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Wood is a heterogeneous, hygroscopic, cellular and anisotropic material. It consists of cells, and the cell walls are composed of micro-fibrils of cellulose (40% – 50%) and hemicellulose (15% – 25%) impregnated with lignin (15% – 30%).
In coniferous or softwood species the wood cells are mostly of one kind, tracheids, and as a result the material is much more uniform in structure than that of most hardwoods. There are no vessels ("pores") in coniferous wood such as one sees so prominently in oak and ash, for example.
The structure of hardwoods is more complex. The water conducting capability is mostly taken care of by vessels: in some cases (oak, chestnut, ash) these are quite large and distinct, in others (buckeye, poplar, willow) too small to be seen without a hand lens. In discussing such woods it is customary to divide them int...
In ring-porous species, such as ash, black locust, catalpa, chestnut, elm, hickory, mulberry, and oak, the larger vessels or pores (as cross sections of vessels are called) are localised in the part of the growth ring formed in spring, thus forming a region of more or less open and porous tissue. The rest of the ring, ...
In diffuse-porous woods the pores are evenly sized so that the water conducting capability is scattered throughout the growth ring instead of being collected in a band or row. Examples of this kind of wood are alder, basswood,[citation needed] birch, buckeye, maple, willow,and the Populus species such as aspen, cottonw...
In temperate softwoods there often is a marked difference between latewood and earlywood. The latewood will be denser than that formed early in the season. When examined under a microscope the cells of dense latewood are seen to be very thick-walled and with very small cell cavities, while those formed first in the sea...
If a heavy piece of pine is compared with a lightweight piece it will be seen at once that the heavier one contains a larger proportion of latewood than the other, and is therefore showing more clearly demarcated growth rings. In white pines there is not much contrast between the different parts of the ring, and as a r...
It is not only the proportion of latewood, but also its quality, that counts. In specimens that show a very large proportion of latewood it may be noticeably more porous and weigh considerably less than the latewood in pieces that contain but little. One can judge comparative density, and therefore to some extent stren...
No satisfactory explanation can as yet be given for the exact mechanisms determining the formation of earlywood and latewood. Several factors may be involved. In conifers, at least, rate of growth alone does not determine the proportion of the two portions of the ring, for in some cases the wood of slow growth is very ...
In ring-porous woods each season's growth is always well defined, because the large pores formed early in the season abut on the denser tissue of the year before.
In the case of the ring-porous hardwoods there seems to exist a pretty definite relation between the rate of growth of timber and its properties. This may be briefly summed up in the general statement that the more rapid the growth or the wider the rings of growth, the heavier, harder, stronger, and stiffer the wood. T...
In ring-porous woods of good growth it is usually the latewood in which the thick-walled, strength-giving fibers are most abundant. As the breadth of ring diminishes, this latewood is reduced so that very slow growth produces comparatively light, porous wood composed of thin-walled vessels and wood parenchyma. In good ...
Wide-ringed wood is often called "second-growth", because the growth of the young timber in open stands after the old trees have been removed is more rapid than in trees in a closed forest, and in the manufacture of articles where strength is an important consideration such "second-growth" hardwood material is preferre...
In the diffuse-porous woods, the demarcation between rings is not always so clear and in some cases is almost (if not entirely) invisible to the unaided eye. Conversely, when there is a clear demarcation there may not be a noticeable difference in structure within the growth ring.
In diffuse-porous woods, as has been stated, the vessels or pores are even-sized, so that the water conducting capability is scattered throughout the ring instead of collected in the earlywood. The effect of rate of growth is, therefore, not the same as in the ring-porous woods, approaching more nearly the conditions i...
Structural material that resembles ordinary, "dicot" or conifer wood in its gross handling characteristics is produced by a number of monocot plants, and these also are colloquially called wood. Of these, bamboo, botanically a member of the grass family, has considerable economic importance, larger culms being widely u...
The single most revealing property of wood as an indicator of wood quality is specific gravity (Timell 1986), as both pulp yield and lumber strength are determined by it. Specific gravity is the ratio of the mass of a substance to the mass of an equal volume of water; density is the ratio of a mass of a quantity of a s...
Wood density is determined by multiple growth and physiological factors compounded into “one fairly easily measured wood characteristic” (Elliott 1970).
