OEL Newsletter Article (Number 2)

This is an article that appeared in an OEL Newsletter during 2000.

Those who read it then may appreciate a second view.

Renewable Energy from Increased Biodiversity

(Or trying to see the wood for the trees) by Christina Bows

Part 1 - Our own experience

When we bought our 11 hectare wood near Colyton in 1991 it was very difficult to see anything - except a challenge - in the blackness of unthinned conifers. It did have a fringe of oak, beech, rowan, holly and birch, a small old coppice area of hazel and ash plus some boggy willowy bits that seemed to offer some diversity potential and, we thought, the conifers might at least help pay some of the costs of realising that potential. It looked a suitable "retirement" project, providing exercise for mind, body and spirit.

Our first objective was to try and understand what we had bought by:

(a) getting to know it, its history natural and otherwise;

(b) taking advice from as many sources as possible on management options;

(c) educating ourselves sufficiently to try and assess the inevitably conflicting advice and make decisions.

So what have we got? What is its significance?

Like most of the larger wooded areas of East Devon, it was, in 1991, largely (6.5 ha.) exotic conifers, but it had been a mixture of probably ancient Devon oak woodland remnants (along the medieval trackway boundary), coppice wood for fuel and crafts, common heathland on its upper greensand, wet willow and alder buckthorn scrub and sphagnum bog on the lower marl. It has as close neighbours a relatively large old deciduous wood, a wet meadow SSSI, some very old hedgerows, as well as many more conifers and pasture. It is typical of its area rather than special.

Wet woods, heathland and lowland mixed broadleaf all now, or shortly will have, Habitat Action Plans'. Devon oak woodland has a Biodiversity Action Plan, so these are all nationally and locally important habitats. Dormice, song thrushes, bullfinches and bluebells (which were and are still present in the wood) are all subjects now of Species Action Plans. There is no shortage of conifer plantation habitat, though it does have its own value, particularly for the invertebrates in the canopy and its birds such as goldcrests.

What would happen to its biodiversity if we did nothing?

The conifers would continue to grow, finally shading out the hazel and the honeysuckle (and so the dormice).

The holly and the beech, the most shade tolerant non-conifers, as the only species able to regenerate, would continue to encroach into the fringe and the old coppice area, further diminishing the bluebells and other ground flora.

The water table would continue to drop in the wet area as the conifers grew, drying out the bog and reducing the willow scrub for warblers.

Ultimately, the conifers might be felled at maturity, in say, another 25 years, when little of the original habitat may be left, or insufficient then to be worth conserving. It would moreover be a very drastic change, perhaps causing run-ofF problems for the SSSI in the valley below.

What could it be?

Vision (a) A Commercially managed conifer plantation.

This would involve selective thinning of all the conifers every 5 years for the next 25 years to leave a 70% canopy each time. The final crop would then be removed. Mosses and ferns would establish themselves in the light after the first couple of years of each thinning and then get shaded out again. It may produce some money some time, but probably also a further decline in biodiversity. The effects could be mitigated by increasing glade areas, widening the existing rides, putting in new tracks, clearing stream sides (as now recommended by the Forestry Commission for conserving the forest environment) but it would do nothing towards restoring the native woodland. This is the professional foresters' approach, as recommended by Silvanus, Devon woodland project advisors, and the Technical Development Branch (TDB) of the Forestry Commission, who kindly prepared a free report on our wood ²

Vision (b) "What it used to be.

It could, because of its different soils and slopes and wetness, be a mosaic of habitats, ranging from high deciduous or mixed forest, through heathland, coppice, bog with streams and pools, glades and rides - rather as it was before the 1970s - a place of magic, full of bluebells, willow warblers and butterflies. This is the conservationist’s approach. But could it also be "productive"? Could it produce at least enough to pay to maintain a mosaic?

In examining that issue - what financial value could be obtained from the waste products of conservation activity - it became clear that for us at least the only real possibility was to return to using the wood as fuel: the traditional way of sustainably managing deciduous wood, which regrows more vigorously when cut. What was needed was a clean, technologically efficient way of burning any species in any condition. That search, and its wider implications, became an integral part of this vision.

What could we not avoid doing?

Everyone, conservationist and forester, agreed that, whatever our objectives, we could not avoid cutting down trees, especially conifers.

We started with a 1 in 4 line thinning to: (a) improve the conifer value; (b) provide some light; (c) improve access to more of the wood.

