Energy crops (in particular willow) can be used in a wide range of bio-engineering applications utilising the rapid growth, extensive root network, nutrient uptake and water-use properties of the crops. Applications include; river bank supports and slope stabilisation (road verges, building projects etc.) which use thick willow stakes and fine branches for weaving, fagots of willow for flood defence and willow and miscanthus which can be used for purification of waste waters (biofiltration) or in buffer zones to protect sensitive areas from nutrient leaching. The living structures also provide a natural and aesthetic wildlife habitat.

Riverbank Stabilisation

Willow had been used for river bank supports for centuries, traditionally using “crack willow “ (Salix fragilis spp.) and more recently using commercially bred biomass varieties. Live willow can be used as an environmentally sympathetic and cost effective alternative to steel and concrete in river stabilisation and restoration. Its quick establishment and strong root growth reduces erosion of riverbanks and therefore reduces loss of agricultural land and river siltation. Willow screens may also reduce leaching of pesticides, nitrates, phosphates and herbicides into the watercourse and promotes local wildlife by providing a more attractive riverbank habitat for fish, birds, invertebrates and small mammals. Willow is also particularly resistant to flooding.
Willow use in river bank stabilisation creates a demand for willow stakes and weaving braches and also for prefabricated river hurdles. Advice on river stabilisation project management may be sought from several of the companies listed on the contact sheet or from the Environment Agency.

Slope Stabilisation

Use of live willow support systems can also be applied to construction projects requiring slope stabilisation. Willow spilling has been used for landscape repair, highway embankment supports and in stabilisation of slopes for construction projects. Using willow is cost effective, has a low impact on the environment actively encouraging wildlife and visually aesthetic. Biomass willow varieties are ideal for hurdles and stabilisation screens as they are fast growing, produce thicker stems and have limited branching. Picture of "willow engineering" slope stabilisation project courtesy of Richards, Moorehead and Laing Ltd.

Trees for Shelterbelts and Windbreaks

When planted in a row formation, willows provide an effective windbreak to protect crops and stock. This can extend the growing season and improve animal and plant growth. It can also provide a buffer strip protecting sensitive areas from agricultural run-off or silt deposition. These can be used in conjunction with native woodland planting and is equally successful when using native willow varieties.

Wildlife Hides & Holts

Willow domes make ideal wildlife hides and otter holts blending into the scenery and providing cover.

Biofiltration

Willow, miscanthus and giant reed have all been demonstrated for use in natural filtration beds in a similar manner to reed beds for the filtration and removal of nutrients from of waste water. Successful examples include treatment of landfill leachate, farmyard washings and runoff water from a sawmill process in Sweden. For more details on Biofiltration see page link.