{{Short description|Wood used for fires}} {{About||the album by Witchcraft|Firewood (album)|the military operation|Operation Firewood}} {{Redirect|Fuel wood|wood as a fuel in general|wood fuel}} thumb|Stack of firewood next to a building [[File:Špalek na štípání.jpg|thumb|Stack of split firewood and a splitting maul, Czech Republic]]
'''Firewood''' is any wooden material that can be used for fuel. The term usually refers to wood fuel that is not industrially processed, such as wood pellets, and instead takes the form of a recognizable log or branch. Firewood can be heat-treated and seasoned (dry) or unseasoned (fresh/wet). Two classes of firewood exist, which are either hardwood or softwood, depending on the species of tree that was cut. thumb|Bucking, splitting, and stacking logs for firewood in Kõrvemaa, Estonia (October 2022)
Firewood is a renewable resource, although demand for this fuel can quickly outpace its ability to regenerate on a local or regional level. Good forestry practices and efficiency advances in devices that burn firewood can improve local wood supplies.
Smoke from burning wood can cause respiratory issues and other diseases.<ref>{{Cite web |date=2022-04-07 |title=Women using firewood face increasing health risks |url=https://www.afro.who.int/countries/nigeria/news/women-using-firewood-face-increasing-health-risks |access-date=2024-01-29 |website=WHO {{!}} Regional Office for Africa |language=en}}</ref><ref name=":1">{{Cite web |last=US EPA |first=OAR |date=2013-05-28 |title=Wood Smoke and Your Health |url=https://www.epa.gov/burnwise/wood-smoke-and-your-health |access-date=2024-01-29 |website=www.epa.gov |language=en}}</ref> Transporting firewood long distances can also spread plant pests, diseases, and invasive species.<ref>{{cite web|url=https://www.dontmovefirewood.org/|title=Protect the Trees You Love From Tree-killing Bugs|access-date=2020-11-18}}</ref>
==History== [[File:A Woman of Ōhara Carrying Firewood, Nagasawa Rosetsu.jpg|thumb|upright|''A Woman of Ōhara Carrying Firewood'' (:ja:大原女, the peddler lady of Kyoto), Japanese painting by Nagasawa Rosetsu (1754–1799).]] For most of human history, firewood was the main fuel, until the use of coal spread during the Industrial Revolution.<ref>S Pinker, ''Enlightenment Now'' (2019) p. 143</ref> As such, access to firewood was a valued resource, with wood botes, or the right to gather firewood, being a significant aspect of many medieval leases.<ref>R Fortey, ''The Wood for the Trees'' (2016) p. 127 and p. 207</ref> As late as 19th century America, Henry David Thoreau considered that it was "remarkable what a value is still put upon wood even in this age and this country...the prince and the peasant, the scholar and the savage, equally require still a few sticks from the forest to warm them and cook their food".<ref>H D Thoreau, ''Walden '' (OUP 2008) p. 225</ref>
==Harvesting== Harvesting or collecting firewood varies by region and culture. Some cultures designate specific areas for firewood collection, while others rotate collection areas to allow environmental rebound. Collection can be a group or an individual activity, and tools and methods for harvesting firewood vary by region. <gallery mode="packed" heights="160"> File:Mozambique - firewood collector.jpg|Firewood collector in Mozambique File:Paysans à vélo.jpg|Firewood transportation from farm to home in Maroua, Cameroon </gallery>
===North America=== Some firewood is harvested in "woodlots" managed for that purpose,<ref>{{Cite web|url=https://extension.unh.edu/news/2006/05/where_does_firewood_come_from.html|title=Where does firewood come from? |archive-url=https://web.archive.org/web/20071127132536/https://extension.unh.edu/news/2006/05/where_does_firewood_come_from.html |archive-date=2007-11-27 |website=extension.unh.edu}}</ref> but in heavily wooded areas, it is more often harvested as a byproduct of natural forests. Deadfall that has not started to rot is preferred, since it is already partly seasoned. Standing dead timber is considered better still, because it has less humid organic material on the trunk, which allows collection tools to stay sharper longer, and is less likely to be rotten. Harvesting this form of timber reduces the speed and intensity of bushfires, but it also reduces the available habitat for snag-nesting animals such as owls, bats, and some rodents.
