Ash wood, derived from the Fraxinus genus, has long been a highly regarded fuel source. The simple answer to whether dead ash trees make good firewood is a resounding yes; it is considered one of the best hardwoods for burning. This wood is prized for its high energy content and unique characteristic of having a naturally lower moisture level than many other hardwoods, even when freshly cut. The widespread death of ash trees due to the Emerald Ash Borer has created a large, sudden supply of this high-quality fuel. Using this dead wood is practical, but it requires understanding the wood’s performance, the legal restrictions surrounding its cause of death, and the safety hazards of harvesting it.
Firewood Performance Characteristics
Ash is a dense hardwood, a physical trait that directly contributes to its superior performance as firewood. Its density means that more combustible material is packed into each log, leading to a higher heat output compared to less dense woods. Seasoned White Ash typically yields energy values around 23.6 to 24.2 million British Thermal Units (BTUs) per cord, placing it in the upper tier of commonly burned woods, slightly below oak and hickory but far exceeding softwoods like pine.
This high energy content allows ash to produce a strong, steady heat that lasts for a considerable time, often sustaining a fire for over 90 minutes per log. Unlike some other dense woods, ash has a reputation for igniting quickly and burning cleanly, producing minimal smoke and little sparking.
The wood’s lower natural moisture content is another significant advantage, which is why it is known for burning well even when “green.” When an ash tree dies and remains standing, the process of desiccation is accelerated, allowing the wood to dry out much faster than many other species. This rapid drying means that dead ash wood can often be ready to burn with minimal or no traditional seasoning time.
The Emerald Ash Borer (EAB) Context and Regulations
The primary reason for the abundance of dead ash trees is the Emerald Ash Borer (Agrilus planipennis), an invasive beetle. The beetle’s larvae create galleries underneath the bark, which disrupts the flow of water and nutrients, effectively girdling and killing the tree. This infestation does not diminish the quality of the wood as a fuel source.
The most serious consideration is the potential for spreading the EAB to uninfested areas, resulting in strict state-level regulations. Although the federal EAB quarantine was lifted in 2021, states and individual counties maintain their own quarantines and restrictions on moving ash wood. Moving any hardwood firewood, including ash, out of a quarantined area without proper certification is often illegal and can result in significant fines.
The core guideline for all consumers is to burn ash wood locally, ideally on the property where the tree was cut down. Infested firewood can easily carry the EAB larvae to new locations, where they emerge as adults to attack healthy trees. If the wood must be moved, it is imperative to check with the state department of agriculture for current regulations and to only transport wood that has been heat-treated, or kiln-dried, to kill the pests.
Physical Safety When Harvesting Dead Trees
Harvesting dead ash trees presents unique and serious physical hazards. Dead trees, often referred to as “snags,” become brittle and highly unpredictable during felling. The primary danger comes from “widowmakers,” which are dead branches that can unexpectedly break loose and fall from the canopy while the trunk is being cut.
The wood dries out rapidly, making it brittle and prone to fracturing. This brittleness increases the risk of the tree splitting or “barber-chairing” as it is being felled, which can cause the trunk to kick back violently toward the cutter. Due to these dangers, many professional arborists refuse to climb dead ash trees and instead rely on specialized equipment like bucket trucks or cranes for removal. Anyone without extensive professional training should consider hiring a certified arborist to remove standing dead ash, particularly trees near structures or high-traffic areas.
Preparation and Storage Requirements
Dead ash wood is generally easy to process. Ash has a straight grain structure that makes it straightforward to split, often requiring less effort than other hardwoods like oak. Splitting the wood is a necessary step, even for dead trees, because it significantly increases the surface area exposed to air, allowing any remaining moisture to escape.
While dead ash may seem ready to burn immediately, proper seasoning is still beneficial for optimal performance. If a tree has been standing dead for a long time, the wood may already be below the recommended 20% moisture content. Splitting the wood and allowing it a short drying period—typically much less than the 6 to 12 months required for green wood—will ensure the driest, most efficient burn.
To maintain dryness and prevent reabsorption of moisture, the split wood must be stacked correctly. Stacking firewood off the ground, such as on pallets or runners, and covering the top of the pile will prevent decay and keep the wood dry. Good airflow around the sides of the stack is important for the final stages of drying.