Age, diameter, height, radial growth, geographical location, site and growing conditions, silvicultural treatment, and seed source, all to some degree influence wood density. Variation is to be expected. Within an individual tree, the variation in wood density is often as great as or even greater than that between diff...
It is common to classify wood as either softwood or hardwood. The wood from conifers (e.g. pine) is called softwood, and the wood from dicotyledons (usually broad-leaved trees, e.g. oak) is called hardwood. These names are a bit misleading, as hardwoods are not necessarily hard, and softwoods are not necessarily soft. ...
There is a strong relationship between the properties of wood and the properties of the particular tree that yielded it. The density of wood varies with species. The density of a wood correlates with its strength (mechanical properties). For example, mahogany is a medium-dense hardwood that is excellent for fine furnit...
The chemical composition of wood varies from species to species, but is approximately 50% carbon, 42% oxygen, 6% hydrogen, 1% nitrogen, and 1% other elements (mainly calcium, potassium, sodium, magnesium, iron, and manganese) by weight. Wood also contains sulfur, chlorine, silicon, phosphorus, and other elements in sma...
Aside from water, wood has three main components. Cellulose, a crystalline polymer derived from glucose, constitutes about 41–43%. Next in abundance is hemicellulose, which is around 20% in deciduous trees but near 30% in conifers. It is mainly five-carbon sugars that are linked in an irregular manner, in contrast to t...
In chemical terms, the difference between hardwood and softwood is reflected in the composition of the constituent lignin. Hardwood lignin is primarily derived from sinapyl alcohol and coniferyl alcohol. Softwood lignin is mainly derived from coniferyl alcohol.
Aside from the lignocellulose, wood consists of a variety of low molecular weight organic compounds, called extractives. The wood extractives are fatty acids, resin acids, waxes and terpenes. For example, rosin is exuded by conifers as protection from insects. The extraction of these organic materials from wood provide...
Wood has a long history of being used as fuel, which continues to this day, mostly in rural areas of the world. Hardwood is preferred over softwood because it creates less smoke and burns longer. Adding a woodstove or fireplace to a home is often felt to add ambiance and warmth.
Wood has been an important construction material since humans began building shelters, houses and boats. Nearly all boats were made out of wood until the late 19th century, and wood remains in common use today in boat construction. Elm in particular was used for this purpose as it resisted decay as long as it was kept ...
Wood to be used for construction work is commonly known as lumber in North America. Elsewhere, lumber usually refers to felled trees, and the word for sawn planks ready for use is timber. In Medieval Europe oak was the wood of choice for all wood construction, including beams, walls, doors, and floors. Today a wider va...
New domestic housing in many parts of the world today is commonly made from timber-framed construction. Engineered wood products are becoming a bigger part of the construction industry. They may be used in both residential and commercial buildings as structural and aesthetic materials.
In buildings made of other materials, wood will still be found as a supporting material, especially in roof construction, in interior doors and their frames, and as exterior cladding.
Engineered wood products, glued building products "engineered" for application-specific performance requirements, are often used in construction and industrial applications. Glued engineered wood products are manufactured by bonding together wood strands, veneers, lumber or other forms of wood fiber with glue to form a...
These products include glued laminated timber (glulam), wood structural panels (including plywood, oriented strand board and composite panels), laminated veneer lumber (LVL) and other structural composite lumber (SCL) products, parallel strand lumber, and I-joists. Approximately 100 million cubic meters of wood was con...
Wood unsuitable for construction in its native form may be broken down mechanically (into fibers or chips) or chemically (into cellulose) and used as a raw material for other building materials, such as engineered wood, as well as chipboard, hardboard, and medium-density fiberboard (MDF). Such wood derivatives are wide...
Wood has always been used extensively for furniture, such as chairs and beds. It is also used for tool handles and cutlery, such as chopsticks, toothpicks, and other utensils, like the wooden spoon.
Further developments include new lignin glue applications, recyclable food packaging, rubber tire replacement applications, anti-bacterial medical agents, and high strength fabrics or composites. As scientists and engineers further learn and develop new techniques to extract various components from wood, or alternative...
