Wood economy

History of use of wood

The wood economy is historically the starting point of the civilizations worldwide, since eras preceding the Paleolithic and the Neolithic. It necessarily preceded ages of metals by many centuries, as the melting of metals was possible only through the discovery of techniques to light fire (usually obtained by the scraping of two very dry wooden rods) and the building of many simple machines and rudimentary tools, as canes, club handles, bows, arrows, lances. One of the most ancient handmade articles ever found is one smoothed pricked of wood (Clacton Spear) 250,000 years old (third interglacial period), that was buried under sediments in England, at Clacton-on-Sea.

Successive civilizations such as the Egyptians and Sumerians built sophisticated objects of furniture. Many types of furniture in ivory and valuable woods have survived to our time practically intact, because secluded in inviolated secret tombs, they were protected from decay also by the dry environment of desert. Many buildings and parts of these (above all roofs) contained elements in wood (often of oak) forming structural supports and covering; means of transport such as boats, ships; and later (with the invention of the wheel) wagons and carriages, winches, flour mills powered by water, etc.

Dimensions and geography

The main source of the lumber used in the world is forests, which can be classified as virgin, semivirgin and plantations. Much timber is removed for firewood by local populations in many countries, especially in the third world, but this amount can only be estimated, with wide margins of uncertainty.

In 1998, the worldwide production of "roundwood" (officially counted wood not used as firewood), was about 1,500,000,000 cubic metres (2.0×10⁹ cu yd), amounting to around 45% of the wood cultivated in the world. Cut logs and branches destined to become elements for building construction accounted for approximately 55% of the world's industrial wood production. 25% became wood pulp (including wood powder and truccioli) mainly destined for the production of paper and paperboard, and approximately 20% became panels in plywood and valuable wood for furnitures and objects of common use (FAO 1998). The World's largest producer and consumer of officially accounted wood is the United States, although the country that possesses the greatest area of forest is Russia.

In the 1970s, the countries with the largest forest area were: Soviet Union (approximately 8,800,000 km²), Brazil (5,150,000 km²), Canada (4,400,000 km²), United States (3,000,000 km²), Indonesia (1,200,000 km²) and Democratic Republic of Congo (1,000,000 km²). Other countries with important production and consumption of wood usually have a low density of population in relation to their territorial extension, here we can include countries as Argentina, Chile, Finland, Poland, Sweden, Ukraine.

By 2001 the rainforest areas of Brazil were reduced by a fifth (respect of 1970), to around 4,000,000 km²; the ground cleared was mainly destined for cattle pasture—Brazil is the world's largest exporter of beef with almost 200,000,000 head of cattle. The booming Brazilian ethanol economy based upon sugar cane cultivation, is likewise reducing forests area. Canadian forest was reduced by almost 30% to 3,101,340 km² over the same period.

Importance in fighting greenhouse effect

Regarding the problem of climate change, it is known that burning forests increase CO₂ in atmosphere, while intact virgin forest or plantations act as sinks for CO₂, for these reasons wood economy fights greenhouse effect. The amount of CO₂ absorbed depends on the type of trees, lands and the climate of the place where trees naturally grow or are planted. Moreover, by night plants do not photosynthesize, and produce CO₂, eliminated the successive day. Paradoxically in summer oxygen created by photosynthesis in forests near to cities and urban parks, interacts with urban air pollution (from cars, etc.) and is transformed by solar beams in ozone (molecule of three oxygen atoms), that while in high atmosphere constitutes a filter against ultraviolet beams, in the low atmosphere is a pollutant, able to provoke respiratory disturbances.

In a low-carbon economy, forestry operations will be focused on low-impact practices and regrowth. Forest managers will make sure that they do not disturb soil based carbon reserves too much. Specialized tree farms will be the main source of material for many products. Quick maturing tree varieties will be grown on short rotations in order to maximize output.

In Australia

In Brazil

Brazil has a long tradition in the harvesting of several types of trees with specific uses. Since the 1960s, imported species of pine tree and eucalyptus have been grown mostly for the plywood and paper pulp industries. Currently high-level research is being conducted, to apply the enzymes of sugar cane fermentation to cellulose in wood, in order to obtain methanol, but the cost is much higher when compared with ethanol derived from corn costs.

In Canada and the US

There is a close relation in the forestry economy between these countries, they have many tree genus in common, and Canada is the main producer of wood and wooden items destined to the US, the biggest consumer of wood and its byproducts in the world. The water systems of the Great Lakes, Erie Canal, Hudson River and Saint Lawrence Seaway to the east coast and Mississippi to central plains and Louisiana allows transportation of logs at very low costs. In the west coast the basin of the Columbia River has plenty of forests with excellent timber.

