Environmental Engineering Reference
In-Depth Information
subsequent year. In the absence of weeding and manuring, by the third year,
a site was overwhelmed with indigenous growth and abandoned. Remove
fire completely and at some point the fields will fail.
Such fire practices shaped whole landscapes. Other pyrotechnologies,
however, could chisel features on a more delicate scale. Consider how peo-
ple could cook the boreal forest of northern Europe to feed their general
economy. The range of things heated, steamed, boiled, or roasted is huge. Of
course, there was widespread swidden farming, without which cultivation
was impossible, and broadcast burning for pasturage, essential to livestock and
especially dairy products. Beyond that, however, it was possible to chop up
and cook the remaining forest to human purposes. One could collect and
open-burn the unfarmed woods (aspen was particularly desirable) to get
potash, a valued source of potassium used as fertilizer in farming and in the
manufacture of goods from soap to gunpowder. One could anaerobically
burn hardwoods to get charcoal. One could slow-cook pine to siphon off tar,
pitch, turpentine, and other fugitive distillates that made up the “naval stores”
industry (so called because the products were vital to wooden ships). Scor-
ing patches of pines—a kind of raw orchard—assured a good supply of pitch
as the trees poured forth sap, which then hardened, to cover the injuries.
Through such means people could colonize an otherwise uninhabitable
forest, one often sited on morainic soil resistant to the plow and in a cli-
mate hostile to winter grazing. What foods people could not cultivate
locally, they could trade for.That traffic, of course, relied on wooden ships,
which got their masts from the Scots pines that sprouted in dense throngs
in the aftermath of fires, their caulking from the tars and pitch distilled from
lesser pines, and their ropes from the hemp that flourished on burned plots.
Little of the landscape escaped: its human residents bent such places to their
will with a kind of second-order firestick farming, sometimes on the scale
of individual trees slashed for pitch or tapped for resin, often of swidden-
sized patches cultivating charcoal or potash. Without fire to rework the
woods, however, their labor meant nothing. Without their fires they were
little better off than moose or voles.
COOKING STONES
The firing of rock is perhaps more spectacular because it has no obvious
natural origins, save perhaps volcanoes. (The Roman philosopher Lucretius
thought that a forest fire had led to the discovery of metallurgy by melting
