia
saplings proceed to grow rapidly and in the direction of the strongest
source of light available. Trunks (25 cm) of mature trees
are therefore invariably bending and curved as they wind there
way up through the forest understory. Cylindrical, Cecropia
boles bear many thin, elevated leaf scars that ring the trunk
at more or less evenly spaced intervals. Generously dusted with
dark, point lenticels, the thin bark is otherwise gray or creme
colored.
Usually, the trunk ceases to exist at a point just above the soil
line, where it is transformed into a set of rapidly diverging
roots that penetrate the substrate and provide support for the
tree. Young Cecropia trees grow monopodially until reaching
several meters in height. Even, the weak branches that appear
in adolescent individuals die and rot away as the trees grow taller.
As a consequence, the adult Cecropia shows no branching
along the lower portion of its trunk. The few limbs that do remain
are thin, long and wiry, often growing nearly horizontally and
with leaves clustered around their tips. Cecropia crowns
are thus extremely open, thin, and well lit - ideal for observing
the wildlife that frequents them. Leaves are simple, alternate
and very large - with blades measuring 30 cm or more in diameter
supported by long, 40 cm petioles. Each rounded, disk-shaped blade
possesses nine palmately-arranged primary leaf veins and an equal
number of conspicuous, finger-like lobes. Strongly curled about
the primary veins, these lobes form deep troughs, giving the leaf
a thick, wavy, three dimensional quality that helps to fill the
otherwise Spartan crown. Leaf undersurfaces are markedly whitish
and pale, starkly contrasting with their deep green uppersurfaces.
(When the advance winds of an approaching storm blow, Cecropia
trees seem to communicate an air of urgency as their upturned
leaves signal by flashing their startlingly white or silver sides
- this effect is especially apparent and noticeable when the trees
are viewed from a large distance). New foliage grows aggressively
year round, slowing - but not stopping - only during the dry summer
months. The fresh, expanding leaves of this species are often
a striking red or orange color. Cecropia trees are dioecious:
their flowers are unisexual, and the male and female blossoms
appear on different individuals. Minute and numerous, male flowers
are borne on tassel-like panicles composed of about 10 or 15 thin,
white, stringy strands attached to a stout pedestal. Measuring
10 cm in length, these panicles appear in the axils of new leaves
and from underneath large, waxy, and maroon-colored protective
sheaths. Female flowers are supported by similar panicles containing
fewer (around six), thicker, rod-like strands. Fruits develop
on the old, female inflorescences. The flower strands swell and
thicken until they have become finger-sized or larger. Fleshy
and soft, they are then composed of a fruity mass containing hundreds
of minute (2 mm) brown seeds. Fruits and flowers are visible year
round.
Similar Species: Only other species of Cecropia could be confused with C. peltata, since all members of this genus have similar foliage that is nonetheless unique in the plant kingdom.
Natural History: A pioneer species
of the first order, Cecropia needs abundant sunlight in
which to grow. Reportedly, seeds may remain in the cool, moist
forest soil for many years, lying dormant until some calamity,
natural or otherwise, allows a shaft of sunlight to reach the
forest floor. The warmer temperatures thus generated stimulate
germination and Cecropia seedlings become established in
the light gap well before the seeds of most other species have
even arrived. Through rapid growth, Cecropia trees maintain
their lead over competing vegetation. The hollow bole - constructed
of light, porous wood - reflects this strategy, for it allows
the tree to reach significant heights without making the huge
energy investment necessary to construct a massive and sturdy
trunk. However, it also restricts the amount of weight the tree
can support and ultimately severely limits longevity.
For most of their life span of about 20 years, Cecropia
trees reproduce, scattering seeds - with the aid of dispersers
- throughout the forest. Meanwhile, the shade they create helps
to cool and stabilize the environment near the forest floor, enabling
the seedlings of more sensitive but longer lived species to take
root. Soon, the Cecropia trees die, disappearing from the
scene and relinquishing their hold on the sunlight to the slow
growing, arboreal vegetation beneath them. Meanwhile, dormant
Cecropia seeds lie elsewhere, patiently waiting in the
cool forest soil for the next emergent tree to fall.
Cecropia leaf scars provide an accurate record of every
petiole a particular tree ever bore. By comparing the spacing
between rings, one can get a sense for what growing conditions
were like at different times during the tree's life span. In places
with a marked seasonal difference in the availability of moisture,
trees grow slower during the excessively dry summer months. Such
slowed growth translates into smaller spaces between leaves -
and leaf rings - along the
Cecropia
trunk. As a result, older boles typically show repetitive, ring
spacing patterns. Here, a series of closely spaced scars alternates
with an even more numerous set of rings whose spacing is wide
- corresponding to leaves produced during successive dry and wet
seasons, respectively. Using this information, it is possible
to determine the age of Cecropia trees and even to compare
the severity of different dry seasons.
Cecropia trees are inhabited by a species of Aztec ant.
These insects, finding shelter within the hollow bole of the tree,
pay for their lodging by providing protection from potentially
damaging plant and insect parasites. This type of close interrelationship
between two species, formally known as symbiosis, is further said
to be mutualistic, since both organisms benefit from the association.
Finally, a wide range of animals can be observed foraging within
the cage of spindly branches that make up the Cecropia
crown. Perhaps most famously, two and three-toed sloths feed on
this tree's flowers and fruits, and they are frequently seen among
its branches, either resting and immobile or slowly moving from
limb to limb. It is sometimes thought that sloths prefer Cecropias
to other forest trees, because they are seen in them so often.
However it is likely that these frequent sightings are a reflection
of the relative ease with which sloths can be spotted in the open
Cecropia crown. Sloths in other forest trees, whose thick
crowns obscure visibility, generally go unnoticed. Birds, too,
can be seen on Cecropia branches, looking for fruits and
insects - or just in need of an open perch to peer from. Euphonias,
laughing falcons, and Trogons are some of the species commonly
observed in this way.
As a side note, many experienced hikers have been momentarily
fooled - and even startled - by two pieces of discarded Cecropia
anatomy. First, the dead, curled leaves scattered on the ground
and seen at a glance can resemble coiled snakes. The deadly nature
of certain venomous, Costa Rican species (particularly the Fer
de Lance - Bothrops asper), make this an unpleasant - if momentary
- perception. Second, the core of the hollow Cecropia trunk
is lined by a translucent, plastic-like material that is divided
into hollow cells. When the wood of the tree decays away, these
chambers remain behind - lying on the forest floor and strongly
resembling the vertebral bones of some unfortunate animal.
Uses: The Cecropia is
an ideal species to use in the initial stages of a land reclamation
or reforestation program. Hardy, these trees can grow in poor,
eroded soils while still withstanding the full brunt of the tropical
sun. (In Manuel Antonio National Park, Cecropia trees actively
colonizing a formerly primary forest region after a devastating
storm have been observed to reach 22 cm in diameter and 13 m in
height less than 3.5 years after germination). In time, they will
help to provide the shade and organic material necessary to allow
other, less rugged species to survive. Cecropia trees also
benefit the local ecology, for they perpetually produce flowers
and fruits that are staple foodstuffs to many bird and mammal
species.
The soft, resilient wood of Cecropia roots resists splitting
- and it has been used to make tool handles.
Distribution: Cecropia can be found in any secondary forest, along road and trail sides, and in light gaps inside the primary forest. It ranges from Mexico and the Antilles to Panama and northern South America.