How to select firewood for the coming winter season

Split and ready for the fire, this pile of pine will burn hot and fast. Anza Valley Outlook/Diane Sieker photo

With autumn nights becoming cooler and winter rains coming, Anza Valley residents’ thoughts are turning to preparing for the colder months ahead.

Many people in the valley heat their homes with wood, a renewable biofuel. Using firewood as a main heating fuel means becoming familiar with heating properties, storage, measurements and safety.

Heating properties associated with different types and species of wood are calculated in British thermal units, which is a traditional unit of measurement. BTU is defined as the amount of heat required to raise the temperature of 1 pound of water by 1 degree Fahrenheit. In wood burning, the BTU defines the amount of heat produced by a cord of wood.

A cord is the unit of measurement of dry volume used to quantify firewood and pulpwood in the United States and Canada. The interesting name may have come from the use of a cord or string to measure it in olden days. A cord is the amount of wood that occupies a volume of 128 cubic feet.

It means that a tightly stacked woodpile measuring 4 feet high by 8 feet wide by 4 feet deep constitutes a cord. Any other arrangement of linear measurements that equal 128 cubic feet are also acceptable.

In classified ads and online sales formats, a cord may be advertised for a certain price, and consumers need to be sure they receive an actual cord of firewood. An average truck bed full of wood may not represent an accurate cord, so buyers must understand the unit of measurement. The properly measured cord is also required to understand the BTUs associated with the various woods offered for sale.

World Forest Industries offers a BTU table as a guide to the most heating bang for the buck of different common species of trees. The types readily available in the Anza Valley include hardwood and softwood species.

The Western Hardwood Species, measured in million BTUs per cord, include Live Oak at 36.6, Eucalyptus at 34.5, Manzanita at 32.0, Pepperwood at 26.1 or Cottonwood at 16.8.

Western Softwood Species, measured in million BTUs per cord, include Douglas Fir at 26.5, Western Juniper at 26.4, Lodgepole Pine at 22.3 and Ponderosa Pine at 21.7.

There is great variation in heating properties between certain species. More heat is produced with oak than cottonwood, by a large margin; therefore, a cord of oak is much more valuable than a cord of cottonwood.

Firewood needs to be dry before it is used. Users should ensure it is well seasoned and ready to burn efficiently. Green, or freshly cut live wood is a very poor fuel and very hard to get lit and burning, due to a high-water content.

Correct storage is all-important. Keep wood off the ground, as it helps the wood continue to lose moisture. Space between logs that allows air flow is also recommended.

Storing wood in an area that is exposed to sunlight and wind is also a good idea. In fire-prone Southern California, fire departments advised residents to store their woodpiles at least 3 feet away from the home and other structures, in case of wildfire.

Additionally, Cal Fire recommended storing firewood away from live trees, to prevent the spread of pests or diseases that may be present in the firewood. Many jurisdictions have laws regarding the importation of firewood from out of the area to prevent the spread of insects and disease. They recommend that firewood only be transported locally and within the same ecosystem.

Wood stoves are designed to burn wood, not trash or chemically treated wood products like plywood or pressure-treated lumber. It is recommended to use mostly hardwoods like oak and smaller amounts of softwoods like pine.

Empty ashes frequently and safely, by using a metal fireplace shovel and putting ashes in a metal or other fireproof container in case there are hot coals still burning. Proper disposal of the ashes can be made at home or at the Anza Transfer Station.

The chimney and pipes should be cleaned once a year by a professional, licensed chimney sweep. An accumulation of tars and combustible built-up creosote can reduce efficiency or even catch fire.

When cutting and harvesting firewood, wear protective gear, be familiar with chain saw, ax and maul or wood splitter safety and learn safe methods to fell trees. Do not overload your truck or trailer with green wood, as it can be very heavy. Know your limits and that of your equipment.

Staying warm using this renewable biofuel should be efficient and rewarding this winter.

To learn more about the effectiveness of wood as a biofuel, visit

Diane Sieker can be reached by email at