APPLICATIONS OF WILLOW

IN ART, TECHNOLOGY AND THE ENVIRONMENT

STEVE PICKUP

PART 1: SIXTEEN REASONS TO PLANT WILLOW

1. EASY TO PLANT, QUICK TO ESTABLISH, EXTENDED PLANTING SEASON

Willow stools are established by planting good quality selected hardwood cuttings approximately 9" (23 cm) long. They can be planted by hand using a thin metal bar. This could take one person up to 35 hours per hectare. Tractor-mounted equipment is available for larger areas. The planting season is normally November to March, i.e. the dormant season. This can be extended by holding back the cuttings in cold storage.

First year growth will typically be 1 - 3 metres. They can then be cut back to produce more rods in the following season and subsequently cropped annually or according to the cutting cycle chosen.

2. ADAPTABILITY

Willows will grow on a variety of soil types. Better quality land with ample moisture and fertility will of course produce higher yields, however willows will also grow adequately on poorer soils and even on contaminated land where little else will grow (Rutter [4]). They will also tolerate harsh conditions such as high altitudes, exposed wind blown sites and even salt laden winds by the sea.

3. VIGOROUS AND HIGHLY PRODUCTIVE

Expected yields of fast-growing varieties managed as Short Rotation Coppice (SRC), i.e. harvested every 1 - 3 years or so, may be as much as 20 to 30 tonnes of fresh cut material per hectare per year, or 10 - 15 tonnes of dry matter.

Depending on variety and growing conditions, individual rods may be anything from 6' to 12' plus. On one particular site, which is part of a filtration system for cider effluent, some rods grow over 15' tall on 2 year old stools in one growing season. A substantial crop of large willow rods were then sold as a standing crop to a local basket/hurdle maker.

4. LONG LIFE

In Somerset the life of a willow bed may vary from 20 to 50 years (Stott [6]).

5. RESILIENCE

Because willow is so vigorous and tenacious, if stems are broken (even down to the base) they will simply resprout sending out several more shoots. Therefore an accident or wilful act of vandalism merely becomes inadvertent coppicing.

6. SHELTER

Because willow is fast growing and will tolerate exposed windy situations it is ideal for quick, effective shelter. Salix viminalis and hybrids are suitable for fast-growing, medium size (up to 8m) windbreaks and can reduce windspeeds by up to 60% even when leafless. Salix alba, Salix fragilis and hybrids can also be used to create tall shelter belts up to 20 metres tall (Stott [1]). Smaller-growing species will make attractive garden hedges. They can be used to create sheltered microclimates for plants, animals and people alike. Unsightly buildings can also be effectively screened from view.

7. ENVIRONMENTAL AND CONSERVATION VALUE

Firstly the humus building quality of willows improves the soil conditions and promotes the build up and diversification of the soil life which in turn increases habitat value for other plants and animals. The plant itself is host to a wider range of insects than other tree species in GB and consequently attracts a large number of different insect eating bird species (ETSU [9]). Resident and migratory songbird species that are otherwise in decline have been associated with willow SRC. The total numbers and range of species are both high. It also provides good roosting and nesting sites and ground cover for mammals. This would seem to suggest that predators would also find willow SRC attractive. Abundant catkins provide a valuable food source for bees and other pollinating insects early in the season when little else is available.

The huge number of willow varieties available, which display a very wide range of leaf shape, colour, size, stem colour, flowering periods, growing habit, size and shape, combined with their fast growing nature, enables an ugly site to be transformed very quickly into an amenity for the local community.

If the willow is burned as chips this will only release carbon that has been consumed by the crop since it was last cut. In other words it is carbon neutral. Where the willow is dried and used for craft purposes the carbon is stored over a long period of time. If sculpture or bio-engineering projects are constructed using live willow material they will carry on consuming carbon as they grow, resulting in a net reduction of carbon dioxide in the atmosphere.

8. SOIL BUILDING AND LAND-RECLAMATION

Willows are very effective pioneers on poor or degraded soil. Their root activity and abundant leaf mould will improve the humus content, nutrient levels and soil structure making it possible for a wider range of plant species to establish themselves (Stott [1]). Research has shown that some varieties are tolerant of heavy metals whilst others will actually absorb some of the heavy metals into their tissues (Ostmann [2]). Slag-heaps in the north of England have benefitted from willow planting, rendering them attractive to both wildlife and the local community (Rutter [4]).

