Oaks

Have you ever wondered why oak trees and oak groves were considered sacred in the past? In the next couple of posts I will talk about oaks, acorns, and people who worshiped Oaks and ate acorns. I hope you will enjoy the story.

I will start with Oaks.

Oaks are the most widespread trees in the world. They belong to the family Fagaceae, native to the Northern Hemisphere. This plant family also includes beeches, chestnuts, and chinquapins. Fagaceae are woody trees and shrubs whose nut is enclosed in a shell-like casing. The Fagaceae family originated in Asia, first appearing in the fossil record during the Early Cretaceous, more than 100 million years ago. Subsequent radiation toward Europe and North America produced geographic dispersion as well as divergence of genera. The extinct genus Dryophyllum, one of the earliest known Fagaceae, is believed to be the ancestor of modern oaks.

Based on molecular genetics analysis, the genus Quercus is estimated to have separated from Castanea about 60 million years ago. Oaks first appear in the fossil record in North America during the Paleogene between 55 to 50 million years ago. Most interspecific separations occurred within the Quercus species between 22 and three million years ago. During this period, oaks became the most dominant tree type in the Fagaceae family.

Depending on the classification scheme, there are somewhere between 450 and 600 oak species; one of the chief points of confusion is the taxonomic status of many hybrid oaks. North America contains the largest number of oak species, with approximately 90 occurring in the United States. Mexico has 160 species, of which 109 are endemic. The second greatest center of oak diversity is China, which contains approximately 100 species. However all the oaks can be divided into two broad sub groups: white oaks and red and black oaks.

The white oaks of Europe, Asia and North America. Acorns mature in 6 months and taste sweet or slightly bitter; The inside of an acorn shell is hairless. The bark is light in color, gray to light gray. The leaves mostly lack a bristle on their lobe tips, which are usually rounded.

The red and black oaks of Europe Americas and Asia. Acorns mature in 18 months and taste bitter to very bitter. The inside of the acorn's shell can be hairless but is in most cases woolly. The bark darker in color. Its leaves typically have sharp lobe tips, with bristles at the lobe tip.

The greatest concentrations of oaks are between subtropical and middle-temperate climate regimes. Further north than this, conifer species typically become dominant; further south, oaks cannot successfully compete with taller trees of tropical rainforests with respect to sunlight, and in some cases due to intolerance to high rainfall combined with high temperatures. Many oaks occur as top level canopy species, but an equally large number are shrubs or sub-canopy level associates.

In Europe, fossil pollen evidence indicates that during the last Glacial Maximum (20 000 years ago), oak species were confined to three main Pleistocene refugia in southern Europe, in Iberia, Italy and the Balkans, and it is believed that oak started to emerge from these refugia as the ice caps began to retreat at the beginning of the Holocene, 12 000 years ago. Since then oak trees have been an important element of the vegetation of much of Europe. The common presence of oaks in forests throughout prehistory is evidenced by the numerous charcoal fragments found within the archaeological record of most prehistoric cultures. In the Boreal period, 9000 - 7500 years ago, mixed oak forests increasingly dominated the forest landscape. Mixed forests expanded from the floodplains into their current range and then gradually transformed to acidophilous (acid loving) oak forests. A new type of forest, in which beech and fir were the dominant species, spread and became dominant in the Subboreal period, late Bronze Age and early Iron Age, 5700–2600 years ago. However, the process of the degradation of mixed oak forest and the spread of modern forest communities did not happen everywhere at the same time and with the same effect. For instance in Central Serbia, ancient oak forests survived until the 19th century giving the place its name "Šumadija" meaning the land of forests.

There is a strong association between human civilisations and oaks, beginning at least 30,000 years ago in Europe and Asia, and 14,000 years ago in North America. The reason for this is that oak is one of the most useful trees in the world.

Oak trees are hardwoods which means that they are strong and hard yet easy to work with. In addition, oak wood is one of the most dense naturally occurring materials, while high content of tannin makes it resistant to both fungal diseases and insects. Because of all these properties, oak wood has been used since ancient times for general construction purposes as roundwood for pillars and split for planks for flooring and furniture. Oak is also used to make shingles for traditional roof construction. In Slavic countries Oak has been the main wood used for house and furniture building since neolithic times. This is an example of a traditional house from Montenegro which contains storage for animals, carts, and tools on the ground level and living spaces on the upper level for the family. The ground level walls are constructed using stones and two wooden reinforcing bands made from oak for stabilisation as well as portions made with oak timber and planking. The upper level walls are constructed using oak timber frame with wattle and daub covered with a plaster material. The covered exterior stair and gallery are typically found in the region. The roofing is framed with oak wooden rafters and purlins and covered with oak wooden shingles (šindra)

Because of its toughness and water and rot resistance, oak has also been used to make agricultural tools like ploughs (19 century Serbia):

 
as well as waggons (20th century Croatia).

