Biomass of the bocage in the Léguer valley

Chaire Paysage et énergie (ENSP), 2022

À télécharger : rapport_simplifie_connaissance_vallee_leguer.pdf (5,7 Mio), ppt_resultats_label_bois_bocager_gere_durablement-cbvl25102018-1.pdf (1,3 Mio)

The age-old bocage in the valley

1 - A living, networked motif of the Breton landscape

The Léguer valley is located in the department of Côtes-d’Armor and in the Trégor, a former administrative and religious division constituting one of the nine provinces of Brittany. It is dominated by the town of Lannion. The bocage, composed of a network of hedges and embankments, is a characteristic landscape of the Léguer catchment area. Its presence can be explained, for the main factors, by the geology, climate, rainfall and human activities. The management that the hedgerow requires makes it a landscape in constant mutation where the different stages of development of the hedge give rhythm to the slopes of the Léguer. Beyond the simple segment of hedge, this landscape is to be considered as a living network, which metamorphoses and is never identical from one year to the next.

2 - The hedge in the landscape over time

The bocage was established from the 16th century onwards to protect plots of land supplying hay or cereals, as the livestock had previously been free to roam the countryside. Gradually, all cultivated land or land that was simply used on a regular basis was enclosed. The hedge thus served to organise the spatial distribution of crops and livestock. In Brittany, the enclosure is most often rectangular in shape, making it suitable for ploughing. Hedges also developed around aristocratic residences, abbeys and priories to mark the boundary between the property and the rest of the territory. Little by little, collective spaces regressed, agrarian individualism developed and in the same proportions the multiplication of enclosed land. It was during the 18th and 19th centuries that the bocage network reached its peak. At the end of the 19th century, the bocage enclosures were no longer used to protect the crops from freely circulating animals, but to park the animals, whose numbers had greatly increased; the bocage and livestock farming were markers of the agricultural specialisation of the landscapes of northern Brittany. It was around 1930 that the bocage was most developed.

3 - The hedge, a biomass resource

Historically, the hedgerow also serves as an active source of wood in a region with little woodland due to the numerous clearings carried out over time to increase agricultural land. Barrels are used as timber for construction and crafts, and pruned branches and cut coppice provide firewood for farmers. Within this bocage, the pruning trees, whose branches along the trunk are regularly cut for firewood, still mark the landscape with their singular silhouettes.

4 - The loss of memory of old agricultural practices

Since the 1960s, the bocage has been subject to regular erosion estimated at 3 metres per hectare per year. This gradual disappearance can be explained in particular by the evolution of agricultural practices in connection with the national policy of reparcelling. During the second half of the 20th century, agriculture increased from 5 million to 1 million farmers, with yields rising from 20 to 70 quintals of wheat per hectare, with peaks of 100 quintals. The territory thus increased its cereal acreage. The Breton agri-food sector was then in full expansion. Mechanisation did not sit well with the dense network of hedgerows, which became an « obstacle ». More recently, the intensification of livestock farming in stalls, and its economic fragility, led to a reversal of meadows and pastures in favour of cereals, which aggravated the disintegration of the bocage network. The advent of fossil fuels made these major changes possible and justified the abandonment of hedge management.

« Here we spoke Breton for two millennia, the birds have lost their names like other animals, plants, stones and people. We witnessed the collapse of the peasant memory in one generation […] Their history was studied from the point of view of progress, the future, modernity, instead of also from the point of view of loss. Film: A Well-Kept Secret, Tipping Point No. 1, Patrick Prado, 2008

A whole part of the age-old peasant culture disappears with the evolution of practices, from breeding in the bocage to large-scale cereal production. The land register was reorganised, the plots of land grouped and redistributed. The fields were larger and more accessible to mechanisation.

5 - The return of the hedgerow

In the face of environments under pressure Intensive livestock farming, the main economic activity in the region, has contributed to endangering shared environments. From the 1970s onwards, the pollution of the Léguer river and the proliferation of green algae on the coast were significant. Regional struggles arose between environmentalists and supporters of intensive agriculture. In the Léguer valley, an awareness is developing, gradually rethinking the role of the hedge.

