Hard and Soft

• Hardwoods are preferable to softwoods as a rule. Hardwood is denser, and so it burns slower to produce the same amount of heat as lighter wood. Many softwoods are conifers, and they contain higher levels of pitch--oily resins that have a turpentine smell and that smoke when burned. Hardwoods like oak, ash or maple are heavier to handle and harder to split. Hardwoods are also harder to ignite; but once lit, they don't spit as badly as softwoods, and they burn longer.
  
  

Seasoning

• Whatever wood you have on hand, the key to preparing it for the fireplace or wood stove is seasoning. Unseasoned wood will burn badly, steam and smoke more and pop frequently. Seasoning means allowing the wood to dry. To season well, cut the un-split wood into 2-foot lengths, and split the 2-foot lengths into pieces that are less than 8 inches in diameter. Stack the wood on a dry place with overhead cover outdoors. Stack the wood loosely to ensure maximum air flow around each piece, and leave the pile for a year before using it.
  
  

Split-ability

• If you are splitting the wood yourself, you may want to consider ease of splitting. Mechanical splitters take the work out of splitting and allow you to ignore this aspect of firewood; but if you are using the old-fashioned splitting maul, you will want to pick woods that separate easily with a clean maul stroke. Extremely dense wood is resistant to splitting, and some woods are "stringy," which means their grains are interlaced in a way that doesn't allow for that nice snap-split. Oak is dense, but it has a splittable straight grain. Cottonwood and most pines will separate cleanly with a well-aimed stroke. Elm and sycamore can tie the splitter up in tough bands of interlaced grain.
  
  

Burn Quality

• The quality of the burn is based on safety, smoke, heat and fragrance. The best-rated firewoods on these accounts in the United States are black locust and hickory, followed by white oak, honey locust, red oak and white ash. Good-quality woods include hard maple, soft maple and Osage orange. Usable, but not great, species for firewood are sycamore, elm, hackberry, southern pine, red cedar and mesquite. Last-resort woods include cottonwood and willow.