Wood has long been used as an artistic medium. It has been used to make sculptures and carvings for millennia. Examples include the totem poles carved by North American indigenous people from conifer trunks, often Western Red Cedar (Thuja plicata), and the Millennium clock tower, now housed in the National Museum of Sc...
Certain types of musical instruments, such as those of the violin family, the guitar, the clarinet and recorder, the xylophone, and the marimba, are traditionally made mostly or entirely of wood. The choice of wood may make a significant difference to the tone and resonant qualities of the instrument, and tonewoods hav...
Despite their collective name, not all woodwind instruments are made entirely of wood. The reeds used to play them, however, are usually made from Arundo donax, a type of monocot cane plant.
Many types of sports equipment are made of wood, or were constructed of wood in the past. For example, cricket bats are typically made of white willow. The baseball bats which are legal for use in Major League Baseball are frequently made of ash wood or hickory, and in recent years have been constructed from maple even...
Many other types of sports and recreation equipment, such as skis, ice hockey sticks, lacrosse sticks and archery bows, were commonly made of wood in the past, but have since been replaced with more modern materials such as aluminium, fiberglass, carbon fiber, titanium, and composite materials. One noteworthy example o...
Little is known about the bacteria that degrade cellulose. Symbiotic bacteria in Xylophaga may play a role in the degradation of sunken wood; while bacteria such as Alphaproteobacteria, Flavobacteria, Actinobacteria, Clostridia, and Bacteroidetes have been detected in wood submerged over a year.
Somalis (Somali: Soomaali, Arabic: صومال‎) are an ethnic group inhabiting the Horn of Africa (Somali Peninsula). The overwhelming majority of Somalis speak the Somali language, which is part of the Cushitic branch of the Afro-Asiatic family. They are predominantly Sunni Muslim. Ethnic Somalis number around 16-20 millio...
Irir Samaale, the oldest common ancestor of several Somali clans, is generally regarded as the source of the ethnonym Somali. The name "Somali" is, in turn, held to be derived from the words soo and maal, which together mean "go and milk" — a reference to the ubiquitous pastoralism of the Somali people. Another plausib...
An Ancient Chinese document from the 9th century referred to the northern Somali coast — which was then called "Berbera" by Arab geographers in reference to the region's "Berber" (Cushitic) inhabitants — as Po-pa-li. The first clear written reference of the sobriquet Somali, however, dates back to the 15th century. Dur...
Ancient rock paintings in Somalia which date back to 5000 years have been found in the northern part of the country, depicting early life in the territory. The most famous of these is the Laas Geel complex, which contains some of the earliest known rock art on the African continent and features many elaborate pastorali...
Inscriptions have been found beneath many of the rock paintings, but archaeologists have so far been unable to decipher this form of ancient writing. During the Stone age, the Doian culture and the Hargeisan culture flourished here with their respective industries and factories.
The oldest evidence of burial customs in the Horn of Africa comes from cemeteries in Somalia dating back to 4th millennium BC. The stone implements from the Jalelo site in northern Somalia are said to be the most important link in evidence of the universality in palaeolithic times between the East and the West.
In antiquity, the ancestors of the Somali people were an important link in the Horn of Africa connecting the region's commerce with the rest of the ancient world. Somali sailors and merchants were the main suppliers of frankincense, myrrh and spices, items which were considered valuable luxuries by the Ancient Egyptian...
According to most scholars, the ancient Land of Punt and its inhabitants formed part of the ethnogenesis of the Somali people. The ancient Puntites were a nation of people that had close relations with Pharaonic Egypt during the times of Pharaoh Sahure and Queen Hatshepsut. The pyramidal structures, temples and ancient...
In the classical era, several ancient city-states such as Opone, Essina, Sarapion, Nikon, Malao, Damo and Mosylon near Cape Guardafui, which competed with the Sabaeans, Parthians and Axumites for the wealthy Indo-Greco-Roman trade, also flourished in Somalia.
The birth of Islam on the opposite side of Somalia's Red Sea coast meant that Somali merchants, sailors and expatriates living in the Arabian Peninsula gradually came under the influence of the new religion through their converted Arab Muslim trading partners. With the migration of fleeing Muslim families from the Isla...
