Ash wood (Fraxinus species) is widely regarded as one of the best options for heating with wood. It is a dense hardwood offering a superior combination of high heat output and ease of preparation. Its characteristics allow it to burn cleanly and efficiently, often outperforming many other common species. However, modern sourcing is complicated by a severe ecological threat that impacts both its availability and the safety precautions required for its use.
The Burning Quality of Ash
Ash is a dense hardwood, typically falling just below the heaviest varieties like Oak and Hickory. This density is directly related to its high heat output, with well-seasoned Ash producing between 20 and 26 million British Thermal Units (BTUs) per cord. This energy content ensures a steady, intense fire effective for heating a home, rather than a quick, flashy burn. The two most common species, White Ash and Green Ash, both perform well, though White Ash generally provides a slightly higher BTU value.
A distinctive quality of Ash is its relatively low moisture content when freshly felled, a trait uncommon among hardwoods. While all wood must be seasoned for optimal performance, Ash can burn better than most species even before reaching the ideal low moisture level. This inherent dryness means less energy is wasted boiling off water during combustion, contributing to a cleaner burn with low smoke and minimal sparking. The clean burning characteristic also reduces creosote accumulation within chimneys, which is a factor in fire safety and maintenance.
Preparation and Seasoning
Ash wood is highly prized because it is remarkably easy to split. Its straight grain structure means that log rounds often yield to a splitting axe or machine with little effort, making the preparation less demanding compared to woods like Elm or Sycamore. Splitting the wood promptly after felling is recommended, as this practice creates more surface area and accelerates the drying process.
The seasoning period for Ash is notably shorter than for many comparable hardwoods. While dense woods like Oak may require 18 to 24 months to dry, split Ash wood can often reach the optimal moisture content of 20% or less within 6 to 12 months. To ensure proper seasoning, wood must be stacked off the ground and placed in a location that receives ample sun and airflow. Using a moisture meter to confirm the wood is below the 20% threshold before burning guarantees a hot, clean fire.
Navigating the Emerald Ash Borer Crisis
The availability of Ash wood has been severely compromised by the Emerald Ash Borer (EAB), an invasive beetle that has killed millions of Ash trees across North America. When an Ash tree dies from an EAB infestation, the wood dries out quickly while standing, often becoming ready to burn faster than wood from a healthy tree. However, wood left standing or on the ground for too long after death can begin to decay and become “punky,” which reduces its heat output and burning quality.
The presence of the EAB has led to strict quarantines and regulations governing the movement of Ash firewood. Moving infested wood, even unknowingly, can spread the beetle, as EAB adults emerge from the wood between May and September to lay eggs. Many jurisdictions prohibit transporting Ash wood outside of local areas, often recommending it be burned within 10 miles of where it was cut. To comply with these measures, consumers should only purchase certified kiln-dried firewood if they plan to transport it across state or county lines.