Monday, August 26, 2019

Boardwalk heads between gypsum dunes

White Sands National Park's Interdune Boardwalk heads over and between
gypsum dunes. White Sands NPS photo.
Interdune Boardwalk aerial map. Click for larger map.
Day hikers can walk a boardwalk above the world's largest gypsum dunefield at White Sands National Park.

The 0.4 mile round-trip Interdune Boardwalk’s flat aluminum “bridge” heads through a fragile interdune area. While plant life is sparse on the dunes, it flourishes in the lower spots between them.

To reach the trailhead, from U.S. Hwy 70 west of Alamogordo, New Mexico, go north onto Dunes Drive into the park. After 3.6 miles, turn right/north into a parking lot. The trail leaves from the lot's northwest side.

Ten signs along the boardwalk tell about the interdunal ecosystem. You’ll probably spot animal tracks in the sands just off the boardwalk and certainly see plenty of flora.

Array of plants
Among the many plants visible from the boardwalk are soaptree yucca, little bluestem, Mormon tea, rubber rabbitbrush, little sand verbena, Gypsum centaury, and blazing star.

A long stalk rising high from a leafy shrub, soaptree yucca is the easiest to spot. If visiting in spring, watch for its large, cream-colored flowers. Native Americans dined on the yucca flower pods, used the leaves to construct rope and sandals, and boiled the roots to make soap and rugs.

Grasses thrive in the interdunal area. The prairie grass little bluestem is one such species. Because the water table is only a couple of feet below the surface at White Sands, the interdunal soils are moist, allowing the grasses to thrive. Alkali sacaton and Indian rice grass are two other grasses found at the park.

The short Mormon tea plant is spiny and stick-like, as if bamboo. Its leaves act as tiny scales. Each spring, pale yellow flowers bloom. It garnered its name from early pioneers who brewed a weak tea from its stems.

During late summer, hundreds of golden flowers bloom and produce downy white seeds on the tall rubber rabbitbrush. Migrating butterflies flock to the gray-green shrub for food. Native Americans used the plant to make arrows shafts, baskets, and as a yellow dye.

The Gyp Nama, which grows only a couple of inches high, needs the sulfur in gypsum to grow, so the interdunal flats are a perfect habitat for it. They grow in tangled coils of thin green leaves with white edging, so look like a succulent plant; it’s actually part of the waterleaf family.

Wildflowers also thrive in the flats. Gypsum centaury blossoms from April to October; the flower consists of five bright pink petals around a white center. Purple petals grow in tiny clusters on the little sand verbena while the blazing star looks like a yellow fireworks shooting out of a foot-high stalk.

Great view
The boardwalk ends with a viewpoint showing the dunefield and the mountain range beyond the valley floor. Sierra Blanca Peak stands out on the range's left side. Southern New Mexico's highest point, the usually snow-capped peak sits more than 7000 feet above the desert floor.

Note that the boardwalk's surface can be slick because of blowing sand. Also, avoid using the handrails unless you enjoy getting a shock due to static electricity buildup.

The trail is entirely exposed to the sun, so be sure to don sunscreen, sunglasses and sunhat. A structure offering shade is about midway along the boardwalk.

Wheelchairs and strollers will have no trouble using the boardwalk. Dogs are allowed on the trail but must be on a leash no longer than 6 feet.

Learn more about national park day hiking trails in my Best Sights to See at America’s National Parks series.