Walnut wood is super popular. It has a nice texture, a dark color that can’t be beaten, it’s hard and there are many other benefits that make woodworkers love it.
However, working with wood is not without its dangers. The most well-known danger is sawdust. Another danger that people are often less aware of is that wood can also be toxic. This is very important when creating items that come into contact with food. So, is walnut wood toxic?
Due to the presence of juglone, walnut wood is poisonous. The greatest concentration of juglone is present in the roots, but also in the wood, sufficient juglone is present to cause both short-term (throat and lung irritations) and long-term (chronic poisoning) effects.
I’ll answer the topic “is walnut wood toxic” in this article so that you, as a woodworker, are aware of the black walnut toxicity to humans.
This way, you’ll be able to correctly analyze the dangers of black walnut toxicity to humans and what you can do to avoid juglone invading your body. Before you begin working with walnut wood, be sure to read this article about walnut toxicity.
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Is walnut wood toxic? The details you need to know as a woodworker!
As beautiful as the wood is, unfortunately, walnut is toxic in some respects, but you could already read that in the intro to this article. In this part, I’ll take a closer look at black walnut toxicity to humans, juglone poisoning symptoms in humans, and how you can protect yourself against it.
What is Juglone
Juglone (5-hydroxyalphanapthaquinone) is a toxic substance produced by the roots of Black Walnut (Juglans nigra L.) and Butternut (Juglans cinerea L.). Other varieties of walnut trees, such as Persian (English or Carpathian) walnut trees, are occasionally grafted onto black walnut rootstocks, implying the presence of this toxic chemical.
The substance juglone, from which the scientific name juglans derives, can be so toxic to plants such as tomato, potato, blackberry, blueberry, apple, and many other plants that if planted nearby, they will be injured or killed.
This poisonous zone surrounding a mature tree can reach a radius of 50 to 60 feet (15 to 18 meters) from the trunk. However, Juglone is poorly soluble in water and does not move very far in the soil.
What part of black walnut is toxic
The toxin juglone is found in walnut leaves, bark, and wood, albeit at lower concentrations than in the roots.
The leaves and bark will not be a problem for us as woodworkers, because we will never be in contact with them. As a result, the woods pose the greatest threat. Below, I’ll go over this in greater depth.
Walnut pollen (typically in May) can induce allergic reactions in both humans and animals (especially horses). Walnut-induced allergic reactions can range in severity from mild oral allergy syndrome (itching in the mouth and/or tongue) to severe and even fatal systemic reactions (anaphylactic shock, hives, and swelling of the throat, asthma)
What does Juglone do to the human body
Juglone is a natural organic compound predominantly found in the black walnut tree and its various parts. It’s essential to be aware of the black walnut toxicity to humans and its effects on its surroundings. Here are the common juglone poisoning symptoms in humans but also for the environment and animals:
Effects on Humans:
- Skin Irritation: Coming into direct contact with juglone or walnut wood might cause skin irritation. In some cases, the chemical binds to the skin, leading to an irritant reaction. However, simply coming into contact with walnut wood is generally not harmful.
- Direct Consumption: Ingesting even a minute amount of pure juglone can result in severe poisoning.
- Indirect Contact: Using walnut wood for kitchen utensils, cutting boards, or any items that come into contact with food may not be advisable. Juglone can potentially transfer from the wood to the food, posing a risk of ingestion. While the walnut itself is not directly harmful to consume, it is the juglone compound within that poses potential risks.
- Discomfort: For some individuals, exposure to walnut toxicity might lead to immediate discomfort, although more extensive research might be needed to ascertain the full range of reactions in humans.
Effects on the Environment:
- Toxic Radius: The toxic effects of a mature black walnut tree can extend as far as 50 to 80 feet from its trunk. The highest concentration of toxicity is found within the tree’s dripline.
- Plant Toxicity:
- Sensitive Plants: Certain plants wilt or die upon exposure to juglone. Examples include vegetables like tomatoes, potatoes, eggplants, and peppers. Ornamental plants like lilacs, peonies, rhododendrons, and azaleas are also particularly susceptible.
- Tolerant Plants: On the other hand, some plants remain unaffected by juglone and will continue to grow as usual.