Canada

The agency Canada Wood Council calculates that in the year 2005 in Canada, the forest sector employed 930,000 workers (1 job in every 17), making around $108 billion of value in goods and services. For many years products derived from trees in Canadian forests had been the most important export items of the country. In 2011, exports around the world totaled some $64.3 billion – the single largest contributor to Canadian trade balance.

Canada is the world leader in Sustainable forest management practices. Only 120 million ha (28% of Canadian forests) are currently managed for timber production while an estimated 32 million ha are protected from harvesting by the current legislation.

US

In the Caribbean and Central America

Italy

The species that are ideal for the many uses in this type of economy are those employed by arboriculture, that are very well known for their features and the need for certain types of ground and climates.

Portugal

In Scandinavia and Russia

In Sweden, Finland and to an extent Norway, much of the land area is forested, the pulp and paper industry is one of the most significant industrial sectors. Chemical pulping produces an excess of energy, since the organic matter in black liquor, mostly lignin and hemicellulose breakdown products, is burned in the recovery boiler. Thus, these countries have high proportions of renewable energy use (25% in Finland, for instance). Considerable effort is directed towards increasing the value and usage of forest products by companies and by government projects.

Combustion

The burning of wood is currently the largest use of energy derived from a solid fuel biomass. Wood fuel may be available as firewood (e.g. logs, bolts, blocks), charcoal, chips, sheets, pellets and sawdust. Wood fuel can be used for cooking and heating through stoves and fireplaces, and occasionally for fueling steam engines and steam turbines that generate electricity. From many centuries many types of traditional ovens were used in order to benefit from the heat generated by wood combustion. Now, more efficient and clean solutions have been developed: advanced fireplaces (with heat exchangers), wood-fired ovens, wood-burning stoves and pellet stoves, that are able to filter and separate pollutants (centrifuging ashes with rotative filters), thus eliminating many emissions, also allowing to recover a higher quantity of heat that escaped with the chimney fumes.

Mean energy density of Wood, was calculated at around 6–17 Megajoule/Kilogram, depending on species and moisture content.

Combustion of wood is, however, linked to the production of micro-environmental pollutants, as carbon dioxide (CO₂), carbon monoxide (CO) (an invisible gas able to provoke irreversible saturation of blood's hemoglobine), as well as nanoparticles.

In Italy poplar has been proposed as a tree cultivated to be transformed into biofuels, because of the excellent ratio of energy extracted from its wood because of poplar's fast growing and capture of atmospheric carbon dioxide to the small amount of energy needed to cultivate, cut and transport the trees. Populus x canadensis 'I-214', grows so fast that is able to reach 14 inches (36 cm) in diameter and heights of 100 feet (30 m) in ten years.

Charcoal

Charcoal is the dark grey residue consisting of impure carbon obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis, the heating of wood or other substances in the absence of oxygen. Charcoal can then be used as a fuel with a higher combustion temperature.

Wood gasogen

Wood gas generator (gasogen): is a bulky and heavy device (but technically simple) that transforms burning wood in a mix of molecular hydrogen (H₂), carbon monoxide (CO), carbon dioxide (CO₂), molecular nitrogen (N₂) and water vapor (H₂O). This gas mixture, known as "wood gas", "poor gas" or "syngas" is obtained after the combustion of dry wood in a reductive environment (low in oxygen) with a limited amount of atmospheric air, at temperatures of 900° Celsius, and can fuel an internal combustion engine.

In the time between World War I and World War II included, because of the lack of oil, in many countries, like Italy, France, Great Britain and Sweden, several gasoline-powered cars were modified, with the addition of a wood gas generator (a "gasogen"), a device powered by wood, coal, or burnable waste, able to produce (and purify) gas that immediately, in the same vehicle, could power a slightly modified ICE engine of a standard car (low-compression engine). Carburetor had to be changed with an air-gas mixer). There were several setbacks, as the great reduction of maximum speed and the need to drive using low gears and wisely dosing the amount of air. In modern cars, modified with a wood gas generator, gas emissions (CO, CO₂ and NOx) are lower to those of the same vehicle running with gasoline (keeping the same catalytic converter).

Methanol

Methanol (the simplest alcohol) behaves as a liquid at 25 °C, is toxic and corrosive, and in organic chemistry basic books is often called "the spirit of wood", since it can be obtained from wood fermentation. Rarely, when unwise wine-makers mix small chunks of wood and leaves with grapes, methanol can be found as a pollutant of the blend of water, ethanol and other substances derived from grape's fermentation.

The best way to obtain methanol from wood is through syngas (CO, CO₂, H₂) produced by the anhydrous pyrolysis of wood, a method discovered by ancient Egyptians.

Methanol can be used as an oxygen-rich additive for gasoline. However, it is usually much cheaper to produce methanol from methane or from syngas. Methanol is the most important base material for industrial chemistry, where it is often used to make more complex molecules through reactions of halogenation and chemical addition reaction.

