Two weeks ago, before the recent blast of warm air melted the snow, I made my first visit in almost a year to Somme Woods. The changes were amazing. The big oak grove at the southern end of the land has been totally opened up. It looks truly sacred.

When the North Branch Prairie Project (NBPP) started working on Somme Woods 12 years ago, this grove, like many others in northeastern Illinois, was rendered practically invisible by a dense screen of European buckthorn shrubs. European buckthorn, Rhamnus cathartica, was originally imported as an ornamental plant, but it quickly escaped from cultivation and spread into the wild.

Birds are the main agent of dispersal. They eat buckthorn berries and defecate the seeds. The berries are mildly poisonous to humans, producing, among other effects, a serious case of the runs, something suggested by the plant’s species name.

Once buckthorn is established, it creates thickets so dense that nothing can grow under them. The usual forest-floor plants die out. Oak seedlings fade away as soon as the food stored in the acorn is consumed. The ground under a vigorous stand of buckthorn is totally bare.

Buckthorn is as ruthlessly dominating visually as it is botanically. Walking through a buckthorn thicket, you have to devote almost all of your attention to avoiding a poke in the face with a sharp twig. And the tangle of branches and leaves on all sides and overhead is so overwhelming that most of the time, you can’t see five feet in any direction. At Somme Woods you used to be able to see the broad crowns of the oaks from a distance. But once you got in among them, it took careful searching to find any of the big trees.

The unveiling of the Somme Woods oak grove began several years ago on an early spring Sunday. I happened to be there that day, volunteering my services as part of a work crew that spent the day attacking a wall of brush that divided the grove from the open ground the NBPP was restoring to prairie. It’s interesting what people will do for fun. If we had been convicts assigned to attack buckthorn thickets with handsaws and lopping shears, our work would have been classed as hard labor, chain-gang stuff. But as gainfully employed, free adults, we could think of it as recreation, a pleasing way to spend a Sunday.

As we hacked and hewed and the buckthorn fell before us, we uncovered an enormous oak, a pillar at least three feet in diameter covered with rough bark. With the buckthorn removed, we could look up and see the gnarled branches of the broadly spreading crown. Oaks grow slowly, and trees as big as this one must have started growing before people settled here. This was a piece of primeval Illinois, the first of many uncovered by NBPP work crews.

Foresters would call it a wolf tree, because its broad crown eats up sunlight and stunts the growth of young trees striving to grow in its shade. But in Illinois dense forests were mainly confined to the wet ground on the river floodplains. On the drier upland soils, where fire was a common occurrence, oak savannas shared the land with prairie. In the savannas the oaks did not grow close together; they were scattered and had enough room to spread broad, leafy crowns.

Oak savannas had disappeared from Illinois before any botanists had a chance to study them, but recent historical detective work by Steve Packard of the Nature Conservancy uncovered some early writings on the plants that once grew in the shade of the oaks. Using those writings as a guide, the NBPP seeded the ground under the oaks with native savanna plants. So now we have at least the beginnings of a revived savanna–an open grove dominated by huge oaks and carpeted with wildflowers and native grasses.

The NBPP, which is also a brainchild of Steve Packard, started cutting brush in forest preserves along the north branch of the Chicago River 13 years ago. Somme Woods, at Dundee and Waukegan roads in Northbrook, is the northernmost of the preserves the project is working on. Sauganash Prairie Grove, the southernmost, is within the city limits at Bryn Mawr and Kilbourn.

The project is entirely a volunteer operation; so far more than 1,000 volunteers have spent time restoring native communities on the six preserves the project manages. In recent years the volunteer force has become an army. Last year alone almost 300 new volunteers came out, and work crews put in over 3,600 volunteer hours.

Some of the organization’s efforts are now going into work carried on away from the preserves. A prairie gardening project has volunteers growing prairie plants in their backyards in order to provide seeds that can be sown in the preserves. This winter educational programs ranging from plant identification courses to seminars on fire management were offered to anyone who was interested.

Perhaps the most important feature of the NBPP is its relationship to the Cook County Forest Preserve District (FPD). The project had to gain FPD approval from the very beginning of its work. At first the FPD granted permission only to cut brush and to plant native species. Later it approved permits allowing the NBPP to carry out prescribed burns. Current arrangements essentially turn management of the preserves over to the NBPP, subject to FPD approval of overall plans.

It was frustrating at times in the early days to have to wait for the FPD to give permission to carry out essential tasks, but it is easy to see why officials were cautious. Placing management of public lands in the hands of amateurs is risky. If they screw things up, it is always the bureaucrats who take the heat.

Fortunately, the NBPP was very circumspect in its behavior in the early days. Work was organized so that changes came about gradually. They didn’t just march in and start sawing down trees. By now, of course, the work has proceeded to the point where everyone can see the marked improvement in the appearance of the preserves, from the unveiling of the oaks to the gorgeous wildflower displays on the summer prairie. At this point we are unlikely to see groups of irate citizens going to the county board with complaints about the FPD mistreating the land.

Thanks to the trust built up between the FPD and the volunteers, restoration efforts have been approved for several other preserves. At Poplar Creek, near Palatine, a large-scale prairie and savanna restoration effort began last year on 600 acres of FPD land. Gangs of as many as 50 volunteers are already turning out to cut brush, gather and distribute seed, and help with prescribed burns. In the Palos preserves, volunteer crews are working on Cap Sauers Holdings, a complex of woodland, savanna, prairie, and marsh that is, at more than 2,000 acres, the largest roadless area in Cook County.

All this work is influencing preserve systems elsewhere, in Illinois and in other states. The Cook County system is the oldest and largest system of its kind anywhere; its more than 65,000 acres account for about 11 percent of Cook County’s total land area. When a system that big gets rolling on ecological restoration, the impact can be felt all over the country.

For anyone with even a mild interest in nature and the outdoors, these restoration efforts are a wonderful thing to get involved in. The volunteers work with hand tools, for both safety and philosophical reasons, and the work gives you the most intimate connection possible to the land and the plants and animals that live on it. Workday schedules are published well in advance, and if you want to take part, all you have to do is show up. You don’t need to make a commitment for every Sunday for the next six months. If you can spend the day, that’s great; if you only have the morning free, that’s OK too.

The work is very satisfying.

This is prelapsarian gardening–not conquering the landscape and forcing it to do your bidding, but helping it do what it wants to do anyway.

If you’re interested you can call the North Branch Prairie Project at 312-878-3877. For Poplar Creek, call Rick McAndless at 708-843-0489. For the Palos preserves, call John Sheerin at 708-636-4812.