Fall is an ideal time to consider outdoor architectural upgrades. While it may be your last major project of the season, your appreciation for the effort will grow when spring 2004 arrives. The structure is already in place, ready to enjoy as plants grow and flowers bloom around it.

A popular building material for a wooden pergola is Western red cedar. Its stable, resilient, and durable without the dangers of chemical treatment.

Safety is important for people making building material choices, says Peter Lang, general manager for the Western Red Cedar Lumber Association. Cedar looks beautiful and is among the most durable woods. For hundreds of years, cedar has been highly prized for its natural compounds that resist rot and mildew.

While western red cedars natural qualities have always been recognized, these are taking on new, heightened value among builders -- from professionals to do-it-yourselfers. Earlier this year, the Environmental Protection Agency issued a recommendation to avoid chemically treated wood, specifically wood treated with a form of arsenic. Recent studies have linked the arsenic in treated wood to cancer.

Above-ground structures like pergolas, which might once have been built with treated wood, can be safely built with real cedar, known as the Tree of Life to the Indians of the Northwest Pacific coast.

You may have seen pergolas on houses and called them trellises or arbors. Like a trellis or an arbor, a pergola can support vines or climbing roses. And like a free-standing arbor, a pergola can filter light with its lattice-like canopy. Pergolas are often used as covered or open-roofed gateways to homes, paths, and gardens.

Consider attaching the pergola to your home, using it to shelter a path between the main house and a garage or other outbuilding. Because the overhead spans are supported by uprights, they can be made any size. Remember, one of the great appeals of the pergola is that it's a piece of architecture.

In its simplest form, a freestanding pergola in the garden provides a unique focal point. It can also serve as an effective soft screen from neighbors, additional shelter for a walkway, or the frame for a view of another feature within the garden.

A pergola gives a deck character and provides new options for decoration and design. Pergolas and arbors are great for vines, other climbing plants such as roses, and hanging baskets. If you don't have a green thumb, adorn the pergola with lights or decoration for special occasions. With slight changes of the supporting columns and overhead lattice, a pergola can fit almost any house style.

The basics of pergola construction are readily available online or from your trusted home improvement store. Before you tackle the project on your own or with professional help, here are few handy reminders.

* Ensure that the posts can handle the weight of the overhead beams. For optimum performance, posts should be attached to ready-made concrete footings purchased from your building supply dealer. This will help keep moisture away from the base of the posts.

* Take special care when deciding the proportions of posts and crossbeams. A set of 4-by-4 inch posts would be ideal with 2-by-6 inch boards nailed vertically for main-beams and crossbeams.

* Make sure the structures angles are precise to fit the dimensions you want.

* Make sure the posts are vertically straight and even in height. Ensure the main beams are level and evenly spaced in parallel to each other. Use a carpenters level for precision.

* Finally, add decorative flair to the crossbeams with a simple cutting, such as a quarter circle from the underside ends of each crossbeam.