We then cleared old field banks, providing dry paths across the bog, widened the existing ride, put in a large new ride for extraction, enlarged glades and cleared stream edges as both "sides” agreed on the desirability of this.

All of it produced timber - or at least "wood" (traditionally less than 2 feet in girth). None of it however was saleable, except for half of the line thinning - for which we received £127 in 1992.

What else could we not avoid doing depended on which vision we adopted. Vision (a) seemed to offer only financial advantage, largely at some time in the future. Unless that advantage was there, vision (b) seemed preferable, especially if it could be productive too.

So was the financial advantage there? The TDB report in late 1997 thought a selective thinning of all the conifers at that time would produce around £2,500 and that thinning every 5 years thereafter for 25 years would yield increasing financial rewards. Just 2 years later, when we had brashed and marked the trees to comply with the advice to make the thinning attractive to a contractor, we could only get one offer despite extensive enquiries. The offer was to thin at no cost - or payment - to us but with the contractor taking all the wood.

The explanation is in the graph below. The reasons are many: cheap imports from E. Europe, storms in France and the glut of conifers all planted at the same time in the 1970s largely for tax reasons. Should we trust that prices would improve and would do so sufficiently to outweigh the loss of biodiversity involved in persisting in commercial forestry management?

What was the alternative? If we found and invested in a heating system that used any wood efficiently there was, it seemed, the potential to save us £750 a year (with oil at 13p per litre) to heat a 4 bedroom house and 2 small holiday cottages as well as extending our letting season. Though we were going to be guinea pigs, we decided to gamble on timber prices going down or being more stable than oil prices. Even if the economic advantage proved illusory, we would be saving fossil fuel and restoring our wood.

The management consequence of opting for wood now rather than maximization of timber value in the future was that premature clear fell coupes were possible rather than continual overall thinning. By choosing coupes close to good seed sources, natural regeneration and biodiversity is encouraged and the woodland is restored naturally. Once most of the conifer has gone, some of the older birch, ash and hazel can be recoppiced, followed by the regenerated coupes. Biodiversity can therefore be progressively increased and sustainably maintained.

A condition of the obligatory Felling Licence from the Forestry Authority is that we fence against deer to protect the regeneration. This is so whether or not grant is claimed. This is therefore something else we could not avoid doing if we wished to restore the broadleaf. Fencing is expensive - £2,700 per ha. minimum - of which the Forestry Authority will pay half (plus £500 towards the very considerable labour of removing the remaining brash and debris after felling). The sale of the first hectare of conifers as timber at £6 per cubic metre just about covered the rest of the fencing cost. However, we have also retrieved from the ' brash about 18 months supply of fuel wood - worth about as much to us now as we were paid for all the timber!

How will we know whether it has worked?

Increase in Biodiversity. We will contine to monitor the species of birds, butterflies, dragonflies and ground flora and start to monitor the increase in abundance as well. Already though we have wild daffodils, heather and slender St. John's wort, of which there was not a trace before and masses of different pioneer species including banks of foxgloves and hugely increased bluebells. All the original tree species plus hawthorn, Douglas fir and sitka spruce are regenerating. The numbers of singing blackcaps, songthrushes, bullfinches and chiffchaffs have increased. Spotted flycatchers, snipe and willow warblers have been seen. We now have clouded yellow and brimstone butterflies, beautiful and banded demoiselle damselflies and egg-laying golden ringed dragonflies - and really we have only just started. If we continue to keep the dormice and our woodcock - and even get silver-washed fritillaries, sundews, and nightjars - (all possible with this management strategy I believe) - we will probably consider it has worked.

Renewable Energy. Of course, in the past, before man started burning fossil fuels, our energy from wood was renewable and sustainable as long as no more was cut annually than the annual growth. However, in open fires 85% of the heal went up the chimney and it was often very smoky. Although one read that there had been huge advances in wood-burning technology in recent years, mainly in Scandinavia, N. America and Austria, the revolution has largely by-passed the UK with a few notable exceptions. How could we test the technology and its potential for helping increase biodiversity except by trying it?

Our system

A feasibility study from renewable energy consultants suggested a whole log boiler with an accumulator tank for storage of heat, with integrated oil back-up. Eventually in April 1998 a 60kW Arimax boiler, taking logs up to 0.5m. long and up to 10cm. diameter, was installed, with a 500gallon accumulator tank. It needed a new chimney and a woodshed big enough to hold around 20 cu. m. of logs.

