Firewood BTU Values: Choosing the Best Species
Ranking the energy content of common North American trees.
Not all firewood is created equal. One cord of Shagbark Hickory contains as much heat as two cords of White Pine. If you are buying firewood or harvesting it from your property, knowing the BTU (British Thermal Unit) density of the different species allows you to plan your winter heating strategy more effectively. You want 'High-Density' woods for overnight burns and 'Low-Density' woods for quick, bright fires in the spring and fall.
The Heavy Hitters: High-Density Hardwoods
The champions of wood heating are the dense hardwoods: Hickory, Oak, Black Locust, and Rock Maple. These woods are heavy because they have tight grain structures and very little air space. They produce long-lasting coal beds and steady heat for 8-12 hours. A cord of high-quality White Oak provides approx 24-26 million BTUs, which is the equivalent of burning ~200 gallons of heating oil.
The Mid-Range: Ash, Birch, and Fruitwoods
White Ash and Yellow Birch are favorite 'everyday' woods. They are easy to split, season relatively quickly (12 months), and provide a respectable 20-22 million BTUs per cord. Fruitwoods like Apple and Cherry are also excellent; they smell fantastic when burning and produce a very hot, clean fire, making them prized for both heating and cooking.
Softwoods: The 'Shoulder Season' Fuel
Pine, Fir, and Cedar are often looked down upon, but they have a vital role. They ignite easily and burn very hot and fast. This makes them perfect for the 'Shoulder Seasons' (spring/fall) when you just need a quick fire to take the chill off the morning. They are also essential kindling for starting your heavy hardwood fires. Just ensure they are perfectly dry to avoid excess creosote.
The Importance of Weight and Volume
BTU values are always given 'per cord.' Since a cord is a measurement of volume (128 cubic feet), the denser the wood, the more it weighs, and the more energy it contains. When you pick up a piece of dry wood, it should feel lighter than a wet piece, but a dry piece of Oak will still be much heavier than a dry piece of Pine. Our species chart helps you estimate the total energy sitting in your woodshed.
FAQ
Does burning pine cause chimney fires?
This is a myth. Creosote is caused by cool, smoldering fires, not the resin in the wood. If pine is well-seasoned and burned hot, it is perfectly safe. The problem arises when people burn wet pine or damp down the stove too much, causing the smoke to condense.
Which wood splits the easiest?
Ash is widely considered the easiest wood to split by hand. Elm and Sweetgum are the most difficult because their grain is 'interlocked' and twisted, often requiring a hydraulic log splitter.
Is wood heat cheaper than electric or gas?
If you harvest the wood yourself, yes, it's virtually free. Even if you buy it by the cord, wood heat is often significantly cheaper than electricity or propane, especially in rural areas, though it requires much more physical labor.