Removal of the entire vegetation layer and the raw humus layer, partly including a thin portion of the top layer of the mineral soil horizon.
Sod-cutting can be used to restore heavily grazed heaths or even areas dominated by wavy-hair grass or moor grass to vital heaths.
How much work is involved?
Average sod-cutting volume in the Lüneburg Heath: 1,000 m³ to 1,300 m³/hectare.
About 1,685 kilograms of pure nitrogen are discharged per hectare.
So far, about 280 hectares have been treated with sod-cutting in the nature reserve.
“Twigg”/Hoe for sod-cutting
- Average speed (2 persons): 100 m²/day
- Used to obtain material for thatching ridges, for example, or for replanting heath (sod principle).
- Average speed: 0.5 hectares/day
- Used in stony or woody areas or steep terrain and to create particularly small or deep sod-cutting areas.
- Average speed: 2 hectares/day
- The sod-cutting machine removes vegetation cover, humus layer and parts of the top mineral soil layer at a working depth of up to 15 cm in a single pass and is equipped with a conveyor belt for transferring the sod-cutting material to parallel tractors with transport containers.
- Sod-cutting machines are used for large, preferably long areas in a terrain where two tractors can drive in parallel.
Scientific justification for the decision to cut sods
Apart from the general justification of returning grassed areas to vital heaths, sod-cutting areas are also created to maintain pioneer stages and open soil in the heaths.
Many species profit from the resulting open sand areas.
Species with low competitive strength and/or long development times can be promoted by deep sod-cutting.
The costs for sod-cutting measures are between 4,000 € and 7,000 €/hectare.
Removal of the entire vegetation layer and most of the raw humus layer. In other regions, choppering is often understood to mean only the removal of the vegetation and the moss layer.
Heath plants on choppered areas often sprout directly from the rootstock remaining in the soil and come back to flower in the first year.
Originally, areas with only moderately thick layers of raw humus (up to 4 cm) and not more than 30 % overgrown with grass were choppered.
With modern chopping machines it is now also possible to remove heavily grassed heaths. Often an area is worked twice to achieve the desired result.
How much work is involved?
Average volume of choppering in the Lüneburg Heath: 400 m³ to 600 m³/hectare.
About 1,046 kilograms of pure nitrogen are discharged per hectare.
So far, about 300 hectares have been choppered in the nature reserve.
- Average speed: 1 hectare/day
- Cuts away the vegetation cover and most of the raw humus layer at a removal depth of up to 8 cm. A conveyor belt transports the organic matter into a container with a push floor. The container can only hold about 15 m³, so the material is always first stored in heaps on the cultivated area. The material is then removed by tractors with skips.
- For optimal work progress, the working areas should be as long as possible. The width, on the other hand, is not relevant in terms of economy, as long as the cultivation strips are in proximity to each other.
- At present, only two or three companies specializing in heather management offer work with chopper machines throughout Germany.
Mowing containers and mounted forage harvesters
- As an alternative to chopper machines, mounted choppers (Taarup, Gyro, etc.), which were originally used for chopping rape or for grass silage, can be used. They are nowhere near as effective, but often also produce good results in dry weather.
- A mowing container with a reinforced shaft for shallow chopper work has proved particularly effective in the case of additional woody vegetation.
- The mowing container is also mostly used to obtain chopper material for sowing new heath areas.
Windrower and band rake
- In terrain with strong micro relief, a satisfactory choppering result can be achieved by scraping out moss and raw humus with a windrower or a belt rake.
- However, the vegetation cover must first have been shredded by mulching or chopping (usually by a forestry mulcher). The swath can be picked up directly by a tractor shovel or, in dry weather, by a loader wagon.
Scientific justification for the decision to schopper
In addition to the general purpose of restoring mossy and grassy areas to vital heaths, choppering areas are created to release seeds from the heaths’ seed bank.
The costs for choppering measures are between 1,500 € and 2,500 €/hectare.
Removal of moss and raw humus parts by raking or scarifying while the rootstock of the heather plants remains.
This method has only been in use on a large scale since 2014.
In terms of the nutrient removal achieved, demossing is the most cost-effective management measure.
