The Tree of Heaven (Ailanthus altissima), native to China, is a fast-growing deciduous tree and one of North America’s most aggressive invasive species. Its tolerance for poor soil and urban pollution, combined with rapid growth, allows it to quickly dominate landscapes and crowd out native flora. Many people consider burning the cut wood as a disposal method, but this approach carries significant health risks and is biologically ineffective for true eradication.
Health and Safety Concerns When Burning Tree of Heaven
Burning the wood of Ailanthus altissima presents specific health hazards. The tree’s tissues contain natural defense compounds, including the allelopathic chemical ailanthone, a powerful phytotoxin. When the wood burns, these compounds, along with other chemicals like 2,6 dimethoxybenzoquinone, enter the smoke and can potentially cause irritation upon exposure.
Handling the plant material before burning also poses a risk of contact dermatitis from the sap, which can be moderately irritating to the skin. In rare cases, exposure to the sap through broken skin has been associated with more severe reactions, including the inflammation of the heart muscle known as myocarditis. Any heat applied to the wood, such as during a burn, can exacerbate the release of these irritants, making the process hazardous to those nearby.
The tree has a foul, disagreeable odor that is particularly strong when the foliage or wood is crushed or burned. The smell is often described as rancid or similar to burnt peanuts or cashews, making the burning process extremely unpleasant for the operator and neighbors. The smoke itself contains fine particulate matter (PM2.5) that can travel deep into the lungs, triggering or worsening pre-existing respiratory conditions like asthma and chronic obstructive pulmonary disease. Inhaling this smoke can also cause cardiovascular stress, a general health concern associated with any open burning.
The Effectiveness of Burning as a Removal Method
Attempting to eliminate Ailanthus altissima by fire is counterproductive due to the tree’s biological defense mechanisms. This species is an exceptionally successful resprouter, meaning that damaging the above-ground trunk or branches does not kill the plant. Instead, it stimulates the extensive subterranean root system to react aggressively.
When the trunk is cut or subjected to fire, the remaining root structure responds by rapidly producing a massive number of new shoots called root suckers. These suckers can emerge from the lateral roots up to 50 feet away from the original trunk, quickly turning a single tree problem into a widespread infestation. The heat from a fire is rarely sufficient to penetrate the soil and destroy the deep taproot or the entire lateral root network, which is necessary for true eradication.
The tree’s survival strategy ensures that any physical trauma, including burning the stump or cut wood in place, simply redirects the plant’s energy into creating a dense thicket of new growth. This reaction makes the infestation much more difficult and costly to control in the long term. Therefore, fire acts more as a catalyst for spread and regrowth than as an effective method of removal for this particular invasive species.
Alternative Disposal Methods and Regulatory Guidance
Because burning is both biologically ineffective and a health risk, the most recommended and successful removal strategy involves chemical treatment combined with physical removal. The preferred method for mature trees is the cut-stump herbicide application, often using systemic herbicides like triclopyr or glyphosate. This process involves cutting the tree and immediately applying the herbicide directly to the fresh cambium layer of the stump, allowing the chemical to translocate down into the root system and kill it.
Alternatively, young seedlings and saplings can be mechanically removed by hand-pulling, ensuring the entire root is extracted, or by treating the base of the trunk with a basal bark herbicide application. Once the tree has been cut and the root system is chemically controlled, the wood waste must be disposed of properly. The cut wood can be chipped for use as mulch in non-sensitive areas, or the logs can be transported to a landfill or an approved waste facility.
Local fire codes and air quality regulations must be checked before considering any open burning of yard waste. Many municipalities and counties prohibit or severely restrict open burning due to air quality concerns and fire hazards, and burn bans are frequently declared during dry conditions. Even where allowed, a permit is usually required, and burning waste that generates excessive smoke or odor, such as the wood of the Tree of Heaven, can result in fines.