Harvesting timber for firewood is normally carried out by hand with chainsaws. Thus, longer pieces, requiring less manual labour and less chainsaw fuel, are less expensive and only limited by the size of the firebox. In most of the United States, the standard measure of firewood is a cord, or {{convert|128|cuft}}; however, firewood can also be sold by weight. The wood's heating value can affect the price. Prices also vary considerably based upon the distance from woodlots and the quality of the wood. Buying and burning firewood that was cut only a short distance from its final destination helps prevent the accidental spread of invasive tree-killing insects and diseases.<ref>{{cite web|url=http://www.dontmovefirewood.org|title=Don't Move Firewood - Trees and forests are threatened by invasive foreign insects and diseases|work=dontmovefirewood.org}}</ref><ref>{{cite web|url=http://www.inspection.gc.ca/english/plaveg/for/prod/firee.shtml|title=Firewood|publisher=Government of Canada, Canadian Food Inspection Agency, Plant Health and Biosecurity Directorate|website=www.inspection.gc.ca|date=2015-04-14|access-date=2011-03-03|archive-date=2011-07-06|archive-url=https://web.archive.org/web/20110706181625/http://www.inspection.gc.ca/english/plaveg/for/prod/firee.shtml|url-status=dead}}</ref>
=== Nigeria === {{Further|Firewood in Nigeria}} Due to its affordability, firewood in Nigeria is used for various purposes, which includes the preparation of food (particularly in traditional stoves), heating buildings, producing charcoal, and within various cultural and religious practices.<ref>{{Cite journal |last1=Matemilola |first1=Saheed |last2=Elegbede |first2=Isa O. |last3=Kies |first3=Fatima |last4=Yusuf |first4=Gbolahan A. |last5=Yangni |first5=Ganbobga N. |last6=Garba |first6=Ibrahim |date=2019-01-01 |title=An Analysis of the Impacts of Bioenergy Development on Food Security in Nigeria: Challenges and Prospects |url=https://www.sciendo.com/article/10.2478/rtuect-2019-0005 |journal=Environmental and Climate Technologies |language=en |volume=23 |issue=1 |pages=64–83 |doi=10.2478/rtuect-2019-0005 |bibcode=2019SJRUE..23...64M |issn=2255-8837|hdl=10281/236662 |s2cid=198964019 |hdl-access=free }}</ref><ref name=":0">{{Cite journal |last1=Ijeomah |first1=HM |last2=Ijeomah |first2=UD |last3=Okagbare |first3=OH |date=2013-11-08 |title=Ecological Survey of Avifaunal Resources in University of Port Harcourt, Nigeria |journal=Ethiopian Journal of Environmental Studies and Management |volume=6 |issue=6 |doi=10.4314/ejesm.v6i6.8 |issn=1998-0507|doi-access=free }}</ref><ref>{{Citation |last=Bowyer |first=J. L. |title=Wood: Future Availability |date=2001-01-01 |url=https://www.sciencedirect.com/science/article/pii/B0080431526017460 |encyclopedia=Encyclopedia of Materials: Science and Technology |pages=9637–9641 |editor-last=Buschow |editor-first=K. H. Jürgen |access-date=2023-05-21 |place=Oxford |publisher=Elsevier |language=en |doi=10.1016/b0-08-043152-6/01746-0 |bibcode=2001emst.book.9637B |isbn=978-0-08-043152-9 |editor2-last=Cahn |editor2-first=Robert W. |editor3-last=Flemings |editor3-first=Merton C. |editor4-last=Ilschner |editor4-first=Bernhard|url-access=subscription }}</ref><ref>{{Cite web |title=Wood energy |url=https://www.fao.org/3/y4450e/y4450e10.htm |access-date=2023-05-21 |website=www.fao.org}}</ref><ref>{{Cite journal |last1=Wood |first1=T S |last2=Baldwin |first2=S |date=1985 |title=Fuelwood and Charcoal Use in Developing Countries |journal=Annual Review of Energy |volume=10 |issue=1 |pages=407–429 |doi=10.1146/annurev.eg.10.110185.002203 |issn=0362-1626|doi-access=free }}</ref><ref>{{Cite journal |last1=Akintan |first1=Oluwakemi |last2=Jewitt |first2=Sarah |last3=Clifford |first3=Mike |date=2018 |title=Culture, tradition, and taboo: Understanding the social shaping of fuel choices and cooking practices in Nigeria |url=https://linkinghub.elsevier.com/retrieve/pii/S2214629617304346 |journal=Energy Research & Social Science |language=en |volume=40 |pages=14–22 |doi=10.1016/j.erss.2017.11.019|bibcode=2018ERSS...40...14A |s2cid=115739869 }}</ref> Firewood is also often used in small-scale and artisanal production processes.