The machine can only work effectively on areas that are hardly grassed over. As a rule, mown heath areas are subsequently demossed.
How much work is involved?
The average discharge volume of demossing in the Lüneburg Heath is 200 m³ to 400 m³/hectare.
About 500 kilograms of pure nitrogen are discharged per hectare.
So far, about 100 hectares have been demossed in the nature reserve.
- Average speed: 3 hectares/day
- Chopper machine in which a special shaft with scarifying blades and clearing flails is installed.
Windrower or belt rake
- Average speed: 0.5 hectares/day
- Demossing of mown heath is also possible by raking with the aid of a windrower or belt rake with separate pick-up of the swath. However, with these implements the work rate is much lower.
- An advantage of this method is the better adaptation to the micro relief, for example in the area of historical wagon tracks.
Scientific justification for the decision to demoss
Due to the high costs of sod-cutting and choppering it is not possible to sustainably rejuvenate the heath areas to counter the accumulation of biomass as a result of the constant nutrient input in the long term with these measures alone.
Since demossing takes place with a certain delay on areas that have already been mechanically worked by heather mowing, the additional disturbance for wildlife is only minor. With regard to the protection of reptiles, which is difficult to take into account in heath regeneration, this procedure is a good supplement if the areas are sized accordingly (as narrow strips as possible).
As the mowing in the heath is usually done quite high, the work itself is unproblematic for reptile protection. If there is an activity phase of the reptiles between the mowing of the heath and the demossing of the areas, the animals burrowed in the moss layer leave the cover-free mown area quickly, so that so far no victims have been observed during the demossing.
In terms of volume, the highest proportion of nitrogen in the heath ecosystem is bound in the moss layer together with the raw humus layer. The targeted removal of these two layers with the lowest possible mineral soil amounts is therefore particularly effective, especially since the removal of the biomass usually generates about half the costs of sod-cutting, choppering or moss removal work.
Demossing seems to be particularly conducive to the typical heath lichens. This may be because fragments remain on the worked area, the area becomes temporarily sunnier and drier, and lichens have a competitive advantage over the undesirable moss species.
The costs for moss removal measures range between 700 € and 1,000 €/hectare.
Mowing the heath to a minimum stubble height of three centimetres with removing as much of the material as possible.
For years, only heaths with very little grass have been mown in the nature reserve. Mowing areas with a higher proportion of grass or moss is often not sufficient to revitalise the heath there. Moreover, the mown material from such areas cannot be sold.
The cycle in which heaths (which are not subject to additional grazing) can (and should) be mown is now five to seven years in the Lüneburg Heath due to nitrogen inputs. Historically, periods of over 20 years are documented in literature.
How much work is involved?
The discharge volume through mowing fluctuates extremely due to parallel grazing and the varying height of the stands. Pressed as small square bales, between 25 and 45 m³ of mown material are obtained per hectare. This corresponds to a maximum of 300 heath bales.
The output of pure nitrogen was calculated at 96 kg/ha for the average heather mowing.
Every year, almost 100 hectares of heath are mown in the nature reserve, and this volume will continue to increase slightly due to the development of the former tank training areas.
The type of equipment used for heather mowing depends primarily on the desired end product:
Seed-rich heather mown material:
Mowing containers or mulchers with appropriate loading equipment.
These attachments are used when seed-rich mown heath is desired for new heath plants. The chopped heather is particularly easy to spread on the sowing area.
As the capsules with the seed must already contain dry seeds during mowing, but should not yet have burst open, there is only a window of 14 days (usually at the end of October) for obtaining heather seed-rich mown heather.
Small heather bales:
Circular mower, disc mower, cutter bar
Each of the mower types mentioned, which are also used identically for grassland mowing, have been used for heather mowing in recent years.
The most environmentally friendly method for insects and reptiles is the cutter bar. However, due to many stones and stumps, this technique is hardly ever used on the heath.
The best results so far have been obtained with the disc mower, as it glides best over the boulders lying hidden in the heath. Working widths of more than 3 m have not proved effective.
The mower is followed by the rotor rake and high-pressure baler with bale spinner, which catapults the bales into a tipping bale wagon.
If the terrain and the heath allow it, the mowing is mainly done in strips of about 6 m width.
