Development and Conservation of Open Landscapes
Heath landscapes are anthropo-zoogenic ecosystems created by varying land use regimes. They are an important part of Europe's cultural landscape. They were usually created by clearing forests on dry sites and preventing reforestation by grazing. Another cause is the military use of areas where explosive ordnance often produce fires that create ideal sites for heather on wide open fire areas.
In the uninfluenced natural ecosystem, heathland is not a permanent habitat, but occur as transitional biotope that develops after fire events until they are gradually replaced by forest again. Since such natural dynamics, in which one allows such enormous catastrophic events do not occur in today's landscapes, heather relies solely on the maintenance by artificial care.
The natural fate of heathland is the reforestation. After the heather have colonized wide empty areas as a classic frugal pioneer plant, processes of soil formation begin. The conditions are becoming more suitable for many tree species, which increasingly immigrate and displace the heather gradually. Birch trees, pines and aspen play the pioneering role here.
In addition, there is the process of aging of heathland. With age, the heather dwarf shrubs lose their vitality, they flower less intense and have high numbers of dead branches. They can hardly be replaced by younger individuals, because the developed thick moss layer prevents germination. In any case, the heather only germinates best after a fire and otherwise remain dormant, that means, in the status of dormancy.
Free places to germinate are additionally used from other now established plants in succession. They compete with the young plants of heather and can use the now fortified nutrients much better than these frugal slow-growing dwarf shrubs.
- Removal of trees
- Rejuvenation of heath stands
- Reduction of nutrient supply in the soil
If you leave the heath to itself for 30 years, it will have turned into a forest. In order to restore the heath, conventional forestry methods such as harvesters or chainsaws are needed. By sawing off the trees, massive new growth from the stump and root occur, especially in birch, aspen, robinia or bird cherry. This means that a large number of shoots grow out of the remaining root and form a thicket of young trees within two to three years. For these reasons, all root material must be removed from the soil and tree stumps must be cleared. For young trees, the method of pulling out the entire tree with stump and stem is recommended.
Mowing and Mulching
One method to rejuvenate and revitalize old heather stands is mowing. As a result, most of the above-ground biomass is removed, so that from the remaining rootstock new branches will sprout. The heath population itself does not change as a result: the old individuals just re-grow. The rejuvenation is purely vegetative - seedlings from seeds have little chance of rejuvenating the stock even after mowing.
Similar to mowing, mulching removes the overground parts of the heath. This is done by many fast rotating flails which cut off and crush the heath material at high speed. A downstream component collects the material. With regard to nutrient balance, mulching is the same as mowing, but requires more energy. A chance of escaping from the separated heath material is not given for small animals in contrast to mowing.
The material after mowing is used by roofing company that uses heather for roof ridges of thatched roofs. Another application is the use as a biofilter substrate in chimneys.
Schoppern and Sod Cutting
A technically demanding method of habitat shaping is the removal of the upper humus layer - the Schoppern. If everything except the mineral soil is removed, it is called sod cutting. This also greatly reduces the nutrient reserves of the soil and allows valuable early succession phases of the heather, in which very special species can exploit the barren, open conditions before the vegetation becomes denser again.
This fiery method provides near-natural management, as heather is the natural secondary biotopes after fires. The fire destroys the aboveground biomass of the heath and also the moss layer and additionally causes the death of emerged trees. The fire encourages heath seeds to germinate, so that in addition to the surviving old bushes new plants have a chance to come up. Some of the nutrients are removed by the heather fires, but the majority remains available as ash.
However, the targeted implementation is complex, because in advance comprehensive precautions need to be realized such as fire strips are created and maintained. For possible emergency, extinguishing material must be provided.
In order to keep this method in line with civil fire protection and nature conservation regulations, strict conditions must be met for their implementation. In particular, the season and the weather are crucial. Ideally, fire management is carried out in late winter during a prolonged dry and cold period. The wind conditions must also be suitable so that the "cold burning" with the highest possible management effect can be carried out at the same low risk of breaking out of the fire. Due to the great effort and the small time window, the overall effectiveness of the method is unfortunately limited and it happens that planned management assignments can not take place.
Grazing by goats or sheep is a common method to preserve heath landscapes. Emerging tree seedlings are bitten by the animals at an early stage and are not able to establish themselves. Also the heath is eaten and thus stimulated to new sprouts. Livestock pressure from footprint creates open soil and thus possible germination places of young heather plants. Nutrients are hardly reduced by grazing in the ecosystem.
Our Vision / New Approaches
The biggest enemy of the heath is the reforestation due to neglected habitat management: in a surprisingly short time vast heath areas disappear under the treetops of pines and birches and aspens and with the heath most of their spectacular inhabitants who want it open and warm. There is therefore a need for ideas on how heaths can be managed more effectively and in a way that protects nature. New methods should not replace measures such as fire or grazing. However, these are in their recent extent and implementation intensity much too small to really preserve the still existing heaths.
As support for existing methods, we want to develop a machine that will reliably and effectively rejuvenate heath, reduce nutrients and remove emerging trees from large areas where maintenance is normally difficult, e.g. for reasons of former military use. In order to take care of the threat posed by residual ammunition and other explosive ordnance, the machine should be able to operate unmanned and remotely, even in heavily polluted areas. Information on the condition of the areas to be maintained should be collected in advance by remote sensing and expert analysis of this data and serve as a basis for implementation.