We always say that water is wood's worst enemy. When it is in excess it creates conditions for the growth of micro-organisms that feed on the wood, causing it to rot. And yet, there are logs that have been immersed in water for a long time and are still in very good condition. Such logs taken from the lake or swamps can be used without problems to make furniture or other objects. Not really without problems, because sometimes the wood is so hard that it can jeopardize the integrity of tools. Find out how submerged wood is preserved in water and how it becomes harder or resonates more pleasantly below.
Why doesn't wood rot in water?
Because there is no air. Wood rot is caused by specific fungi that feed on the components of wood - cellulose, hemicellulose and lignin. This causes important changes in structure and properties. However, a suitable environment is needed for the fungi to develop: water content in the wood above 20%, presence of oxygen, temperature in the range 0-40°C. As the wood is submerged in water, oxygen is at a very low level so the organisms responsible for decay cannot live.
This explains why logs that are not immediately cut and dried are sometimes stored in pools of water. Wood is a hygroscopic material with a high absorption capacity. It floats because there is air in the hollows inside, density of wood mass compact being for all species about the same - 1500 kg/m³. Gradually the air inside is replaced by water, the density increases and exceeds that of water and the trunk sinks. Species react differently, with denser species sinking faster.
The durability of wood submerged in water is not the same for all species
Durability in water is also linked to the fact that lignin, which gives the wood its stiffness and strength, is very stable in an aqueous environment. Cellulose swells in the presence of water and, over time, can become food for various aquatic life. Hemicellulose is the least resistant. It dissolves in water under the action of salts which, under certain conditions, form dilute acids and gradually separate from the cellulose skeleton. Therefore, the higher the lignin content, the longer the wood resists submerged in water.
Below are the best known native species and their average durability fully immersed in water:
- oak, larch - 500 years
- Scots pine - 400 years
- acacia, elm - 300 years
- walnut - 200 years
- frasin - 90 years
- spruce - 80 years
- fag - 70 years
- brad - 60 years old
- birch - 40 years
- anin, plop - 30 years old
- willow - 15 years
(source: J. Filipovici - Study of Wood)
Harder wood with denser and more consistent fiber
Sometimes, wood that has been removed after hundreds of years from water or bog is very hard. One explanation for this hardness is the time when the tree grew. Hundreds of years ago, growth was much slower and forests were not intensively logged. Trees were felled at full maturity, when they were very tall and thick. The slow growth meant that the wood was very dense, with the annual rings close together. On the other hand, salts from the water penetrate the wood and take the place of hemicellulose. If it has been in the water for very long periods (thousands of years), the wood can even reach the hardness of stone (petrified wood). The deposited salts do not spoil the design of the wood, and the processing produces slabs with the appearance of wood and the hardness of rock. Petrified wood is used to make jewelry, ashtrays or decorative objects.
There are companies all over the world working to recover wood that was washed up on the bottom of lakes, seas and oceans in the 18th and 19th centuries. This was the period when a lot of high-quality timber was transported from the colonies to Europe. In the USA, a lot of building was done due to emigration and timber was sometimes brought by water from the forests of Canada or Alaska. During transportation some rafts or ships sank. The wood that was not brought ashore ended up on the bottom of the water, stuck in the mud. With modern machinery, the wood is identified, recovered and sold to furniture manufacturers. They say the fiber is denser and more consistent, and the wood is often of higher quality than today's wood.
Wood with better resonance than Stradivarius violins
Studying the properties of submerged wood can reveal special aspects. For example, Joseph Nagyvary, a professor of biochemistry and biophysics at Texas A&M University, is passionate about building resonating instruments, especially violins. He has spent years studying violins built by Stradivarius and Guarneri. When he came into possession of a very small piece of wood from a Stradivarius violin, he saw under a microscope that part of the hemicellulose was missing.
In his quest to understand the phenomenon, he traced the thread of history and discovered that at the time, the biggest gateway for timber was Venice. The city built in the lagoon offered very little storage space so the wood was kept in the water. The wood lost not only its hemicellulose but also some of its gums, which gave it a much better resonance and made it perfect for musical instruments.
Wanting to prove his theory, Nagyvary built a violin following Stradivarius techniques with wood held in a sea-like salt solution. When the violin was ready, he organized a concert duel, The other violin is a Stradivarius from 1725, the heyday of the great violin-maker. The concert was attended by 600 people who sat behind a screen that prevented them from seeing the violins. By a narrow margin the vote went Nagyvary's way, with the audience deciding that his violin sounded better. It was the first time a Stradivarius had been compared to an instrument built in the modern day.
I hope you find the above information useful. As always, additions are welcome. And if you have any questions or queries, please leave them below in the space provided. I will be sure to reply.
Ask someone why logs from very old constructions resist,.....because they were carried on water by floats and the sap was washed away by water...etc etc...and logs from salty lakes cannot be processed because over time the air between the fibres has been replaced by salts in the water...
Thank you for the additions!
A method of drying hardwoods in running water is also mentioned in the past. Unfortunately very little information was found.
I couldn't find any information. I'll keep looking through old books. I'm guessing it's a pre-treatment method, because you can't dry wood if it sits in water. I'm thinking something similar to what Fane says above. The sap washed out and replaced with river water, which then came out of the wood faster and without much strain. Just an opinion. I'll look for info, it must exist somewhere. 🙂
Thanks for the interesting article. I watched something similar related to the properties of logs in immersion related to Spirit Lake, Mount St. Helens. If you recall the 1980 eruption "raked" (among other things) a huge area of trees, mostly firs, much of which ended up in the nearby lake, nearly covering it. As the area was declared a post-disaster nature study area, the logs in the lake (too many to recover or salvage) were left behind. After a few decades it was found that some had degraded, others had sunk, and here's the interesting part, some of the sunken ones had become upright and some of them had reached the bottom of the lake and, as the ecologists put it, "replanted" (observations made with sonar). Obviously the researchers' considerations were mostly related to the petrified forests that occur in places on Earth and the theories about their formation, nor do I claim to have perfectly understood everything they were saying, as the documentary was not translated. But I hope that if you look into what was said/written about what happened after the eruption, you will find a lot of useful material, especially since there was an American Timberlake company in the area affected by the disaster, which had leased part of the pine forests, and they themselves worked both on harvesting the wood ripped out by the volcanic explosion and on replanting the forest and documenting the effects of the disaster.
Very interesting, thanks for the addition!
I will try to find more information about this phenomenon.