ESTABLISHMENT AND MONITORING OF LARGE SCALE TRIALS OF SHORT ROTATION COPPICE FOR ENERGY
ETSU B/W2/00514/REP
Contractor University of Aberdeen
Prepared by C P Mitchell E A Stevens M P Watters
The work described in this report was carried out under contract as part of the New & Renewable Energy Programme, managed by ETSU on behalf of the Department of Trade and Industry. The views and judgements expressed in this report are those of the contractor and do not necessarily reflect those of ETSU or the Department of Trade and Industry.______
First published 1998 © Crown copyright 1998 executive summary
This report covers the progress and results of the twelve year research and development project: Establishment And Monitoring Of Large Scale Trials Of Short Rotation Coppice For Energy; ETSU Contracts E/5A/CON/1171/ 1413, E/5A/CON/ 1255/2079, E/ 5A/ CON/1384/ 2835 and E/ 5A/ CON/ 514/ 00/ 00.
The objectives of the project were to obtain information on cost, logistics, productivity and overall biology of short rotation coppice crops in order to evaluate their potential for producing wood for fuel. the trials
As part of the Depatment of Trade and Industry's_ continued commitment to renewable energy Aberdeen University, Wood Supply Research Group were sponsored to establish 7 Salix and 3 Populus coppice trials across the UK on sites representing a wide range of latitudes, climatic conditions and soil types. The trials were planted using a range of genera, species and clones thought to have potential for biomass production in the UK. The production plots were established on a larger scale than had previously been used for research to provide technical and economic data that would better reflect commercial production.
The twelve year project was funded in 4, three yearphases. The trials were established during the first two phases, allowing the evaluation of establishment techniques and the development of best practice guidelines. The latter 2 phases concentrated on the collection of technical and economic data on the management of SRC systems, particularly: weed control, crop nutrition, pest and pathogen control, harvesting and crop removal.
Throughout the twelve year programme, the trials have formed the basis of numerous add on studies covering many aspects of SRC management. These studies, where relevant, are summarised and cited in this report.
Each of the 10 trials sites have been individually managed using the bestknowledge available at the time. A full history of site management together with the data obtained from each trial is given in Section One of this report. As a result of this project, significant advances have been made in the level of knowledge and quality of SRC management, these are described and discussed in Section Two of this report.
The work was initiated by the Department of Energy in 1986, and adopted by the Department of Trade and Industry in 1989. site selection
The trials were established on sites thought to be representative of land that might become available for SRC in the UK, covering a range of soil, climate and land use types. The work highlighted three factors of primaryimportance when determining the suitability of sites for SRC: climate, soil type, and ease and efficiency of mechanisation.
Climate
Climatic factors including, quantity and type of precipitation, quantity and quality of radiation, and maximum and minimum daily temperatures, directly affect crop growth potential. In addition, climate influences the development of pest and disease populations, which also impact on plant growth. Ironically, climatic conditions that promote rapid coppice growth also favour the development of the leaf rust Melampsora spp. Levels of the leaf rust, on both willow and poplar, are higher in areas with high annual rainfall and above average winter temperatures.
Prior to this project, susceptibility to frost damage, particularly in early autumn and late spring, were thought to restrict the geographic range of SRC poplar to the south of England. Results from the project indicate that poplars can be established and managed in more northerly latitudes; plant survival rates and mean first rotation yields at Markington, North Yorkshire, (84% and 5.9 odt/ha/yr respectively) are comparable with those achieved at the more southerly sites of Swanbourne and Water Eaton.
Soil Type
Soil type, particularly pH and nutrient levels, influence potential growth rate. The highest growth rates have been recorded at trials established on deep, fertile sites, generally ex arable land, with good water availability but without prolonged waterlogging. Several of the sites selected for early trials were established on marginal grassland areas which suffered winter waterlogging. As well as impeding crop development, the site conditions restricted effective ground preparation and weed control, and preclude the use of mechanised harvesting. In general the crops at these sites produced low yields, suffered high stool mortality and incurred high management and harvesting costs; marginal, wet sites are not considered appropriate for the establishment of commercial SRC.
Mechanisation of operations
The efficacy of many management operations is dependent on a high degree of mechanisation, including planting, weed control (chemical and mechanical) and harvesting. Sites should be selected, and plantations designed to maximise the efficiency of these operations. Ideally, sites should be flat with long straight rows and the soil should contain a minimum of large stones that might cause damage to equipment. Harvesting of SRC occurs during winter when ground conditions are also soft, and trafficking of heavy machinery can lead to soil and crop damage; sites that are prone to winter waterlogging are not considered suitable for commercial SRC. suitability of genera
The project tested the suitability of five genera, thought to have potential for use in SRC for energy systems.
Salix
Seven sites were planted with willow ranging from Buckfast in Devon, to Brahan in Inverness- shire. In general, the clones used were easily established from cuttings, frost tolerant and coppiced well. However, many of the clones used in the programme suffered from infection by the leaf rust Melampsora spp. which reduced crop growth and plant survival rates. The highest levels of infection are recorded at sites where warm, wet climate conditions favoured rust development, and where crops were weakened by other pest and weed problems.
Melampsora epitea has been shown to have numerous distinct pathotypes or ‘races’, each infecting specific clones. The use of clonal mixtures to reduce the impact of rust infection by slowing the spread of individual pathotypes through a crop was investigated at three sites: Castle Archdale, Parbold and Buckfast. Results are conflicting; the evidence from Castle Archdale clearly indicates a higher yield in the mixed plots over the mono-clonal plots, but the figures from the other two trials show no yield benefit from the mixtures. Plant survival rates of two of the clones in the five way mixture is down to below 50%, indicating that inter-clonal competition will eventually reduce the mixture to three clones, reducing any potential disease protection. New breeding programmes are generating clones with multi-gene disease resistance, which when planted in non-competitive mixtures, should offer long term protection from rust infection.
The insect pest Phyllodecta spp. (Brassy willow beetle) has been identified as a serious threat to SRC willow. In the worst case, at Long Ashton, Avon, it defoliated over one hectare of crop and resulted in a plant mortality rate of over 80% and the abandonment of the trial.
Populus
Three production trials were established using poplar: Swanbourne, Buckinghamshire, Water Eaton, Wiltshire and Markington, North Yorkshire. In addition screening plots were established at three further sites. Poplar was found to be more difficult to establish than willow, requiring increased care with ground preparation and early weed control. Once established however, management requirements of the two genera were similar. Poplar was seen not to respond to cut-back in the same way as willow, tending to remain as a single stem crop until after the first harvest. It is recommended that poplar is not cut-back at the end of year one, unless access is required for remedial weed control.
During the project, the poplar crops have not suffered the same level of pest and disease pressure as willow plantations. However, Melampsora spp. infection, first seen in summer 1994, has been noted as occurring earlier in the season and resulting in higher levels of infection and crop damage. It is thought that a new race of the rust has become established in the UK which may result in the removal of two of the highest yielding Belgain clones (Beaupre and Boelare) from the Forestry Authority approved planting list.
Phyllodecta spp. were noted at all the poplar trials during the project but only caused minor leaf damage; they are not considered a barrier to the use of poplar SR C.
Eucalyptus
Eucalyptus was established in a number of small screening trials at Long Ashton, Avon. The species and clones used proved easy to establish from seedlings, with plant survival rates in the year after planting of 98% During their first five year cycle the plots suffered no pest or disease problems and were not affected by frost as was hypothesised prior to the trial. However, following their first harvest, the plants were infected by Chrondrostereum purpureum (silver leaf disease), which reduced survival rates to below 20% forcing the abandonment of the trial.
Despite generating the highest yields of anytrial in the project (18.0 odt/ ha/ yr), the risk of silver leaf disease precludes the use of eucalyptus in SRC for energy systems.
Northofagus
Four screening plots of Northofagus were established at Long Ashton, Avon using nursery transplants (1+0). By the end of the first year plant survival was below 50% and at the end of the second growth season the plots were abandoned. N othofagus is not suitable for use in SRC production systems in the UK.
Alnus
Four screening plots of Alnus were established at Long Ashton, Avon using nursery transplants (1+1). Initial establishment was successful but the plants did not respond well to coppicing, with a fall in survival rate at cut-back to 70% Growth was slow throughout the first five year cycle (yield of 3.4 odt/ ha/ yr) and although the plants suffered no pest or disease problems, the species chosen proved susceptible to spring frost. Alnus is not therefore considered suitable for use in SRC in the UK.
Of the five genera evaluated Salix and Populus are thought to have the greatest potential for use in UK SRC to energy production systems. yield
The production trials generated a wide variation in clonal productivity, reflecting the influence of site, climate and management techniques, experienced at the different sites. The average yields achieved at the sites are low, with the poplar crops performing marginally better than the willow; averages of 6.0 and 4.9 odt/ ha/ yr respectively. These figures are well below what is anticipated as being a commercially acceptable yield level. The low yields recorded are attributed in part to the experimental nature of the trial work. The plantations were used to develop best practice techniques of plantation establishment and management, often through a process of trial and error. It is anticipated that current management systems will result in increased plant vigour and higher yields. At the start of the project little was known about plant:site interaction, and it was not always possible to select the most appropriate genera, species and clone for a given trial. Data from this and other projects has led to an improved understanding of plant:site interaction allowing better selection of plant material to match prevailing site and climate conditions.
Much of the clonal material planted twelve years ago is now considered obsolete. Breeding programmes have focused on improved disease, pest and frost tolerance, as well as increased productivity, and should result in higher future yields. long term sustainability/health
The trials established under this project are amongst the oldest in the UK, some having completed four full rotations. As such they have proved a unique source of information on the long term development of SRC plantations.
U sing the data collected, the project analysed the pattern of yield that might be expected from a commercial SRC plantation. Of the 102 data sets available, less than half showed an increase in yield from first to second rotation. Crops with a low yield in the first rotation (< 6.0 odt/ ha/ yr) were seen to improve their productivity in the second cycle, taking advantage of better weed control. However, crops with a high first rotation yield (> 10.0 odt/ ha/ yr) showed a significant decrease in productivity despite good establishment.
The reasons for this decline are unclear. Damage to both plants and soil, caused by winter harvesting, are cited as a possible explanation at some sites. At others, increased disease, pest and weed pressure may have had a negative impact on yield. However, a large number of plots which have been manually harvested, show no increase in disease, pest or weed pressure, and maintain high fertility levels, still show a significant decline in yield with time; it is these plots that raise concern. It is concluded that in these cases, the actual regular cutting of the stools is resulting in a loss of plant vigour. Further investigation is required but, if this is found to be the case it would cast substantial doubt on the sustainability of SRC for energy systems. plantation management
Establishment
The first trials to be established used predominantly conventional forestry techniques, which in hindsight were unsuited to SRC plantations. Later trials employed management techniques more akin to agriculture, with complete ground cultivation starting in the autumn before planting and aggressive pre and post-planting weed control, to successfully establish the crops. All the sites were manually planted using a variety of initial plant densities ranging from 5,000 to 20,000 plants per hectare.
Poor crop establishment is considered one of the main causes of low plantation productivity and is emphasised as being the most critical stage of plantation management. The impact of poor establishment technique can be seen during the first rotation, and potentially remains throughout the plantation life; the effects include:
• increased plant mortality rates • reduced natural weed suppression leading to weed control problems often necessitating expensive remedial treatment • reduced plant vigour which may lead to a reduction in plant resistance to pest and disease pressure • low crop yield
Weed Control
In addition to effective weed control during the establishment phase, the need to maintain a weed free site throughout the life of plantation is highlighted by the project. Harvesting of SRC breakscanopy cover, allowing light to penetrate the crop and facilitating the development of weeds. An overall post-harvest application of contact and residual herbicides is effective in suppressing weed growth sufficiently to allow the re-establishment of canopy cover, and allow natural weed suppression.
A range of suitable techniques and chemicals for use in SRC are recommended by Clay (1996) based on experimental work at UK trial sites, including those in this project. Aggressive weed growth has been shown to be a symptom of other pest or disease problems, which have resulted in the defoliation of the crop. Remedial treatment of this type of weed growth is expensive and rarely effective in the long term. It is therefore recommended that mid-rotation remedial weed control, required as a consequence of disease or pest damage, should not be undertaken, rather the crop should be removed and replaced with a more vigorous clone or species.
Nutrition
Two trials, one poplar and one willow, were established on ex-arable land to investigate the balance of nutrient removal through harvesting, and fertilisation. Regular post-harvest applications of mineral N:P:K over a 10 year period, failed to indicate yield benefit from the addition of fertiliser at either site. Foliar analysis, carried out during phase 3 of the project, recorded a macro-nutrient status well above the critical level and in most cases near the optimum growth levels.