The logs are stacked and dried for at least one summer,

preferably two, in the wood and then transported by trailer home to be cut - but not split - before use. In the summer the demand is for hot water for around 12 people, and the boiler needs filling every one and a half days. In the winter the extra heating demand means that the boiler needs to be filled once, and sometimes twice a day. The boiler takes about 10 minutes to light and fill. It burns very hot and efficiently for several hours, transfers all its heat to the accumulator tank and goes out. We estimate that it will use about 25cu.m. a year for heating and hot water, with the cottages let continuously from April to October and occasionally in between.

We have had problems, particularly on waste of heat in the system, caused by initial poor design and its integration as a guinea pig into a partially existing system. Its original designers arranged for it to be monitored for efficiency and potential wider use by ETSU³, but the monitoring inevitably stopped just before the defects were remedied. As from June 2000 the system has been working as intended.

The initial cost, including the cost of extending the existing oil system to the cottages and installing the chimney, was £10,600 plus VAT. Remedial works cost a further £2,500 plus VAT. To set against that cost we were given a monitoring payment from ETSU of £2,000.

On the basis of our now anticipated saving (current oil prices) of £1,000 p.a. and our estimated profit on the increase in number of weeks let (there are other factors in the increase) of £1,000 p.a., our payback period is still at least 6 years away.

In the belief that "it is better to light a candle than to curse the darkness" we will continue to try and make our own environmental links. Although ours is clearly not a path open to everyone, it does I believe have wider relevance and implications and these I will look at in Part 2 of this article.

Part 2 - The bigger picture

Following the Rio Earth summit in 1992 and the resulting Convention on Biological Diversity, we now have a UK Biodiversity Action Plan. In this the importance of the wider nonspecial countryside is recognized. Biodiversity cannot be maintained just in nature reserves. Disregard of the common leads to it becoming rare.

Woodland management

After 30 years of trying to make woods profitable, the policy emphasis now seems to have reverted to conservation and the restoration of some of the biodiversity lost in the process. While this is highly desirable, it is hard enough trying to get labour and funding for existing nature reserves. In order to encourage the owners and managers of the wider countryside to manage for biodiversity, there needs to be some financial incentive. This can be simply by usually inadequate and - indefinite - direct grants or by using the resource produced by management for biodiversity. Let us look more closely.

Management for biodiversity

It is recognized in the relevant Habitat Action Plans that the first priority, if biodiversity decline is to be stemmed, is to maintain existing woods. The plans provide for lowland mixed broadleaves and wet woods to be restored and expanded within the next 10-15 years. "Restoration" usually means a planned rotation of cutting - replacing conifer with broadleaf, coppicing. or re-establishing and maintaining a stage in succession before high forest. Nightjars, spotted flycatchers and dormice, for example, are all priority species (with Species Action Plans) to whom clear fell and coppice mosaics are particularly important. Birch, the major pioneer species after clear fell, is of particular importance for the large number of priority species associated with it, largely invertebrates and fungi (which together comprise more than 90% of all species). Wet woods often become dry unless there is regular cutting to reduce accumulation of sediment and transpiration.

Cutting needs labour, which costs money and produces large quantities of mixed species, mixed size, mixed condition wood.

Furthermore, from a nature conservation or biodiversity point of view, the ideal way to create new areas of woodland, or restore or expand existing ones, is by natural regeneration rather than planting. The right species, with the right genes, grow in the right place at the right time. As long as there is a good seed source near by, there should be no problem in establishing native trees without planting. One would hope that, increasingly, restoration and expansion will not be done by further planting. Regeneration is sometimes said to be impractical or too costly! It is certainly not suitable for timber production and it may take slightly longer to establish as woodland, but it will provide valuable successional habitats along the way. Fencing against stock or deer is the expensive part, but cheaper than planting. The Woodland Grant Scheme certainly favours regeneration by paying half the costs of necessary establishment work. Again, when established it will need cutting, producing wood not timber.

Wood as renewable energy

Need. From the second world summit on the environment - Kyoto -the Government is committed to reducing C0₂ emissions below their 1990 level by 2010. But emissions are due to start rising again this year if nuclear power stations are decommissioned. In order to come anywhere near meeting those commitments, in the interests of slowing global warming, it might be thought that more than a token investment in all renewable technology would be desirable.

Wood as fuel is C0₂ neutral: the C0₂ released on burning should not be more than is taken up by new growth. Burning fossil fuels adds extra C0₂ to the atmosphere. The EUs target on renewable energy by 2010, shown later seems to appreciate this.