Survival of the bocage as a common feature: bringing back the past to take care of it

1 - Landscape and care: creation of a « Léguer Valley » catchment area/living area

The health issues raised by the observation of the rise in nitrate levels in the Léguer river have led to a collective awareness. A coherent territorial policy was put in place, first of all through the creation of the association for the protection and development of the Léguer valley, which has now been dissolved. It has been replaced by the Léguer watershed committee, administered by the Lannion-Trégor, Guingamp-Paimpol and Morlaix communities. The main motivation of all the elected representatives and residents is the drinking water supply of the sector. Indeed, the Léguer supplies the whole territory with water, and it is therefore very important to limit its pollution rate. « The big challenge was to get everyone around the table, especially the agricultural world. The Chamber of Agriculture did a lot of work and the farmers participated from the start, which was not easy for them because this awareness implies changing practices. » Film: La rivière " Léguer « , histoire d’une reconquête, Philippe Laforge, 2018

2 - The bocage as a landscape repairer

The reclaiming of the bocage has been and still is one of the responses to environmental problems. It is made possible by the recognition of the essential role of the hedgerow in limiting diffuse pollution in water, in regulating the water regime of watercourses to limit flooding, in soil conservation to limit erosion of plots, and in hosting biodiversity. The bocage has thus become a form of local heritage, invested with new ecological and social functions. The actors in the area have implemented a bocage policy in close collaboration. They have accompanied the redefinition of the profession of farmer, which can no longer have as its sole vocation food production based on the use of fossil resources. This has led to policies to enhance the value of the landscape and the work of the farmers who maintain it, as well as to the mobilisation of wood resources for energy purposes while guaranteeing the long-term maintenance of the hedgerow.

3- The long term of the landscape and the collective

From the year 2000 onwards, the first actions for the development of a wood industry were set up collectively under the impetus of the association for the protection and development of the Léguer valley. In 2004, the creation of the Trégor Bois Énergie association, which brings together local farmers, enables the creation of wood boilers and collective shredding sites. The association quickly tried to convince local authorities to join the process. Between 2005 and 2010, elected officials installed communal wood boilers, with the purchase of surplus wood from farmers. A hedgerow management policy is being implemented by municipalities and farmers through the Plan de Gestion Bocage (PGB) tool. Recognition of the economic viability of hedgerow management has led to the structuring of biomass energy production at different levels.

In 2010, the Lannion-Trégor agglomeration community took over from the association to lead and coordinate the structuring project and run the network.

In 2013, the Cooperative Society of Collective Interest (SCIC) Bocagénèse associating communities, farmers, foresters, service providers and individuals was created to ensure sustainable management of the resource in the face of hedge plundering. The company produces and sells wood chips from the bocage for use in boilers for local authorities, companies, farmers and individuals with boilers. It also produces wood for mulching, timber and logs. It carries out communication and environmental education activities and provides expertise for wood chip heating projects.

As of 2015, the Association for the Protection and Development of the Léguer Valley, the Fédération Départementale des Chasseurs des Côtes-d’Armor and the Institut National de Recherche pour l’Agriculture et l’Environnement (National Research Institute for Agriculture and the Environment) are improving the PGB, to integrate the ecological functionality of forest species: « a quality hedge in a quality bocage ».

Careful management and development of the bocage, through local promotion and global levers

1 - Two axes of animation of the bocage

Two main axes of a strategy in favour of the bocage are followed by the territory of Lannion-Trégor Communauté:

• Programmes in the Léguer catchment area allow for the creation of bocage management plans at the farm or commune level.

• They offer training for farmers who are committed to the sustainable management of their woodland, as well as for municipal agents and private individuals. The construction and management of an adapted and remunerative agro-environmental and climatic measure (MAEC) « maintenance of the hedgerow » consolidates sustainable hedge management practices.

• The SCIC Bocagénèse makes it possible to develop the bocage wood sector, which guarantees sustainable management of the resource. It develops wood boilers on the territory to ensure a sustainable outlet for the crushed wood from the bocage.

2 - First links in the chain: farmers and municipalities

The Sustainable Hedge Management Plan (PGDH) and the Roadside Bocage Management Plan (PGB) make it possible to set up an adapted proposal for wood harvesting programmes and bocage work at the farm and commune level. In the commune of Plouaret, a roadside bocage management plan has existed for nearly 12 years. It ensures the sustainable management of hedges along communal roads. On average, three agents for three months of the year are specifically involved in the maintenance of the hedges. The management of the hedgerow allows the commune to invest in the farmers. The wood cut represents an average of 250 tonnes of wood chips per year.