The Sultanate of Ifat, led by the Walashma dynasty with its capital at Zeila, ruled over parts of what is now eastern Ethiopia, Djibouti, and northern Somalia. The historian al-Umari records that Ifat was situated near the Red Sea coast, and states its size as 15 days travel by 20 days travel. Its army numbered 15,000 ...
In the Middle Ages, several powerful Somali empires dominated the regional trade including the Ajuran Sultanate, which excelled in hydraulic engineering and fortress building, the Sultanate of Adal, whose general Ahmad ibn Ibrahim al-Ghazi (Ahmed Gurey) was the first commander to use cannon warfare on the continent dur...
In the late 19th century, after the Berlin conference had ended, European empires sailed with their armies to the Horn of Africa. The imperial clouds wavering over Somalia alarmed the Dervish leader Mohammed Abdullah Hassan, who gathered Somali soldiers from across the Horn of Africa and began one of the longest anti-c...
Following World War II, Britain retained control of both British Somaliland and Italian Somaliland as protectorates. In 1945, during the Potsdam Conference, the United Nations granted Italy trusteeship of Italian Somaliland, but only under close supervision and on the condition — first proposed by the Somali Youth Leag...
To the extent that Italy held the territory by UN mandate, the trusteeship provisions gave the Somalis the opportunity to gain experience in political education and self-government. These were advantages that British Somaliland, which was to be incorporated into the new Somali state, did not have. Although in the 1950s...
A referendum was held in neighboring Djibouti (then known as French Somaliland) in 1958, on the eve of Somalia's independence in 1960, to decide whether or not to join the Somali Republic or to remain with France. The referendum turned out in favour of a continued association with France, largely due to a combined yes ...
British Somaliland became independent on 26 June 1960 as the State of Somaliland, and the Trust Territory of Somalia (the former Italian Somaliland) followed suit five days later. On 1 July 1960, the two territories united to form the Somali Republic, albeit within boundaries drawn up by Italy and Britain. A government...
On 15 October 1969, while paying a visit to the northern town of Las Anod, Somalia's then President Abdirashid Ali Shermarke was shot dead by one of his own bodyguards. His assassination was quickly followed by a military coup d'état on 21 October 1969 (the day after his funeral), in which the Somali Army seized power ...
Alongside Barre, the Supreme Revolutionary Council (SRC) that assumed power after President Sharmarke's assassination was led by Lieutenant Colonel Salaad Gabeyre Kediye and Chief of Police Jama Korshel. The SRC subsequently renamed the country the Somali Democratic Republic, dissolved the parliament and the Supreme Co...
The revolutionary army established large-scale public works programs and successfully implemented an urban and rural literacy campaign, which helped dramatically increase the literacy rate. In addition to a nationalization program of industry and land, the new regime's foreign policy placed an emphasis on Somalia's tra...
Somali people in the Horn of Africa are divided among different countries (Somalia, Djibouti, Ethiopia, and northeastern Kenya) that were artificially and some might say arbitrarily partitioned by the former imperial powers. Pan-Somalism is an ideology that advocates the unification of all ethnic Somalis once part of S...
According to Y chromosome studies by Sanchez et al. (2005), Cruciani et al. (2004, 2007), the Somalis are paternally closely related to other Afro-Asiatic-speaking groups in Northeast Africa. Besides comprising the majority of the Y-DNA in Somalis, the E1b1b1a (formerly E3b1a) haplogroup also makes up a significant pro...
According to mtDNA studies by Holden (2005) and Richards et al. (2006), a significant proportion of the maternal lineages of Somalis consists of the M1 haplogroup. This mitochondrial clade is common among Ethiopians and North Africans, particularly Egyptians and Algerians. M1 is believed to have originated in Asia, whe...
According to an autosomal DNA study by Hodgson et al. (2014), the Afro-Asiatic languages were likely spread across Africa and the Near East by an ancestral population(s) carrying a newly identified non-African genetic component, which the researchers dub the "Ethio-Somali". This Ethio-Somali component is today most com...
The analysis of HLA antigens has also helped clarify the possible background of the Somali people, as the distribution of haplotype frequencies vary among population groups. According to Mohamoud et al. (2006):
The history of Islam in Somalia is as old as the religion itself. The early persecuted Muslims fled to various places in the region, including the city of Zeila in modern-day northern Somalia, so as to seek protection from the Quraysh. Somalis were among the first populations on the continent to embrace Islam. With ver...