<ref>{{Cite journal |last1=Sola |first1=Phosiso |last2=Cerutti |first2=Paolo Omar |last3=Zhou |first3=Wen |last4=Gautier |first4=Denis |last5=Iiyama |first5=Miyuki |last6=Schure |first6=Jolien |last7=Chenevoy |first7=Audrey |last8=Yila |first8=Jummai |last9=Dufe |first9=Vanessa |last10=Nasi |first10=Robert |last11=Petrokofsky |first11=Gillian |last12=Shepherd |first12=Gill |date=2017-02-13 |title=The environmental, socioeconomic, and health impacts of woodfuel value chains in Sub-Saharan Africa: a systematic map |journal=Environmental Evidence |volume=6 |issue=1 |pages=4 |doi=10.1186/s13750-017-0082-2 |issn=2047-2382|doi-access=free |bibcode=2017EnvEv...6....4S |hdl=10568/94158 |hdl-access=free }}</ref><ref>{{Cite journal |last=Morgan |first=W.B. |date=1978 |title=Development and the fuelwood situation in Nigeria |url=http://dx.doi.org/10.1007/bf00156221 |journal=GeoJournal |volume=2 |issue=5 |page=437 |doi=10.1007/bf00156221 |bibcode=1978GeoJo...2..437M |s2cid=154561400 |issn=0343-2521|url-access=subscription }}</ref>
==Preparing== In most of the world, firewood is only prepared for transport at the time it is harvested. Then it is moved closer to the place where it will be used as fuel and prepared there. The process of making charcoal from firewood can take place at the place where the firewood is harvested.
Most firewood also requires splitting, which allows for faster seasoning by exposing more surface area. Splitting can be done with a hydraulic splitting machine or manually (using a splitting maul or a wedge and sledge hammer). Steel wedges have an angled blade so the mechanical advantage increases with depth. More unusual is a tapered screw-style design that augers into the wood, splitting it, which can be powered by a power take-off drive, a dedicated internal combustion engine, or a rugged electric pipe-threading machine. Another method is to use a kinetic log splitter, which uses a rack and pinion system powered by a small motor and a large flywheel used for energy storage. Firewood processors are also utilized in some parts of the world to process larger quantities of firewood.
<gallery mode="packed" heights="160"> Scure nel tronco.jpg|Italian-style splitting axe Automatic axe dsc00844.jpg|Hydraulic wood splitting machine Wedge-1.jpg|Steel wedge for splitting firewood </gallery>
==Storing== Methods of firewood storage range from simple piles to free-standing stacks or specialized structures. Usually, the goal of storing wood is to keep water away from it and to continue the drying process.
'''Stacks:''' In the simplest stack logs are placed next to and on top of each other, forming a line the width of the logs. The height of the stack can vary, generally depending upon how the ends are constructed. Without constructing ends, the length of the log and the length of the pile help determine the height of a free-standing stack.
When determining whether wood should be covered during the drying process, there is a trade-off between preventing the surface of the wood from getting wet and allowing as much wind and sun as possible to access the stack. A cover can be almost any material that sheds water – a large piece of plywood, sheet metal, terracotta tiles, an oiled canvas cloth, or plastic sheeting. Wood will not dry when ''completely'' enclosed. Ideally, pallets or scrap wood are used to raise the wood from the ground, reducing rot and increasing air flow.
