TERMITE TOWERS
The termite is the acknowledged master architect of the
creature world. No other insect or animal approaches the termite in the size and
solidity of its building structure. The world's tallest non-human structures are
built by Australian or African termites. If a human being were the size of an
average termite, the relative size of a single termite nest is the equivalent of
a 180 story building--almost 2000 feet high. It would easily be the tallest
building in the world. How is it possible that this tiny creature has the
engineering know-how to erect an edifice of this magnitude? Obviously this
knowledge is innate to the termite. The process of construction, the materials
and correct combination of materials to yield an elegant, structurally efficient
and durable structure is simply awe-inspiring.
The building material is usually local soil mixed with
saliva. Sometimes dung is mixed in. It becomes so hard and impervious that the
native people of the area use it for building their mud and stick shelters. The
termite mound, or termitary, consists of hard, thick walls that seal in moisture
and keep heat out. The Australian and African variety of termite towers are
designed for cooling. A system of channels and ducts circulates air through the
mound. These passageways run through areas of the mound that have walls that are
porous or have tiny ventilation holes. The pores act as fresh air ventilation
and stale air exhaust. This supply and return system performs solely on heat and
gravity with no moving parts. Can our tall building work with such efficient
simplicity?
At the lower core of the termitary are the living and
working quarters. This area is the coolest and most insulated zone of the nest.
The royal chamber, which is the largest chamber in the nest, houses the queen
and king. Below the royal chambers are where the workers store food and care for
the young termites, called nymphs. In some colonies the workers tend gardens
where tiny mushrooms and varieties of fungus are grown. The termites grow this
fungus inside a comb which is located in several pockets in the central zone of
the inner nest. The comb, made of termite droppings, provides nourishment for
the growing fungus and the termites feed on both the fungus and the comb.
Termites live on cellulose, the substance which makes the framework of
vegetation, and fungi. Ingress and egress from a termite tower is provided by a
series of underground tunnels. The tunnels lead outward and branch into a
network of passage that open to the outside. The insects make their trips to the
outside at night, when it is cooler, and collect twigs, leaves, seeds and other
food. In very hot, dry climates some species in the desert dig straight down
exceeding 125 feet(38m) to connect with underground water. Underground wells
supply the termitary with water and a source for cooling the interior. The peaks
and towers of the termite's nest act as lungs that expel rising hot air, which
is generated by the breaking down of the fecal comb by the fungus. The air then
rises via a large central air duct, and moves up through the long porous
chimneys.The carbon dioxide in the air then diffuses to the outside, while
oxygen diffuses into the chimneys. The oxygenated air eventually loses its heat
to the cooler outside air and cools sinking down into the cellar.[4] Such an
ingenious HVAC system is necessary for the survival of some three million
termites to a single colony.
The exterior form of the termite nest depends upon the climate. For instance some termite nests have adapted to their rainy surroundings by creating umbrella-like roof structures that direct water from heavy rains away from the nest. Compass termites appear like giant wedges with the broad side facing due east and west. This solar orientation serves to keep the high, intense sun from hitting any appreciable portion of the mounds surface and allows the weaker morning and setting sun to warm the greater surface area of the structure; thus, the structure attempts to create an even heating situation whereby the mound does not overheat.
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