Qur'anic schools (also known as dugsi) remain the basic system of traditional religious instruction in Somalia. They provide Islamic education for children, thereby filling a clear religious and social role in the country. Known as the most stable local, non-formal system of education providing basic religious and mora...
In the Somali diaspora, multiple Islamic fundraising events are held every year in cities like Birmingham, London, Toronto and Minneapolis, where Somali scholars and professionals give lectures and answer questions from the audience. The purpose of these events is usually to raise money for new schools or universities ...
In addition, the Somali community has produced numerous important Muslim figures over the centuries, many of whom have significantly shaped the course of Islamic learning and practice in the Horn of Africa, the Arabian Peninsula and well beyond.
The clan groupings of the Somali people are important social units, and clan membership plays a central part in Somali culture and politics. Clans are patrilineal and are often divided into sub-clans, sometimes with many sub-divisions. The tombs of the founders of the Darod, Dir and Isaaq major clans as well as the Abg...
Somali society is traditionally ethnically endogamous. So to extend ties of alliance, marriage is often to another ethnic Somali from a different clan. Thus, for example, a recent study observed that in 89 marriages contracted by men of the Dhulbahante clan, 55 (62%) were with women of Dhulbahante sub-clans other than ...
In 1975, the most prominent government reforms regarding family law in a Muslim country were set in motion in the Somali Democratic Republic, which put women and men, including husbands and wives, on complete equal footing. The 1975 Somali Family Law gave men and women equal division of property between the husband and...
Somalis constitute the largest ethnic group in Somalia, at approximately 85% of the nation's inhabitants. They are traditionally nomads, but since the late 20th century, many have moved to urban areas. While most Somalis can be found in Somalia proper, large numbers also live in Ethiopia, Djibouti, Kenya, Yemen, the Mi...
Civil strife in the early 1990s greatly increased the size of the Somali diaspora, as many of the best educated Somalis left for the Middle East, Europe and North America. In Canada, the cities of Toronto, Ottawa, Calgary, Edmonton, Montreal, Vancouver, Winnipeg and Hamilton all harbor Somali populations. Statistics Ca...
While the distribution of Somalis per country in Europe is hard to measure because the Somali community on the continent has grown so quickly in recent years, an official 2010 estimate reported 108,000 Somalis living in the United Kingdom. Somalis in Britain are largely concentrated in the cities of London, Sheffield, ...
In the United States, Minneapolis, Saint Paul, Columbus, San Diego, Seattle, Washington, D.C., Houston, Atlanta, Los Angeles, Portland, Denver, Nashville, Green Bay, Lewiston, Portland, Maine and Cedar Rapids have the largest Somali populations.
An estimated 20,000 Somalis emigrated to the U.S. state of Minnesota some ten years ago and the Twin Cities (Minneapolis and Saint Paul) now have the highest population of Somalis in North America. The city of Minneapolis hosts hundreds of Somali-owned and operated businesses offering a variety of products, including l...
There is a sizable Somali community in the United Arab Emirates. Somali-owned businesses line the streets of Deira, the Dubai city centre, with only Iranians exporting more products from the city at large. Internet cafés, hotels, coffee shops, restaurants and import-export businesses are all testimony to the Somalis' e...
Besides their traditional areas of inhabitation in Greater Somalia, a Somali community mainly consisting of entrepreneurs, academics, and students also exists in Egypt. In addition, there is an historical Somali community in the general Sudan area. Primarily concentrated in the north and Khartoum, the expatriate commun...
The Somali language is a member of the Cushitic branch of the Afro-Asiatic family. Its nearest relatives are the Afar and Saho languages. Somali is the best documented of the Cushitic languages, with academic studies of it dating from before 1900.
The exact number of speakers of Somali is unknown. One source estimates that there are 7.78 million speakers of Somali in Somalia itself and 12.65 million speakers globally. The Somali language is spoken by ethnic Somalis in Greater Somalia and the Somali diaspora.
Somali dialects are divided into three main groups: Northern, Benaadir and Maay. Northern Somali (or Northern-Central Somali) forms the basis for Standard Somali. Benaadir (also known as Coastal Somali) is spoken on the Benadir coast from Adale to south of Merca, including Mogadishu, as well as in the immediate hinterl...
