Dune Succession Trail: from beach to oak forest at West Beach

Welcome to Indiana Dunes National Park, on the southern shore of Lake Michigan. This walk is the Dune Succession Trail at West Beach: a loop of about three quarters of a mile, with more than two hundred and seventy stairs, that finishes right beside the parking lot.

Long before there was a park, this shore was home to many people. By the late sixteen hundreds, the Miami were the main nation near the south end of the lake. Later the Potawatomi became the leading people along these shores, with more than thirty documented settlements by the late seventeen hundreds. Each year they moved south to spend the winter along the vast marshes of the Kankakee River, then came back north in the spring.

On this walk you'll pass through a change that took thousands of years, from bare beach sand to an oak forest. Watch for the numbered posts beside the trail. I'll tell a story at a few of them and stay quiet in between, so you can enjoy the sound of the lake.

Here's the start of the trail, just beside the West Beach bathhouse.

The idea behind this walk is called succession: the way one community of plants and animals is slowly replaced by others, sometimes very different ones. In the early nineteen hundreds, that was a controversial new idea. A young University of Chicago scientist, Henry Chandler Cowles, first came to these dunes in 1896, and his study of their plants became, as the park puts it, the first doctoral dissertation on ecology. He went on to become one of the first ecology professors in the world, and he brought his students right here, using the dunes as an outdoor laboratory to show how succession works.

That's why these dunes became known as the birthplace of American ecology. Over the next three quarters of a mile, you'll walk through the same story he taught, from the open beach all the way to a shady oak forest.

Bare sand and sunbathers hardly look like the first step toward an oak forest. Yet only a few thousand years ago, the shoreline was about a mile inland from here. Waves wash plant and animal debris onto the beach, and that debris feeds herring gulls, raccoons and bright-colored beetles. Water and wind roll the sand inland until the first line of plants catches it and piles it up. That's how the long, narrow ridge you're standing on, the foredune, was built.

The most important builder is marram grass, the tough grass all around you. It actually thrives on being buried. Most of its growth happens underground, and the roots and runners of a single plant can spread up to twenty feet in every direction, knitting the dune together.

Look for cottonwood trees, too. When a cottonwood is buried, its stems start working as roots and send new shoots up through the sand, so some of the short cottonwoods along this trail may be only the tops of trees that are sixty feet tall.

Along this stretch, behind the first dune ridge, the wind loses some of its force. On this sheltered side a different grass moves in, little bluestem. It can't build dunes the way the beach grass does, but it grows in thick, sturdy clumps that help hold the sand in place. Sand cherry, three-leaved hop trees and wildflowers join it, like the tiny white blossoms of sand cress. As these plants die and decay, they make the sand a little richer, so that other plants can follow.

Watch, too, for the jack pines. Most of their range is in Canada, and the park describes the jack pines here as among the most southern in the world. The first ones flourished here soon after the glaciers melted back north, around fourteen thousand years ago, when the climate was much cooler. Poor sandy soil and the lake's own cool climate have let them hang on. Look beneath them for bearberry, a low, ground-hugging plant that is another northern species still living here.

Near here, the trail passes an intermittent pond, a pond that comes and goes. The park calls this kind of coastal wetland a panne. Its water level depends on rain falling at the surface, and on Lake Michigan itself, working underground. The wind made it. It carved a channel through a low spot between the dune and the lake, and scooped the sand out right down to the water table.

In summer the pond can dry up, and its level changes as the climate varies. Around its edges grow plants you won't find on the dry slopes, like Baltic rush and small wildflowers that need wet ground. And Fowler's toads lay their eggs in the larger, permanent ponds of these dunes.

A pond like this is a good reminder that in nature, succession doesn't always move neatly from one stage to the next.

From up here you look out across Lake Michigan, and on a clear day you can pick out Chicago on the far side of the water.

Around these stairs are two more chapters of the story. One is a blowout, a steep-sided valley the wind carved when it whistled through a low spot in the dunes. Heavy foot traffic off the trail has worn away more of its protective plants, so here succession has actually gone backward, to the same pioneer grasses you saw near the beach. Look for the roots of cottonwoods and beach grass exposed beside the stairs.

The other chapter is the woods. In summer, it's often as much as ten degrees cooler under these trees than on the open sand. Most of the tall trees are black oaks, with hickories, basswoods and ashes, and beneath them grow sassafras, dogwood and witch hazel. A forest like this means the dune is far enough from the lake to be sheltered from winter storms, and old, at least two thousand years. Even here, sand blowing down from the open dune can push the story backward, which is why the park asks everyone to stay on the trail.

The flat land stretching west from the bottom of those stairs once held rolling dunes like the ones you just climbed. About a hundred years ago, sand miners leveled them and hauled the sand away, much of it for construction. Since then, succession has started over. Small mounds of sand are building, held by beach grass, little bluestem and sand cherry, and if nothing interrupts it, an oak woodland could one day return.

Losing dunes like these is what started the fight to save them. In 1916 the director of the National Park Service held hearings in Chicago on a Sand Dunes National Park. No one spoke against it, but the First World War pushed it aside. In 1952, Dorothy Buell, then sixty-five years old, gathered a group of women in her living room and founded the Save the Dunes Council. Senator Paul Douglas of Illinois took the cause to Congress, and in 1966 Indiana Dunes National Lakeshore was created. In 2019 it became Indiana Dunes National Park, the sixty-first national park.

That's the end of the tour, and the parking lot is close by. Thank you for walking the dunes with me today, from the edge of the lake all the way to the forest and back.