Coastal Reed Project
The objective of the Coastal Reed Project is to recycle the nutrients bound to reedbeds from eutrophicated coastal waters to land. At the same time, the project promotes the sustainable and diverse utilisation of the reed biomass as a raw material that could replace peat, and protect the biodiversity in coastal habitats are threatened by overgrowth.
When the reeds are mowed large amounts of nutrients removed from the coastal waters. Photo: Ilkka Vuorinen
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The project was launched in August 2020 with a joint pilot of the John Nurminen Foundation and the Metsähallitus Parks and Wildlife unit, focusing on the maintenance and care of the nature reserves on the coast of the Gulf of Finland. Based on experiences from the pilot, plans are to expand the operations in the coming years.
The common reed (Phragmites australis) is a common, perennial grass that grows in shallow waters and on land, on coastlines in fresh and brackish waters, estuaries, and in wetlands. The reed can grow into thick stands that are 1-3 metres tall and can cover hundreds of hectares. According to estimates, there might be tens of thousands of hectares of reedbeds on the coast of Finland that would be suitable for mowing. Nutrient loads from catchment (areas) and the decrease in cattle grazing in seashore meadows have accelerated the spread of reedbeds, and the coastal overgrowth. A thick reedbed binds significant amount of nutrients that cause eutrophication in the Baltic Sea. A hectare reedbed can contain 10 kg of phosphorus, 100 kg of nitrogen, and more than 2 tonnes of organic carbon.
When the reeds are mowed and the reed biomass utilised in the manufacture of e.g. growing media, green manure, and bedding materials, large amounts of nutrients removed from the coastal waters. Opening up the impenetrable reed thickets also adds to the recreational use options of the seashore, and restores already lost traditional landscapes. However, mowing of reedbeds is planned and implemented so that species that are specialised in reed environments do not lose their habitats.
Utilisation of reed biomass has positive outcomes for the climate, as it can replace peat, which generates heavy carbon emissions, and rock wool, which is manufactured from non-renewable raw materials. Moreover, when reedbeds are removed, the release of methane, that accelerates climate change, from the dead reed biomass rotting in the coastal waters is decreased.
The benefits of reed mowing have been known for quite some time, but activities have so far been project-based and rather small in scale. The key bottlenecks that prevent reed mowing in larger scale involve harvesting technologies and logistics. The objective of the Coastal Reed Project is to accelerate the utilization and further processing of the reed biomass; to boost harvesting entrepreneurship; and to build business models in a way that allows us to utilize reedbeds sustainably and in a market-driven manner.
Planning of mowing sites and sustainable mowing – ground rules
- Both the Centre for Economic Development, Transport and the Environment and the landowner must always be notified about mechanical mowing at least one month before the work begins.
- A permit from the Centre for Economic Development, Transport and the Environment is required to carry out mowing in a Natura nature protection area or nature reserve.
- Mowing should not be scheduled to take place during bird nesting season. Instead, it should be done outside the nesting season, after July, especially in locations that are valuable for birds (to be verified from the Centre for Economic Development, Transport and the Environment).
- As necessary, the most important nesting areas of birds that nest in reed growths must be excluded from the mowing areas (even mowing during winter can be detrimental to species that nest in reeds).
- Before carrying out measures in coastal areas (such as mowing reed growths or dredging), the Centre for Economic Development, Transport and the Environment must be contacted to verify whether there are habitats of strictly protected species at the site or in its vicinity that might restrict the implementation of said measures.
- In moor frog habitats, any mechanical mowing of reeds in the water or on the shore should be carried out in the winter (on ice) from November to March.
- The most effective means of removing the maximum amount of nutrients is to mow reeds growing in water in late summer (August), as the largest amounts of nutrients are bound to the living reed biomass at that time. Winter reeds contain less nutrients.
- Mowing at the beginning of the growing season might cause stored nutrients to be “pumped” from the roots into the water.
- Permanently inhibiting reed growth in estuaries with frequently recurring mowing should be avoided, as the reeds trap solids and nutrients carried by rivers.
- Suitable mowing equipment should be selected for each site to avoid the release of nutrients from coastal bottom sediment, for instance.
- Cut reeds must be transported away from the water and shore.
- During the mowing planning phase, the location of the mowing site, the availability of a suitable temporary storage location nearby and adequate transportation connections for the removal of the cut reed mass should be taken into account in advance.
- The intended use of the cut reeds could influence how the mowing is to be carried out. It is thus a good idea to take the intended use of the reeds into consideration in the planning phase.
