surrounding them. Only those activities carried out by people through technology
are paid for with money; but energy flow drives both the human-technological
system and the park system, Energy is consumed by both and are necessary
components to the whole system.

 This holistic perception is shown diagrammatically in Figure 1 for the
Capitol complex. As Figure 1 indicates, the sun provides the energy dirve to
Capitol Park and fossil fuels (as embodied in goods and services) provide the
energy drive to the Capitol structures. Certain functions from the park (e.g.,
climate buffering) are shown as additional inputs to the Capitol structures
and certain wastes from the structures (e.g., heat) are shown being recycled
to the park for processing. The conceptual framework is one of an interaction
between the structures and the park. This theoretical framework suggests that
a city's energy budget is the sum of the fuels used by its technologies plus
the sun's used by its ecosystems. It suggests that both the technologies and
the ecosystems contribute to the productivity of the city.

 A city's economic producticity is usually taken to be the dollar value of
the goods and services produced there for final demand, its contribution to the
nation's Gross National Product. This energy based theory suggests, however,
that urban economic productivity is supported by and dependent on natural
environmental work as well as technological work. That is, it is dependent
on solar energy as well as on fuels. Such a dependency on two-primary energy
sources suggests opportunities to substitute solar energy for fuels (trees
for technology) and consequent opportunities to reduce costs. But the history
of city development is one of reverse substitutions (technology for trees)
with exponentially rising costs. For example, trees are removed to provide
space for subdivisions where air conditioners are invoked to control climate.
The air conditooners reject waste heat to the environment which in turn causes
everyone's air conditioner to run longer and produce more waste and so on in
an exponential fashion. Retaining the trees in the subdivision, while not
eliminating the need for air conditioners, greatly mitigates the exponential
increase in their use. The price of electricity at the level of entire cities
provides another example. The average cost of electric power to a consumer in
the U.S. was $.024 per kw/hr in 1975. In the same year in New Yoek City,
electricity was $.068 per kw/hr. The cost of power in New York City may be
high because no ecosystems are available to provide any services which might
otherwise subsidize the utliity. All environmental controls are carried out
with technology at an added economic cost. The effect becomes exponential again
as, for example, taxes increase to pay for city services and the cost of heating
and cooling buildings increases. At the extreme, products manufactured in cities
where few services are provided by ecosystems can no longer compete with
the same products manufactured in other cities which use the environment at
no cost.

 In summary, this energy based theory suggests that technology and humans
in cities depend on natural ecosystems. The natural ecosystems subsidize
the technologies and may even be required for competitive economic production
(Odum, 1975). Capitol Park is an example of such a relationship where the
landscape features offer energy and economic subsidies to the operation of the
state government. The Capitol buildings have the advantage of the noise and
climate control provided by the 35 acres of greenery and of their pollution
absorption and recycling capacity.