Environmental Engineering Reference
In-Depth Information
imported) by afl uent countries are not for human consumption but are feed crops
for animals.
Long-term trends in biomass consumption for fuel and as raw material have
resembled those of food production. Notable improvements in the typical efi cien-
cies of wood and straw combustion (as well as in wood conversion to charcoal) and
better ways of harvesting and using timber came only after millennia of no or very
slow change, but these gains did not lower the overall need for woody biomass or
crop residues. The opposite has been true: the combination of larger post-1850
populations (after 1950 particularly in low-income countries, where many people
had no access to modern fuels) and a much higher per capita consumption of
all raw materials resulted in an unprecedented demand for fuelwood, timber, and
pulpwood.
