Environmental Engineering Reference
In-Depth Information
traditional artisanal furniture-making and modern industrial manufacturing is that
veneers and plywood have largely displaced solid wood. And the advent of modern
papermaking during the latter half of the nineteenth century created another large
market for wood as the source of pulp.
Fuelwood in Traditional Societies
The preindustrial combustion of wood had an undesirable common characteristic:
poor efi ciency in converting the fuel's chemical energy into heat, which led to high
consumption rates even for the simplest heat-demanding tasks. Moving the open
i res indoors did little to improve their efi ciency but did result in chronic exposure
to high levels of indoor air pollution, a problem that has persisted in many of the
world's poorest societies (especially in Africa and Asia) into the twenty-i rst century
(McGranahan and Murray 2003). Typical wood combustion efi ciencies rose a bit
once the richer traditional societies moved their i res into stone or brick i replaces.
Some food (meat on spits, stews in cauldrons) could be cooked a bit less wastefully
than in the open (thanks to the controlled ascent of heat through a l ue and its
reverberation from i replace walls), but i replaces did a poor job heating large rooms:
their radiated heat reached only the immediate vicinity of the hearth, and on cold
days the room's warm air was drawn outside to support combustion; moreover,
combustion was dangerous (i re hazard, CO emissions) and difi cult to regulate.
Some early space-heating arrangements—the Roman
hypocaust,
whose oldest
remains date to the third century BCE (Ginouvès 1962), and the Korean
ondol
led
hot gases through brick or stone l ues under l oors, while the Chinese
kang
was a
heated platform that was also used as a bed at night—were both more efi cient and
more comfortable. Chimneys became common in Europe only during the late
Middle Ages (elsewhere only centuries later), and iron-plate stoves followed only
during the seventeenth century. These stoves raised typical combustion efi ciencies
to at least 15%-20%, compared to less than 5% for open i res as well as most
i replaces. After 1860, household heating and cooking in European cities rapidly
converted to coal or coal gas, but the continent's rural areas and both urban and
rural populations outside Europe continued to rely on wood or, in forest-poor low-
lands, on crop residues.
The third major category of wood and charcoal consumption has been in the
production of goods: in small-scale artisanal manufactures, in brick, pottery, and
china kilns, in forging metals, shoeing horses, and brewing beer. And starting in the
nineteenth century a fourth category could be added, wood combustion to generate