In this video you will see a 3 month- journey experiment with tomato plants where you can see the effects of juglone, the toxin produced by the black walnut tree:
Effects on Animals:
While the primary focus here is on humans, it’s worth noting that some animals, especially horses, are incredibly sensitive to juglone. For this reason, walnut chips or walnut sawdust should never be used in horse bedding.
In Conclusion: Juglone possesses certain toxic characteristics that can adversely affect humans, plants, and animals. While humans might experience skin irritation and potential poisoning upon ingestion, plants and certain animals can exhibit more severe reactions. As always, it’s recommended to exercise caution when handling or coming into proximity with substances containing juglone.
Is walnut dust toxic
As you could read earlier, the chemical found in walnut is called juglone. It is most present in the roots of the tree and in some fewer proportions in the wood. Also, the moisture level of the wood plays a huge role in the quantity of the juglone.
This substance is present in a higher concentration in wet wood. Therefore, never cut walnut wood that is not sufficiently dried out. When cutting wood, no matter what type of wood, dust is released and is always carcinogenic!
When cutting walnut wood, sawdust is released, which contains the toxic substance juglone. This walnut sawdust will dry out the sinus, throat and gives you a very dry cough. Continued intake of walnut sawdust will increase the juglone level in your body, resulting in chronic poisoning.
In any case, when sawing wood, it is strongly advised to always use a dust mask. Walnut sawdust is considered a “sensitizer.” This means that you may not have an instant reaction, but you may build one over time if you continue to be exposed.
The reaction can’t be reversed once your body has become sensitive, and it gets worse over time.
In addition to wearing a mouth mask, I recommend washing dusty clothing as soon as possible after a day of working with walnuts to avoid the walnut sawdust being absorbed by the body.
Is walnut wood food safe
Videos and pictures of people constructing cutting boards, wooden spoons, and a variety of other kitchen items abound on the internet.
Some people will also do this with walnut wood. And somehow I understand it because it is a beautiful type of wood that adds a touch of color to your project.
But I think it is especially unfortunate that they pretend to be an expert and give wrong information because they don’t have the knowledge themselves and do not understand the black walnut toxicity to humans. So whatever you build, keep in mind that walnut wood is poisonous.
So, is walnut wood food safe? The answer is no! Due to the presence of toxic juglone in the walnut wood, I would never recommend making objects that come into contact with food. There is a chance that the food will absorb the juglone, resulting in chronic poisoning.
To make wooden objects that come into contact with food, I would rather recommend woods such as maple or beech. Above all, remember that walnut is not food safe. To get inspired with a list of food save woods, check out my article, what kind of wood is food safe.
By the way, if you want to glue wooden parts that come into contact with food, you don’t just use any glue. Earlier I wrote the article: “Is super glue food safe”, there you can find all information about the food-safe gluing of wood.
Recommended article: Walnut vs Oak, a quick guide to help you choose
Walnut wood characteristics
Walnut comes in a wide range of varieties that can be utilized in woodworking. The black walnut, or juglans nigra, is the most often used species. Other species used in woodworking include the butternut (Juglans regia), and the English walnut, sometimes known as white walnut (Juglans cinerea).
Black walnut is a strong, durable, and fine-grained wood that is dark, hard, and dense. It’s a sort of wood that resists warping and isn’t easily affected by shrinking. The grain is variable, but usually straight, with a medium texture. The end grain has visible growth rings and is semi-porous.
Walnut is a wood species that is susceptible to insects but, thanks to its hardness, quite resistant to spoilage. When Walnut wood is processed by sawing or milling, a typical scent is released that is very recognizable. Once the wood is finished, walnut feels soft and smooth and gives your project a unique and natural dark look.
(Source pictures: wood database)
What is walnut wood used for
Black walnut wood is valued by woodworkers for its strength, grain, and color. That is why this type of wood is often used for furniture, musical instruments, carvings, decorations, and veneers. The big advantage of walnut is that this type of wood can be polished to a smooth finish. The color of walnut can vary, with the sapwood (or the outer layer of the wood) being a creamy white color, and the heartwood (the inner part of the wood) being a dark chocolate-like color.
The longer the time elapses after finishing natural walnut wood, the more this wood develops a glossy patina. The condition is, of course, that you give it the necessary care. As a dark brown wood, it is popular among dedicated woodworkers and lovers of fine furniture. That is why walnut is often used in luxury products such as luxury cabinets, natural wood floors, boat building, and more.