There are many ways to create the ends of a stack. A crib end is created by alternating pairs of logs to help stabilize the end. A stake or pole placed in the ground is another way to end the pile. A series of stacked logs at the end, each with a cord tied to it and the free end of the cord wrapped around the log in the middle of the pile, will also suffice.
'''Under a roof:''' Under a roof, there are no concerns about the wood being subjected to rain, snow, or run-off, but ventilation needs to be provided if the wood is stored green so that moisture released from the wood does not recondense inside. Whether split or in 'rounds' (flush-cut and unsplit segments of logs), the wood is stacked lengthwise. If the wood needs further seasoning, adequate air flow must be maintained through the stack.
'''Storing outdoors:''' Firewood is stacked with the bark facing upwards. This allows water to drain off, and standing frost, ice, or snow to be kept from the wood. Storing wood near a dwelling increases the likelihood that insects such as termites will become established indoors. Storing firewood indoors for any extended period of time increases the risk of introducing insects such as termites into the home.
Round stacks can be made in many ways. Some are piles of wood with a stacked circular wall around them. Others, like the American Holz Hausen, are more complicated. A Holz hausen, or "wood house", is a circular method of stacking wood; proponents say it speeds up drying on a relatively small footprint. A traditional Holz hausen has a 10-foot diameter, stands 10 feet high, and holds about 6 cords of wood. The walls are made of pieces arranged radially and tilted slightly inward for stability. The inside pieces are stacked on end to form a chimney for air flow. The top pieces are tilted slightly outward to shed rain and are placed bark side up.<ref>{{cite web|url=http://www.thechimneysweep.ca/6seasoningwood.html|title=Seasoning Firewood How and When|work=thechimneysweep.ca|access-date=2008-09-22|archive-date=2008-11-05|archive-url=https://web.archive.org/web/20081105181703/http://www.thechimneysweep.ca/6seasoningwood.html|url-status=dead}}</ref>
<gallery mode="packed" heights="160"> Puuriidad Kuremäe kloostris.jpg|Firewood stacks at Pühtitsa Convent in Estonia are about {{convert|6|m|ft}} high. FirewoodFrancheComte.jpg|Stacked with crib end, in eastern France, covered by terracotta tiles. stackingwood.jpg|Stacking firewood in a shed </gallery>
== Heating value == [[File:Fire, Fireplace, Rostov-on-Don, Russia.jpg|thumb|Firewood in fireplace]] [[File:Hiillos Aitokiuas.jpg|thumb|Birch embers on sauna stove]] The moisture content of firewood determines how it burns and how much heat is released. Unseasoned (green) wood moisture content varies by its species; green wood may weigh 70 to 100 percent more than seasoned wood due to water content. Typically, seasoned (dry) wood has 20% or less moisture content. Use of the lower heating value is advised as a reasonable standard way of reporting this data.{{citation needed|date=September 2021}}
The energy content of a measure of wood depends on the tree species.<ref>{{cite web|url=http://northidahofirewood.com/learnfirewood|title=Northidahofirewood.com|url-status=usurped|archive-url=https://web.archive.org/web/20090206165122/http://northidahofirewood.com/learnfirewood|archive-date=2009-02-06}}</ref> For example, it can range from {{convert|15.5|to|32|e6Btu/cord|GJ/m3}}.<ref>{{cite web|url=http://www.woodheat.org/firewood.html|title=A non-commercial service in support of responsible home heating with wood - Firewood|author=John Gulland|work=woodheat.org}}</ref> The higher the moisture content, the more energy that must be used to evaporate (boil) the water in the wood before it will burn. Dry wood delivers more energy for heating than green wood of the same species.
