Site Selection and Preparation

When considering a site for planting, thought should be given to the site’s ecological and historical value and the visual impact of the crop on the landscape. Willow grows taller than most arable crops and could be more visually intrusive than sheep grazed pasture particularly when planted at exposed sites. Guidance for fitting SRWC into the landscape can be found in literature produced by the Forestry Commission.

Public access, archaeological features and machinery access for planters and harvesters should be taken into account in plantation design.

Willow can tolerate most soil conditions and types (preferring free draining loamy soil), the optimal pH being neutral (5.5-7.5). In very acidic areas (<pH 4.5), magnesian limestone may be applied to the soil in the first year. Ideally, the site should not be in an area with particularly waterlogged soil as the crop is harvested in the winter and wet ground would restrict machinery access, the use of heavy machinery in these conditions may also cause soil compaction which would hinder root growth.

Prior to planting SRC it is essential to contact the Forestry Commission and complete an Environmental Statement which will determine if a full Environmental Impact Assessment (EIA) is required.

Ground Preparation

The quality of site preparation is vital to the establishment of the crops and its subsequent ease of management. Preparation should begin in the autumn before planting, starting with the application of an appropriate broad-spectrum residual herbicide (e.g. glyphosate) to control any perennial weeds present. The area should then be ploughed and allowed to over winter when frost activity will break down the soil further. Immediately before planting in the following spring the site should be rotivated to produce the fine tilth required for root establishment and limed if required. In addition, the application of a pre-emergent herbicide is advised for good SRC establishment and will ultimately reduce the amount of weed control required.

Planting

Planting takes place between February and April. This can be done by hand, pushing 25cm long cuttings into the ground leaving approximately 1cm above ground, or on a larger scale by using mechanical planter.

Currently the machinery available offers two methods of planting. The more traditional ‘step-planter’ is the most commonly used machine. It works by cutting long lengths of willow into 25cm cuttings and inserting vertically into the soil at predetermined intervals. A wide range of step planters are available planting between 2 and 6 rows at a time at the required spacing intervals.

The second planting machine is the ‘lay-flat planter’ which lays lengths of willow end to end in a furrow at a depth of 2-8cm. This method does not control distance between shoots and consequently the grower has no control over crop density. However, this method requires less preparation of planting material, is quicker and to date has shown to produce coppice yields equivalent to step planted plots (with certain willow varieties) and is therefore potentially a more economic option although not widely available.

Plantation Design

When designing the planting plan it is important that machinery access is considered, that suitable rides (5-8m) are left and that landscape factors are considered. The Forestry Commission has produced guidelines for all of these aspects. The most effective and manageable design is the Swedish twin row system which is designed to allow machinery to move easily between the rows without causing damage.

Typically the Swedish twin row has spacing of 1.5m and 0.75m between alternate rows and 0.5-0.9m spacing between trees along the rows. This spacing range produces a density of 10,000 - 20,000 planted cuttings ha-1. The Forestry Commission recommend planting at 17,500 cuttings ha-1 however higher densities are possible with closer within-row spacing and some authors have suggested hat with the new varieties, which tend to be less dense in their growing structure, planting densities of > 100, 000 cuttings may be possible (this is costly since the planting material is the most expensive outlay when establishing an SRWC crop).

Many of the new varieties are also bred for pest, disease and frost tolerance. However, in order to provide protection against the spread of pests and disease it is recommended that a mixture of varieties is planted. When deciding which willow varieties to plant the grower should seek advice for each locality bearing in mind that new varieties are frequently available.