Biodiversity

SRC can significantly improve ecological diversity within the agricultural landscape. The presence of large numbers of invertebrates within willow leads to an increase in the number of small mammals, bird species and also individual birds present. High numbers of birds can be found within willow SRC throughout the year and also over the 3-year harvest cycle with many of the bird species being of high conservation value such as skylark, lapwing, reed bunting, song thrush and many breeding migrant warblers.

Headlands and rides provide further habitats for a wide range of plants and animals.  For example 14 species of butterfly have been recorded within SRC headlands so an increase in the establishment of the crop might help to prevent the decline of many butterfly species associated with the agricultural landscape.

To enhance the conservation value of SRC, the headlands and rides should be seeded and only mown once a year in late summer after flowering. Weed control should not be necessary. Although effective herbicide applications are required during the establishment of SRC ie the first 12 months, once canopy closure has occurred after cutback and if land preparation has been carried out efficiently there should be no further need for herbicide applications to the crop. It is expected that, with time, a non-competitive, ecologically beneficial ground flora will develop made up of shade tolerant plants often found within woodland and hedgerows. These will encourage the presence of many predatory small mammals and invertebrates that in turn will provide food for birds and also help to control invertebrate pests.

As many bird species in particular are associated with specific age classes of the coppice, e.g. after planting, cutback and harvest, one of the best methods of ensuring suitable habitat is available each year is to plant coppice annually over a three year period. This allows birds requiring open ground to move to newly harvested areas each year. Establishing SRC adjacent to or near existing woodland, hedges and open water can also enhance biodiversity by encouraging the colonisation or use of the coppice by the local wildlife.

A willow SRC plantation is ideal for holding game although, if planted purely to maximise energy crop yield, access for beaters to drive birds would not be easy and there would also be difficulty in flushing the birds. The plantation can be designed to maximise use for game-driving and holding by aligning the crop in an appropriate direction, providing frequent rides for access and by planting higher densities of willow immediately adjacent to the main crop which are cut annually to provide low, dense edge cover. SRC does not provide a plentiful food source for game birds therefore it is recommended to supply grain as necessary.

Growers should be aware of the main insect pest species on SRC which are the Chrysomelids or willow beetles, both the adults and larvae of which feed on the leaves and are therefore capable of significant damage if their numbers reach a critical threshold. Currently the main form of control is by the targeted use of an appropriate insecticide i.e. edge spraying in early spring if the threshold is reached. No SRC plantation has been killed due to defoliation by the beetles but yields can be reduced by 40-50% if 90% defoliation occurs.