In winter 2021, the municipal technical services maintained 4 km of roadsides, the equivalent of 8 km of hedges. The wood is sold to SCIC Bocagénèse, which is responsible for storage and drying. In the two boiler rooms it owns, the commune of Plouaret burns 600 tonnes of wood chips per year. One of the 500 kW boilers, combined with a 500 kW oil-fired boiler, supplies a heating network to which the town hall, a heritage centre, a development centre, a sports hall, a children’s centre, a nursery and primary school, a secondary school and its restaurant are connected. The Sustainable Hedge Management Plan (SHMP) is a tool that improves on the initial Bocage Management Plan (BMP) by integrating ecological considerations. It is a project led by INRAE, the Fédération Départementale des Chasseurs des Côtes-d’Armor and Lannion-Trégor Communauté.

Other tools are used to identify local landscape entities and ecological continuities. The major geographical areas are first recognised on a regional scale, and then « eco-landscapes » are identified at different scales. Landscapes are defined as territories whose landscape characteristics correspond to relatively homogeneous geological, geomorphological and climatic conditions, and also to their own ecological, ecosystem and biological characteristics. This makes it possible to identify the macro-issues linked to the bocage landscape. The management plan will make it possible to adapt management to the particularities of each farm.

3- Hedge label

The hedge label project started in 2016 is a certification system adapted to landscape issues. It provides a framework for hedge management practices on the one hand, and for the distribution of hedged wood on the other. Thus, the label’s requirements concern both the quality of hedge management and the local and sustainable nature of the supply chain. However, it does not cover the quality of the wood. The label is based on two distinct specifications ("Management" and « Distribution »), a certification system in which an independent certification body operates and a computerised traceability tool. The PGDH is a necessary prerequisite for acquiring the label. afac-agroforesteries.fr

4 - Localized production and consumption to contribute to the harmony between town and country

The pruning and chipping of hedge wood is done on the farms. The chipped wood is then transported to platforms where it is stored under cover to dry. The resource is then transported from the platforms to the outskirts of urban centres to supply boiler rooms. A heating network then distributes the energy produced to various public buildings. The boiler houses and storage platforms are mainly located in cities and along major roads.

The long history of the hedge in the face of current concerns

1 - Progress in common… and the retreat of the bocage

It is the recognition of a historical path and the issues it highlights that has enabled a voluntary territorial policy to be put in place: a shared vision that has brought the issue of energy production to the forefront in a sustainable manner for all the actors involved. The role of the landscape has played a major role in the success of the project. It helped to reveal the importance of the bocage in the local identity. It also made it possible to coordinate and apply actions adapted to the dynamics present in well-defined areas. Finally, this landscape dimension has helped to set up a balanced project in which everyone benefits. Agricultural and communal practices are improved by the actions carried out on the bocage, which provide farmers and communities with a sustainable biomass resource, a significant economic and energy resource. Today, the bocage continues to retreat and many farmers do not yet recognise themselves in the project, as they depend on a still powerful conventional agricultural model. Some plots of land are enlarged, hedges are removed or poorly maintained. The deployment of the fibre is a current example of the problems encountered in preserving the bocage. The removal of the hedgerow saves time for the installation of underground electricity networks, and its benefits take a back seat. But all in all, if the influence of the project does not yet embrace all the actors of the Léguer catchment area, it remains an exemplary project.

2 - Bocage landscapes on a national scale

The hedge label was initiated locally by the SCIC Bocagénèse, Lannion-Trégor Communauté. Drawing on this experience, local partners Afac-Agroforesteries, SCIC Bois Bocage Énergie and SCIC Mayenne Bois Énergie have started to set up a national certification system for wood that promotes the sustainable management of hedgerows. The label will strengthen and recognise an agricultural production chain for this sustainably managed resource among farmer-producers. It was officially launched on 4 October 2019 at the Ministry of Ecological and Solidarity Transition. In 20 years, the industry project initiated by a group of farmers in Trégor has greatly influenced the creation of a management and development label with a national scope, on which any territory with bocage landscapes can rely.

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