A further EU specific goal has been set of heating 1 million new dwellings with biomass by 2003.

In the UK there seems as yet to be no specific official goal, but British Biogen, the trade association for the biofuel industry, has set a target of heating an additional 176,000 new homes with biomass by 2010. It is less wasteful of energy to use wood for heating buildings as close to the site of production as possible, rather than convert it into electricity and transmit it back again to users, losing more energy in the process.

Resource. The forestry industry presently produces approximately 2 million tonnes of residues. If the price of timber falls even further, presumably this figure would also rise.

There are around 1 million hectares of unmanaged woodland in the UK. The total area of woodland/forest cover in the UK has increased by 18% since 1980 and is continuing to increase - while still being lower than in most other European countries. One hectare can produce two and a half tonnes of dry wood per annum. Cutting just the annual increment rotationally could bring the woods back to management (and consequent increased biodiversity) and double the national resource.

Additionally, farmers are being encouraged to grow specific energy crops, though in monocultures and often with herbicides.

Rural unemployment, especially in winter when woodland work needs doing, remains high.

Technology. The technology ranges from our system (or smaller) to thermostatically controlled fully automatic chip or pellet systems for heating schools or colleges, for example; to power stations to produce electricity and even combined heat and power systems. It is usually easier to install systems in new buildings, but old buildings can be adapted.

Renewable Heat & Power Ltd. in Barnstaple is leading a cooperative wood fuel venture in North Devon and Somerset and, in particular, will train people in the present technology.

Present implementation. According to British Biogen, there are at present only 17 installations in the UK with a combined capacity of 2,155 kW. This includes us, the Centre for Alternative Technology, West Dean College, Sussex, and a couple of schools. The Government's Energy Technology and Support Unit (ETSU) has been monitoring 9 of these for 18 months for efficiency, apparently with a view to deciding whether the technology is worth encouraging. Additionally, Yorkshire Water are building a wood-fired gasification plant at Selby.

Meanwhile, in Europe there is, for example, a village in France heating nine of its buildings, school, tax office, town hall, community centre, with wood from its community woodland. Shell Renewables, in a joint venture with a Swedish utility company have just announced their first wood-fuelled combined heat. and power plant. It will be fuelled entirely from forest and wood processing waste. It will beat more than 500 homes

The efficient burning of wood fuel means there is very little smoke and very low NOx or S0x emissions. It produces very little waste ash.

Economics.

The cost of the capital equipment is high, there are often space restraints and there is usually a long payback period depending on the actual capital cost and the relative price of fossil fuel and wood during that time.

Barriers to wider implementation in the UK

Perceptions. Wood is perceived as a primitive fueL dirty and inefficient, and it means cutting down trees. Big problems need big solutions.

Convenience. Despite the new developments, it still remains easier to use fossil fuel and its highly refined established technology. There may be implementation and supply problems in a new industry. Unless non-fossil use is significantly cheaper, there is little incentive in the market to choose the least convenient.

Cost. It is more expensive in capital costs than fossil fuel technology. The running costs are not significantly lower unless the wood is one's own and the labour would be done anyway for a different reason.

Government Policy. All renewables, except nuclear power, have been expected to compete in the market place with only the most token assistance. Nuclear power has had subsidies of up to £1 billion per annum. Its decommissioning costs, trying, they know not how, to deal with its horrendously toxic waste, are presently estimated at another £40 billion. It swallowed all but a tiny fraction of the Non-Fossil Fuel Obligation cake. Even ETSU is run from Harwell.

Although fossil fuels are heavily taxed, and rightly so, none of the revenue seems to find its way to real encouragement to people to use alternative energy where possible. Are 50% grants towards any equipment using renewable energy and the abolition of VAT on it really too much to ask?

Wood fuel schemes could, excuse the expression, kill two birds with one stone and contribute both to increased biodiversity and reduced CO₂ emissions, not to mention generating satisfyng rural employment.

joined-up Government? Any comments from anyone would be most welcome.

References:

1. Habitat and Species Action Plans as part of the UK Biodiversity Action Plan prepared by Government.

2. TDBReportXX/97

3 Energy Technology and Support Unit

Acknowledgements are particularly due to the following..

Renewable Heat & Power Ltd., New Mills, Snapper, Barnstaple, FM32 MZ (Tel. 012 71850859);

Econergy Ltd and LRZ Ltd. and to David Russell of the National Trust for his talk on "Forestry and the Art of Frying Small Fish ".

Return to Newsletter Selection Page