It is concluded that SRC crops planted on fertile ex-arable sites are unlikely to require fertilisation within the first ten years of management. However, the regular removal of woody biomass will eventually lead to a decline in soil fertility and, if no fertiliser is added, a reduction in the productivity of the plantation.
Site Hygiene
The importance of good site hygiene is hard to assess but there is some evidence to suggest that poor site hygiene is a possible contributory factor to increased pest and disease pressure. It is thought that the infestation of S. viminalis Bowles Hybrid with Brassy beetles (Phyllodecta spp.) at Long Ashton was in part due to high numbers of beetles successfully overwintering on cut shoots stacked adjacent to the crop. It is recommended that on site storage of cut material is avoided, where possible, to help minimise the risk of pest and disease damage.
The design and management of the open areas around plantations is important to improve site access, increase the habitat diversity and value of a site, and prevent the ingress of weeds to the main crop.
Appropriate techniques for open space management will vary depending on the previous land use. Plantations established on grassland were generally found to have non-aggressive perennial weed species and regular mowing is recommended as the best management practice. Ex-arable sites tended to develop more annual weed species and aggressive perennials, which proved problematic throughout the project, requiring intensive management, including chemical control. It is therefore recommended that on ex-arable sites, open areas are planted with a non-aggressive grass mix to increase the wildlife habitat value of the site and to reduce the management requirement. crop removal and site restoration
Returning land from SRC to agriculture or replacing a poorly performing clone with a new variety, requires that the existing crop is killed and then removed from the ground. During phase 4 of this project, a range of different techniques were evaluated at 4 sites in order to evaluate their efficacy and generate costs of the operations.
A range of possible techniques should be considered including: spray-off and kill the crop only, spray-off and plough-out the crop, grub-out with a JCB, spray-off and establish an interim fodder crop before ploughing-out. The technique most appropriate for use will be determined by the crop to be removed, time available for the complete operation and the subsequent land use requirement.
The most appropriate techniques for the majority of land types, combines killing the stools with a contact herbicide, leaving the land fallow for approximately 10-15 months, and ploughing out the stumps or conditioning the top soil. Grubbing out the crop with a JCB was found to be fastest and most expensive technique tested (£ 480/ha), but only justified on high quality farmland where the opportunity cost of lost potential revenue is high. It maybe possible to generate revenue during the restoration period by direct drilling a fodder crop, such as turnips or kale, and using the land to support livestock during the fallow period. costs of operation
The trials have provided unique data on the cost of operations on a commercial, albeit pioneering, scale including, site preparation, planting and tending, harvesting and eventually crop removal.
The establishment phase including planting and all operations up to the first harvest make up over 38% of the total cost of growing SRC, emphasising the importance of this stage of plantation management. The costs incurred during the establishment of the plantations in this project ranged from £ 2793 to £ 5995 per hectare; the main variables being fencing and remedial weed control. These figures however, reflect the pioneering nature of the project work and it is anticipated that the current cost of establishing a commercial SRC plantation would be approximately £ 1,800 per hectare. Following the first harvest, and assuming that the plants are relatively unaffected by defoliating pests and disease, the ongoing cost of management is low (approximately £ 80/ha/yr). Generally, a single post-harvest application of herbicide, the addition of fertilser in later years, and mowing of the open areas around the crop are the only operations required.
Harvesting costs have not been generated directlyby this project, although the sites have provided the opportunity to evaluate the cost and logistics of a variety of mechanised harvesting techniques. Detailed analysis of the harvesting operations, together with costs are given in Deboys (1996), Mitchell (1997) and Mitchell et al (1997).
The cost of crop removal and site restoration must be considered when evaluating the economics of producing wood fuel from an SRC plantation. The full cost, including an opportunity cost for the time when the land is unproductive, varies depending on the technique used, the crop being removed and the required subsequent land use (ranging from £ 199 - £480/ha).
U sing the technical research data generated by the project, together with current farm contractor costs, a base case total cost of managing an SRC plantation can be estimated at £ 4,768 per hectare. This cost assumes a standard management system of establishment, routine maintenance, harvesting and site restoration for a 24 year period (seven, 3 year rotations). To generate the base case cost, several technical and management assumptions were made, all of which may vary in a commercial situation resulting in a change in total cost.
The unit cost of producing wood fuel from an SRC system is highly dependant on the productivity of the crop. U sing the base case management costs, and assuming the level of yield achieved by the trials in this project of 4.6 and 6.0 odt/ ha/ yr for willow and poplar respectively, the discounted unit cost of producing wood fuel from SRC would be £ 62.41 and £ 47.85 per odt. However, it is anticipated that the yields attained by well managed coppice plantations will increase, and the cost of management will be brought down through further improvement in technology and management techniques. Assuming a yield of 9.0 odt/ ha/ yr and a decrease of 10% in management cost, the unit cost of production of wood fuel from SRC would be £ 28.71. annual growth and minimal destructuve sampling
The trials were planted using a variety of initial plant densities and rotation periods to determine the optimum combination. To observe the pattern of growth during a three year growth cycle, the yield at two sites, Parbold and Buckfast, was assessed annually, using techniques of minimal destructive sampling (MDS) developed during phase 3 of the project. Of the four clones included in the study, only two showed what is considered to be a normal growth pattern, achieving maximum mean annual increment in year three and indicating that at a density of 10,000 plants per hectare, three years is the optimum rotation age. The remaining two clones were affected by severe Melampsora spp. rust infection, and the pattern of growth was considered anomalous.
The study also validated the principles of MDS, and it is recommended that this technique is utilised to allow the annual assessment of commercial crop development. Annual assessment would highlight slumps and peaks in crop growth and would facilitate the adjustment of cycle length to ensure the optimum production from the plantation. the future of the sites
Planted between 1986 and 1991, the trials managed under this project are amongst the oldest in the UK. Each has been carefully managed and a full record of all operations, treatments, yields, pest and disease problems as well as soil nutrient status and recent climate, has been maintained.
Of the remaining trials, it is proposed that the bestthree are maintained to provide a resource and opportunity for further study: Brahan, Inverness- shire (established 1989) 1.0 hectare willow Buckfast, Devon (established 1991) 0.9 hectares willow Swanbourne, Wiltshire (established 1986) 1.8 hectares poplar table of contents
executive summary i
TABLE OF CONTENTS xi Table of Tables xv Table of Figures xvi
ACKNOWLEDGEM ENTS xvii
PROJECT AND OBJECTIVES xviii
INTRODUCTION
SECTION ONE: TRIAL MANAGEMENT
1.1 LONG ASHTON PRODUCTION TRIAL 1 1.1.1 SITE CHARACTERISTICS 2 1.1.2 ESTABLISHMENT 3 1.1.3 MANAGEMENT 4 1.1.4 HARVESTING 5 1.1.5 CLONE PRODUCTIVITY 6 1.1.6 CROP REMOVAL AND SITE RESTORATION 6 1.2 SWANBOURNE 8 1.2.1 SITE CHARACTERISTICS 8 1.2.2 ESTABLISHMENT 9 1.2.3 MANAGEMENT 10 1.2.4 HARVESTING 11 1.2.5 CLONE PRODUCTIVITY 12 1.2.6 CURRENT STATUS 15 1.3 LONG ASHTON SCREENING TRIAL 16 1.3.1 SITE CHARACTERISTICS 16 1.3.2 ESTABLISHMENT AND MANAGEMENT 16 1.3.3 CURRENT STATUS 21 1.4 CASTLE ARCHDALE 22 1.4.1 SITE CHARACTERISTICS 22 1.4.2 ESTABLISHMENT 24 1.4.3 MANAGEMENT 25 1.4.4 HARVESTING 26 1.4.5 CLONE PRODUCTIVITY 27 1.4.6 CROP REMOVAL AND SITE RESTORATION 29 1.4.7 CURRENT STATUS 30 1.5 KINCARDINE 31 1.5.1 SITE CHARACTERISTICS 31 1.5.2 ESTABLISHMENT 32 1.5.3 MANAGEMENT 33 1.5.4 HARVESTING 33 1.5.5 CLONE PRODUCTIVITY 33 1.5.6 CURRENT STATUS 35 1.6 GUISACHAN 36 1.6.1 SITE CHARACTERISTICS 36 1.6.2 ESTABLISHMENT 37 1.6.3 MANAGEMENT 38 1.6.4 HARVESTING 38 1.6.5 CLONE PRODUCTIVITY 39 1.6.6 CURRENT STATUS 39 1.7 WATER EATON 40 1.7.1 SITE CHARACTERISTICS 40 1.7.2 ESTABLISHMENT 41 1.7.3 MANAGEMENT 42 1.7.4 CLONE PRODUCTIVITY 43 1.7.5 CROP REMOVAL AND SITE RESTORATION 44 1.8 BRAHAN 45 1.8.1 SITE CHARACTERISTICS 45 1.8.2 ESTABLISHMENT 46 1.8.3 MANAGEMENT 47 1.8.4 HARVESTING 47 1.8.5 CLONE PRODUCTIVITY 48 1.8.6 CURRENT STATUS 49 1.9 MARKINGTON 50 1.9.1 SITE CHARACTERISTICS 50 1.9.2 ESTABLISHMENT 52 1.9.3 MANAGEMENT 52 1.9.4 HARVESTING 52 1.9.5 CLONE PRODUCTIVITY 53 1.9.6 CROP REMOVAL AND SITE RESTORATION 53 1.10 PARBOLD 55 1.10.1 SITE CHARACTERISTICS 55 1.10.2 ESTABLISHMENT 56 1.10.3 MANAGEMENT 57 1.10.4 HARVESTING 58 1.10.5 CLONE PRODUCTIVITY 58 1.10.6 CURRENT STATUS 59 1.11 BUCKFAST 60 1.11.1 SITE CHARACTERISTICS 60 1.11.2 ESTABLISHMENT 61 1.11.3 MANAGEMENT 62 1.11.4 HARVESTING 63 1.11.5 CLONE PRODUCTIVITY 63 1.11.6 CURRENT STATUS 4
SECTION TWO: EXPLOITATION OF RESULTS 65
2.1 ESTABLISHMENT AND INITIAL WEED CONTROL 66 2.2 CROP MANAGEMENT 67 2.2.1 CONTINUED WEED CONTROL 67 2.2.2 SITE NUTRITION 67 2.2.3 SITE HYGIENE 68 2.3 QUALITY OF CLONAL MATERIAL 69 2.3.1 DISEASE 69 2.3.2 PESTS 70 2.3.3 FROST TOLERANCE 70 2.4 HARVESTING 71 2.5 PLANTATION PRODUCTIVITY 73 2.5.1 YIELDS ACHIEVED 73 2.5.2 SUSTAINABILITY OF YIELD 74 2.5.3 GROWTH M ODELLING 75 2.6 CROP REMOVAL AND SITE RESTORATION 78 2.6.1 FACTORS AFFECTING CROP REM OVAL 78 2.6.2 TECHNIQUES OF CROP REMOVAL 81 2.7 COSTS OF OPERATIONS 83
REFERENCES 86 APPENDIX 1 SUSTAINAIBILTY OF YIELD 88 APPENDIX 2 GROWTH MODELLING 93 APPENDIX 3 CLIMATE DATA 98 APPENDIX 4 MANAGEMENT COST DATA 105 Table of Tables
(N ot in correct format electronically)
Table 1. Productivity of Salix viminalis Bowles Hybrid at Long Ashton._ 6 Table 2. Productivity of 3yr old, Section 1 of Populus spp. at Swanbourne (odt/ha/yr) 13 T able 3. Productivity of Section 2 of Populus spp. atSwanbourne (odt/ ha/ yr). 13 T able 4. Survival and productivity of Alnus. 16 Table 5. Survival and productivity of Eucalyptus. 18 T able 6. Productivity of Populus plots 19 Table 7. Productivity of P. deltoides x nigra (Dorskamp) in spacing trial 19 T able 8. Productivity of Canadian Poplus clones 20 T able 9. Productivity of Salix clones at Castle Archdale, Phase 1 27 Table 10. Productivity of Salix clones at Castle Archdale, Phase 1 27 T able 11. Productivity of Salix clones at C astle Archdale, Phase III 28 T able 12. Productivity of Populus clones at Castle Archdale, Phase III 29 Table 13. Yields (odt/ha) from Kincardine screening trial. 34 Table 14. Yield of Salix at Kincardine production Block 1. 35 T able 15. Productivity of Salix clones at Guisachan. 39 T able 16. Productivity of Populus clones (odt/ ha/ yr) at W ater Eaton. 43 T able 17. Productivity of Salix clones at Brahan. 48 Table 18. Productivity of Populus clones at Markington. 53 T able 19. Productivity of Salix and Populus clones at Parbold. 59 T able 20. Productivity of Salix and Populus clones at Buckfast. 64 T able 21. Summary of yields (odt/ ha/ yr) for Salix production trials. 73 T able 22. Summary of yields (odt/ ha/ yr) for Populus production trials. 73 Table 23. Crop removal techniques for SRC 81 Table 24. Management costs of SRC plantations. 83 Table 25. Unit cost of wood fuel production from SRC 84 Table 26. Comparison of MAI in first and second rotation, by genus: R esults of a Single T ail Paired t-test. 90 T able 27. Annual growth of Salix at Parbold 94 T able 28. Annual growth of Salix at Buckfast 95 table of figures -(not all available electronically)
Figure 1. Short Rotation Coppice Trials Sites. xix Figure 2. Layout of 1.96 ha Long Ashton Salix trial 3 Figure 3. Layout of 1.8 ha Swanbourne Populus trial. 9 Figure 4. Layout of Long Ashton screening trial 17 Figure 5. Layout of 3.3ha Castle Archdale Salix trial Phase I. 23 Figure 6. Layout of 3.0ha Castle Archdale Salix trial Phase II. 23 Figure 7. Layout of 3.4ha Castle Archdale Salix trial Phase III. 24 Figure 8. Layout of Kincardine Salix trial. 32 Figure 9. Layout of Guisachan Salix trial. 37 Figure 10. Layout of Water Eaton Populus trial. 41 Figure 11. Layout of Brahan Salix Trial 46 Figure 12. Layout of Markington Populus Trial 51 Figure 13. Layout of Parbold Salix Trial 56 Figure 14. Layout of Buckfast Salix Trial 61 Figure 15. Unit cost of wood fuel production from SRC. 85 Figure 16. Distribution of MAI yield change: first to second rotation. 89 Figure 17. Distribution of MAI yield change: first to third rotation. 89 Figure 18. Distribution of MAI yield change: second to third rotation. 89 Figure 19. Annual growth of Salix at Parbold 94 Figure 20. Annual growth of Salix at Buckfast 95 acknowledgements
The authors would like to acknowledge the numerous Wood Supply Research Group research and technical staff who have contributed to this project during its twelve year programme, without whose quality and consistency of work this final report would not have been possible.
