The easiest way to get your home holiday-ready isn't trimming the tree or decking the halls: It's letting scents set the scene.

Decorating with strategic scents such as vanilla, cinnamon and pine instantly creates a nostalgic mood, evoking memories of warmth and comfort.

Smells can affect our moods quicker than sight or touch because they stimulate the brain's limbic system, a primitive area that processes deep-seated emotional responses to such threats as fire, poison or being pursued.

"Nothing impacts our brain as fast or as hard as scents," says Mark Crames of the Demeter Fragrance Library in New York. "It's why the smell of that fresh-cut Christmas tree is more important than the tree itself."

Families desperate for that sense of "home sweet home" have catapulted home fragrance sales to $5.1 billion in 2007, according to a report by Packaged Facts. Dozens of products, from candles and sprays to diffusers and plug-ins, saturate the market.

Home-fragrance products such as candles and potpourris have long been popular as inexpensive holiday gifts. But their ability to lift spirits may make them even more valuable during today's harsh economic times, marketing and industry experts say.

Retailers recognize the importance scent can play during the buying process, says Crames. In the past six months, several companies have asked Demeter to create a signature scent for a more favorable spending environment, increasing people's willingness to buy.

"The difficult economic conditions have accelerated aroma marketing," says Crames, whose seasonal-based scents this year include Christmas tree, eggnog, fruitcake and hot toddy. "When times are tough, people look for edges to differentiate their business. They want to find ways to own that emotion now, and they know that certain scents can make a person feel happier."

Fragrances can also be key to helping families manage emotions at home and cope with holiday stressors, says Russell Brumfield, author of the book "Whiff! The Revolution of Scent Communication in the Information Age."

Certain scents can ease tension at family gatherings by reducing blood pressure. They leave impressions on our mind which Brumfield calls "scent tattoos." "Universal scents" such as vanilla, cinnamon, gingerbread, spice, pine and chocolate help control environment and mood, Brumfield says. "If there are a lot of issues and fighting among family members, I suggest picking a strategic scent that's associated with a happier memory in not just your childhood, but everyone else's childhood in the family," Brumfield says.

When purchasing items, Brumfield says to stick with products made of essential oils and avoid gel-based fragrances that evaporate in the air because they have too many chemicals. Allergy sufferers, for example, are less likely to have a negative reaction to liquid-based, scent-diffuser systems such as reeds.