Environmental Engineering Reference
In-Depth Information
Traditional cereal cultivars yielded much more straw than do modern varieties (and much
more straw than grain). Joachim Patinir's 1514 Rest on the Flight to Egypt (now hanging in
Madrid's Prado) illustrates that reality: a scene on the far right of the painting shows a peasant
harvesting wheat, with the grain ears well above his head and all but hiding armed men car-
rying halberds.
(the process that culminated in the intricate designs of the early modern era) and
conveyances (wheelbarrows, carriages). Other important uses of phytomass as raw
material include the use of i brous plants (cotton, l ax, hemp, agave) to make cloth
(as well as ropes), as a source of colorants and medicines, and the pulping of woody
biomass to produce paper.
The number of plants ever harvested by humans for food, i ber, medicinal and
ornamental uses, and animal feed runs into the thousands, but only about 50 species
have accounted for the bulk of all harvested phytomass during the millennia of
preindustrial agriculture, and this number was reduced by large-scale intensive
cultivation and modern dietary preferences to fewer than 20 dominant species.
A similar simplii cation has affected wood harvests: large-scale monoculture tree
plantings, begun in the late eighteenth century, and modern afforestation favor
a small number of fast-growing species, now increasingly grown on intensively
managed tree plantations.
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