WSRG also acknowledges the help and support of the land owners and farm managers who have lent their knowledge and support to this project, in particular: Guy Donaldson, Commander Freemantle, Murray Carter, Peter Ainscough, Father Richard, Michael and David Lewis, Andrew Matheson.
This project was supported financially by the Department of Trade and Industry and the Highlands and Islands Enterprise, and administrated by ETSU.
Throughout the project WSRG have maintained close links with numerous research, industrial and commercial partners who ’s valuable contributions to the work are also acknowledged, including:
Long Ashton R esearch Station Department of Agriculture Northern Ireland Forestry Authority, Technical Development Branch David Clay, Avon Vegetation Research Border Biofuels Ltd. project and objectives
This report covers the results of a twelve year ETSU contract, initiated in 1986 and continued through four, 3 year phases up to March 1998. It summarises research carried out during the 4 consecutive ETSU contracts: E/5A/CON/ 1171/1413, E/5A/CON/ 1255/2079, E/5A/CON/ 1384/2835 and E/5A/CON/514/00/00.
The overall objective of these trials was to obtain information on costs, logistics, productivity and biologyof short rotation coppice crops in order to evaluate their potential for producing wood for fuel.
More specifically, the objectives of the final and most recent phase of the research work, April 1995 to March 1998, were:
• The continuing management and monitoring of the following coppice trial sites established during phases 1 and 2 of the project: 1.0 ha Long Ashton, Bristol 1.8 ha Swanbourne, Buckinghamshire 9.7 ha Castle Archdale, Northern Ireland 2.0 ha Water Eaton, Wiltshire 0.9 ha Markington, N. Yorks. 0.9 ha Buckfast, Devon 0.9 ha Parbold, Lancashire 1.0 ha Brahan, Ross and Cromarty • To provide technical and economic data on the management and maintenance of the continuing coppice trial sites. • To identify appropriate methods for stool removal and land reclamation and provide technical and economic data on those operations at the following sites: 1.0 ha Long Ashton, Bristol 2.0 ha Water Eaton, Wiltshire 0.9 ha Markington, N. Yorks. • To undertake yield assessment at the remaining sites using appropriate methods of yield estimation.
During the twelve year duration of this project, the trial sites provided a platform for several ‘add-on’ studies, undertaken bythe University of Aberdeen and many other organisations. These studies are highlighted within this report and the relevant publications cited and referenced where appropriate. introduction
In 1986, as part of the Departments of Trade and Industry and Energy's commitment to renewable energy, Aberdeen University Wood Supply Research Group (WSRG) were sponsored to establish ten short rotation coppice trials, totalling 18.2 hectares, across the UK on sites representing a wide range of latitudes, climatic conditions and soil types (Figure _ seq f map _1_).
Figure 1 Short Rotation Coppice Trials Sites.
_(not available electronically)
The sites were successfully established during phases 1 and 2 of the project, using a range of genera, species and clones thought to have potential for biomass production in the UK. The trials have proved unique in their ability to produce technical and economic data on every aspect of crop establishment, management, harvesting and crop removal. The trials have also formed a platform for numerous ‘add-on’ studies undertaken by the WSRG and other organisations, including most recently: a study of the insect pest Phyllodecta spp., by Long Ashton Research Station, a study of the Melampsora spp: willow clone interaction by LAR S, a study of the wildlife and conservation potential of coppice plantations by The Game Conservancy Trust, a field evaluation of harvesting equipment and techniques by both WSRG and the Forestry Authority, Technical Development Branch (FA/TDB). Phase 4 of the project (April 1995 to March 1998) is the concluding phase of this twelve yearresearch programme. It was therefore considered appropriate to include in this report a summary of all the work carried out in the three preceding phases from 1986 to 1995; more detailed accounts of management activity can be found in the relevant end of phase reports: ETSU B1171, B1255 & B00126. SECTION ONE: TRIAL MANAGEMENT LONG ASHTON PRODUCTION TRIAL
This 1.9 hectare production trial was established in 1986 to determine management systems, production level yields, logistics and costs of operations, and nutrient removals from short rotation coppice willow.
The initial trial layout is illustrated in Figure 2
SITE CHARACTERISTICS
Location Pearce's Field Long Ashton Bristol Long. & Lat. 2O38W 51O25'N O S National Grid Ref. ST 557 701 Altitude 15m
Climate Average of data from 1921 to 1997 Average annual rainfall (mm) 892.6 Mean max. daily temperature 13.9OC Mean min. daily temperature 6.2OC For more detail see Appendix _ seq a climate _3_.
Soils Soil type Stony, clay loam Solid Geology Red mudstone Drift Geology Permo-triassic reddish mudstone and alluvium Soil Association Brockhurst 2 Previous Land Use Permanent pasture Figure 2 . Layout of 1.96 ha Long Ashton Salix trial
(not available electronically)
Plots 1-4: S. burjatica Korso plots. Abandoned in 1989. Plot 5: S. viminalis Bowles Hybrid - 2 year cutting cycle, no fertiliser. Plot 6: S. viminalis Bowles Hybrid - 2 year cutting cycle, fertiliser. Plot 7: S. viminalis Bowles Hybrid - 4 year cutting cycle, fertiliser. Plot 8: S. viminalis Bowles Hybrid - 4 year cutting cycle, no fertiliser. Plot 9: S. burjatica Korso - 4 year cutting cycle, no fertiliser. Spacing = 1m x 1m
ESTABLISHMENT
The trial was planted by hand in spring 1986 with 2 clones of willow: Salix viminalis Bowles Hybrid (plots 4-8), and Salix burjatica Korso (plots 1-4 &9), both at 1m x 1m spacing. The site was ploughed and rotovated prior to planting, and glyphosate (Roundup at 5l/ ha) was used to kill any exposed vegetation. Simazine (Gesatop 500L at 4.5l/ ha) was applied after planting. Glyphosate (Roundup) was also needed for spot weed control during year 0.
The shoots were cut-back using a brush-cutter at the end of year 0. Paraquat (Gramoxone at 4l/ ha) and simazine (Gesatop 500L at 5l/ ha) were sprayed over the cut stools before bud- burst, but summer weed control was once again required.
Fertiliser was applied in year 1 over one half of the trial (June 1987), at a rate of 60:30:80 kg elemental N :P:K per ha. No further operations were carried out until the first harvest.
MANAGEM ENT
Weed Control
Following the first harvest of blocks 1,2,5 and 6 (January 1989) an application of amitrole (W eedazol TL @ 10l/ ha) and simazine (Primatol SE 500L at 10l/ ha) were used to cap the site and suppress weed growth.
Two weeks after the second harvest (February 1991), simazine (Gesatop 500L at 4.5l/ha) was applied over the cut stools of Bowles Hybrid (blocks 5,6,7 & 8), and regrowth was sufficiently vigorous to close canopy and suppress further weed growth within a few weeks.
Nutrition Soil samples were not taken prior to planting, so the fertiliser application in year 1 was according to standard rates recommended for mineral soils (Sennerby-Forsse 1986). Only one half of the site was fertilised (see Figure _seq f larslay_2_), so that the effect of nutrient additions could be assessed.
Fertiliser was applied post harvest every 4 years. The Bowles Hybrid plots received two applications of mineral N :P:K at rates of 60:30:80 kg/ ha and 20:10:10kg/ ha in years 1 and 5 respectively.
Pests and Diseases
Although rabbits and hares were seen in the plantation no serious damage occurred and protective fencing was not required.
Severe infection of the Korso plots with Melampsora spp. in years 0 and 1, resulted in premature defoliation, allowing weeds to develop throughout the crop. Despite an attempt to control the infection with the fungicide benodanil (Calirus), the crop was re-infected following the first harvest in January 1989 and the decision was taken to abandon the plots 1-4. Melampsora spp. infection was noted on the Bowles Hybrid plots following their first harvest. This severe infection, although resulting in only minor defoliation, is considered to have been a contributory factor in the decline of the plots.
Brassy willow beetles (Phyllodecta spp.) have always been present in the plots at Long Ashton but only became a significant problem in June 1993. Heavy defoliation in the summers of 1993 and 1994, caused by larvae and adult beetles, resulted in stool mortality rates of up to 90% and allowed weeds, predominantly brambles, to establish within the plots. The decision was taken to abandon the remaining production plots in autumn 1994. In March 1995, the plots were flailed to waste by the FA/ TDB and the site subsequently used by LARS to investigate Phyllodecta spp. population dynamics and help develop an integrated pest management strategy (Kendall et al., 1996).
HARVESTING
When planted in 1986, mechanised harvesting of SRC was limited and design requirements to facilitate efficient harvesting unknown. Short row lengths and narrow headlands have made all harvesting operations slow difficult.
January 1989
Due to the weed growth and poor form of the Korso plots it was not possible to mechanically harvest these areas, and plots 1-4 were flailed to waste. With the exception of a few outer rows which were cut motor-manually, the Bowles Hybrid plots were harvested using the Loughry Coppice Harvester (LCH). The shoots were removed from the site with a buck-rake, and subsequently chipped with a Vermeer 1250 trailer-mounted chipper.
February 1991
As at the first harvest in 1989, it was not possible to mechanically harvest the Korso plots and they were again flailed to waste; no yield assessment was possible. The LCH was used to harvest both the 2 and 4 year old shoots of the Bowles Hybrid crop. As with the first harvest, some manual harvesting was necessary to remove edge rows and rows between blocks, to create a headland and facilitate access Each block was harvested separately, and the bundles removed by a tractor equipped with a grapple and forwarder trailer.
December 1993
The third harvest of the Bowles Hybrid plots was carried out using a standard 300bhp Class self propelled forage harvester fitted with an unmodified Kemper header. The trial was successful with the machine achieving a productivity of 4.86 odt/ pmh. The only problem was the quality of the cut, considered to be too high (300-500mm) and too rough, leaving the tops of the shoots shattered. It was estimated that the high cut resulted in a potential yield loss of 20%
A full report was produced on this harvesting trial (Mitchell et al 1994).
February 1995 & 1996
Due to heavy bramble and thistle growth, it was impossible to harvest the remaining plots. The crop was flailed to waste using a combination of a forestry chain flail and a tractor mounted hedge flail in two consecutive year.
Clone productivity
Productivity of the blocks of Salix viminalis Bowles Hybrid are shown in Table _seq t larsyield_1_. The mean figure for the two 2 year cutting cycles is comparable with the yields for the blocks harvested on a 4 year cycle. These figures suggest that there is very little difference between the yields obtained from the different cutting cycles. The low yields obtained for the 2 year cycles in 1995 (not included in the mean) are as a direct result of the brassy beetle infestation and the associated weed control problems. Although the two 4 year cutting cycle plots were also badly affected by beetles, the yields obtained in 1995 would suggest that the older shoots were better able to withstand the premature defoliation.
