Swaying reeds and white clouds in a blue sky reflected in the water. The small ripples on the surface suggest the presence of numerous fish and aquatic insects. On the water, framed by a colorful palette of green-yellow grassland, pink cuckoo flowers, white daisies and red poppies, waterfowl float. A watchful lapwing patrols the borders of its territory.
Oh, how I would like to settle down in this enticing spot! With a rug and a picnic basket to watch the clouds drift above me, lying relaxed on my back. Impossible, unfortunately! Because this small green oasis is also a mirage: visible, but inaccessible.
My dream paradise is embraced by the arch of the exit from the A1 to the A50 at the Beekbergen traffic junction and is surrounded by a web of asphalt. Inaccessible to ordinary people, who can only take a brief look at it from the car. And then: if I could get there at all – crossing the highway at the risk of my life – my idyll would be rudely disturbed by the noise of the road traffic speeding by a few meters away.
There are hundreds of these mini-nature areas in the Netherlands, at motorway entrances and exits and around traffic junctions; unobtrusive and introverted, barely noticed by the speeding motorist who has to keep his eyes on the road. Sometimes accentuated by a row of trees, almost always around a reed-lined water.
Their existence has intrigued me immensely for a long time. What is their function? Who designs them and for what purpose? What actually grows? Questions to which Jan Willem de Jager and Peter-Jan Keizer know the answers. The first is a spatial planning consultant at Rijkswaterstaat, the second is an ecologist at the same organisation. I’m going out with them today.
Organic mini treasuries
There is a purely pragmatic reason for the existence of these small oases, De Jager shatters my romantic dream image: water storage. “During a downpour, a huge ditch of water falls on the road. From the point of view of road safety, you must dispose of these as quickly as possible. That’s what those areas are for.”
But land is scarce in the Netherlands, a highway may look a bit nice – Rijkswaterstaat has a special department for that – and if you can do something for nature and landscape, why not combine functions, as we are used to in the Netherlands ? So both water storage and beautification of the landscape and space for nature; limited of course, because such an area is never larger than a few hectares.
Those different functions also appear to go very well together, says ecologist Keizer. “Nobody ever comes, because those areas are inaccessible to the public. If you wander around without permission, you will be sent away with a fine by a Rijkswaterstaat inspector within half an hour. Nature can therefore run its course undisturbed, which is quite unique in a densely populated country like the Netherlands.”
The result: those small, often unnoticed areas are true biological mini-treasures, where numerous plants and animals can thrive undisturbed. Rare insects, such as the digging bee and the parasitic wasp, butterflies, such as the hay bug and the small fire butterfly, dragonflies, but also (water) birds and plants find a safe refuge here. Keijzer: “It depends a bit on the type of soil, but I know of areas where more than forty species of plants grow on sixteen square meters.”
Animals quickly become accustomed to the speeding traffic and are not deterred by it. Conversely, traffic is usually not bothered by the animals; only geese and swans can sometimes cause nuisance because they take off so slowly. “This is undesirable for road safety reasons. By planting high vegetation or placing poles along the edges, we try to force them to take off faster,” says De Jager.
The water is usually crystal clear, because it is purified by the sand body of the highway. There are fish – roach, sticklebacks – and frogs that usually hitch a ride on the legs of waterfowl as tiny eggs or frogspawn. They then again attract birds that feed on aquatic animals. “A small area like this shows the power of nature well,” says Keijzer. “You just have to create the right conditions and nature develops spontaneously.”
But in the Netherlands, nature is never just nature – and that also applies to the nature around the highway. However ‘natural’ those green oases may look, they were designed on the drawing board. The design must both meet the primary objective of water collection and be suitable and attractive in the landscape, offer space for the development of nature and make management as simple and cheap as possible. Most complex. Rijkswaterstaat used to have its own design department for this, but nowadays the job is outsourced to specialized landscape offices.
The construction requires a lot of digging by men with bulldozers and cranes. The water feature must be constructed, often in what De Jager calls ‘a Barbapapa shape’, a natural-looking, meandering body of water with inlets where animals can hide. The soil must be excavated to the original soil layers. “Then you get back the stratification in the soil that is necessary for that great variety in species.”
If you don’t do anything, such an area will be closed within five years
That’s not the end of it, because without good management most highway oases would soon be overgrown by unwanted fast-growing species, such as the American bird cherry, leaving nothing of the open and ‘natural’ image.
“Good management is essential,” says Keizer: “Mowing must be done at least once a year and the hay must be removed to prevent suffocation of the subsoil. We remove the unwanted, fast-growing plants and shrubs to prevent them from taking over. If you don’t do anything, such an area will become dense within five years.”
We continue along the A1, which winds its way languidly through the hilly landscape of the Veluwe like a true American parkway. De Jager is visibly proud that he is jointly responsible for the design. He points to indentations in the slope through which the underlying centuries-old tree structures are visible and grumbles. “Those pines have to go. They obscure the view of the avenue trees behind it.”
Just past Radio Kootwijk we leave the highway and park the car under the viaduct of the N302. A little later we look out over a bare sandy plain with an old pine tree here and there. Traffic rushes past in an endless stream left and right.
Unsightly, is my first impression. Yet here, in the no man’s land between the separated carriageways, a special and unique experiment is taking place. It is Keijzer’s last child – he will retire in three years.
“We removed the pine trees that were here and soded the ground. This creates a habitat of scanty sandy soil where few, but very special plants, feel at home. This is the most nutrient-poor area in the Netherlands, where almost nothing wants to grow. In a sense, on this strip of eighty meters wide and two kilometers long, we are bringing the Veluwe back from the past.”
This project, too, initially stems from functionality. Traffic on the A1 was and is regularly hindered by forest fires. By order of the fire brigade, the pines between the lanes had to be cut down to reduce the chance of the fire spreading. This gave Keijzer the opportunity to realize his plans here.
It is not spectacular or lovely. You have to have an eye to see the specialness of it. “In contrast to those areas near traffic circles, the diversity of species here will be limited. But it’s not about how much grows, but what grows.”
Keijzer points to the low, inconsiderable, apparently dried out plants on the sandy bottom. “Those are lichens, very vulnerable. If you walk over them, you pulverize them. You used to find lichens everywhere on the Veluwe, but they have disappeared in many places due to recreational pressure and because the open sand has closed up.”
He hopes that the mosses, which have come up spontaneously, will be able to maintain themselves and that other plants that thrive on very nutrient-poor soils will also find a place. “The redevelopment of this area will only be completed at the beginning of this year, but I see that it is going in the right direction. Although we have to keep a close eye on that gray curly stem, an invasive moss from South Africa. Before you know it, it will overgrow the other mosses.”
Insects and birds have also discovered the area. Keijzer points to the holes in the ground, an indication that digging bees have settled there. A parasitic wasp zigzags in search of prey, a hay bug (butterfly) flutters around a tree, a woodlark sings. Larger animals are not to be expected anytime soon due to their isolated location. They would immediately be flattened when crossing the road, Keizer knows. “Although it wouldn’t surprise me if the sand lizard manages to reach this area.”
The same applies to this area: management is everything. Pointing to his colleague De Jager, who pulls an unruly young pine tree out of the ground with his head reddened: “It is enough with one or two men to remove the emerging plants, shrubs and trees that you do not want a few times a year. Doesn’t mean anything, but you have to do it. Otherwise, in a few years it will be full of pine trees again and you can start over because all the special plants have disappeared.”
A version of this article also appeared in NRC in the morning of July 26, 2021