The average speed is 4 to 5 hectares per day when using two tractors.
The mown material is mainly sold as small bales to thatchers. In addition, there are numerous requests for special uses, such as decorative material typical of the heath, but also rough fodder for elephants, breeding material for penguins or as filling material for a salina.
Strong, loose heather
Heather from heavily over-aged but grass-poor stands can be sold to companies that use it for the production of biofilter systems for exhaust (e.g. from feedlots or biogas systems).
Here, after mowing and swathing, a common loader wagon is used, which is also used for salvaging mowed material from marsh meadows.
Scientific justification for the decision for heath mowing
Today, heather plants with their above-ground shoots rarely grow older than 10 to 15 years. Without pruning, the regeneration rate from the rootstock is low.
Higher and denser heath stands are also characterised by a cool damp microclimate near the ground, which in turn promotes the growth of undesirable mosses. Mowing interrupts this development.
In contrast to grazing, mowing can create a structurally rich coexistence of the most diverse age stages of the heath in a confined space, which is beneficial for the biodiversity of the heaths.
Today, mowing ungrassed heaths is the only management measure that is completely self-supporting. The prices for heath bales depend on the market situation and must be enquired about at the time.
Widespread prescribed burning of the heath vegetation and part of the raw humus layer
Until a few years ago, all heath areas with sufficiently dense growth, and even completely grassed areas, were regarded as potential burning areas and burnt down if the weather was right. Often, however, the fire in these cases led to further grass encroachment and the immigration of moor grass, so that some years after the fire sod-cutting became necessary.
Today, burning is almost exclusively done in heaths that have only low layers of raw humus and are hardly interspersed with grasses. The drier the weather, the thicker the moss layers that can be burnt. The age of the heather plants hardly plays a role in the selection of the areas. Burning is often used to remove the unnaturally sharp boundaries created by mechanical heather management by burning across areas.
As a rule, the size of the burning areas is less than one hectare.
How much work is involved?
Quite a lot of personnel is needed to safely manage a heath fire. In addition to two to three people for the tractors, at least three more people are needed to light the fire in the area and to observe the surroundings.
In principle, a firebreak is first created around the burn area. This can be done by mowing the heath and then clearing the mown material, by mulching with the mowing container or by wide strips watered with the water truck.
In any case, the fire safety strip is first extended by fire at a distance of one to a few metres from the fire safety strip on the side of the burn area facing away from the wind. Only when the fire safety strip on the flanks and the leeward side has been appropriately cleared, the entire area is burnt by a co-wind fire.
The processing speed can vary greatly. The factors dryness, wind, the position of the individual fire areas in relation to each other and the individual area size play a decisive role.
Therefore, the daily output of burnt heath areas varies between 5 and 35 hectares.
Per hectare, about 100 kilograms of pure nitrogen are discharged directly during the fire event. A further nitrogen discharge occurs in the year after the fire as a result of mineralisation and leaching on the area blackened by the ash.
Firebreaks are created by mowing heather (see there) or by the mowing container (see choppering). This is done immediately before burning the area, as dried moss and raw humus layers burn very well.
If two large water trucks (more than 10,000 m³) are available at the same time, it has proved particularly useful to secure the firebreaks exclusively by burning on the downwind side of the intended burn area parallel to an irrigation strip and then proceeding in the same way with the flanks. This creates a more natural-looking boundary line of the burn area and possible machine damage caused by stones can be avoided. A third tractor with a forestry mulcher is ready on site to support the fire-fighting work of the water trucks by creating a firebreak, if necessary.
The work of the machines is supplemented by people with fire paddles. They are positioned around the fire area and secure it or report to the water truck driver if the fire crosses the firebreak, for example due to flying sparks.
Today, the fire areas are no longer lit by gas cylinders, but with a drip torch. Such a drip torch contains a mixture of petrol and diesel and was developed for the National Fire-Fighters in the USA for setting up counter fires at massive wildfires.
Scientific justification for the decision for heath burning
Along with grazing by wild animals, fire is the most natural cause for the creation and maintenance of heathland. The flora and fauna are therefore evolutionarily particularly well adapted to fire events on heathland.