Table 1 Productivity of Salix viminalis Bowles Hybrid at Long Ashton. Block_Cutting cycle_Fertiliser_1989_1991_1993_1995_Mean_ Productivity in odt/ ha/ yr__ 5_2 years_no_5.7_8.3_8.7_2.1*_7.5_ 6_2 years_yes_7.1_9.5_6.3_0.3*_7.6 7_4 years_yes_- _7.85_-_6.3*_7.8__ 8_4 years_no_- _7.3_-_7.4*_7.3 __ * figures not included in mean.
Figures from the 1991 harvest would suggest that the fertiliser application was not sufficient to make a significant impact on yield. The high level of crop damage sustained in 1994 and 1995 has over-shadowed any effect that fertiliser application might have had on the 1995 yields.
Crop removal and site restoration
Operation
Following the flail operation in February 1996 to clear the final area of satnding crop, the stools were allowed to flush in spring and reach approximately 150-200mm in height, before being treated with an application of glyphosate (6l/ ha). The herbicide was applied in mid May across the whole site using a tractor mounted boom sprayer and was effective in killing all but a few stools as well as keeping other problematic weed species in check. A second dose of glyphosate (3l/ ha) was applied in July to kill any remaining stools. An attempt was made to sow the site with winter barley in October 1996, but the willow stumps proved too much of an obstruction for the German built, Dutzi soil conditioner and the work was abandoned. The site was left without further attention until spring 1997, when the area was treated with a low rate application of glyphosate (2l/ ha) to suppress weed growth.
The soil was successfully worked with the Dutzi conditioner in the last week in April 1997 and the larger pieces of woody material were removed by hand from the soil surface. Immediately after conditioning, the site was drilled to spring barley which grew well and was harvested in August 1997.
Results
16 months after flailing, it was possible to plant and arable crop on the site. The Dutzi soil conditioner successfully cultivated the top 100mm of soil, incorporating all but the largest pieces of woody material into the soil. It should be noted that the crop at Long Ashton had very poor growth and extremely low stool survival rate; it is considered that the Dutzi conditioner would not have been able to cope with a better established crop in the same time period. SWANBOURNE
The 1.8 hectare trial site was established using six Belgian poplar clones. The trial was utilised to study the effects of cutting cycle and nutrition on crop yield. The layout is illustrated in Figure 3
SITE CHARACTERISTICS
Location Swanbourne Estate Swanbourne Buckinghamshire MK17 0SW Long. & Lat. 0O51W 51O57N O S National Grid Ref SP 795 281 Altitude 112m
Climate Average of data from 1959 to 1997: Average annual rainfall (mm) 645.5 Mean max. daily temperature 13.4 OC Mean min. daily temperature 5.3 OC For more details see Appendix 3
Soils Soil type Clay loam Solid Geology Oxford clay Drift Geology Chalky till Soil Association Hanslope Previous Land Use Permanent pasture
Figure 3 Layout of 1.8 ha Swanbourne Populus trial.
(not available electronically)
R ows are monoclonal and include 6 clones: 1 = P. trichocarpa x deltoides Rap 2 = P. trichocarpa Fritzi Pauley 3 = P. deltoides x nigra Dorskamp 4 = P. trichocarpa x deltoides Beaupre 5 = P. trichocarpa x deltoides Boelare 6 = P. (trichocarpa x deltoides) x deltoides 75.028/3 Rows 1-28, 3 year cutting cycle, no fertiliser Rows 29-46, 3 year cutting cycle, fertiliser Rows 47-60, 5 year cutting cycle, fertiliser Rows 61-90, 5 year cutting cycle, no fertiliser Spacing = 1m x 1.5m
ESTABLISHMENT
The site was prepared in autumn 1986 (year -1) with an overall application of glyphosate (Roundup at 3l/ha), followed by ploughing and disking. Some new fence and some additions to existing fencing were required to keep out stock and rabbits.
The site was planted with six poplar clones, established using unrooted cuttings and planted in random mono-clonal rows at a spacing of 1 x 1.5m. A post harvest application of simazine (Gesatop 500L at 6l/ha) and subsequent applications of glyphosate (Roundup at 4l/ ha) and a further simazine treatment were required to keep weed growth in check until the first cut-back.
The shoots were cut-back with a brush-cutter in December 1987. Glyphosate was applied by knapsack early in April 1988, followed by an overall application of simazine (Gesatop 500L at 4l/ ha). Weed control was good throughout year 1.
MANAGEM ENT
The trial was established in two sections, one to be managed on a 3 year cutting cycle and the other on a 5 year cycle. After the first harvest of the 5 year section, and despite high yields, it was decided that a 5 yearrotation period was too long for poplar coppice for energy. The primaryreason was that shoot diameter after 5 years was too large for specialised coppice harvesting machinery to cope with, limiting harvesting to expensive motor manual techniques. The rotation period was therefore cut to 2 years for the next two cycles in order to synchronise the harvesting of the entire site. Both sections of the trial were harvested in winter 1996/7 and are currently being managed on the same 3 year rotation.
Weed Control
With the exception of a spot weed control treatment in year 1, no further treatment was required until the first harvest.
Following the first harvest of each section of the trial, overall applications of simazine (Gesatop 500L at 5l/ha) were applied in winter to prevent weed growth. Rapid canopy closure facilitated natural suppression of weed growth until second harvests. Following all subsequent harvests, the cut areas were treated with a mix of amitrole (W eedazol TL @ 20l/ ha) and simazine (Gesatop 500L @ 4l/ ha). These combined treatments have proved effective in providing sufficient protection until canopy cover allows natural suppression; weeds have never posed a serious problem at Swanbourne. In addition to the routine weed control, a small portion of the area harvested in winter 1993/4 was utilised by Avon Vegetation Research to evaluate different herbicide treatments. The results of this work are reported in Clay and Dixon (1996).
Nutrition
A standard agricultural dose of fertiliser (80:40:40: kg/ ha elemental N :P:K) was applied to the trial by hand during year 2 (1989). Soil analysis, following the first harvest, highlighted low levels of P and Mg, which was rectified by a hand application of Enmag (72:108:108:102 kg/ha N:P:K:Mg). A third fertiliser treatment was undertaken in August 1994, applying N :P:K at a rate of 69:46:60 kg/ha.
All three applications were made to only half the site (see Figure _seq f swanlay_3_) in order to assess the impact of increased nutritional levels on crop growth and health. Yield assessments made prior to each harvest indicated no increase in crop yield as a result of fertilisation. It is considered that this maybe due in part to the initially high levels of nutrients available at this ex-arable site. It is likely that regular removal of biomass will eventually result in the depletion of nutrients from the site which will need to be replaced through fertilisation if yield levels are to be maintained.
Pests and Diseases
Until summer 1997, Melamspora spp. leaf rust had only been noted on Fritzi Pauley and Trichobel, only occurring late in the summer and never causing leaf necrosis or premature defoliation; it was not considered to be a threat to crop health. In September 1997, all six of the clones included in the production trial were infected by rust, the most severe infection was to the P. trichocarpa x deltoides clones, Beaupre, Boelare and Rap. The impact of the infection was notably worse on older shoots of Boelare and Rap, which showed total leaf necrosis and heavy levels of premature defoliation. The long term effects of this infection are unknown but it is likely to have caused a decrease in plant vigour and crop yield.
The reason for this sudden increase in the susceptibility of the poplar clones to rust is thought to be linked to temperature. The unusually hot summer of 1997, may have facilitated the spread of a new strain of Melampsora species. previously restricted to continental Europe.
The leaf feeding Brassy willow beetle (Phyllodecta spp.) was noted regularly throughout the 12 year project at Swanbourne, but never caused any significant damage to the crop. In 1989, the pathology laboratories at the University of Aberdeen identified Fusarium and Phytospora spp. to be infecting a single stool of Rap. The stem canker Xanthomonas populi, for which the clone R ap was withheld from the Forestry Authority’s approved planting list, was never noted at Swanbourne.
HARVESTING
February 1991
The first harvest of the section of the crop on a 3 year cycle was achieved using an early prototype of the Loughry Coppice Harvester. After first removing the edge rows to facilitate access, the machine performed well achieving a productivity of 1.4gt/ pmh.
February 1993
The second half of the production trial was harvested using a Mini-Brunett forwarder fitted with a felling head and Siba 7/45 RC chipper. The productivity of the machine was low, the small size of the poplar stems resulted in the felling head being unable to match the chippers ’ capacity. The machine was considered to be unsuited to the task and unable to operate economically.
In addition, the weight of the chip bin resulted in heavy rutting to the site which caused severe difficulties with subsequent harvest operations. The operation is described in full in an internal report to ETSU (Mitchell et al 1993).
January 1994
The second harvest of the portion of the crop on a 3 year cycle was undertaken bythe FA/ TDB in January 1994 using a modified sugar cane harvester (Austof t), a purpose build coppice harvester (Frobesta) and a motor manual approach. The operations are reported fully by the FA/TDB (Deboys, 1996).
December 1994
The second harvest of the portion of the crop originally on a 5 year cycle was harvested prematurely by the FA/ TDB in December 1994 when the standing shoots were 2 years old.
The crop was cut using 3 different machines: 2 purpose built coppice harvesters (Salix Maskiner Bender I and Segerslatt Empire 2000) and a maize harvester fitted with an unmodified Kemper header (John Deere/ Kemper). The operations are reported fully by the FA/TDB (Deboys, 1996).
February 1997 The entire site was harvested to synchronise the cutting cycle in February 1997. The latest prototype of the Salix Maskiner Bender (III) was used to cut and chip the crop. Despite problems caused byprevious rutting of the site, the operation was successful achieving a productivity of 6.35odt/pmh. The operations are reported fully in Mitchell et al (1997).
Clone productivity
The yields at first harvest of the 3 year old poplar in the production trial were calculated by weighing all the cut material from the rows. Yields at all subsequent harvests were estimated by destructive sampling of randomly selected stools. Yields per hectare was then extrapolated using initial stocking density with a correction for stool mortality.
Table 2. Productivity of 3yr old, Section 1 of Populus spp. at Swanbourne (odt/ha/yr) Species_Clone_1 st harvest_2nd harvest_3rd harvest_mean ___ Fert_No fert_Fert_No fert_Fert_N o fert_Fert_N o fert_ P. t x d_Rap_10.3_9.7_5.1_6.2_5.8_9.2_7.1_8.4 ____ (-)_(-)_(58)_(73)_(59)_(65)_(-)_(- _P. t x d_Boelare_7.2_7.3_5.8_7.7_8.6_7.2_7.2_7.4 ____ (-)_(-)_(61)_(68)_(60)_(64)_(- _P. t x d_Beaupre_6.7_6.9_10.8_10.8_10.1_12.5_9.2_10.1____ (-)_(- )_(92)_(91)_(92)_(91)_(-)_(-)_ P. d x n_Dorskamp_6.2_5.8_8.7_8.3_5.1_6.6_6.7_6.9 ____ (-)_(-)_(62)_(74)_(49)_(73)_(- )_(- )__ P. t_Fritzi-Pauley_3.5_3.0_1.6_2.3_1.3_1.5_2.1_2.3 ____ (-)_(-)_(45)_(57)_(42)_(55)_(- )_(-)__P. (t x d) x d_75028/ 3_1.9_1.6_2.8_2. 1_1.3_1.7_2.0_1. 8____ (-)_(- )_(67)_(71)_(61)_(70)_(-)_(-) ______M ean 6. 0_5 .7_5 .8_6 .2_5.4_6.5 ______(-)_(- )_(64)_(72)_(6 1 )_(70) ___ Site Mean___5.8__6.0__6.0 ______(-)__(68)__(65) ____
Table 3. Productivity of Section 2 of Populus spp. at Swanbourne (odt/ha/yr). Species_Clone N ame1st harvest (5yrs)_2nd harvest (2 yrs)_3rd harvest(2 yrs) Fert_N o fert_Fert_N o fert_Fert_N o fert__ P. t x d_Rap_14.9_12.5_7.6_8.4_10.0_9.6 (92)_(93)_(92)_(-)_(91)_(80)^P. t x d_Boelare_12.5_6.2_5.2_5.9_6.3_5.1 ___ (90)_(88)_(89)_(-)_(65)_(52)__P. t x d_Beaupre_8.4_8.8_6.2_6.0_10.0_9.0 ____ (92)_(97)_(92)_(-)_(92)_(99)__P. d x n_Dorskamp_6.0_4.9_6.0_5.1_10.7_5.7 ____ (95)_(82)_(91)_(-)_(90)_(90)__P. t_Fritzi- Pauley_4.2_2.9_2.1_1.9_4.1_2.4 ____ (90)_(80)_(83)_(-)_(82)_(76)__P. (t x d) x d_75028/ 3_1.9_1.3_0.5_1.4_1. 1_1.5 ___ (65)_(34)_(59)_(- )_(55)_(46) ______Mean__ 8.0_6.1_4.6_4.8_7.0_5.6 ____ (87)_(79)_(84)_(- )_(79)_(74) __ Site Mean___ 7.0__4.7__6.3 _____ (83)__(-)__(77)__ • t = trichocarpa, d = deltoides, n = nigra Table 2 shows the yield achieved at the first three harvests of Section 1 managed on a 3 year cycle. The average yield from this section of the trial, has remained constant at approximately6 odt/ ha/ yr. The figures indicate no significant benefit from the addition of fertiliser, in fact the average yield was higher in the unfertilised treatment than the fertilised, at the second and third harvests. The relative ranking in terms of yield of the six clones also varied between harvests. In the first rotation Rap and Boelare were the highest yielding clones but in the second and third rotations Beaupre gave significantly higher yields. This may suggest that Beaupre, once established, is well suited to being managed on short rotations, and is able to tolerate the physiological stress of repeated harvest.