Whatever you produce with walnut will have a distinctively warm appearance that, thanks to the high quality of the wood, will last a long time. I’ve listed a few more features in the table below that may be useful if you want to start working with walnut wood yourself.
PS: To learn more about what Janka hardness is, check out my in-depth article, What Is Janka Rating And Is It Still Relevant?
|Average Dried Weight
|38 lbs/ft3 (610 kg/m3)
|27 lbs/ft3 (435 kg/m3)
|40 lbs/ft3 (640 kg/m3)
|1,010 lbf (4,490 N)
|490 lbf (2,180 N)
|1,220 lbf (5,410 N)
|Radial: 5.5%, Tangential: 7.8%, Volumetric: 12.8%, T/R Ratio: 1.4
|Radial: 3.4%, Tangential: 6.4%, Volumetric: 10.6%, T/R Ratio: 1.9
|Radial: 5.5%, Tangential: 7.5%, Volumetric: 13.0%, T/R Ratio: 1.4
Advantages and disadvantages of walnut wood
As with any type of wood, walnut has a few advantages and disadvantages. In the lists below, I go over the most important. Because of these pros and cons, you as a woodworker can decide whether this wood is suitable for your project or not.
Advantages of walnut wood
- Environmental & Eco-Friendly: growing walnut wood causes no damage to air, soil, water, animals etc. unless pesticides have been used.
- Attractive wood grain: Texture and dyeing in grain are very individual and lively.
- Durable Wood: Walnut wood is very durable, and its lifespan is up to 150-400 years.
- Highly resistant to wear and tear: This type of wood is also resistant to mold and water.
- Stains and polishes well: If the user is very much experienced, then the installation process of walnut wood items are quite easy as compared to other woods.
- Walnut wood is pretty water resistant, you can discover more about that in my in-depth article, is walnut wood water resistant. Be sure to read that article, because that knowledge can make or break your project.
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Disadvantages of walnut wood
- Walnut toxicity: working with walnut can cause chronic poisoning in the long run.
- Cost: walnut wood is pretty expensive as compared to other woods like oak wood. Please check my in-dept article “Why is walnut wood so expensive“.
- Scratches: This wood can easily get damaged or scratched by a knife or with other sharp items.
- Difficult To Install: for beginner users, walnut wood installation will be more difficult because it can easily be damaged by scratches.
- Maintenance: The user needs to apply a new layer of finish on the surface of walnut wood after a few years of its usage.
- Weight: The weight of walnut wood is pretty heavy, and it is not easy to handle and transport.
Is walnut wood toxic – Conclusion
In conclusion, the topic of black walnut toxicity to humans, specifically focusing on juglone poisoning symptoms in humans, sheds light on the potential health risks associated with this popular tree species. While black walnut trees (Juglans nigra) are valued for their beautiful wood and tasty nuts, they can pose certain risks to human health due to the presence of juglone, a natural chemical compound found in various parts of the tree, particularly in its roots, leaves, and hulls.
It is essential for individuals to be aware of the potential dangers posed by juglone, which can cause adverse effects when humans come into contact with it. Symptoms of juglone poisoning in humans may include skin irritation, rashes, and gastrointestinal discomfort. Furthermore, the consumption of black walnut husks or other parts of the tree can lead to more severe symptoms such as nausea, vomiting, and diarrhea. It is worth noting that while cases of severe juglone poisoning in humans are relatively rare, it is crucial to exercise caution and take preventive measures when working with or around black walnut trees.
To mitigate the risk of black walnut toxicity, individuals should avoid direct contact with the tree’s sap, leaves, or husks, especially if they have sensitive skin or allergies. Proper disposal of fallen leaves and nuts, along with washing hands and clothing after handling black walnut tree parts, can help reduce the chances of adverse reactions.
In conclusion, while black walnut trees offer numerous benefits, including their aesthetic appeal and delicious nuts, it is essential to be mindful of the potential for juglone poisoning symptoms in humans. By understanding the risks associated with these trees and taking appropriate precautions, individuals can continue to enjoy the beauty and utility of black walnut trees while safeguarding their health.
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