Plantation de Haies :From Design to Monitoring
Detailed information on the functions, types, species, maintenance and regulations of hedges is available in the article "Hedge".
Hedge planting is a long-term investment that requires careful planning, from the choice of species to initial maintenance, to ensure their establishment and optimal development.
Design and choice of species
The choice of species is crucial and must take into account the pedoclimatic conditions (soil and climate) of the planting area, as well as the specific objectives targeted for the hedge.
Various objectives
- Wood production (timber or energy).
- Protection of livestock against weather hazards.
- Supplementary Forage.
- Support for biodiversity and creation of ecological corridors.
- Water regulation and infiltration, carbon storage.
- Windbreak.
Technical guidelines
Keep at least 20% of young trees permanently to ensure natural regeneration of the hedge.
To maximize agroecological effects, maintain a minimum width of 1.5 meters and avoid topping, which limits growth and reduces ecological and agronomic value.
The planting must consider the characteristics of the plot: slope, erosion risk, prevailing winds, drought. The projected shade should also be anticipated.
| Advantages | Disadvantages | |
|---|---|---|
| Seedling | Fastest growth |
|
| Cutting | Faster than seed, can be free | Clone production thus increased disease risk, less efficient root system |
| Seed |
|
Slowest growth |
- Prefer seedlings grown from seeds and take the youngest possible plants, ideally 1-year-old scions
- Stored refrigerated at the nursery
- Take the seedling out of the fridge at the last moment, before a rainy day, water if dry weather
- Plant until June (if the seedling has not budded)
- Not refrigerated
- No need to water (except in particularly dry conditions)
- Plant from late November to March (before bud break)
- Choose small bare-root seedlings
- More vigorous plants that grow more efficiently
- The collar should be at soil level, not buried to avoid rot
- Roots are spread out and overly long ones are cut to avoid curling
- Possibility to "praline" the plants
Mix of clayey soil, manure (dehydrated or not), compost and water, the texture should be somewhat pasty, not completely liquid nor thick
- Speeds up healing of damaged or cut roots
- Prevents fragile roots from drying out before planting
Favor local species
- It is recommended to use local species, preferably from wild individuals. The "Végétal local" label guarantees this origin.
- A composition of local species adapted to the environment ensures the longevity of the hedge and offers a diversity of shapes, colors, and scents.
The best practice to define your planting project is to contact the town hall to learn about any specific rules that may apply. It is also advisable to pay attention to the choice of species by targeting local origins.
When uprooting
Common law sets a number of rules further supplemented by CAP provisions concerning agricultural operators. Thus, anyone (legal or natural person) wishing to uproot a hedge must first ensure compliance with the following regulations.
Composition favorable to biodiversity
- A biodiversity-friendly hedge is heterogeneous in composition and structure.
- It must be rich in flowering species (flowering spread over the year) and fruit-bearing species (winter food resource for birds).
- Including several vertical layers (trees, shrubs, vines) as well as a grassy strip at the hedge base is essential to provide various habitats and nesting sites.
- Wide hedges (double or triple rows) constitute an effective refuge for terrestrial fauna.
The diversity of layers also provides nesting sites for all birds dependent on hedges (warblers, thrushes…).
It is preferable to plant hedges wide enough (double or triple rows) to constitute an effective refuge for terrestrial fauna. Maintaining a grassy strip at the hedge base is also wise to enhance attractiveness for beneficial insects, but also to facilitate farmer access to the hedge.
The countryside hedge
The countryside hedge is a balanced environment, with a natural appearance but contained and artificially delimited. It requires regular maintenance to prevent plant spread that would lead to its widening. Some species, disliked or little known, are absolutely necessary for the countryside hedge:
- Including spiny plants (blackthorn, hawthorn), lesser-known species (viburnum, privet, spindle tree, dogwood), vines (bramble, honeysuckle, ivy), and herbaceous plants.
Herbaceous plants
Their morphologies
Depending on the associations of shrubs and trees, the diversity of ages and sizes of the plants composing it, but especially depending on the owner's will and the frequency of interventions, the countryside hedge presents a great diversity of morphologies.
Species to avoid
To be supported in a planting project, it is possible to contact a local specialized structure.
- Conifers are generally less interesting for crop auxiliaries and can host some pests (e.g., Agrotis).
- Prunus species (cherry, wild cherry) can host aphids (e.g., Rhopalosiphum padi) attacking cereals and maize.
- The plum tree is a primary host of the green peach aphid (Myzus persicae) which can attack rapeseed.
Examples of planted species
Romary Courtois chose lindens, elms, downy oaks, mulberries (non-local but drought-resistant), vines (non-fruit varieties), and privets for his fodder beds. Jean-Louis Nogues planted oaks, Hazel, Chestnut, Elderberry and blackthorns. (add link to the adapted rex)
Preparation of the planting
Good site preparation is essential for the establishment and optimal development of young plants and allows rapid implementation of mulching.