Tanks

The American M1 Abrams main battle tank is powered by a gas turbine of 1,500 hp (1,100 kW), that it is able to function also with a mix at 50% of wood powder and biodiesel, diesel fuel or kerosene. Its advantages over turbo-diesel engine, are the small size and light weight, the lack of a radiator (which gives an advantage against the effect of gun and cannon shots and missile strikes suffered in battle). A setback is the high fuel consumption, since the turbine engine has not the ability to work at a low revolutions per minute rate, much lower than ideal, and during the march this engine consumes twice as much fuel as a modern turbo-diesel engine with intercooler and direct injection.

Construction

Wood is relatively light in weight, because its specific weight is less than 500 kg/m³, this is an advantage, when compared against 2,000-2,500 kg/m³ for armed concrete or 7,800 kg/m³ for steel.

Wood is strong, because the efficiency of wood for structural purposes has qualities that are similar to steel.

Bridges, levees, microhydro, piers

Wood is used to build bridges (as the Magere bridge in Amsterdam), as well as water and air mills, and microhydro generators for electricity.

Housing

Hardwood is used as a material in wooden houses, and other structures with a broad range of dimensions. In traditional homes wood is preferred for ceilings, doors, floorings and windows. Wooden frames were traditionally used for home ceilings, but they risk collapse during fires.

The development of energy efficient houses including the "passive house" has revamped the importance of wood in construction, because wood provides acoustic and thermal insulation, with much better results than concrete.

Earthquake resistant buildings

In Japan, ancient buildings, of relatively high elevation, like pagodas, historically had shown to be able to resist earthquakes of high intensity, thanks to the traditional building techniques, employing elastic joints, and to the excellent ability of wooden frames to elastically deform and absorb severe accelerations and compressive shocks.

In 2006, Italian scientists from CNR patented a building system that they called "SOFIE", a seven-storey wooden building, 24 meters high, built by the "Istituto per la valorizzazione del legno e delle specie arboree" (Ivalsa) of San Michele all'Adige. In 2007 it was tested with the hardest Japanese antiseismic test for civil structures: the simulation of Kobe's earthquake (7.2 Richter scale), with the building placed over an enormous oscillating platform belonging to the NIED-Institute, located in Tsukuba science park, near the city of Miki in Japan. This Italian project, employed very thin and flexible panels in glued laminated timber, and according to CNR researchers could brought to the construction of much more safe houses in seismic areas.

Shipbuilding

One of the most enduring materials is the lumber from virginian southern live oak and white oak, specially live oak is 60% stronger than white oak and more resistant to moisture. As an example, the main component in the structure of battle ship USS Constitution, the world's oldest commissioned naval vessel afloat (launched in 1797) is white oak.

Classical Greece

One of the most famous crisis of a wood-based economy is what happened in Classical Greece, where trees began to disappear specially in the areas of Attica, Boeotia and Peloponnesus where indiscriminate cutting of trees for several uses, associated to drought and wildfires led to a severe lack of timber in order to build lances, shields, ships, etc. and to a slow but progressive weakening in military and naval power of the peninsular kingdoms in Greece, that were overwhelmed by Epirus and by the Kingdom of Macedon, much more fertile lands because of their rainy winters. This process arrived to the apex with the conquest of Greece by Phillip II of Macedon.

The secret weapon of the Sarissaphoros soldiers (supported by peltast javelineers), commanded by Philipp II in the Battle of Chaeronea (338 BC) and in those that followed fought by Alexander the Great (which brought to the conquest of Lesser Asia, Babylon, Persia and Egypt), was the sarissa, a type of pike, longer and stronger (5–7 m.) than the other Greek lances, obtained from the heavy and strong cornel wood.

Rapa Nui

Rapa Nui, best known as "Easter Island", is a typical example of malthusianism, specifically how the exponential growth of a populace leads to the end of a renewable resource. At a certain point, the compelling societal need forces exploitation of the resource above and beyond the resource's natural rate of renewal.

It has been calculated that after the year 1000, around 10 million palmtrees were cut in Rapa Nui, resulting in the erosion of the fertile land, and eventually to a desertification around the 15th century. (This deforestation may have also been aggravated and/or caused by a rat infestation). This provoked a population reduction from 15,000 to 2,500 individuals. Without palmtree wood, no boats, or lances could be constructed. Without palm fibers, construction of ropes and fishing nets halted. This led to a decrease in the local fish harvest, which in turn led to a decrease in the quantity of dietary protein available to the island's inhabitants. At the end, the society became an easy prey for hunger and civil war. From 1600 to 1700, the people became superstitious in a fanatical way. In the last moments, there was a disintegration of society and total chaos. The destruction of the traditional symbols followed, leading to the eventual extinction of the Moais civilization and culture, even if there was not any external human enemy.