Naturally Rot-resistant Woods

Natural range of black locust in the US
Natural range of black locust in the US

Osage orange fruit
Osage orange fruit

Wiki: Naturally rot-resistant woods
These species are resistant to decay in their natural state, due to high levels of organic chemicals called extractives, mainly polyphenols. Extractives are chemicals that are deposited in the heartwood of certain tree species as they convert sapwood to heartwood. Huon pine, merbau, ironbark, tōtara, puriri, kauri, and many cypresses, such as coast redwood and western red cedar, fall in this category. (This article also covers wood preservation techniques such as borate preservatives, linseed oil, glass fortified wood using sodium silicates, heat treatment, the Boucherie process and more.)

Black locust
FAO: “Farmers find that black locust meets nearly all the demands of rural life. It can be planted and regenerated easily, has no serious diseases, and grows well on good sites. The wood is hard, has great strength and durability, and is easily workable. The timber may soon be utilized for both high-quality fibreboard and for structures produced from glued and jointed black locust boards. Poles may be utilized by the mining industry, vineyards and orchards. Because it is abrasion-resistant and of good colour, interior architecture can use black locust for parquetry and wall panelling. Since it is very durable, black locust is also good for garden furniture and equipment for forest recreational areas, and outdoor sports activities. Because of its high caloric value and its ability to burn even when wet, it is popular also as firewood.” (The lengthy article lists many other attributes such as nitrogen fixing, animal feed, coppicing, erosion control, reforestation, veneer, charcoal and firewood.)

Osage orange
Wiki: “The Osage-orange is commonly used as a tree row windbreak in prairie states, which gives it one of its colloquial names, “hedge apple”. It was one of the primary trees used in President Franklin Delano Roosevelt’s “Great Plains Shelterbelt” WPA project, which was launched in 1934 as an ambitious plan to modify weather and prevent soil erosion in the Great Plains states, and by 1942 resulted in the planting of 30,233 shelterbelts containing 220 million trees that stretched for 18,600 miles (29,900 km). The sharp-thorned trees were also planted as cattle-deterring hedges before the introduction of barbed wire and afterwards became an important source of fence posts.

The heavy, close-grained yellow-orange wood is very dense and is prized for tool handles, treenails, fence posts, electrical insulators, and other applications requiring a strong dimensionally stable wood that withstands rot. Straight-grained osage timber (most is knotty and twisted) makes very good bows. In Arkansas, in the early 19th century, a good Osage bow was worth a horse and a blanket. Additionally, a yellow-orange dye can be extracted from the wood, which can be used as a substitute for fustic and aniline dyes. When dried, the wood has the highest BTU content of any commonly available North American wood, and burns long and hot.”

Image source: FAO
Image source: Betsy from Tennessee blog

4 thoughts on “Naturally Rot-resistant Woods”

  1. I understand there is a “ship mast” form of Black Locust. It has a very straight growing trunk. It is, or was , planted widely in Hungary I believe. This form also had less thorns. An older gentleman once told me you had to work it while green. This, he said, was due to the fact it becomes as hard as iron once fully seasoned. I have not had the chance to work with any so it is only secondhand information. Thank you for a very interesting read each day.

    • Thanks, that’s interesting. I did read where lots have black locust trees have been planted in Hungary and the surrounding area. I wonder how many are ship mast type trees?

      Update: One article says there are 4 million hectares of black locust trees in Hungary. They have 250 years of research and propagation of trees with superior traits.

      “The primary use of black locust wood has been for fence posts which, due to flavonoids in the heartwood, can endure for over 100 years in the soil… Widely used for erosion control and reforestation, black locust is ideally suited for woody biomass plantings, and commercial energy production may eventually become one of its primary uses in the U.S. Its virtues include nitrogen fixing ability, inexpensive propagation by seed, rapid vegetative propagation, adaptability to a wide range of site conditions, rapid juvenile growth, high heat content of the wood, and prolific regrowth after cutting (Miller et al. 1987).”

      Discussion about shipmast black locust:
      This looks like a US forum and they may not know the details about black locust trees in Hungary where they’re intensively researching and propagating these trees.

  2. Interesting info on the Black Locust. Would never have thought the wood was good for much other then burning. I would add that do not plant anywhere close to garden or landscaped areas. Black Locust are invasive, send up suckers, and have and abundant amount of litter. They form seed pods and the blossoms are allergenic. Maybe a great tree for the back 40 that is to be harvested, but not something you would want to intentionally plant near a residence. In California they are found all over the high desert areas. They are a nuisance tree comparable with the Siberian Elm and Cottonwood..They are prolific and fast growing.They are a member of the legume family and can fix nitrogen in poor soils. Black Locust roots spread out and can send up suckers 50-60 ft away from the tree..


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