Marking out and layout
- Define the position of future tree lines manually with stakes or using GPS.
- For intra-field lines, it is advisable to align with the longest edge of the plot and follow its curve. To limit shading, position lines along the North-South axis if possible.
Connect the planted tree lines to existing structures (woodland edge, hedge, riparian forest, meadow...)
These recommendations apply to all crops but other guidelines exist for agroforestry in arable farming, viticulture and livestock farming.
- For hedges and windbreaks, leave a spacing of 100 to 200 meters between two hedges and connect new lines to existing structures (woodland edges, hedges, riparian forests).
Soil preparation
Good soil preparation is essential for good establishment and optimal development. It allows rapid implementation of mulching and facilitates planting. Proper soil work should result in a permeable structure over a maximum depth (min 60 cm).
- For hedges, prepare the soil over 1.50 meters wide.
- Refine the surface to obtain a seedbed with a rotary harrow or rotavator.
- This preparation is preferable in autumn before winter planting or early spring.
- For isolated trees, loosen 1 m³ with a mechanical shovel or backhoe, then refine the surface.
Choice of plants
- Prefer first-choice plants, certified healthy and genetically sound, from controlled nurseries.
- Young plants (1 to 2 years) are preferred, ideally 1-year-old scions. They must be well-formed with an abundant and balanced root system, without spiraling.
- Deciduous plants are often bare-rooted, evergreens in pots.
- It is possible to collect young plants from nearby areas with the owner's permission.
- To speed root healing and prevent drying, pralinage of plants (mixture of clayey soil, manure, compost and water) is recommended.
Planting
Planting period
- Planting is preferably done in winter, during the vegetative rest period, avoiding days of frost, strong winds or overly wet conditions.
- For plants not refrigerated, plant from late November to March (before bud break).
- For refrigerated plants, planting is possible until June, as long as the plant has not budded.
Planting technique
- Plant trees 30 to 50 cm apart for hedges.
- If a mulching film is used, open it in a cross about 20 cm.
- Dig a hole the size of the roots with a spade.
- Prune the plants (stems and roots).
- Place the plant vertically with roots well spread downward, ensuring they are not compacted.
- The collar should be slightly below soil level, under the mulch.
- Bring fine soil to fill the hole and cover the roots, creating a "basin" around the plant to collect rainwater.
- Firmly tamp the soil by hand, then with the heel.
- Add gravel or fine soil around the plant to hold the mulch and prevent rodents from passing underneath.
Mulching and protection
These steps are essential for successful planting, providing a favorable environment for establishment and growth of young plants.
Mulching
- Mulching limits weed competition and maintains soil moisture. It warms the soil, preserves its structure and contributes to feeding it if plant-based.
- It should be spread over a minimum width of 20 cm on each side of the plant, ideally up to 50 or 60 cm.
- Types of mulch:
- Straw: about 25 cm thick, lasts 1 year.
- Wood chips (RCW): about 15 cm thick, lasts 2 years. Prefer deciduous species and avoid more than 20% conifers or species rich in tannins. Chips must not come from resinous trees to avoid acidifying the soil.
- Wool: free, lasts several years, protects against deer.
- Biodegradable or biocompostable films: unrolled before planting, require collars at the base of each plant.
- Mulches made of plant fibers: require staples or must be buried at the edges.
- Plan for additional mulching in case of rapid degradation during the first 3 years after planting. Romary Courtois observed high mortality due to heavy mulching without watering during dry periods.
Protection
- Plants must be protected from wildlife (deer, rabbits).
- Stakes (in chestnut) and protective tubes serve as supports.
- Against deer: Climatic 4-ply tubes (20 cm diameter, 120 cm height).
- Against rabbits and hares: Climatic Nortene tubes (14 cm diameter, 60 cm height).
- Against livestock:
- Solid fences, if necessary reinforced with electric wires, placed 1.5 meters from the planting line for cattle and at least 1 meter for sheep, allowing sufficient growth space while giving access to foliage and young shoots.
- Other devices: mechanical corslets, Ursus mesh, split sleeves, metal mesh.
Monitoring and maintenance of young plantations
Regular monitoring during the first three years is a guarantee of success to replace dead plants and prune trees and hedges.
Watering
Only in case of exceptional drought (one month without rain) to save the plants.
Brush clearing
Clear vegetation bordering the hedge after 1 year to avoid light competition.
Coppicing
Coppice trees and shrubs at planting or after 1 year to make them more vigorous and strengthen their root system.
- Done a few centimeters above the collar, from December to March
- Allows densification of the lower layer, increases root number and rejuvenates the hedge
Continuous protection
Ensure protection of young plants against grazing and wild animals.
Patience
It is a long-term investment; patience is required and it takes 4-5 years before benefits can be reaped.
Additional information
The technical sheet Erosion TTool / Hedge Planting explains in detail how to plant and maintain hedges to combat erosion, with practical advice and information on costs and regulations.
