[Cet article a initialement été publié le 1er mai
2025]
At a time when the ecological transition requires concrete choices, the restoration of hedges stands out as a discreet but strategic priority. Long neglected in favor of intensive agriculture, these vegetation alignments prove essential for slowing soil erosion, storing carbon and maintaining vital corridors for biodiversity.
In France, nearly 70% of hedgerows have disappeared since the 1950s due to the consolidation and enlargement of plots. Faced with this massive loss, public policies now encourage the replanting and sustainable management of these landscape structures. However, enthusiasm for hedges raises questions: between a credible ecological lever and a fashion phenomenon, their true effectiveness deserves to be examined in the light of climatic, agricultural and social challenges.
Ancestral barriers become living sanctuaries
Much more than simple agricultural fences, hedges form real sanctuaries for biodiversity. In France, particularly in the Normandy and Breton bocages, certain hedges still follow the boundaries of medieval properties or even older lines. According to “Hooper’s Rule”, formulated by British ecologist Max Hooper in the 1970s, it is possible to estimate the age of a hedge. To do this, you must count the number of plant species present over thirty linear meters. Thus, a diversity of seven species suggests more than 700 years of existence.
Their age explains their exceptional biodiversity. According to the BBCsome British hedgerows are home to more than 2,000 species, including pollinators, small mammals, nesting birds and rare plants. The particular configuration of the hedge – superposition of herbaceous, shrub and tree layers – creates microclimates favorable to a diverse fauna. Species such as the muscardin, the turtle dove, bats and even small mammals such as field mice and shrews depend directly on hedges to feed, move or reproduce, according to a study relayed by The Guardian.
Hedgerows also play a vital role as ecological corridors. According to researchers at UK Centre for Ecology and
Hydrologythey facilitate the movement of species in territories fragmented by intensive agriculture and urbanization. They thus reduce genetic isolation, allowing animal populations to maintain themselves in the long term. In an era where landscapes are becoming standardized, old hedges represent a major natural heritage, structuring and further energizing our countryside.
A fragile ecological value without appropriate management
The mere existence of hedges does not guarantee their ecological effectiveness. Their value depends on their maintenance. A damaged, missing or poorly trimmed hedge quickly loses its role as a refuge for wildlife. According to a 2024 survey, despite agro-environmental efforts, only one hedge in two in England is considered to be in “good structural condition”. In France, among the remaining hedges, a significant part is degraded or poorly maintained. This motivated the launch in 2023 of an ambitious national plan. It aims to restore 50,000 kilometers of hedgerows by 2030.
Maintaining a living hedge requires regular interventions, adapted to its natural cycles. Ancestral practices such as plessage consisted of intertwining and tilting branches to create thick hedges. They were resistant to bad weather and were conducive to biodiversity. Today, the widespread use of mechanical hedge trimmers, often at the wrong time of year, depletes plant diversity and destroys the layers necessary for small animals.
© © Wikimedia commons
Located in Northamptonshire. © Wikimedia commons
In France, many rural associations are redeploying training in plessage and intaglio to limit brutal cuts. Projects like those supported by Hedgelink UK insist on the importance of moderate annual maintenance to prevent hedges from becoming rows of old, spaced-out trees, inaccessible to terrestrial fauna.
Without adequate management, the ecological corridor function is compromised. Discontinuous hedges then cease to protect species against predators and climatic stress. To restore an effective green network, it is not enough to plant. We must relearn how to sustainably maintain these living structures, keys to the ecological connectivity of territories.
Climatic and economic advantages… provided you invest
Much more than refuges for biodiversity, hedges actively contribute to climate regulation. By capturing atmospheric carbon, they sustainably transform the underlying soil. A recent study from the University of Leeds showed that hedgerows store on average 40 tonnes more carbon per hectare than neighboring intensive grasslands. They also slow down erosion and reduce the impact of heavy rain on the soil. In addition, they reduce heat peaks in localized climates.
On an agricultural level, their presence promotes more resilient production. By housing wild pollinators and natural predators of pests, hedges limit the use of chemical inputs. They also protect livestock against heat stress and bad weather, indirectly improving yields.
In addition, according to researchers at the University of Reading, hedges also bring indirect economic gain to farmers. By limiting soil erosion, by harboring auxiliary insects which replace pesticides, or by slowing down runoff, they reduce several areas of agricultural expenditure. These effects remain difficult to quantify, but their positive impact is recognized over time.
However, these benefits come at a cost. Planting a hedge requires between 20 and 25 euros per linear meter, not including the regular maintenance costs essential to its sustainability. Thus, despite support programs, only 55% of existing hedges are in good condition. In addition, the pace of planting remains below the objectives set for 2050. The lack of sustainable financing, administrative complexity and the absence of practical training for farmers are slowing progress. Added to this is a space constraint. In certain regions, economic pressure on the usable agricultural area makes it difficult to massively integrate new hedges without strong financial compensation.
A sincere, but fragile, citizen enthusiasm
Interest in hedges is no longer limited to farmers alone. In rural areas as well as in peri-urban areas, citizen initiatives are increasing. On Dartmoor, England, thirty volunteers recently replanted 300 meters of hedges in a single day. An illustration of the growing enthusiasm for these natural structures. In France, events such as “National Hedge Week” or actions carried out by platforms such as HedgeHub are raising awareness among an increasingly wider public of the importance of restoring, pruning and maintaining these elements of the landscape.
This enthusiasm has tangible effects. For garden birds, often deprived of shelter in recent housing developments, hedges represent a vital necessity. The scarcity of hedges has contributed to the severe decline of certain species such as the house sparrow or the European starling, experts point out. Replacing fences with diversified hedges could reverse these local trends.
However, this momentum has weaknesses. Some recent plantations lack plant diversity. Or they favor species not adapted to local ecosystems, reducing their ecological effectiveness. The absence of reinforced technical supervision risks reducing the expected benefits. Finally, communication around hedges must remain measured. According to a study published in Philosophy of Scienceit is essential to adopt nuanced communication. Certainly it must clearly explain the benefits observed. But it must also recognize the limits or the specific contexts in which they operate.
The civic momentum around hedges opens up promising prospects. Provided that popular enthusiasm, technical expertise and long-term vision are combined, hedges could once again become a powerful lever for restoring biodiversity, protecting soils and sustainably reconnecting agricultural and urban landscapes.
