Sowing the seeds of the future: change in the quarry
When the Kapf quarry near Istein in southern Germany was laid out, fields and woodland had to make way for it. It has now been partially backfilled. However, nothing is the way it was before: With specific areas for rare plant and animal species alongside the typical woodland, the former quarry is intended to stand out from its surroundings.
While lorries transport material away from the quarry, conveyor belts refill it with material from the Katzenberg tunnel. |
In the past year, there was a rare sight to be seen in the Kapf quarry in the Lörrach rural district. Suddenly, not only were fully loaded lorries driving away from the quarry, as usual, but some were arriving too. The reason for this seemingly upside-down state of affairs: besides the quarrying activities, half of the quarry was being backfilled. The material came from the overburden of the Katzenberg tunnel, which was being built nearby. This brought around two and a half million cubic metres of argillaceous earth into the Kapf quarry. |
"We are now able to return an area of nine hectares to nature", enthuses Peter Leifgen, plant manager at the Istein lime plant, which operates the Kapf quarry. The biologist Wolfgang Röske from the Freiburg specialist institute IFÖ formulated a detailed master plan for this purpose in collaboration with Dr. Michael Rademacher, Team Leader Recultivation and Nature Protection at HeidelbergCement – in close consultation with the responsible forestry and nature conservation authorities. This set out precisely where and in what form the material from the Katzenberg tunnel was to be unloaded and the details of what should be done with each area. No easy task, considering the fact that the biologists were proposing something unusual, requiring a great deal of persuasive effort: They were not only planning to allow the area's typical woodland to grow again, with the aim of putting it to subsequent economic use. They also wanted to preserve quarry areas as a refuge for rare plant and animal species. "Nothing is to happen here, we will not intervene", stresses biologist Röske. "It should be very exciting, watching nature take its course."
| The two biologists introduced a new approach for recreating the woodland: instead of working with saplings straight away, they rely on the power of seeds. "Most of the saplings come from operations in which they grow in a protected environment. Here in the quarry, they are exposed to other environmental influences. This means that a lot of them die, and new seedlings have to be planted. That costs time and money." If, on the other hand, you scatter a variety of seeds, |
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only the ones that are best suited to this location will prevail. "This does take a few years longer, but saves effort and money", Röske is convinced.
First of all, though, the backfilled areas had to be prepared: They were given a coating of topsoil, around one metre thick and held down by a jute net, so that the first rainfall would not simply wash everything away. The first layer to be formed on the new terrain was mown meadow grass from the neighbouring area. The grasses seeded themselves, which meant that the first greenery was an ecological match to the surroundings. "Originally, the copper beech dominated in this area, and it should grow again here", says Michael Rademacher. "However, in order to give the soil more stability, we have also incorporated seeds from native bushes into the top layer, such as dogwood, hawthorn, spindle tree, varieties of wild rose or European cranberry." In seven separate recultivation periods, the biologists sowed eleven different tree and bush varieties. "With this approach, we are treading new ground in the area of recultivation, and we also want to pursue recultivation in our other quarries worldwide", says Rademacher.
Flowers are already blooming in the backfilled area of the quarry. |
The first flowers and grasses are already sprouting and, in two years' time, small bushes and tree offshoots will dominate the landscape. By then, the jute net will be rotten, and the plants themselves can give the earth the necessary stability. "Once a healthy stock of bushes has developed in five to ten years, we can promote the growth of tall forest trees through specific nurturing", explains Wolfgang Röske. It will be another thirty to fifty years before the area is covered in woodland as it was before, however. And even then it will not |
look the same as it did before. The abandoned, decommissioned quarry areas will be home to plant and animal species that were previously very rare in this landscape, e.g. the praying mantis or the blue-winged grasshopper.
Kapf
The Kapf quarry forms the basis for the Istein lime plant, one of the largest and most modern lime plants in southern Germany, some two kilometres away. Around 100 people are employed there. Very pure Oxfordian limestone, which formed around 160 million years ago from the remnants of corals and shells, is quarried in Kapf. Geologically, it belongs to the White Jura, the Malm. The quarry was re-exploited in 1982 and can be operated until around 2040, with 650,000 tonnes quarried per year. |
For more info contact
peter.leifgen@heidelbergcement.com michael.rademacher@htc-gmbh.com