So you have a new wood stove or outdoor fire pit you’re planning to put to use. Or maybe you’d like to toast marshmallows on that camping trip you’ve been planning? Either way, if you’re building a wood fire, it’s important to remember that not every piece of timber makes good fuel.
Sure, you know enough not to burn trash like toxic pallets or pressure-treated lumber. But even when choosing between two logs, there are greener (and less green) options out there. Here are some tips on firewood NOT to buy.
Note: None of the advice below applies to the netting or plastic-wrapped bundles of firewood sold in stores and marked kiln-dried or heat-treated. If you only need a little wood, bagged commercial firewood can be a good and safe choice and is usually a high-quality hardwood that will burn hot and clean.
If you live in, or are visiting an area currently affected by invasive wood pests, such as the emerald ash borer, the Asian longhorned beetle, or the goldspotted oak borer, ask the seller where the wood was cut. If it was cut or stored more than even a few miles away, you should leave the firewood where it is and keep looking. According to Leigh Greenwood, campaign manager for the Don’t Move Firewood Campaign, firewood that travels too far is the number one way that invasive insects and diseases rapidly spread. Though the pests travel slowly on their own, moving an infected log can put new forests at risk and undermine convervation efforts. Millions of trees and thousands of acres of forest have been seriously damaged or even killed by these non-native pests.
New outbreaks almost always originate in or near public campgrounds or can be traced back to a homeowner who bought firewood from an infested area. David Adkins, an inspection manager with the Ohio Department of Agriculture, says that if you have any suspicions, buy only enough for a single fire and follow the “use it all, burn it all” rule. “Don’t leave questionable wood lying around, and certainly don’t take any home with you from a distant campground.” If you’re not sure whether your area or nearby areas are affected, contact your state’s Department of Agriculture or visit Dont Move Firewood to find out.
When a living tree is cut down, the wood needs to age or “season” for a minimum of six to nine months before burning to let it dry out. Freshly cut wood, called “green” wood, is loaded with sap (mostly water). It’s hard to light and once you get it going, it burns very ineffieciently and smokes horribly—throwing more particulates into the air and making it harder to breathe— the very antithesis of eco-friendly. If you’re unsure if the wood is green, ask the seller when it was cut. You can also check the bark: Firmly attached bark that’s still sticky with sap when you nick it is a bad sign.
Ask the seller what kind of wood it is. Trees like pines, firs, or cypress have “soft” wood, which burns fast, leaving few coals, and makes a lot of smoke that can coat your chimney with soot (not a safe thing in the long run). Seasoned softwood is OK for outdoor fires, but you may want to avoid it if a chimney is involved or you want a long-lasting fire or coals to cook over.
Don’t buy firewood that is too long to fit easily inside your fireplace or firepit. If it’s more than 5 inches in diameter, you will need to recut or split it before you can use it. The work can be fun and is great exercise, but if you just want a quick fire, it’s a drag.
Burning salt-saturated driftwood is a bad idea as the chlorine in the salt can be converted into cancer-causing compounds that end up in the smoke. Salt makes for prettily colored flames, but it’s probably safer to use driftwood for making airplant mounts instead.
Poison ivy, poison sumac, poison oak, or pretty much anything else with “poison” in the name can release the irritant oil urushiol into the smoke, and breathing the smoke can be life-threatening for susceptible individuals.
Mexican elder, found in the American South, is a fast-growing, semi-evergreen tree that contains a natural form of cyanide. Breathing the smoke can cause cyanide poisoning. You are unlikely to find it for sale, but don’t be tempted to cut one down and burn it.
Oleander shrubs thrive in frost-free climates and every part of it is toxic: Definitely don’t burn it, and don’t even use a branch to toast your marshmallow on.
Blue ash, American chestnut, the Kentucky coffee tree—there are only about a dozen threatened or endangered kinds of native trees in North America, and by their very rareness you are unlikely to find any in a batch of firewood for sale. However, should you be looking to collect your own, you might want to peruse this list before chopping anything down to make sure you’re not accidentally felling something endangered in your area.