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Excavation of morta from Sava river in Croatia


Bog-wood, also known as abonos and morta, especially amongst pipesmokers,[1] is a material from trees that have been buried in peat bogs and preserved from decay by the acidic and anaerobic bog conditions, sometimes for hundreds or even thousands of years. The wood is usually stained brown by tannins dissolved in the acidic water. Bog-wood represents the early stages in the fossilisation of wood, with further stages ultimately forming lignite and coal over a period of many millions of years. Bog-wood may come from any tree species naturally growing near or in bogs, including oak (Quercus – "bog oak"), pine (Pinus), yew (Taxus), swamp cypress (Taxodium) and kauri (Agathis). Bog-wood is often removed from fields etc. and placed in clearance cairns. It is a rare form of timber that is "comparable to some of the world's most expensive tropical hardwoods".[2]

Formation process[edit]

Soils that are mostly wet, sandy, gravel and clay-like -- usually found above high underground waters -- are the most suitable habitats for oak forest. These forests thrive best on lowland and slight upland soils of the diluvial geological era, the valleys of river basins being especially suitable sites for this type of oak.[1]

Morta color based on age

Variations in the water level, floods, marshes formation promote the growth of oak trees. Because of a continuous change of the direction of the river flow on a greater or lesser degree, the mainstreams weave through the valleys constantly forming live meanders. In its meandering course, the river undermines the banks covered with trees, which fall into the river and are swept away in the water. When the trunk gets trapped by its branches and roots in the river bed, over time layers of mud, sand and gravel cover it. Deprived of oxygen the wood undergoes the process of fossilization and a long process of morta formation.[1]

During hundreds and thousands of years, under the influence of the minerals and iron from the water, the decomposition of oak timber is considerably slower. A special role is played by the currents of the underground waters in the creation of morta, binding its ingredients with larger quantities of the tannin in the wood and in this way darkening the wood. This centuries-long process, often termed "maturation", turns the wood from golden-brown to completely black, while increasing its hardness to such a level that it can only be carved with the use of specially grind and exceptionally firm tools.[1]

The time necessary for the oak to transform from the end of its biological growth to abonos varies. The "maturation" commonly lasts thousands of years. Due to the ecological reasons mentioned above no two trunks can be found of the same colour.[1]

Excavation sites[edit]

Bog-wood from Sava river, BiH

Sites of bog-wood in the world are very rare. In the sites expected to accommodate it (e.g., in Croatia mainly in the valley of the Sava River and its tributaries) morta is hard to find, the access to the river bank and its bed is often difficult, preventing morta recovery. Therefore, excessive preparations and engagement of a large number of professional divers are necessary. Morta is located in conditions of total darkness and its extraction marks its first exposure to light after many thousands of years. The age of morta found in Croatian rivers ranges from several hundred years in the rivers on the southern part to the oldest retrieved so far from the Krapina River being 8290 years old.[1]

Saving the quality of wood as the material for further processing is a very delicate matter.The process of wood desiccation is complex, but despite great care most of the raw wood is unsuitable for further processing. For this reason the price of quality raw abonos is very high.[1]


Aesthetic effect of morta is based on the very experience of naturally formed colour, noticeable wood structure, its “imperfect” appearance, and the fact that parts of the wood are combined which by their variation in the colour, directions of growth rings, or certain “damage” convey a strong aesthetic and ethical message about the immensity of the past times. Deep impression of the passing of time is also grounded on the knowledge of longevity of wood and the miracle of its intactness indicates that wood is not affected by usual weather conditions or vermin which naturally spoil the looks and strength of wood. Semi dry bog-wood is exceptionally hard, sometimes of the golden or copper colour, or with a tint of some other hue. Older wood can be completely black. This colour is particularly specific so every connoisseur of materials is able to notice the profound permeation of the wood structure by darkness, noble black colour of “live” wood so different from that of black fossil or coal. This value of deep darkness is a special feature of abonos as construction material whether it be used for the making of semi manufactured goods, veneer, planks or bams, depending on purpose of the final product, or for final goods: floor coverings, furniture, doors, window frames, sculptures, and various decorative objects and items for everyday use.[1]


Bog wood in an aquarium releases tannins into the water, turning the water brown.

Because bog-wood can remain undecayed for thousands of years it is of use in dendrochronology, often providing records much older than living trees. Wooden artefacts lost or buried in bogs become preserved as bog-wood, and are important in archaeology.

Bog-wood may be used in joinery to make furniture or wood carving. Bog-wood sometimes has aesthetically interesting shapes (similar to driftwood) and as such may be use as ornaments. As bog-wood dries out, it may crack or split, but this does not necessarily detract from the aesthetic qualities of a bog-wood sculpture. It is a traditionally favoured wood for the carving of dirks (bìodagan) and sgian-dubh in the Scottish Highlands due to its natural colour.

Bog-wood is used in aquaria for ornaments, providing hiding places for fish and a growing surface for plants such as Java fern.[3] Additionally, the leaching of organic compounds such as tannins into the water causes a brown colouration. It is also a staple part of the diet for loricariid catfish kept in aquaria as it aids digestion.[citation needed]

During the nineteenth century bog oak was used to make carved decorative items such as jewellery [4] and in some parts of the world it is still used for making of unique artifacts.[5]

Souvenirs made out of morta / bog-wood
Tobacco pipe made of morta / bog-wood

Tobacco pipes[edit]

One of the uses of morta is for making of tobacco pipes. It is an ideal material because of a high percentage of minerals, reaching up to 12%, which makes morta especially resistant to burning, and thousand-year long washing erased all traces of tannin, resin and similar ingredients, giving a neutral taste during tobacco smoking. Finalized piece is beautiful, the structure of the wood gives a unique look. When smoked, neutral taste is given to the smoke. All this makes bog-wood invaluable in pipe smoking and results in a high demand by the pipe smokers.[1]

Purchasing quality material is much too complicated and the processing of material is difficult with a relatively high portion of write-offs. Morta is hard to carve, some parts can be supple while others extremely hard, the percentage of hidden flaws in material is huge, which all may cause the pipe during its final production stages to crack, and dozens of hours of work to be in vain. Today there is a relatively small number of pipemakers who make pipes out of morta.[1]

See also[edit]

  • Aquarium substrates
  • Driftwood
  • Mopane wood, recovered from deserts and often sold as an alternative to bogwood for aquaria; it is sometimes incorrectly labelled as bogwood or charred bogwood.
  • Swamp kauri
  • Sweet Track, a timber causeway in Somerset, England, its timbers preserved in waterlogged ground for over 5,800 years.


  1. ^ a b c d e f g h i j Đenović, Davorin. "What is abonos-morta?". Retrieved 2 December 2013. 
  2. ^ "Huge 5,000-year-old oak unearthed". BBC. 2012-09-26. Retrieved 2012-09-27. 
  3. ^ "How to grow plants on bogwood". AquaDaily. 2009-01-20. Retrieved 2009-01-31. 
  4. ^ Tanenbaum, Carole; Rita Silvan (2006). Fabulous Fakes: A Passion for Vintage Costume Jewelry. Toronto: Madison Press. p. 22. 
  5. ^ "Souvenirs made out of abonos". Retrieved 2 December 2013. 

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