The yieldsachieved in Section 2 of the trial (Table_ seq t swprod5 _3_) are more difficult to interpret. The inconsistency of rotation period makes comparison between the harvests difficult, suffice to say that average yields in the shorter 2 year cycles were significantly less than in the first 5 year rotation. This is due to the stools not having time to take full advantage of the wider spacing used in the trial. The impact of fertiliser application on crop yield is also unclear. In the first and third rotations the data indicates a significant benefit from the addition of fertiliser but the yield figures from the second harvest show no increase due to fertiliser. Consistent with Section 1, the highest yielding clones at the first harvest were Rap and Boelare but by the final harvest Beaupre and Dorskamp were matching their yields, perhaps indicating the relative coppicing ability of the 4 clones. Comparing the yields achieved at the first harvest of Sections 1 and 2, it appears that the stools in Section 2, managed on a 5 year cycle, were able to take advantage of the space afforded by the wide spacing resulting in average yields of 5.8 and 7.0 odt/ha/yr from the 3 and 5 years cycles respectively. After three rotations, the overall plant survival rate in Section 2 was significantly higher than Section 1, 77% and 65% respectively. It would appear that the longer first rotation period in Section 2 allowed the plants to establish a stronger root structure which was better able to cope with subsequent harvests.
The mono-clonal row plantation design at Swanbourne, has induced strong competition between the 6 clones. Bythe third harvest, Fritzi Pauley and 75028/ 3 had low survival rates and low yields in both sections of the trial, effectively reducing the plantation to a 4 clone mixture. These two clones have been shown to perform better when planted in mono-clonal blocks, as at Markington and Buckfast (see Tables _ seq t markyld_18_ & _ seq t bfscreen _20_). The implication is that intimate or row mixes of poplar must be carefully planned to ensure that the integrity of the mixture remains throughout the plantation life.
The alteration of the management regime in Section 2 was forced by the limitations of currently available harvesting equipment. Conventional forestry forwarder based harvesters were unable to achieve a sufficiently high productivity to be economic with the relatively small diameter stems. Conversely, the stems proved too large to be cut and processed by purpose built coppice harvesting equipment. The data from Swanbourne would suggest that, at a plant density of 6,666 per hectare, higher yields and increased plant survival rates would be achieved using a rotation period longer than 3 years.
Current Status
Throughout the project, the trial at Swanbourne has remained in good condition with minimal pest, disease and weed problems. It is anticipated that the trial will remain in place after the conclusion of this project, and be managed on a 3 year cycle.
LONG ASHTON SCREENING TRIAL
Established at the same time as the willow production trial at Long Ashton, the objective of this 0.9 hectare trial was to screen a number of genera, species and clones for their coppicing ability, productivity and frost tolerance. The layout is illustrated in Figure 4.
SITE CHARACTERISTICS
This trial is located beside the Long Ashton production trial. For information on site characteristics see relevant section on page 1_.
ESTABLISHMENT and MANAGEMENT
The site was established in the same way as the production trial. Each genus is discussed separately, due to different planting stock and management regimes.
Alnus
Four replicates of Alnus rubra Bong were planted in 1986 using 1+1 nursery transplants. The spacing was 1m x 1m as used in the willow plantation. Initial survival and growth was good, but after cut-back there was only 70% survival and at the end of 1987 the shoots were only 1.2m in height. The plants were susceptible to frost damage, particularly spring frosts, which set back their growth and allowed weeds to colonise the site.
The plots were harvested in April 1992 after 5 growing seasons using chainsaws. The relatively low yields obtained at this harvest (T able _seq t alderyield_4_) and the weak regrowth following harvest, suggest that this species of alder is not suitable for SRC. The plots were abandoned in 1993.
Table 4 Survival and productivity of Alnus. Plot Survival Mean stool Productivity
% weight kg) odt/ha/yr
3 74 7.16 4.6
8 71 2.74 1.7
10 69 6.50 4.0
14 61 5.96 3.2 mean 3.4
Eucalyptus
A selection of varieties of Eucalyptus gunnii were obtained from the Forestry Commission, screened for frost tolerance, and planted in six replicated plots (predominantly divaricata and archerii).
In June 1987 the plots were cut back. The timing of this operation was intended to avoid the period of most prolific spore production of silver leaf disease (Chondrostereum purpureum) and hence reduce infection risk. Survival immediately after coppicing was poor, falling from 98% after planting to only 66%.
Figure 4 . Layout of Long Ashton screening trial (not available electronically)
Plots 1, 11 & 15 Eucalyptus gunii var. divaricarta and E. gunii var. archeri mixture Harvested on a 5 year cycle - spacing 1m x 1m Plots 4, 7 & 18 Eucalyptus gunii var. divaricarta and E. gunii var. archeri mixture Harvested on a 4 year cycle - spacing 1m x 1m Plots 3, 8, 10 & 14 Alnus rubra harvested on a 5 year cycle - spacing 1m x 1m Plots 2, 5 & 9 Populus clones harvested on a 4 year cycle - spacing 1.5m x 1m a = P. trichocarpa x deltoides R ap b = P. trichocarpa Fritzi Pauley c = P. deltoides x nigra Dorskamp d = P. trichocarpa x deltoides Beaupre e = P. trichocarpa x deltoides Boelare f = P. (trichocarpa x deltoides) x deltoides 75.028/ 3 Plot 17 P. deltoides x nigra Dorskamp at different spacings - 4 year cycle x = 1.5m x 1.5m spacing y = 1.0m x 1.0m spacing x = 1.0m x 0.5m spacing Plots 6, 12, 13 & 16 Canadian P. deltoides x nigra clones harvested on a 4 year cycle - spacing 1.5m x 1m p = DN55 q = DN70 r = DN74 s = DN125 t = DN136 In June 1991, following 4 years growth after cut back, 3 of the plots (nos. 4, 7 and 18) were harvested motor-manually using a chainsaw. The remaining 3 plots were cut at age 5 in June 1992 using a motor-manual method. Yield figures are given in Table _seq t eucs1_5_.
Table 5 Survival and productivity of Eucalyptus. Plot_Survival_Mean stool_Productivity_ %_weight (kg)_odt/ ha/ yr 4_63_24.0_16.7 7_72_28.3_22.3_ 18_54_27.2_16.2__ 1_61_29.2_16.1 11_63_38.4_21.9 15_62_26.6_14.9__
The yields achieved in the first rotation of eucalyptus at Long Ashton remain the highest of any genus used in this project. However, following the first harvest the stools became infected by Chondrostereum spp. resulting in high levels of mortality. Weeds established within the plots and by summer 1993 stool survival was down to approximately20% and the plots were abandoned.
It is considered that this susceptibility to Chondrostereum spp. precludes the use of eucalypts in SRC systems in the UK at present.
Nothofagus
In spring 1986, Nothofagus procera and N. obliqua transplants (1+0) were each planted in 4 plots at 1m x 1m spacing. Bythe end of year0, over 50% of each species was dead or dying, so 2 plots of each were removed, to be replaced by poplars from Belgium.
The remaining plots were not cut back due to fears of poor coppicing ability. Survival was below 50% by July 1987, and growth was poor; at the end of the year, it was decided to remove the remaining 4 plots and replace them with more promising poplar clones from Canada.
Populus, Belgian clones
In spring 1987, four plots were planted with the same 6 Belgian poplar clones as used in the production trial at Swanbourne. Three plots were established with all 6 clones at a standard I x 1.5m spacing (plots 2, 5 & 9) and the final plot was used to investigate the effect of plant spacing on yield, by planting Dorskamp at 3 different spacings (plot 17).
II 4 plots have completed two, four year cycles and the yieldsobtained at each harvest are given in Tables _ seq t popscree _6_ and _ seq t popspace _7_. Table 6 Productivity of Populus plots. _Productivity (odt/ ha/ yr)_Final Clone_Plot 2_Plot 5_Plot 9_Mean_survival ___ H 1_H2_H 1_H2_H 1_H2_H 1_H2_(%) __Rap_7.0_9.0_13.0_16.4_6.0_11.9_8.7_12.4_83 __ Fritzi Pauley_10.0_8.9_6.0_7.3_11.0_7.2_9.0_7.8_64 __Dorskamp_10.0_15.4_10.0_14.7_17.0_8.3_12.3_12.8_67 __Beaupre_8.0_12.9_11.0_11.4_13.0_14.2_10.7_12.8_78 __ Boelare_13.0_11.3_14.0_7.7 _9.0_12.9_12.0_10.6_64_ _75.028/ 3_3.0_5.0_13.0_0.4_5.0_7.1_7.0_4.2_37 __Mean_8.5_10.4_11.2_9.7_10.2_10.3_9.9_10.1_- __H1, H2 - Harvests 1 and 2.
Table 7. Productivity of P. deltoides x nigra (Dorskamp) in spacing trial. Plant spacing_Plant density_Productivity (odt/ha/yr) _Final stool survival_Final plant density____ H 1_H2_(%) ___ 1.5 x 1.5m_4,444_10.0_7.6_46_2044 __* 1.0 x 1.5m_6,666_12.3_12.8_67_4466 __1 x 1m _10,000_10.0_10.1_48_4800 __ 1 x 0.5m_20,000_9.0_14.2_31_6200 __ * figures are taken from plots 2, 5 & 9.
The yield of the Belgian poplar clones was high, mean figures ranging from 4.2 - 12.8 odt/ ha/ yr with an average of approximately 10 odt/ ha/ yr at both harvests. Survival of stools within the plots was generally good, with only one clone, 75028/ 3, not reacting well to coppicing which resulted in a survival rate of only 37% after 2 rotations.
The data from the spacing trial of Dorskamp is more difficult to interpret. At the first harvest there was a clear indication that when harvested on a four yearcycle, a spacing of 1 x 1.5m (6,666 plants/ ha) would result in maximum yield. The data from the second harvest did not directly support this conclusion, with the highest yield being achieved at a spacing of 1 x 0.5m (20,000 plants/ha). It is worth noting however, that the plant survival in the 20,000 plants per hectare treatment had fallen to only 6,200 (31%) making it approximately equal to the initial density of the 1 x 1.5m treatment.
The data would suggest that there is a positive correlation between plant density and stool mortality; the highest mortality being recorded at a plant density of 20,000 per hectare. The low survival rate recorded at the 4,444 per hectare stocking rate, can be explained by the difficulty in weed control both during establishment and following cut-back and harvest. At such a wide spacing canopy closure was slow and natural weed suppression was limited, when compared to the higher densityplantings. All 4 plots remained disease free through the first and the majority of the second rotation. In the summers of 1995 and 1996 the clones Boelare and Beaupre suffered a very light infection of Melampsora spp. leaf rust. During summer 1997, all 6 clones became infected by the rust. The most severely infected clones (Boelare, Rap and Beaupre) suffered leaf necrosis and high levels of premature defoliation which undoubtedly reduced crop growth. However, without a disease free control it is impossible to quantify the effect on yield or assess the long term impact on crop health.
Populus, Canadian deltoides x nigra clones
The remaining plots vacated by the failed Nothofagus were planted in February 1993 with 5 P. deltoides x nigra clones, at a standard spacing of 1 x 1.5m. The plots were cut back after 1 year and felled after a further 4 years growth using chainsaws. Due to vigorous re growth it was decided that the second rotation should be shortened to 3 years. Yield and survival figures recorded at both harvests are given in Table _ seq t lacans _8_.