Buffer zones of willow around sites that produce pollutants is another technique that has been employed successfully (Obarska-Pempkowiak [5]). They are also being increasingly used in ecological treatment systems, often with reeds and other plants, for wastes such as sewage, farm slurries, silage liquor, wash-down water and a range of biodegradable wastes from industry (Abrahams [3]).

Therefore by proper analysis, appropriate selection of species and good project design, willows can be used effectively to reclaim degraded or contaminated land at a fraction of the cost of a conventional approach (Rutter [4]).

9. EXPERIENCE & EXPERTISE

Willow has been used by man since early times in differing conditions and for a variety of purposes. There are also extensive research programmes under way in many developed countries. This all adds up to a large body of experience and knowledge to draw on when considering the use of willow for a particular project.

10. WIDE VARIETY

There are literally hundreds of traditional and native varieties of willows displaying a wide range of characteristics. Considerable resources have been devoted to breeding and selecting new willow varieties, particularly in the last few years. This has resulted in a huge number of useful varieties to choose from. By careful selection one may produce material for a wide range of uses. (See Willow Bank Catalogue [7]).

11. MULTIPLE FUNCTIONS

Often there are conflicting demands on a particular site, for instance a need to decontaminate soil/spoil, to be productive and generate income, to improve conservation value and to provide an amenity for local people. In many cases a difficult choice would have to be made. Again, by proper assesssment of the site, careful choice of varieties and good project design and management, most or all of the requiremnts on a site could be satisfied through the use of willow. It might even prove possible to please all of the people all of the time!

12. ANNUAL CROPPING

Unlike other wood crops, willow can be cropped on an annual basis for basketry, sculpture and other purposes, thereby giving a regular and frequent income.

13. VERSATILE AND ACCESSIBLE

There is a large range of uses to which willow plants and material can be put. Some examples are basketry and craft products, living willow sculpture, sound and pollution barriers, waste filtration, riverbank stabilisation, land reclamation, generation of heat and/or electricity, bee fodder, creation of habitat and amenity sites and educational resources.

Although experienced craftspeople work to a high standard of design and production, basic willow craft techniques are fairly easy to learn and the material is generally safe to work with, not requiring any expensive or dangerous equipment. For these reasons it is an ideal material for children to work with, requiring no previous skill but lots of imagination. With the guidance of an experienced tutor it is possible for a group of children to each make a finished craft item in one sitting, giving them a sense of satisfaction and achievement.

14. LOW MAINTENANCE

Once the crop is established, often the only operation required is to harvest it according to the cutting cycle chosen.

Even this may be avoided by the grower by selling as a standing crop to a willow user or trader.

15. EASE OF REMOVAL

If circumstances or requirements of a site change suddenly this could normally cause some problems. The projected products or benefits may not have been realised as yet. This could result in serious inhibitions, financial, psychological or otherwise to radically changing the use of the site. Where willows have been used some products, e.g. 1 year old rods, are available after the first growing season and subsequently thereafter annually in large volume. The benefits of willows are also realisable soon after planting, e.g. amenity or conservation value. Therefore even after a short duration the willows may have paid back the initial investment of resources used in establishing the project. Also in other circumstances returning the site to its former condition could prove technically demanding, time-consuming and costly. In the case of willow plantations it is easy to remove them from the site. After harvesting the current season's crop the rootstcks can be killed off simply by rotorvating them into the ground using a conventional and commonly available tractor mounted rotorvator. Thus part or all of the site could quickly, easily and cost-effectively be put over to building development for example, the willows having paid back in products and/or benefits the initial investment of resources.

16. GRANT AVAILABILITY

Generous grants are available from the FA for establishing willow SRC. Currently set at �600 per hectare establishment grant. In some cases one may also receive a better land supplement and annual set aside payments for the same site. Contact the local FA office for a woodland grant pack and advice. Where willow planting is part of a broader project, e.g. in setting up training schemes or using willow materials for craft or other products one may also obtain worthwhile funding from statutory bodies or charitable foundations (Rutter [4]).