For some species, such as the heath grasshopper, it is assumed that their extinction in most heaths in Central Europe is directly related to the cessation of regular fire events in the heaths. For other species, such as the black grouse, burnt areas are particularly valuable for body hygiene (ash bath) and as feeding areas, among other things.
Heath burning removes large amounts of nitrogen from the vegetation layer. In contrast to grazing and mowing, the other nutrients remain largely on the surface with the ash. This is one of the reasons why burnt heaths are almost always richer in species than neighbouring, non-burnt areas.
The average costs in the past years were about 400 €/ha.
Procedures of the prescribed heath burning
Grazing in year-round herding represents the traditional system of use in the heathlands. The animals (today exclusively Heidschnucken) feed in the heathland during the day and are driven into the pen at night to defecate. Only during the lambing season do the herds not visit the heath daily. There is a transfer of nutrients from the heath to the stable (and then on to the field).
Grazing in paddocks
With rare exceptions, grazing in paddocks only takes place on grassland or arable land in the nature reserve. The animals are fenced off by nets or wire. It serves as a food supplement.
Permanent pastures have been established in some heathland and grassland areas for cattle and horse husbandry as a supplement to herding by heath sheep. In these large fenced areas, the animals remain outdoors all year round. Forest areas included in the pastures provide sufficient protection for the robust breeds used (Dülmener Horses/Wilseder Rote) in very harsh weather conditions.
Grazing is used as the most important measure to preserve the heaths on almost all open land areas of the Stiftung Naturschutzpark in the nature reserve. It is indispensable on slopes, stony heaths, in areas with steam plough channels, dense juniper heaths or for shaping and maintaining large-scale light, deeply staggered forest-heath transition areas.
Scientific justification for the decision to graze
Herding is the backbone of heathland management in the nature reserve. As has been the case for thousands of years, it serves to concentrate nutrients from the heath in the pen. The constant moderate grazing allows the heath to rejuvenate itself vegetatively again and again. Significantly reduced shading on the ground due to grazing ensures that mosses have a much harder time establishing themselves. The tread of the sheep additionally injures the moss layer and can even create open ground in the case of intensive grazing.
The raw humus layer builds up much more slowly in grazed heaths than in ungrazed ones.
Grazing by herded animals creates very uniform vegetation structures in the heath. Age and height gradients are found according to the intensity of grazing with very gradual transitions. With the exception of preferred herding areas of the shepherd or bottlenecks along the sheep’s drift paths, a clear decrease in grazing intensity is visible in each grazing area from the pen towards the fringes of the herding areas.
In front of each pen, there is a zone characterised by bristly grass due to the daily trampling and the droppings emitted by the animals with their first movement in the morning. This is followed by short-grassed, often lichen-rich heath areas. As the distance from the stable increases, the proportion of mechanically maintained heath areas increases significantly.
Small-scale, temporary grazing dormancy zones and zones in which grazing almost completely takes a back seat to mechanical maintenance measures increase the structural richness in the individual grazing areas. In addition to these defined areas, it is up to the shepherd’s art to decide when an area offers particularly good forage for the sheep, or when it needs more intensive browsing, e.g. because of a tendency to become grassy.
If the heath has reached a greater height and density in an area after years of grazing, the shepherd deliberately avoids it for a while. These areas are then mown and intensively grazed again. The shepherd can react particularly well to the occurrence of very rare species by avoiding them or, in return, by selective intensive grazing in certain time windows.
Cattle and horse pastures complement sheep grazing in the nature reserve. In contrast to sheep, both species use very narrow migration routes within their grazing areas. The hooves and claws of the much heavier animals keep these tracks largely free of vegetation at all times. In this way, for example, they create connectivity axes for many heat-loving animal species that are bound to sunny open ground.
One of the many other aspects that make livestock grazing a valuable addition to sheep farming is the animals’ excrement. A large amount of insect and fungal species depend on dung in the landscape. Here, cattle and horses clearly provide a more concentrated food base than sheep. Hardly anyone pays attention to the diversity of species of beetles and flies that depend on this food base, but particularly well-known species such as the sand lizard, curlew, red-backed shrike or black grouse benefit from this insect diversity.