A number of writing systems have been used over the years for transcribing the language. Of these, the Somali alphabet is the most widely used, and has been the official writing script in Somalia since the government of former President of Somalia Mohamed Siad Barre formally introduced it in October 1972. The script wa...
In addition to Somali, Arabic, which is also an Afro-Asiatic tongue, is an official national language in both Somalia and Djibouti. Many Somalis speak it due to centuries-old ties with the Arab world, the far-reaching influence of the Arabic media, and religious education. Somalia and Djibouti are also both members of ...
The culture of Somalia is an amalgamation of traditions developed independently and through interaction with neighbouring and far away civilizations, such as other parts of Northeast Africa, the Arabian Peninsula, India and Southeast Asia.
The textile-making communities in Somalia are a continuation of an ancient textile industry, as is the culture of wood carving, pottery and monumental architecture that dominates Somali interiors and landscapes. The cultural diffusion of Somali commercial enterprise can be detected in its cuisine, which contains Southe...
All of these traditions, including festivals, martial arts, dress, literature, sport and games such as Shax, have immensely contributed to the enrichment of Somali heritage.
Somalis have a rich musical heritage centered on traditional Somali folklore. Most Somali songs are pentatonic. That is, they only use five pitches per octave in contrast to a heptatonic (seven note) scale, such as the major scale. At first listen, Somali music might be mistaken for the sounds of nearby regions such as...
Growing out of the Somali people's rich storytelling tradition, the first few feature-length Somali films and cinematic festivals emerged in the early 1960s, immediately after independence. Following the creation of the Somali Film Agency (SFA) regulatory body in 1975, the local film scene began to expand rapidly. The ...
Somali art is the artistic culture of the Somali people, both historic and contemporary. These include artistic traditions in pottery, music, architecture, wood carving and other genres. Somali art is characterized by its aniconism, partly as a result of the vestigial influence of the pre-Islamic mythology of the Somal...
Additionally, henna is an important part of Somali culture. It is worn by Somali women on their hands, arms, feet and neck during weddings, Eid, Ramadan, and other festive occasions. Somali henna designs are similar to those in the Arabian peninsula, often featuring flower motifs and triangular shapes. The palm is also...
Football is the most popular sport amongst Somalis. Important competitions are the Somalia League and Somalia Cup. The multi-ethnic Ocean Stars, Somalia's national team, first participated at the Olympic Games in 1972 and has sent athletes to compete in most Summer Olympic Games since then. The equally diverse Somali b...
The FIBA Africa Championship 1981 was hosted by Somalia from 15–23 December 1981. The games were played in Mogadishu, and the Somali national team received the bronze prize. Abdi Bile won the 1500 m event at the World Championships in 1987, running the fastest final 800 m of any 1,500 meter race in history. He was a tw...
In the martial arts, Faisal Jeylani Aweys and Mohamed Deq Abdulle also took home a silver medal and fourth place, respectively, at the 2013 Open World Taekwondo Challenge Cup in Tongeren. The Somali National Olympic committee has devised a special support program to ensure continued success in future tournaments. Addit...
When not dressed in Westernized clothing such as jeans and t-shirts, Somali men typically wear the macawis, which is a sarong-like garment worn around the waist. On their heads, they often wrap a colorful turban or wear the koofiyad, an embroidered fez.
Due to Somalia's proximity to and close ties with the Arabian Peninsula, many Somali men also wear the jellabiya (jellabiyad or qamiis in Somali), a long white garment common in the Arab world.
During regular, day-to-day activities, Somali women usually wear the guntiino, a long stretch of cloth tied over the shoulder and draped around the waist. It is usually made out of alandi, which is a textile common in the Horn region and some parts of North Africa. The garment can be worn in different styles. It can al...
Married women tend to sport headscarves referred to as shaash. They also often cover their upper body with a shawl, which is known as garbasaar. Unmarried or young women, however, do not always cover their heads. Traditional Arabian garb, such as the jilbab and abaya, is also commonly worn.
Additionally, Somali women have a long tradition of wearing gold jewelry, particularly bangles. During weddings, the bride is frequently adorned in gold. Many Somali women by tradition also wear gold necklaces and anklets.

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