The Sustainable Energy Development Office (SEDO), part of the Government of Western Australia states that the energy content of wood is 4.5 kWh/kg or 16.2 gigajoules/tonne (GJ/t).<ref>{{cite web|url=http://www1.sedo.energy.wa.gov.au/pages/heat_run.asp |title=Office of Energy - Clean Energy |publisher=Sedo.energy.wa.gov.au |date=2010-01-01 |access-date=2010-07-29 |url-status=dead |archive-url=https://web.archive.org/web/20091013100115/http://www1.sedo.energy.wa.gov.au/pages/heat_run.asp |archive-date=October 13, 2009 }}</ref>
Here are some examples of energy content of several species of wood: {| class="wikitable" |- ! Wood Species ! Heating value (million BTU per cord) ! Heating value (GJ per m<sup>3</sup>) |- | Tamarack | 22.3 | {{convert|22.3|e6Btu/cord|GJ/m3|disp=number}} |- | Birch | 21.3 | {{convert|21.3|e6Btu/cord|GJ/m3|disp=number}} |- | Red Fir | 20.6 | {{convert|20.6|e6Btu/cord|GJ/m3|disp=number}} |- | White Fir | 16.7 | {{convert|16.7|e6Btu/cord|GJ/m3|disp=number}} |}
===Kiln (oven) dried firewood=== {{Main|Wood drying}}
To reduce the drying time to a number of days from the normal one to three years, an external heating source such as a kiln or oven may be used. The process of kiln or oven drying firewood was invented by Anthony Cutara, for which a successful US patent was filed in 1983.<ref>{{Cite web|url=https://patents.google.com/patent/US4597189A/en|title=Packaged kiln dried firewood}}</ref> In 1987 the US Department of Agriculture replicated the method and published a detailed procedure for the production of kiln dried firewood, citing the higher heat output and increased combustion efficiency as a key benefit of the process.<ref>{{cite web|url=http://www.fpl.fs.fed.us/documnts/fplrn/fplrn254.pdf|title=Kiln-Drying Time of Split Oak Firewood|date=August 1987|author1=Simpson, William T.|author2=Boone, R. Sidney|author3=Chern, Joseph|author4=Mace, Terry|location=Madison, WI|publisher=U.S. Department of Agriculture, Forest Service, Forest Products Laboratory |archive-url=https://web.archive.org/web/20060224121200/http://www.fpl.fs.fed.us/documnts/fplrn/fplrn254.pdf |archive-date=2006-02-24}}</ref>
==Measurement== thumb|Firewood on its way to market in Mali. thumb|Firewood for sale at a local market in Mali. Usually firewood is sold by volume. While a specific volume term may be used, there can be a wide variation in what this means and what the measure can produce as a fuel. A measure of green unseasoned wood with 65% moisture contains less usable energy than when it has been dried to 20%. Regardless of the term, firewood measurement is best thought of as an estimate.
===Traditional English=== Early modern England measured firewood in terms of billets and bavins. A billet,<ref>[Billet | Definition of Billet by Merriam-Webster (merriam-webster.com) Definition of Billet]</ref> like a bavin, was a piece of kindling wood.<ref>[Bavin | Definition of Bavin at Dictionary.com Definition]</ref> The 16th century standardised a billet as three foot four inches in length, and ten inches around (for open fires); and a bavin as three foot long and two feet round (a chunkier log, often used for ovens).<ref>R Fortey, ''The Wood for the Trees ''(2016) p. 154 and p. 207</ref>
===Metric=== In the metric system, firewood is usually sold by the stère, equivalent to a volume of {{convert|1|m3|cord|3|sp=us|lk=on}}. The most common firewood piece lengths are {{convert|33|cm|abbr=on}} and {{convert|50|cm|abbr=on}}. Wood can also be sold by the kilogram or by the tonne, as in Australia.
===North America=== In the United States and Canada, firewood is usually sold by the full cord, face cord or bag. A cord which is made from {{convert|4|ft|m|2|adj=on}} logs will not be a cord when it has been cut into 1 foot logs and then split so each piece will fit through a {{convert|3|in|cm|1|adj=on}} circle.