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PART 2: WILLOW APPLICATIONS

1. WOOD CHIPS

In the last few years much research has gone into growing willow for woodchip production. Thw willows are cut, usually every three years (known as SRC), dried and chipped into woodchips. There are a number of power staions being built specifically to generate electricity from willow woodchips.

Typical yields of willow in this country are 10 to 15 tonnes of dry willow per hectare per year.

Smaller-scale units that will generate heat and electricity (known as Combined Heat and Power, or CHP, units) are also available. These are designed for large buildings, from a large country house or block of flats to a school or hospital, or even a district heating scheme. Such units are in common use on the continent.

Alternative uses for woodchips are as mulching material for paths, play areas and weed control, equestrian purposes or, when composted, for soil conditioning or garden mulch. The willow may be cropped using a forage harvester, which also chips the willow, or a tractor mounted coppice harvester, which cuts and bundles it.

Quality control and storage of woodchips are factors which have to be taken into consideration.

Woodchips are of course the lowest value use of willow material, therefore woodchip production is only commercially viable on an agricultural scale.

Where smaller areas are to be grown and hand tools or small scale machinery are to be used then the higher value willow products are more appropriate.

2. LIVING SCULPTURE

This is one use of willow that has really caught the public imagination (Pickup [8]). It is being used for schools, parks, events, community art and the like. The material used is mainly 1-year old rods of fast growing varieties, but on large projects 2- and 3-year old material is often used. The varieties used at present tend to be those normally grown for biomass. There are two reasons for this; firstly, these varieties tend to produce the longest rods, and secondly, other varieties are generally not available in large enough quantities. The main growers at the moment are a few farmers who have diversified into willow with an eye on the woodchip market and consequently grow varieties for volume. Many sculptors would love to use a far greater variety of willows to add a further dimension to their work. Prices charged for willow for sculpture work vary enormously, sometimes reaching several hundred pounds a tonne. Because commercial growers are still few and far between and willow material is bulky, transport costs over long distances can be excessive.

Courses in living willow sculpture are generally over-subscribed at the moment and there is a growing band of willow sculptors; these range from parents working with their children at school to professional sculptors working on high profile projects and, of course, charging professional rates.

To sell willow material for sculpture or bio-engineering projects could be profitable alone. To also sell uncommon and interesting varieties could add more value and capture a wider market.

3. WILLOW PRODUCTS

There is a wide range of willow products being produced by modern day craftspeople. The renaissance in basketry over the last 15 years has contributed to this enormously and laid the foundation for the development of new products.

These include such items as indoor and outdoor furniture; garden products such as trellises and arches; ornamental hurdles and fencing; and figurative works. Currently there is a large demand for such products and many of the craftspeople I am in touch with simply cannot make enough to satisfy the demand. One in particular has a six month waiting list for hurdles alone. I myself received an enquiry for 45 hurdles which I could not obtain from anywhere. The retail price of a standard 6' x 6' willow hurdle is about �35 - �40. Items such as log baskets have been imported cheaply for some time now to satisfy a mass market. A worth while niche for willow products lies in good quality, unusual items, especially those made with uncommon or attractive varieties. I have supplied several basket makers in the past with unusual varieties and the items made with them were in great demand. Basket willows are available from a few growers in Somerset. The main variety grown is Black Maul, a good general purpose type, and small numbers of a few other varieties. The demand has increased so much recently that one of the main growers in Somerset has resorted to buying in from other sources and had sold some of next season's crop while it was still growing. Again craftspeople are constantly frustrated at the lack of variety available and will pay premium prices for anything out of the ordinary. There are dozens of varieties of willow that are easy to grow and which would find a ready market from craftspeople. Processing of basket willow is minimal. Simply sorting into sizes, which is straightforward, and drying, which is done outside in the wind and sun. They are then stored in dry conditions. The basket maker will soak the willow prior to use to make them flexible to work with. In Somerset Salix triandra will produce about 200 bundles or 6 tonnes per acre whereas Salix viminalis crops at about 10 tonnes and Salix purpurea at about 4 tonnes. An experienced cutter may cut, tie and stack 40 to 50 bundles per day (Stott [6]). Current (Winter 95) retail prices of brown (unpeeled) bundles of willow are about �15 each. Adding on value through craft items would increase the economic value considerably. Items made with uncommon varieties and made to a high standard of quality and styling could fetch up to twice the price of a similar standard item. There may also be opportunities to create a new design for a particular specialist purpose. The recent growth (or rise?) in hot air ballooning is a good example.

