Firewood Primer for Leftover Wind Storm Wood

Last week’s winds were a sobering reminder that the foothills are not for sissies. The upending of trees and downing of limbs resulted in uncounted tons of timber and leaf debris blocking driveways, parkways and curbs. But those who lost a tree may have gained a fuel windfall.

Eventually, yes. Arborists and firewood pros tell us we can burn any wood, as long as it is well-dried for a year or two. Seasoned wood gives a higher heating value, measured in BTUs or British Thermal Units. Trying to ignite fresh, green wood is a waste of time and effort.  It will never burn well until its water content has evaporated. For this winter’s fires, rely on wood that was harvested no later than spring 2011.

But, back to the tree in the driveway. Which wood is best for heat or cooking?  Often it’s a matter of personal preference, but there are some characteristics to consider.

Wood is usually classified as hardwood or softwood.

With a few exceptions, hardwoods are slow growing, deciduous, broad-leafed trees. Softwoods are generally evergreen conifers.

Hardwoods

Dense hardwoods are slow to light, but burn hotter and longer, so are a good choice for home heating. Harvest trees such as eucalyptus, oaks, sycamore, acacia, mesquite, arbutus or madrone, dogwood, ash, elms, jacaranda, Tabebuia, Hollyleaf cherry, black locust, California Black Walnut and birch for hot, clean fires. Many heavy hardwoods require two years to completely dry. 

Fruit trees are hardwoods, too, and impart flavorful, smokey aromas to foods. Many cooks prefer barbequing with pecan, peach, apple, apricot, almond and plum wood. Even dried citrus makes a great cooking fuel. Dried grape vines are fine kindling.

Softwoods

If available wood is Ponderosa pine, sequoia, incense cedar or sugar pine, these softwoods are resin-filled. Drying for at least one year is a must. This will result in a quick lighting log with a pleasant aroma and popping as it burns. Poorly seasoned conifers may produce a sooty smoke, the result of burning at low temperatures. Oily creosote is released into the air and accumulates in the chimney when not properly combusted at high temperatures.  Highly flammable creosote can be a fire hazard and should be removed annually.

Combat sooty smoke by increasing the volume of dense hardwood in the fire. Slow starting but high heat, long-burning hardwoods will promote temperatures of 400 degrees or higher to successfully vaporize creosote.

Medium hardwoods and softwoods

Medium hardwoods and soft hardwoods, such as cottonwood alder, aspen, maple, podocarpus, olive, persimmon and pomegranate are widely planted residential trees and good fuel wood.

When burned, avocado produces an odor some find offensive. In a kettle grille, ignite a sample outdoors to test for aroma allergies.

How to break up your wood

For both hardwood and softwood, split the trunk into small, fireplace-sized sections. This exposes the internal xylem fibers to air for speedier drying. Coast live oak, split and stored in a sheltered location but not under a tarp, for example, will take about two years to dry Stacking wood off the ground prevents soil moisture from being absorbed, and storing in a sheltered location without a tarp allows moisture to evaporate.

Fireplace tips

For safety sake, never leave a fire unattended. Always use a fireplace screen, a spark arrestor on top of the chimney and have your chimney cleaned annually by a sweeper certified by the Chimney Safety Institute of America.

While enjoying the fire, remember: winter is the best season to plant many trees in Southern California. It’s not too soon to think about replacing fallen green friends.