Product Profile: April 1997, Wood Elevates Walkways Naturally

In the past, most visitor walkways were paved with asphalt or concrete. Today, environmentally conscious architects and designers are lifting these pathways above sensitive wetlands and wildlife habitats with boardwalks.

Elevated timber walkways are becoming more popular in many projects because they are economical, blend with the landscape and protect the natural terrain. They also permit visitors or employees to view the surrounding landscape from a higher vantage point. This can be particularly useful where nature and people converge.

Designers and landscape architects also specify timber bridges and elevated wood walkways because they eliminate the need for fill and make it easier to get environmental permits. Preservative and pressure-treated Southern Pine lumber protects against moisture and insects and is also considered more compatible than many other materials with wooded surroundings.

PRAIRIE EXHIBIT. Millions of visitors have now viewed the North American Prairie Exhibit at the Sedgwick County Zoo in Wichita, Kan., since it opened. They enjoy a good view of the animals, and they do so without trampling on wetlands or disturb sen-sitive environmental areas.

This elevated design philosophy is seen in the 10-acre preserve. The concept features 600 feet of pine walkways elevated to a height of about 10 feet. These provide views into enclosures containing prairie wolves, bald eagles, bison, elk, deer, grizzly bear and other wildlife.

The walkway is the longest continuous boardwalk in any United States zoo.

The walkways are 10-feet wide and decking is 2 by 6 lumber, supported with 3 by 10 framing on round pilings. All timbers and decking are pressure-treated pine.

The project was designed by Zooplan of Wichita, a consultant firm for zoos and aquariums. J. Michael Rice, project coordinator of Zooplan, explained,

We liked the concept of the elevated walkways winding around the animal enclosures and through the trees.

Rice said there were three reasons for the raised walkways to be selected instead of conventional paths or paved sidewalks:

We wanted the rustic look and natural feel of wood, and we liked the fact that wood is a renewable resource. The timber walkways also gave us an economical way to change elevations and hide barriers between animals and visitors.

The pine framing is a natural material which fits into the environment, and it is adaptable for adjustments as needed at the job site, he continued.

This was valuable as we were able to save many mature trees on the site. This is also the preferred species for pressure treatment.

Structural Engineer Les Baxter of Wichita, commented, "The elevated walkways helped reduce costs because they eliminated expensive foundation work. They also provided good visibility and allowed more freedom of movement for the animals and the visitors."

FONTENELLE FOREST. Another popular walkway project overlooks the Missouri River. It is the Fontenelle Forest Nature Trail in Bellevue, Neb. It was designed with elevated pine walkways to provide open access to rest and interpretation stations.

The trail meets codes for disabled access and features 24 extended decks with benches and signs interpreting features of the forest. The flexibility provided by the walkways meant no terrain was disturbed or altered during installation.

The boardwalk is 6 feet wide and runs for nearly 5,000 feet. Portions are elevated over steep slopes. The all-pine walkway, including posts, beams, joists, curbs, decking and handrails cost $170,000 in labor and materials.

Fontenelle Ranger Manager Gary Garagrandt said, "We ruled out asphalt or concrete due to environmental concerns and because the wood walkway blends into the forest."