Table 8 Productivity of Canadian Populus clones. _Productivity odt/ ha/ yr (stool survival, %) __ Clone_Plot 6_Plot 12_Plot 13_Plot 16_mean ___ H 1_H2_H 1_H2_H 1_H2_H 1_H2_H 1_H2 __ DN 55_10.8_6.3_-_-_10.9_5.7_12.6_8.0_11.4_6.7___ (83)_(81)_(-)_(- )_(92)_(91)_(94)_(94)_(90)_(89) __DN 70_5.4_3.3_5.7_3.9_-_-_7.8_5.7_6.3_4.3___ (80)_(73)_(99)_(98)_(-)_(- )_(99)_(95)_(93)_(89) _DN 74_7.1_5.4_8.5_4.9_11.2_6.4_11.7_7.7_9.6_6.1 ___ (85)_(81)_(96)_(95)_(90)_(83)_(78)_ (82)_(87)_(85) __ DN 125_9.9_4.5_11.2_5.6_13.8_10.2_-_- _11.6_6.8 ___ (52)_(52)_(61)_(57)_(43)_(57)_(-)_(-)_(52)_(55) __ DN 136_-_-_14.8_9. 1_15.7_6.4_1 1.2_8.6_13.9_8.0 ___ (-)_(- )_(78)_(78)_(76)_(75)_(94)_(93)_(83)_(82) __H1, H2 = harvest 1, harvest 2.
Despite the apparentlyvigorous regrowth in the second rotation, yields recorded at the second harvest where significantly lower for all clones than at the first. The reason for this decrease in yield are unclear. Canopy cover was complete from July in the first year of the second rotation and the plots remained weed free throughout the 3 year cycle; it is unlikely that the plants were cut prematurely. Plant survival rates in all plots remained consistently high throughout both rotations, with the exception of DN 125, and no serious pest or disease problems were noted in the plots which might have explained the loss of vigour. Although not considered serious enough to have affected growth, all five clones suffered a extremely minor infection of Melampsora spp. rust during autumn 1997. This was the first time that the Canadian poplars had shown any susceptibility to rust and represents a concerning trend.
Yield in the first rotation compared favourably to the Belgian poplars at Long Ashton and the absence of serious pest or disease problems would indicate a potential for their use in single stem silviculture but the reduced yield when coppiced would suggest that their use for SRC systems is not appropriate.
Current Status
The screening trials have provided a wealth of data during the past 12 years but are thought to have limited further research or commercial value. The remaining plots will be removed following the conclusion of this project in March 1998.
CASTLE ARCHDALE
This site was chosen to provide a large-scale plantation, suitable for testing and evaluating the Loughry Coppice Harvester. Further information would also be generated on costs and logistics, as well as biology and yields of large scale SRC plantations.
The trial was planted in three similar size phases (ca. 3ha), in consecutive years, starting in 1987. Each phase was planted with 5 Salix clones in separate monoclonal and polyclonal plots. Phases I and III also include a number of additional Salix and Populus clone. The layouts of each Phase are illustrated in Figures 5, 6 and 7.
SITE CHARACTERISTICS
Location Grassland Experimental Farm Lisnarick Co. Fermanagh Long. & Lat. 7O 43' W 54O 28' N O S National Grid Ref. H 218 358 Altitude 66m
Climate Average of data from 1963 to 1997 Average annual rainfall (mm) 1095.9 Mean max. daily temperature 12.3 OC Mean min daily temperature 5.2 OC For more details see Appendix 2.
Soils Soil Type Silty Clay Loam (impeded drainage) Solid Geology Old Red Sandstone Drift Geology Carboniferous limestone Previous Land Use Permanent pasture
Figure5 Layout of 3.3ha Castle Archdale Salix trial Phase I.
(not available electronically)
Figure 6. Layout of 3.0ha Castle Archdale Salix trial Phase II. (not available electronically)
Figure 7. Layout of 3.4ha Castle Archdale Salix trial Phase III. (not available electronically)
ESTABLISHMENT
All phases received an application of herbicide to kill the existing weed growth in the autumn before planting. Phase I was sprayed with paraquat (Gramoxone at 5.5l/ha) then ploughed, and Phase II received glyphosate (Roundup at 5l/ha) followed by ploughing. Phase III was sprayed with glyphosate (Roundup at 5l/ha) followed by ploughing and power harrowing.
Standard rabbit fencing with 2 barbed wire strands above proved to be ineffective against the large numbers of hares; a third strand of barbed wire was added on all fences. Planting was almost exclusively with 250mm unrooted hardwood cuttings, manually planted. Survival rates after planting were good in Phase I and Phase III, but poorer in Phase II because of a drought in May/ June 1988. All phases had the dead cuttings replaced by longer setts produced during cut-back at the end of year0.
The residual herbicide simazine (Gesatop 500L at 4l/ ha) was applied to each phase after planting. Phases I and II had to receive applications byhand, due to poor ground conditions, but in Phase III, the best in terms of slope and soil quality, tractor application was possible. Some spot weeding was carried out on each site during the first growth season before cut-back (year 0), using glyphosate (Roundup). After cut-back, the sites were sprayed with amitrole (W eedazol TL at 22.5l/ ha) and simazine (Gesatop 500L at 4l/ ha). At the end of year 0 in Phase I, the blocks which were originally planted with S burjatica Korso were ripped out due to high rust susceptibility and replaced with S viminalis x triandra Q83. The Korso in the polyclonal blocks died out and could not be replaced. MANAGEM ENT
Weed Control
The post cut-back applications of amitrole and simazine were effective in all 3 phases; no further weed control was necessary until after first the harvest. Following each harvest, plots were treated with overall applications of an amitrole (W eedazol TL at 20l/ ha) and simazine (Gesatop 500L at 4l/ ha) mix, applied using either knapsac or tractor mounted sprayers as appropriate.
In addition to operations within the plots, the open space around all 3 phases was regularly mown to prevent the ingress of weeds into the plots.
Nutrition
Fertiliser was applied to all 3 phases in year 1 when the shoots were 200-300mm high using a standard application of 100:25:50 kg/ ha N :P:K. Each section of the trial received a further application at the same rate following their first harvest. Fertiliser was not added after the second harvests of phases I and II but was added to phase III in an attempt to boost the vigour of the plant regrowth.
Pests and Diseases
Throughout the project the leaf rust Melampsora spp. has been a serious problem in all 3 phases at Castle Archdale.
At the end of year 0 in Phase I, the blocks which were originally planted with S burjatica Korso became so severely infected that they were removed from the trials, being replaced with S viminalis x triandra Q83. Rust has been noted every year and on every clone, resulting in poor growth, low plant survival rates and intense weed problems. Compounded by damage from the insect pest Phyllodecta spp. (Brassy willow beetles), the damage lead to the eventual abandonment of the trials during the last phase of the project; the crop removal work is detailed in Section 12.
A study on the use of clonal mixtures to reduce the severity of disease, was carried out during phases 2 and 3 of the project and is reported by Dawson and McCracken (1995). Data from this work suggested that the use of clonal planting mixtures could result in a significant reduction in the severity of disease and an increase in crop yield.
HARVESTING
Phase I Despite two attempts to harvest the crop with the Loughry Coppice harvester, adverse weather and site conditions in winter 1990/91 limited the operation to motor-manual felling combined with forwarder extraction of the cut shoots. Ground and crop damage were limited and did not appear to effect regrowth.
The second harvest of phase I was carried out by the FA/ TDB in January 1994 and is reported fully in Deboys (1996). Machinery tested included: Austoft (sugar cane harvester), Frobesta shoot harvester and the latest version of the Loughry Coppice Harvester. Site and ground conditions were similar to those in winter 1990/ 91 and the operations caused heavy rutting and crop damage, particularly on the headlands. Crop regrowth on the headlands was patchy and slow resulting in reduced yield and a high stool mortality rate. Any future harvesting operations would have been made extremely difficult by the rutting but the abandonment of the plots in 1996 meant that no further harvesting was required.
Phase II
Ground conditions precluded the use of mechanised harvesting in winter 1991/ 92 and the site was cut using a motor manual approach.
The second harvest of phase II was carried out bythe FA/ TDB in December 1994 using: John Deere with an unmodified Kemper header, Segerslatt Empire 2000, Salix Maskiner Bender I and the Loughry Coppice Harvester and is reported fully in Deboys (1996).
Phase III
Phase III was harvested for the first time in January 1993 using predominantly motor manual methods. Although the Loughry Coppice Harvester cut a small portion of the crop it was once again brought to a halt by the adverse weather and ground conditions. The cut shoots were stacked by hand and removed later by forwarder.
The second harvest of phase III was carried out bythe FA/ TDB in winter 1995/ 6 using the Austoft (sugar cane harvester) and the Claas Jaguar. Despite the steep slopes, wet ground conditions and heavy weed growth, the Austof t successfully cut the majority of the site. The Claas Jaguar however, struggled to find traction in the wet conditions, was unable to accurately adjust the cut height to match terrain variation, and the feed system was repeatedly choked by weeds. A full report is given in Deboys (1996).
Clone productivity
Prior to harvest, each phase was destructively sampled to estimate yield. No figures for stool survival are available; all figures given in Tables _seq t cayld1_9_, _seq t cayld2_10_ and _seq t cayld3_11 _ are based on full survival. Planting density in all plots is 20,000 stools per hectare, the one exception being the mixed plot in phase I where one of the original clones (Korso) died out early in the trial leaving only 16,000 stools per hectare. Table 9. Productivity of Salix clones at Castle Archdale, Phase I _Productivity odt/ha/yr___ Harvest 1_Harvest 2*_
_viminalis Bowles Hybrid_6.8_5.3 (7. 7) __ burjatica Germany_11.1_9.1 (10.2) __ x dasyclados_8.0_7.0 (4.8) __triandra x viminalis Q83_6.4_9.7 __ viminalis 683_5.2_7.0 (8.4) __ mixture_9 .71_7.7 __ viminalis Mullatin_5.9 ___ vim x cap x aur R eifenweide_4.9_4. 1 __ x calodendron_4.5_4.8 __ x stipularis_6.0_4. 1 __ * bracketed figures indicate the clones yield in the mixed plots. N o figures for individual clone performance are available for the first harvest. 1 intimate mixture of Bowles, dasyclados, 683, and Germany; Korso died out leaving 16,000 stools/ha.
Table 10. Productivity of Salix clones at Castle Archdale, Phase I _Productivity odt/ ha/ yr ___ Harvest 1*_Harvest 2* __ viminalis Bowles Hybrid_7.7_6.4 (3.4) __ burjatica Germany_7.3_9.1 (17.7) __ x dasyclados_7.2_7.8 (9.6) __triandra x viminalis Q83_10.3_12.4 (20.0) __ viminalis 683_7.3_7.8 (19.5) __ mixture_12.41_14. 11__ * bracketed figures are the clones yield in the polyclonal plots. 1 intimate mixture of Bowles, dasyclados, 683, Germany and Q83.
Table 11 Productivity of Salix clones at Castle Archdale, Phase III _Productivity odt/ha/yr___ Harvest 1*_Harvest 2* __ viminalis Bowles Hybrid_6.7 (13.4) _3.5 (1.9)_ burjatica Germany_10.3 (17.1)_7.0 (11.6) __ x dasyclados_8.8 (10.3)_4.9 (6.2) __triandra x viminalis Q83_9.9 (19.5)_6.8 (12.6) __ viminalis 683_7.5 (20.6)_5.6 (10.5) _ mixture_16.61_8.6 __ x calodendron_10.1_6. 1__ * bracketed figures are the clones yield in the polyclonal plots. 1 intimate mixture of Bowles, dasyclados, 683, Germany and Q83.
Without exception the mixed clonal plantings in each phase resulted in a greater yield than the mean of the constituent clones. This is thought to be partly attributableto reduced disease susceptibility. Any given rust population is comprised of a number of distinct pathotypes or races, each of which is able to infect only certain clones. It is thought that clonal mixes reduce the rate of spread of the pathotypes within the rust population; susceptible stools being further apart (Dawson and McCracken, 1995). Higher yield in the mixed plantings may also be associated with a more efficient use of both above and below ground resources i.e., water, nutrients, light.
Stool survival figures available for the polyclonal plots in phase III prior to their second harvest, show that the relative proportions of the clones within the mixtures are changing as the plantation matures; competition favouring “683 ” and Germany. However, if the remaining 3 clones in the mix continue to decline, the benefitsof the polyclonal planting will be reduced and may eventually be lost altogether.