 
White oak wood is water and rot resistant but also waterproof and was used for making kitchen utensils such as serving bowls and other liquid containers such as casks, butter churns, bread kneading and washing basins, chopping boards...

For the same reason white oak was used for boat and ship building since the neolithic times. The earliest boats were dugouts made from single oak or linden trunks. In Slavic countries oak dugouts were still being made in the 19th century, like this one from Serbia:

 
Oak wood is extremely good firewood. Dense hardwoods like oak have a higher energy content per cord and so release more heat per firebox load. They also produce long-lasting fires and coal beds. This makes them ideal for domestic heating but also as the source of heat in metallurgy particularly in iron working.

Oak is particularly good for making charcoal. Charcoal is a light black residue consisting of carbon, and any remaining ash, obtained by removing water and other volatile constituents from wood, mostly oak. Charcoal is a light black residue consisting of carbon, and any remaining ash, obtained by removing water and other volatile constituents from wood, mostly oak. Charcoal is usually produced by slow pyrolysis, the heating of wood or other substances in the absence of oxygen. Historically, production of wood charcoal in locations where there is an abundance of wood and dates back to a very ancient period, and generally consists of piling billets of wood on their ends so as to form a conical pile, openings being left at the bottom to admit air, with a central shaft to serve as a flue. The whole pile is covered with turf or moistened clay. The firing is begins at the bottom of the flue, and gradually spreads outwards and upwards. The logs burn very slowly and transform into charcoal in a period of 5 days' burning. The massive production of oak charcoal was a major cause of deforestation, especially in Central Europe. The same traditional method of making oak charcoal is still used in the Balkans. These are burning charcoal piles in Bosnia, present time:

Oak bark is also rich in tannin, and is used by tanners for tanning leather. Tanning is the process of treating skins of animals to produce leather, which is more durable and less susceptible to decomposition. Traditionally, tanning used tannin, an acidic chemical compound from which the tanning process draws its name (tannin is in turn named after an old German word for oak or fir trees, from which the compound was derived). This picture is showing bark peeling from a cut down oak tree:

Oak apple or oak gall is the common name for a large, round, vaguely apple-like gall (outgrowth) commonly found on many species of oak. Oak apples range in size from 2–5 cm in diameter and are caused by chemicals injected by the larva of certain kinds of gall wasp in the family Cynipidae. The adult female wasp lays single eggs in developing leaf buds. The wasp larvae feed on the gall tissue resulting from their secretions.Oak galls have been used in the production of ink since at least the time of the Roman Empire. From the Middle Ages to the early twentieth century, iron gall ink was the main medium used for writing in the western world.

Oak is also, with beech and birch, a host to one of the most important fungi in the world, Fomes fomentarius. Fomes fomentarius, commonly known as the tinder fungus, false tinder fungus, hoof fungus, tinder conk, tinder polypore or ice man fungus, is a species of fungal plant pathogen found in Europe, Asia, Africa and North America. The species produces very large polypore fruit bodies which are shaped like a horse's hoof and vary in colour from a silvery grey to almost black, though they are normally brown. It grows on the side of various species of tree, which it infects through broken bark, causing rot. The species typically continues to live on trees long after they have died, changing from a parasite to a decomposer.

Though inedible, F. fomentarius has traditionally seen use as the main ingredient of amadou, a material used primarily as tinder. Tinder is the material used to catch the spark in primitive fire making and also to transport fire across long distances. Tinder fungus can smolder for days preserving the amber alive.

The 5,000-year-old Ötzi the Iceman carried four pieces of F. fomentarius, concluded to be for use as tinder. It also has medicinal and other uses. F. fomentarius has a circumboreal distribution, being found in both northern and southern Africa, throughout Asia and into eastern North America, and throughout Europe, and is frequently encountered. The species most typically grows upon hardwoods. In northern areas, it is most common on birch, while, in the south, beech is more typical. In the Mediterranean, oak is the typical host.

