A Farmer's Guide to Which Wood Chips to Avoid Around Livestock

Why wood type matters

When trees are processed into chips, the material is a mix of wood, bark, leaves, buds, and sometimes seeds or fruit. This matters because in many species, the highest concentration of toxins is not in the wood itself but in the leaves, bark, or cambium layer (layer just beneath the outer bark).

There are a few key risk factors:

• Fresh vs. aged chips. Fresh chips are more likely to contain active compounds. Some toxins break down over time, while others remain dangerous.
• Wilted plant material. Certain species (like wild cherry and red maple) become more toxic after being cut or wilted, not less.
• Animal behavior. Livestock typically do not seek out wood chips as food, but:
• Curious animals may nibble
• Bored animals may chew
• Chips in feeding areas can be accidentally consumed
• Volume and exposure. Small incidental exposure may not cause issues, but large quantities or repeated access increases risk significantly.

Wood species to avoid around livestock

These species are widely recognized as unsafe and should not be used in livestock areas under any circumstances:

Wild Cherry (Prunus species)

• One of the highest-risk species
• Contains compounds that convert to cyanide when wilted or damaged
• Toxicity increases after cutting or chipping
• Even small amounts can be fatal, especially to cattle and horses

Yew (Taxus species)

• No safe exposure level
• Contains taxine alkaloids that affect the heart
• Remains toxic whether fresh, dried, or chipped
• Extremely small amounts can cause sudden death

Black Walnut (Juglans nigra)

• Produces juglone, a compound toxic to certain plants and animals
• Causes laminitis in horses, even from standing on contaminated bedding
• Risk exists even without ingestion

Red Maple (Acer rubrum)

• Wilted leaves cause destruction of red blood cells in horses
• Chips that include leaves are dangerous
• Fresh fallen branches after storms are a common source of exposure

Oak (Quercus species)

• Contains tannins that affect kidney function
• Typically a risk when animals consume large amounts
• Acorns and young leaves are especially problematic

Black Locust (Robinia pseudoacacia)

• Bark and wood contain toxic compounds
• Can cause:
• Weakness
• Digestive upset
• Neurological symptoms

Boxwood (Buxus species)

• Contains toxic alkaloids
• More common in ornamental removals than large tree work
  

Some wood types are not highly toxic in most cases but may still cause issues depending on how they are used:

Cedar

• Contains strong aromatic oils
• Can cause respiratory irritation, especially in enclosed barns or coops
• Some animals are more sensitive than others
• Better for outdoor use than bedding

Pine (especially fresh chips)

• Fresh pine contains resins and volatile compounds
• Can irritate skin or lungs
• Affects small or sensitive animals more strongly
• Becomes safer after aging and drying

Safer wood chip options for livestock

These species are generally considered safe for use around livestock when used appropriately:

• Maple (excluding red maple)
• Ash
• Elm
• Birch
• Poplar
• Beech

These woods have low toxicity, break down relatively predictably, and are commonly used for footing, erosion control, and mud management. That said, “safe” does not mean edible. Wood chips should always be treated as environmental material, not feed.

Best practices when using wood chips on farms

Even when using safe species, how you use wood chips matters just as much as what they are made from.

1. Keep chips out of feeding areas

Avoid placing chips where hay, grain, or minerals are fed. This reduces risk of accidental ingestion.

2. Ask about tree species before work begins

If you’re working with a tree service, confirm what species are being removed and whether chips will be left on-site or taken away.

3. Allow chips to age when possible

Letting chips sit for some time to reduce moisture and allow compounds to break down properly. Aged chips are generally more stable and predictable.

4. Use chips primarily for ground management

Best uses include mud control in high-traffic areas, pathways and walkways, and dry lot footing. Avoid using chips as bedding (unless species is confirmed safe and appropriate)or around anything animals are likely to consume.

5. Monitor animals after introducing new material

Watch for changes in behavior such as reduced appetite or signs of discomfort or lameness (especially in horses). Remove the material if concerns arise.



6. Always err on the side of caution

If you’re unsure about a wood chip pile:

• Unknown source? → Don’t use it in animal areas
• Contains leaves/bark from risky species? → Avoid completely
• Sitting/aged and from a known safe species? → Monitor closely

When in doubt, it’s always better to err on the side of caution, especially with horses and cattle.

Work with a tree company that understands

Not all tree services consider livestock safety when processing or distributing wood chips. For farms, this detail matters. At 4 Seasons, we:

• Identify tree species before removal
• Communicate clearly about chip contents
• Work with clients to ensure materials are appropriate for their animals

If you have livestock, let us know ahead of time. We can help you make informed, safe decisions for your animals.