In addition to the willow plots, a small screening trial of Populus was established in phase III. N o data is available for the first rotation of the plots but figures recorded prior to the second harvest in winter 1995/ 96 show an unadjusted average yield for the 11 clones of 8.8 odt/ ha/ yr (Table _ seq t capops _12_). The general health and vigour of the plots throughout the project was excellent with no none of the pest, disease or weed problems seen in the adjacent willow crop. The second harvest of the poplars was carried out by the FA/ TDB using the Austoft sugar cane harvester and no problems were encountered despite the large stem diameters of the mainly single stem crop.
Table 12. Productivity of Populus clones at Castle Archdale, Phase III _Productivity odt/ ha/ yr__ Donk_9.7 __ Barn_10.6 __R ap_9.0 __ Fritzi Pauley_7.3__Beaupre_9 .8__ Boelare_8 .9__ Balsam Spire_7.6 __Unal_10.5 __ Dorskamp_8.3 __ Trichobel_7.4__ Verecken_8.7__ MEAN_8.8__
Crop removal and site restoration
Throughout the project, the plots in all 3 phases have been severely affected by Melampsora spp., brassy beetles and heavy weed competition; this is reflected in the poor performance of many of the clones. Low yield and decreasing plant survival rate, despite a comprehensive programme of chemical weed control and fertilisation, lead to the desicion to abandon the trial during phase 4.
Before planting with SRC, the land was used as permanent pasture but due to an interest from the forestry sector it was not necessary to restore the land to this condition or to remove the coppice stumps from the majority of the site; simply killing the stools was sufficient.
Operation
Having flailed the majority of the standing crop, the stools were allowed to re-shoot to a height of approximately 150mm and sprayed off with an application of contact herbicide (glyphosate) in late spring. On all phases a second, lower rate treatment was applied in late summer to kill any remaining stools and control weed growth. To assess the costs and logistics of returning willow coppice to quality grassland, a 2.0 hectare plot of the second phase at Castle Archdale was used. The standing crop was removed in January 1997, using clearing saws to simulate a normal post harvest condition. The cleared area was allowed to regrow in early spring to a height of approximately 100mm before being treated with an application of contact herbicide (glyphosate @ 6l/ha) to kill the stools. A second treatment of glyphosate (3l/ha) was applied in June 1997 to kill any remaining stools and suppress weed growth. The soil was conditioned in August using an orchard flail mounted on a standard 80bhp agricultural tractor, which successfully incorporated the woody stumps into the top 70mm of soil. The site was then levelled using a combination of disking and a board leveller to flatten and fill the ruts created by previous coppice harvesting operations. The site was broadcast sown with grass in late August 1997 and first let for grazing sheep in spring 1998.
Results
The total time to convert the area from a coppice plantation to grazing land was 12 months, during which time the land was unusable. One of the major concerns during the operation was the deep rutting caused by coppice harvesters; ruts in some cases were up to 0.5m deep. These ruts necessitated several extra passes with the soil conditioner and the board leveller, increasing the cost of the operation.
Current Status
Following the programme of crop removal and land restoration, the only remaining trial areas are a small poplar screening trial in phase III and a 0.9 hectare section of mixed willow planting in phase I. The continued management of the these crops will be undertaken by DANI.
KINCARDINE
This trial was a result of interest expressed by the Highlands and Island Development Board (now Highlands and Islands Enterprise) during 1986. It was the first to be established in Scotland, and was considered to be typical of the land which would be available in this area for coppice crops. The site exhibits a gradation from freely draining pasture, to waterlogged peat. A range of clones of willow were planted, selected from the collection at Long Ashton Research Station as potentially suitable for the conditions. The trial aimed to establish the productivity, frost tolerance, disease susceptibility and growth patterns of clones in small plots, and then establish a larger production trial with the best clone(s). The original layout is illustrated in Figure _seq f kinlay_8_.
SITE CHARACTERISTICS
Location Kincardine Estate Boat of Garten Inverness- shire Long. & Lat. 3O 45' W 54O 13' N OS National Grid Ref. NH 938 161 Altitude 210m
Climate Average of data from 1966 to 1994 Average annual rainfall (mm) 812.2 Mean max. daily temperature 10.8OC Mean min daily temperature 2.5OC For more details see Appendix _ seq a climate _3_.
Soils Soil type peaty gley with patchy mineral upper horizon Solid Geology Drift Geology Fluvioglacial sands and gravels Previous Land U se Permanent pasture
Figure 8. Layout of Kincardine Salix trial. (not available electronically)
Plots 1-38 Screening trial Blocks I-III Production trial Spacing 0.7m x 0.35m
1&8 = S. burjatica Korso 2&7 = S. x sericans Coles 3&5 = S. spaethii 4&6 = S. viminalis Campbell 9&15 = S. x stipularis 10&16 = S. x calodendron 11&13 = S. viminalis Mullatin 12&14 = S. viminalis Bowles Hybrid 17&23 = S. candida 18&24 = S. viminalis Gigantea 19&22 = S. fruiticosa McElroy 20&21 = S. x sericans Niginians Pruinifolia 25 = S. x dasyclados 26&32 = S. x delamere 27 = S. x sericans 28&31 = S. x sericans Hard Osier 29 = S. caprea (local origin) 30 = S. Golden chrysocoma 33 = P. trichocarpa x deltoides Beaupre 34= P. (trichocarpa x deltoides) x deltoides 75.028/3 35 = P. trichocarpa x trichocarpa TT32 36 = P. trichocarpa x deltoides Rap 37 = P. trichocarpa x deltoides Boelare
Block I - 1500 stools Block II - 400 stools spacing 1.0m x 0.35m planted 1988 spacing 1.0m x 0.5m planted 1988 abandoned in 1990 rows 1&2 = S. x stipularis rows 3&4 = S. spaethii Block III rows 5&6 = S. viminalis Mullatin spacing 1.0m x 1.0m planted 1990 row 7 = S. x hirtei Reifenweide S. viminalis Mullatin rows 8-16 = abandoned in 1990 abandoned in 1990 ESTABLISHMENT
The site was drained, ploughed, fenced against roe deer and the screening plots planted by hand in April 1987. After one year, the most promising of these clones were planted in three larger production plots. Due primarilyto waterlogging, the majority of these larger plantings failed to successfully establish with only plot I yielding useful data.
MANAGEM ENT
Weed Control
Waterlogging and the high organic matter content of the soil, precluded the use of residual herbicides, and as a result weeds were a continual problem across the entire site. Dense initial planting and manual weeding gave a degree of control in the screening plots but several attempts to chemically control couch grass in the production trials failed and plots II and III were eventually abandoned.
Pests and Diseases
One of the objectives of this trial was to assess a variety of clones for their susceptibilitythe leaf rust Melampsora spp. As part of an international disease survey, each site was assessed at least twice during each growing season, to investigate time of infection and severity. During the study period (1988 to 1994) all except one of the clones became infected with the rust. A detailed analysis of the disease survey is given in Mitchell et al 1995.
HARVESTING
The screening plots at Kincardine were harvested annually up to winter 1992/3, after which time the cutting cycle was changed to 2 years to reduce plant stress and facilitate natural control of weed growth. Harvesting was carried out motor manually and shoots were collected and removed from site by hand. Clone productivity
The area covered by the screening trial at Kincardine was divided into two halves; a wet peat and a drier mineral area. Each clone was established with one replicate in each half to enable a comparison of clone performance on the different soil types. Yield was calculated prior to harvest based on whole plot weights (excluding edge rows) and extrapolated using initial stocking rate and plant survival figures. The figures given in Table _ seq t kcscreen _13_ are the mean yields recorded during the project; further detail is given in Mitchell et al 1995.
Table 13. Yields (odt/ha) from Kincardine screening trial. Clone_Yield (odt/ha/yr)___mineral soil_wet peat soil__burjatica Korso_3.0_0.6 __ x sericans Coles_6.0_6.0 __ spaethii_4.0_3.3 __ viminalis Campbell_6.9_4.2 __ x stipularis_6.2_3 .5 __ x calodendron_2.6_1 .5 __ viminalis Mullatin_9.5_5 .5 __ viminalis Bowles Hybrid_6.5_2.3__ candida_4.7_2.6 __ viminalis Gigantea_5.8_1.3 __ x sericans Niginians pruinifolia_4.5_0.0 __ x fruiticosa McElroy_4.0_2.6 __ x dasyclados_7.8_-__ x delamere_5.9_2.4 __ x sericans 6/ 18_-_4.4 __ x sericans Hard Osier_-_3.7 __ caprea_0.9_- __ Golden Chrysocoma_4.0_- __ x sericans Hard Osier_-_4.2 __ MEAN *_5.4_2.8 __ * only clones represented in both soil types are included in the mean. - denotes where clone was not represented
The average of all the clones throughout the trial period, indicated higher yields on the mineral soil than the deeper peat plots. This is due to the combined effect of increased soil pH, higher levels of soil nutrition and better weed control. In the final harvest of the trial, an improvement in yield on the peat plots was noted, and this has been attributed to the root system reaching the deeper mineral soil horizon below the peat. The remaining plots in Block I were harvested in March 1994, 5 years after cut-back. Due to the small amount of material present the plots were felled by chainsaw. Productivities, given in Table _seq t kcb1prod_14_, are based on total plot weights and assume actual survival. Overall the survival rates of the stools was low, but despite this, the yieldsof S. spaethii and Mullatin were surprising high, accounted for bythe long rotation length and the space available for growth created by the high mortality rates.
Table 14 Yield of Salix at Kincardine production Block 1. Clone Productivity Survival (odt/ha/year) (%) spaethii 11.16 70 stipularis 3.82 26 Mullatin 12.41 39 When the Kincardine trial was established it was thought to be typicalof the land type that would be available for SRC. Since then it has become clear that for SRC to be an economically viable production system many operations including planting, and more importantly, harvesting have to be mechanised. The restrictions put on such operations by heavy, wet peat soils as well as the problems associated with weed control, have effectively ruled out the use of this site type for commercial coppice production.
Current Status
The trial at Kincardine was removed from the programme at the end of phase 3. The stools were harvested and then grubbed out using a JCB fitted with a narrow bucket. The site was cultivated and sown to grass in the spring following harvest and is currently used as rough grazing.
GUISACHAN
This site was established in 1988, using the most promising clones from the Kincardine trial, and further clones in screening blocks. The spacing chosen was 1m x 1m (10,000 stools per hectare). The site was considered to be typical of the marginal agricultural land available in the region, i.e. a very wet pasture. The clones were to be tested for productivity, disease resistance and frost tolerance.
The layout is illustrated in Figure _seq f guislay_9_.
SITE CHARACTERISTICS
Location Guisachan Farm Tomich by Cannich Inverness- shire Long. & Lat. 4O 49' W 57O 17' N O S National Grid Ref. NH 299 265 Altitude 99m
Climate Average of data from 1959 to 1994: Average annual rainfall (mm) 1179.1 Mean max. daily temperature 11.5OC Mean min daily temperature 4.6OC For more details see Appendix _ seq a climate _3_.
Soils Soil type Silty deposits; some areas of gravel & deep peat Solid Geology Undifferentiated Schists Drift Geology Fluvioglacial sands and gravels Soil Association Alluvial soils Previous Land Use Permanent pasture
Figure 9 Layout of Guisachan Salix trial. (not available electronically)
Screening trial 1 = S. viminalis 683 2 = S. viminalis Bowles Hybrid 3 = S. viminalis Campbell 4 = S. viminalis Stone O sier 5 = S. viminalis x caprea x aurita R eifenwede 6 = S. spaethii 7 = S. caprea x viminalis x cinerea 455 de Biardii 8 = S. viminalis x caprea x cinerea = x dasyclados 9 = S. viminalis x caprea x cinerea = x calodendron 10 = S. triandra x viminalis SQ83 11 = S. caprea x (aurita x viminalis) = x stipularis 12 = S. viminalis Mullatin
Production trial a = S. viminalis x caprea x cinerea = x dasyclados b = S. viminalis Gigantea c = S. viminalis x caprea x aurita R eifenwede d = S. viminalis Campbell e = S. caprea x (aurita x viminalis) = x stipularis f = S. viminalis Mullatin g = S. viminalis Bowles Hybrid h = S. viminalis x caprea x cinerea = x calodendron I = S. spaethii
ESTABLISHMENT
The site was prepared in autumn 1987 with an overall application of glyphosate (Roundup at 5l/ ha). Drainage was improved by clearing a ditch 140m long, and the site was disked and then ploughed. R otovation was not carried out, which in hindsight, was found to be have been an error. A dam was constructed to prevent the possibility of melting snow scouring the soil. The presence of deer in the locality meant a 2m fence had to be erected around the whole site. The 250mm unrooted cuttings were planted manually in April 1988, and early plant survival rates were good. A delay in applying simazine (Gesatop 500L at 2l/ ha) until July allowed weeds (mainly grasses) to germinate freely. An expensive remedial weed control plan was implemented, using knapsack sprayers to apply paraquat (Gramoxone). Simazine was applied in August to control further weed development.
