We were visiting friends when the doorbell rang. A person was selling firewood. Our friends wanted to buy some, but they didn't have a clue where to stack it or what to look for in wood. Their biggest concern was ruining the design of their landscape.

Our friends can't be the only homeowners with questions about firewood. This is what I told them:

First, you should make sure it's good-looking firewood. You can always make a handsome stack from aged, graying logs that are split into fairly even sizes. The logs should be stacked alternating the direction of the wood on each layer, leaving space between logs for air circulation.

If you stack the logs level, the stack will have architectural interest. A wall of stacked timber can serve as a rustic fence, even though it continually changes in height as wood is used and replaced. Or you can use it to edge the vegetable garden and screen the compost pile. Vegetables such as cucumbers and morning glories or other annual vines can be planted to grow on the stacked wooden wall in summer.

Firewood can serve as an enclosure to create extra privacy for sitting on the patio in summer, or it might screen utilities or the service area. You can also stack it to serve as a physical barrier to keep people out of certain parts of the property.

You can also hide your firewood, as many homeowners do. Use a section of fence, hedge or a shed; or place the wood in a service area or behind a berm on the outer edge of the property.

For wood to be aged, it must be cut into sections and split, then stacked for at least six months to a year in an area that has good air circulation. Other than burning it, there is no accurate way to know if it is well seasoned. Ask the supplier when the firewood was cut.

The standard firewood measure is the cord, a neat stack of logs four feet high, four feet wide and eight feet long. When ordering a cord, be sure you get a full 128 cubic feet of firewood, which can cost $125 to $200 plus delivery and stacking. Don't accept it unless it is aged and split. The cost is higher for smaller quantities. But smaller quantities still should be the correct amount of wood; a half cord is 64 cubic feet and a quarter cord is 32 cubic feet. And note: A full cord is a large quantity of wood unless you are heating or building a wall with it.

Pile firewood away from the house where there is good air circulation. The optimum spot, once the firewood is seasoned, is in a shed. Keep it off the ground. This helps it stay dry and resist rot.

Because fallen trees have value as wildlife habitats and soil amendments, wood gathering is usually not allowed on state lands or in parks without prior special arrangements. To find out more about wood availability on public land, call specific parks or jurisdictions. You may be cited and/or subject to fines if you are caught removing wood from public land without a permit.

When you buy firewood, ask what type it is. If you don't know wood very well and the person claims ignorance as to what it is, don't buy it. Oak is often mixed with maple, hickory, ash, locust, walnut and cherry, all good firewood.

There are some types you don't want. Tulip poplar, catalpa and willow seem to smolder instead of burn, or incinerate too fast, and have such a wide grain that some break apart when split. I also consider mulberry and boxelder poor firewood. They tend to be foul-smelling and burn poorly. These are the woods you typically see stacked in front yards with a "free" sign on them.

Conifers or softwoods, such as pines, firs, spruces and hemlocks, can be used as firewood, but they burn quickly, pop and throw more sparks than hardwoods.

Slow and steady builds the best fires. Put kindling wood under small logs. Leave open areas between the sticks for air circulation. Place larger logs on the fire only after you've built up enough coals. Continue to add wood. The best flames will come when you're burning at least two to three logs at a time.

If it's rain-soaked, firewood can be well seasoned and still not burn. However, wood that's wet from precipitation will dry indoors overnight and light the next day. Bring it into a heated part of the house no more than a day before you plan to use it. Don't keep it inside longer than that or the life cycles of insects that may live inside the wood will start, and creatures may emerge.

I've heard concern about taking termites into the house hidden inside a log. These social insects need a trail to find their way home from the log that you just moved from the pile. So, the termite would be lost, do no damage and perish.

Another common wood-feeding insect is the powder post beetle, because it disintegrates dead wood. Beetles don't feed on properly kiln-dried or treated lumber, so they would find no home in the house, except firewood, which you intend to burn.

There are other borers, beetles and ants specific to rotting wood that won't do anything but meander, fly or scurry to a window or door to escape. At our house, we usually just let them out.

For your safety, don't burn wood found at construction sites, painted or pressure-treated lumber, leftovers from home renovations or plywood, which will coat the inside of your chimney with goo. Burn only unpainted, untreated and unglued wood in your hearth or wood stove.

Lerner is president of Environmental Design in Capitol View Park, Md. His e-mail address is jml@gardenlerner.com