4. BIO-ENGINEERING

Willow has been used for bio-engineering since early times. With the advent of the industrial revolution many techniques were forgotten as people were seduced by modern methods and attitudes. On the continent many traditional techniques were retained and improved. There is now a definite and growing trend in this country towards rediscovering and devising biological or ecological solutions to many of today's (often man-made) problems. The productive and versatile nature of willow has enabled it to play a valuable role in many of these cases. Some typical examples include riverbank stabilisation and flood defence control, erosion control on steep banks (especially near to civil engineering projects), sound and pollution barriers by major roads and airports, etc. Often where a bio-engineering solution using willow is employed, substantial savings can be made on material, set-up and maintenance costs. Self-regeneration and longer life may also be advantages over a conventional approach. So too is the environmental, habitat and aesthetic value. Furthermore a bio-engineered solution may be more effective at dealing with the original problem. The materials required for such projects are fairly standard. In most cases fast growing varieties of viminalis and other species are suitable. In some instances though particular varieties are favoured. 1-, 2- and 3-year old rods are often used. Bundles or faggots of 1-year old rods are specifically required for faggotting on riverbanks. The bundles can also be split to use the rods for spiling and other techniques. Brush layering on steep banks uses 2- or 3-year rods. Stakes are sometimes required also although these take longer to grow and are therefore harder to obtain and are relatively expensive to buy. Trial projects have been under way during the last few years with successful results. I believe the role of bio-engineering is about to expand enormously.

SUMMARY

By adding value to the willow material one may produce a wider range of willow products directed to different markets and derive a greater gross income from a smaller area. By adopting this approach it becomes viable to use low-tech, labour-intensive methods of planting, managing, harvesting, processing, adding value and marketing, thereby creating good quality local employment. The opportunities for widening and improving local skills through training and practice are obvious, as is the scope for educational programmes through local schools. Residential craft and environment courses for the general public or specialist organisations are also a real possibility and would be yet another source of income to the locality.

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REFERENCES

  1. K.G. Stott "Willows in the Service of Man" - Proceedings of the Royal Society of Edinburgh, 98B, 169-182, 1992.
  2. G. Ostman (summarised by P. Aronsson). "Cadmium in Salix - a study of the capacity of Salix to remove cadmium from arable soils." *
  3. J. Abrahams, "WET Systems for Waste Purification and Resource Recovery." Wetland Ecosystem Treatment, a Multifunctional approach to Waste Water Purification. BioLogic Design, 1995.
  4. M. Rutter - "Biomass - A Sustainable Community Development" and "Reed & Willow Filtration of Polluted Waste Water".
  5. H. Obarska-Pempkowiak "Application of willow and reed vegetation filters for protection of a stream passing through a zoo." Swedish University of Agricultural Science, Uppsala, Sweden. *
  6. K.G. Stott "Cultivation and Uses of Basket Willow." Long Ashton Research Station.
  7. The Willow Bank Catalogue 1995/96.
  8. S. Pickup "Building with Living Willow." HDRA Newsletter No. 138.
  9. ETSU (Energy and Technical Support Unit) Agrigulture and Forestry Factsheet, Short- Rotation Coppice No. 12, Songbirds. Department of Trade and Industry.

* From: P�r Aronsson and Kurth Perttu (eds.) Willow vegetation filters for municipal wastewaters and sludges. Department of Ecology and Environmental Research, Section of Short Rotation Forestry - Report 50, 1994 Swedish University of Agricultural Science, Uppsala, Sweden.

For further information and details of services and willows available, contact:

Steve Pickup, The Willow Bank, P.O. Box 17, Machynlleth, Powys, SY20 8EW, UK

Tel/Fax (01686) 430510

Copyright © 1995-1997 Steve Pickup. All rights reserved.

This publication may not be reproduced, stored in a retrieval system, or transmitted, in any form or by any means electronic, mechanical, photocopying, recording or otherwise, except in its entirety (including this message) without the prior permission in writing of the author.

Last updated March 1998 by John Waters

This page is still under construction by John Waters at the Llanidloes Resource Centre