*A '''full cord''' or '''bush cord''' has a volume of {{convert|128|cuft}}, including wood, bark, and air space in a neatly stacked pile.<ref>[http://www.ic.gc.ca/eic/site/mc-mc.nsf/eng/lm03963.html "Buying Firewood? Don't Get Burned!"]. Measurement Canada. Retrieved 2013-08-15.</ref> The actual wood volume of a cord may be in the range of {{convert|80|to|100|cuft|m3}} as stacked wood takes up more space than a piece of solid wood. The most common firewood piece length is {{convert|16|in|cm}}.<ref name="woodheat">[http://www.woodheat.org/cord-wood.html "What is a Cord? And How to Avoid Paying Too Much for One"]. Woodheat.org. Retrieved 2013-08-16.</ref> * The volume of a '''face cord''' or a '''rick'''<ref>{{Cite web|url=http://www.woodsmanreport.com/rick-of-firewood/|title=Rick Of Firewood [Definition, Value, Weight, Tips For Buying]|date=2019-01-25|website=WoodsMan Report|language=en-US|access-date=2019-02-15}}</ref> depends on the length of the logs that are stacked in a {{convert|4|by|8|ft|2|abbr=on}} pile. When {{convert|16|in|cm|abbr=on}} logs are used, the volume is {{convert|42+2/3|cuft}} which is one third of a full or bush cord stack of wood.<ref name="woodheat" />
==Damage to health and environment== Burning firewood causes respiratory and other illnesses.<ref name=":1" /> Along with clearance for agriculture collecting firewood is a cause of deforestation.<ref>{{Cite journal |last1=Bakehe |first1=Novice Patrick |last2=Hassan |first2=Roukiya |date=2023-09-01 |title=The Effects of Access to Clean Fuels and Technologies for Cooking on Deforestation in Developing Countries |url=https://doi.org/10.1007/s13132-022-00913-2 |journal=Journal of the Knowledge Economy |language=en |volume=14 |issue=3 |pages=2561–2577 |doi=10.1007/s13132-022-00913-2 |issn=1868-7873|url-access=subscription }}</ref>
==In popular culture== *Jane Austen in 1814 complained to her sister that "My Mother's Wood is brought in-but by some mistake, no Bavins. She must therefore buy some". (Contemporary charges were between 6 and 15 shillings per hundred bavins).<ref>D Le Faye ed., ''Jane Austen's Letters'' (OUP 1995) p. 264 and p. 432</ref> *In Norway, the non-fiction book ''Hel Ved'' (In English: ''Solid Wood: All About Chopping, Drying and Stacking Wood – and the Soul of Wood-Burning'') by Lars Mytting became a bestseller in 2011–2012, selling 150,000 copies. A version of the book has also been published in Sweden, selling 50,000 copies.<ref>[http://www.aftenposten.no/kultur/Norsk-ved-TV-vekker-oppsikt-i-USA-7127150.html Norsk ved-TV vekker oppsikt i USA] Aftenposten, February 20, 2013</ref> * In February 2013, the Norwegian state broadcast NRK sent a 12-hour live program on the topic of firewood, where a large part of the program consisted of showing firewood burning in a fireplace. More than one million people, 20% of Norway's population, saw part of the program.<ref>Sarah Lyall: [https://www.nytimes.com/2013/02/20/world/europe/in-norway-tv-program-on-firewood-elicits-passions.html?pagewanted=1&_r=1 Bark Up or Down? Firewood Splits Norwegians] ''The New York Times'', February 19, 2013</ref>
==See also== {{div col|colwidth=23em}} *Biomass *Cordwood construction *Estovers *Multipurpose tree *Wood ash * Wood fuel {{div col end}}
==References== {{Reflist|30em}}
==External links== {{Commons category|Firewood}} * [http://pages.sssnet.com/go2erie/FirewoodFacts.htm Website which compares qualities of American wood species in cord measurements.] * [http://nfdp.ccfm.org/data/graphs/graph_51_b_e.php A Graph showing Fuelwood & Firewood Production in Canada since 1940] {{Webarchive|url=https://web.archive.org/web/20160313051614/http://nfdp.ccfm.org/data/graphs/graph_51_b_e.php |date=2016-03-13 }}
{{Firelighting}} {{Wood products}} {{Authority control}}
Category:Firewood Category:Fuels