Mixed oak forests and oak savannahs are also ideal growing ground for numerous edible mushrooms. Some of them grow on fallen trees and stumps, some near the roots, some under the foliage. Different species ripen at different times of the year. Depending on the climate there is at least one type of a mixed oak forest mushrooms that can be harvested pretty much at any time of the year, but the main mushroom season is from late spring to late autumn. Mushrooms would have been one of the main food sources during this time as they are easy to collect and prepare and would by themselves provide enough protein in the diet. The main types of mushrooms which grow on or around oaks are: truffles (tartuf or gomoljača in Serbian), porcini (vrganj in Serbian), lumpy bracket (Jelenovo uvo or hrastov žbunac), Caesar's mushroom (jajčara or rujnica in Serbian), royal bolete (kraljevka in Serbian), the miller or the sweetbread mushroom (brašnjača in Serbian), russula (medena, medenka in Serbian). My favourite is porcini (vrganj in Serbian). Balkans is the home of the giant porcini mushrooms which grow in oak savannahs. Me and my brother used to make a lot of money every year from picking mushrooms in forests. Once when we were 10 and 8, while picking mushrooms with my father on mountain Vlasina in the south east of Serbia, we found a truly giant one which was over half a meter in diameter and over 4 kilos in weight. Unfortunately I don't have any picture of this mushroom, but here are some other giant vrganj (porchini) mushrooms found in Serbia and Croatia:

Oak doesn't lose all the leaves during the winter like other decidious trees. The leaves turn golden but stay on the branches until spring.

In the Balkans at the end of October farmers used to cut the outer branches of young oak trees, specifically grown for this purpose in thickets, and store them in stacks for fodder to feed livestock during the winter. This practise is in English called polarding. Polarding produces "pollard hay", basically dry branches with lots of dry leaves, which are used as livestock feed. The trees are pruned at intervals of two to six years so their leafy material would be most abundant. Apart from oak, ash branches are also cut for this purpose. In Serbian this "pollard hay" is called "lišnjak" or "šuma". The branches are cut and then dried for two days. They are then collected in armloads and brought to the specially prepared stake called "stožina", "stožer" where the armloads of branches are placed around the central stake, leaves towards the stake, in the same way you would place armloads of hay or wheat. As they are laid down, the branches are compressed by standing on them. In the end the top of the stack is covered with fern and hay and thick oak branches with leaves turned outward. This type of fodder is used for feeding sheep and goats during the second part of winter when other animal food like hay is running low. In Croatia Lamb is sacrificed at the beginning of the oak polarding and eaten communally by the men who do the branch cutting. Polarding is considered dangerous, probably because the oak is considered sacred and cutting oaks is activity that brings bad luck. This is a picture of stacked "lišnjak":

The oak inner bark, as well as the inner bark of certain trees like cedar, poplar, linden (basswood, lime), sweet chestnut, willow, elm can be used to make excellent cordage... Tree bark is made up of two portions, the inner bark or phloem (which passes the sugary sap around the tree), and the outer bark, which acts as the waterproof skin of the trunk, protecting from disease and extremes of temperature. The bit that is good for making cordage is the inner bark. It consists of long interwoven fibres that form an interlocking weave. It peels readily from the tree and is easy to work with. Bark from dead limbs provides the best material. The best dead limbs are ones that have been dead for a week or two. Any longer and the bark will have dried out a lot. The inner bark cordage is very strong and durable and it stays flexible without cracking when bent when dry.

Oaks were also used as medicine for millennia. Oak was used to treat bleeding, tumors, swelling and dysentery as well as a diuretic and as an antidote to poison. Snuff made from powdered root was used to treat tuberculosis. The leaves have been employed to promote wound healing. Oak has been used as a Quinine substitute in the treatment of fevers. Tannins provide many of the healing properties of oak. Tannins bind with proteins in tissues, making a barrier resistant to bacterial invasion. Tannins strengthen tissues and blood vessels. They reduce inflammation and irritation, especially of skin and mucus membranes.The plant parts used for healing include the inner bark, root, leaves and acorns. Modern scientific research confirms that oak possesses the following healing properties: astringent, fever reducing, tonic, antiseptic, anti-viral, anti-tumor, and anti-inflammatory actions. In addition, oak has been used to get rid of worms and other parasites.

You can see from all of this that Oak is something of a wonder tree. But the best part is yet to come. Acorns. Oaks produce acorns, a lot of them. Squirrels, deer, wild boar love to eat acorns, sometimes to the point of acorns being 25% of their fall diet.

 
Which makes oak forests ideal hunting grounds for early hunters who hunted with fire hardened spears made from oak or ash like this one.

But people were not going to watch all those animals munching acorns without trying acorns themselves. The rest is history....Acorns have been eaten by humans since at least late Paleolithic times right up to modern times. And I will write about acorns and acorn eaters in my next few posts.