A deck is such a simple concept — essentially just a platform in the backyard. But it can function as an escape, a place to enjoy nature, a family gathering spot or a social hub. Having a deck of your own seems to especially resonate with folks here in the Northwest, where summers can be fleeting.

Since a deck serves as a bridge to the great outdoors, why not make it eco-friendly? Here's a primer on "green" options for installing or replacing a deck:

From bags to boards

Despite the high visibility of recycling, most products in our homes and yards contain little or no recycled material. But here's an increasingly popular exception: recycled composite plastic-and-wood lumber used for decks.

Two top brands of composite lumber, Trex and Weyerhaeuser's ChoiceDek, consist of about 50 percent recycled plastic bags and shrink wrap and 50 percent recycled wood fibers, such as sawdust from a furniture plant.

At my house, we love the small composite-lumber deck we had built two years ago to replace our falling back porch. Cleaning the deck is easy — just wipe it down or hose it off (but don't pressure-wash, because that may damage composite lumber). A couple candle-wax stains have defied cleaning, but it is an outdoor deck, after all. Also, we had heard the color might fade but haven't noticed any major change.

To complement the decking boards, several composite-lumber manufacturers have recently introduced products designed for deck railings. However, because of strength issues, composite lumber will not work for the poles, beams and joists used to support the deck. Use standard pressure-treated wood for those.

Composite lumber costs $2 to $3 per linear foot. It's more expensive than regular pressure-treated lumber, but Trex estimates you can recover that extra cost in four years by not having to buy stains or sealants. Composite lumber also resists pests and will not warp or splinter. Home Depot, Lowe's and other home-improvement retailers carry composite lumber.

Composite vs. all-plastic

You could also go green by using 100-percent-recycled, all-plastic lumber for your deck. Though not widely available locally, you can find sources online.

Some environmentalists prefer plastic lumber over composite lumber, noting that composite lumber can never be recycled at the end of its life, since it contains mixed materials.

But that seems like a moot point. All-plastic lumber may technically be more recyclable, but no recycling options currently exist for it, or are even being considered. Composite lumber decking also should not end up in the landfill anytime soon. Several of those products have 25-year or lifetime warranties.

Seek out plastic lumber or composite lumber products that contain recycled plastic rather than "virgin" plastic. Avoid plastic decking containing polyvinyl chloride (PVC, or vinyl). Production and disposal of PVC are linked to various environmental problems, according to the Washington Toxics Coalition.

Wood lovers have options

Even if you have your heart set on a wood deck, you have greener choices. Look for wood certified by the Forest Stewardship Council (FSC), which means it has been harvested sustainably. Local retailers that carry FSC lumber include Environmental Home Center, Dunn Lumber, Compton Lumber, Lowe's and Home Depot.

The best choice is FSC lumber from the Northwest, which has fewer transportation impacts than ipe, for example. Ipe (pronounced ee-pay), a durable, insect-resistant South American hardwood, has become a trendy choice for decks. But steer clear of non-FSC ipe, since its use may contribute to the destruction of the rain forest.

For the more adventurous — or if you have an adventurous contractor — consider salvaged lumber. For sources, check newspaper or online classified ads or exchanges, or used building-materials stores.

The support beams for our deck include salvaged lumber from our old back porch. Keep in mind that used lumber may have been treated with chromated copper arsenate (CCA), a problematic preservative banned in the U.S. since 2004.

Wood decks often have a much shorter life than they should, as the result of poor maintenance. Clean and stain a wood deck regularly to protect it. Consider low-toxic or nontoxic products for this, such as the Bio-Wash line made in Delta, B.C., and available locally at Environmental Home Center.