The shoots were cut back in November 1988. A commercial formulation of simazine and amitrole (Primatol SE 500L) was applied in mid May 1989 and successfully controlled weeds throughout the first year. managem ent
Flooding during winter 1989/ 90 removed a large portion of top soil and damaged fencing allowing deer to enter the crop. Damage was limited mainlyto clones SQ83 which was grazed down to a height of 0.5m.
Weed Control
The flooding in winter 1989/ 90 also precluded the use of herbicide to control weed growth in year 2. It was hoped that natural suppression would keep the site weed free until the first harvest in winter 1991/92, this was not the case however, and weeds, particularly Juncus spp. and grasses, competed strongly with the willow crop throughout the first cycle. A further wet spring following the first harvest again prevented the application of a residual herbicide and although a contact herbicide (R oundup) was effective in checking weed growth, by mid summer 1992 most plots were again suffering intense weed problems. In a final attempt to prevent weed growth amitrole (W eedazol TL @ 20l/ ha) was applied by knapsack sprayer to the worst areas of weed growth within the plots in spring 1993 but this application also proved ineffective in the long term.
Pests and Diseases
This trial along with the other willow trials in the programme formed part of an intensive disease survey co-ordinated by Long Ashton Research Station. Data collected at Guisachan are given in Mitchell et al, 1995 and preliminary analysis in Royle et al, 1992. harvesting
The trial was first harvested in December 1991. Due primarilyto the ground conditions (uneven surface and waterlogging) the operation was carried out using chainsaws and manual collection of the shoots. Piles of cut stems were left on site, for collection and extraction by forwarder in early 1992.
The continued problems with weed competition, and the resultant poor growth of many of the clones lead to the decision to abandon the Guisachan trial at the end of the second, 3 year cycle. Following destructive sampling of the plots in February 1995, the farmer considered that the site’s value lay in providing shelter for sheep, and accordingly the crop was not harvested.
Clone productivity
The yields from the screening trial have been calculated from actual plot weights, discarding a single edge row from around each plot. At the second harvest in February 1995 the yield of the production plots was assessed using stratified, random destructive sampling. In both cases the yields given (Table _seq t guisyield_15_) are based on actual stool survival.
Table 15. Productivity of Salix clones at Guisachan. _Productivity (odt/ ha/ yr) (Survival Feb 1995, %)__ screening_pro du ctio n___ 1991/ 2_1994/ 5_1994/ 5 viminalis 683_3.7_4.3 (50)_n/a __viminalis Bowles Hybrid_5.9_4.7 (81)_3.2 (78)__ viminalis Campbell_6.1_6.1 (94)_5.0 (86) __ viminalis Stone Osier_6.0_5.0 (84)_n/a __ viminalis x caprea x aurita R eifenweide_3 .8_3 .0 (70)_1.8 (66) __ spaethii_7.1_1.7 (73)_0.0 (0)__ caprea x viminalis x cinerea de Biardii_3.6_1.9 (97)_n/a__ x dasyclados_7.1_3.7 (73)_3.4 (73)__ x calodendron_3.0_0.0 (0)_0.0 (0)__ triandra x viminalis Q83_3.1_5.0 (80)_n/a __ x stipularis_5.0_1.0 (78)_ - (< 20)__ viminalis Mullatin_5.2_4.4 (75)_2.9 (86) __ viminalis Gigantea_n/ a_n/ a_6.6 (92)__Mean_5.0_3.7_3.8__ The poor weed control and repeated waterlogging at Guisachan are reflected in the poor yields achieved in both the screening and production plots. The yield attained the first and second harvest of the screening plots of 5.0 and 3.7 odt/ha/yr respectively, also show a decline in crop vigour with time.
Current Status
The trial was dropped from the programme in winter 1994/ 5 and is currently used to provide winter shelter for sheep.
WATER EATON
This site was chosen as a good quality ex-agricultural site suitable for growing poplars. Two large production trials were planted to produce information on the costs and logistics of establishment and management operations, potential yields, and pest and disease problems. The trial layout is illustrated in Figure 10.
SITE CHARACTERISTICS
Location North Farm Water Eaton Wiltshire Long. & Lat. 1O45W 51O35'N O S National Grid R ef ST 145 945 Altitude 75m
Climate Average of data from 1989 to 1997
Average annual rainfall (mm) 650.1 Mean max. daily temperature 13.7 OC Mean min. daily temperature 6.9 OC For more details see Appendix _ seq a climate _3_.
Soils Soil type Stoneless silty clay loam Solid Geology Oxford Clay Soil Association Polsham Series Previous Land Use C ereals
Figure 10 Layout of Water Eaton Populus trial. (not available electronically)
ESTABLISHMENT
Due to time restrictions, ground preparation did not began at the site until March 1989 and complete ground preparation was not possible. The ground was ripped and sprayed with paraquat (Parable @ 4l/ ha) and the first stage of planting took place in April 1989. A high rabbit population in the local area necessitated a standard rabbit fence to be erected.
Phase I
A combination of incomplete site preparation and low rainfall following planting, allowed weeds to germinate freely across the site. Remedial control, using fluazifop-p-butyl (Fusilade 5) and a labour intensive mechanical programme, had limited success in summer 1989. Following cut-back in March 1990 the site was beaten-up and amitrole (Weedazol- TL at 20l/ha) was applied over the cut stools. The residual herbicide napropamide (Devrinol) was applied in mid-April but sufficient weeds had developed to necessitate an application of clopyralid (Dow Shield at 0.5l/ha) on two occasions (2 weeks apart) later in the season.
Phase II The second stage of planting was planned for spring 1990 but poor quality cuttings, caused by transport delays, resulted in the failure of the planting and the establishment was postponed. Plant material sourced in the UK was hand planted at a 2 x 2m spacing in January 1991, and the site was sprayed with an amitrole/ simazine mix (Primatol SE 500L at 6l/ ha) in March. The stools were cut-back in spring 1992 and the few grass weeds present sprayed off with amitrole (W eedazol TL).
MANAGEM ENT
Weed Control
Following the intensive weed control required during establishment, the plots in phase I required no further attention until their first harvest in December 1993. A single post harvest application of amitrole (Weedazol TL) simazine mix was successful in controlling most weeds, facilitating natural suppression until the plots’ second harvest in February 1997.
Phase II was treated with a post cut-back application of amitrole (W eedazol TL) and a follow up spot treatment of Kerb in spring 1994. These two applications successfully controlled weed growth until the first harvest in February 1997.
Pests and Diseases
Although there have never been any serious pest or pathogen problems at the site, there has been a noted increase in the level of Melampsora spp. infection on the two clones Beaupre and Boelare. First noted in summer 1994, the rust infection has been recorded as starting progressively earlier and becoming more severely in summers 1996 and 1997. Brassy willow beetles (Phyllodectaspp.) have been present throughout the trial but causing only minor leaf damage, and are not thought to have affected crop growth or yield.
HARVESTING
Phase I The first harvest of phase I took place in December 1993 using motor manual methods. The cut shoots were chipped and used in a local domestic heating unit.
The second harvest of this section of the trial was undertaken using the Salix Maskiner Bender 3 in February 1997. The purpose built cut and chip harvester successfully harvested the 0.8 hectare of 3 year old shoot growth in approximately 8 hours; a full report of the operation is given in Mitchell et al, 1997
Phase II At the end of the first 5 year growth cycle of phase 2, the majority of the stools were single stem with diameters at cut height of up to 180mm. Manual felling with chainsaws was therefore the only harvesting option available; the plots were felled for firewood in March 1997. clone productivity
Prior to their harvest, the plots in phases I and II were destructively sampled to assess yield. Each replicate plot was sampled and the mean figures given in Table _seq t wep1yield_16_ are based on actual stool survival rates.
Table16. Productivity of Populus clones (odt/ha/yr) at Water Eaton. _Phase 1_Phase 2___ Harvest 1_Harvest 2_Harvest 1__ P. trichocarpa x deltoides "Beaupre"_3.5_6.8_8. 1__ P. trichocarpa x deltoides "Boelare"_4.8_6.6_7.6 __ P. deltoides x nigra "Dorskamp"_4.7_4.8_4.2__ P. trichocarpa trichocarpa "Trichobel"_7.7_7.0_5.6 __ P. trichocarpa “Fritzi Pauley”_-_-_4.0 __ P. trichocarpa x deltoides "Donk"_9.8_6.2_- __ MEAN_6.1_6.3_5.9_
The low yield of the plots at the first harvest of phase I can be attributed, in part, to initial establishment problems and subsequent poor weed control. It was anticipated that despite relatively poor plant survival rates (average for all plots of 58%) that with good second rotation weed control, the stools would be able to take advantage of the space available and yields at the second harvest would be significantly higher. This was not however the case, with only a marginal increase in the average yield from 6.1 to 6.3 odt/ ha/ yrrecorded. It is possible that the harvest of the shoots at age 3 in the second rotation, given the effective plant densityof approximately 4000/ ha, may have been premature. U nfortunately a change in farm ownership meant that the trial had to be removed by the end of 1997 and a longer rotation period was therefore not possible.
The average yield of the plots in phase II was not significantly different from that recorded in phase I. There was however, a significant difference in the ranking of the clones with Beaupre and Boelare by far the highest yielding clones in phase II. Two possible reasons for these differences are that Beaupre and Boelare may respond well to the increased space available at the wider spacing in phase II or that the two clones have a low ability to compete with weed growth during the establishment, which set back their growth in phase I. Either explanation equally applies to the increase in yield of the two clones between the first and second rotation of phase I.
Crop removal and site restoration
The farmer was committed to returning the land to arable cropping in the shortest possible time following harvest in February 1997, and it was considered that the large poplar stumps would not breakdown sufficiently over one season to allow soil cultivation. It was therefore decided that the stools would be dug out using a excavator based, JCB fitted with a narrow bucket. Operation
Work began in late March 1997, and was carried out using farm labour, during ‘slack time’ over a period of six weeks. Excavation of the stools took a total of 46 hours and a further 10 hours were required to pile and burn the stumps. Few problems were encountered with excavating the stumps but burning the material proved difficult, mainly due to soil being attached to the roots. The root piles were left to dry and successfully burnt in June. The site was cultivated in late spring and treated with an overall application of glyphosate (6l/ ha) to suppress weed growth. It was subsequently drilled with a fodder kale crop which grew well and by mid September had reached 1m in height. It was however noted that some poplar shoots were visible above the kale and close inspection revealed two sources of regrowth. The most vigorous was from stumps that had been missed during the excavation process but there was also a number of new stools established from severed and exposed root material.
The kale was harvested in late September cutting backthe poplar shoots in the process. The farmer re-cultivated the field in late autumn and intends to sow a second fodder crop in spring 1998, which he anticipates will suppress the remaining poplar stools.
Results
Despite digging out the poplar stumps, it was not possible to plant an arable crop in either 1997 or spring 1998. Soil cultivation was possible in spring 1997 but was not of high quality with some large pieces of root material remaining in the soil and on the soil surface. Some stumps were left in the ground and despite a pre-planting application of herbicide these impacted on the quality of the subsequent fodder crop. It is anticipated that after planting further fodder crop, the land will be in a suitable condition to allow a cereal crop to be sown in autumn 1998. The complete restoration work will therefore have taken 20 months, during which time a limited income will have been generated by the planting of fodder crops.
BRAHAN
This site was chosen as being typical of the better agricultural land in this part of Scotland. The soil is fertile and well drained, although one part of the field has a considerable slope. Five clones were selected for a production trial, based on the results of the trials at Kincardine and Guisachan, and a further 6 clones were included in a screening trial on the steeper bank.
The layout is illustrated in Figure _seq f brahlay_11_. SITE CHARACTERISTICS
Location Brahan Farms by Dingwall Ross & Cromarty Long. & Lat. 4O29W 57O33'N OS National Grid Ref. NH 516 565 Altitude 107m
Climate Average of data from 1989 to 1997 Average annual rainfall (mm) 821.5 Mean max. daily temperature 123 OC Mean min. daily temperature 4.1 OC For more details see Appendix _ seq a climate _3_.
Soils Soil type Mineral Solid Geology SedimentaryOld Red Sandstone Drift Geology Boulder Clay Conglomerate Previous Land Use Arable
Figure 11. Layout of Brahan Salix Trial (not available electronically)
Screening trial Production trial 1 = S. viminalis Campbell a = S. candida 2 = S spaethii b = S. viminalis Bowles Hybrid 3 = S. viminalis Gigantea c = S. caprea x (aurita x viminalis) 4 = S. burjatica Germany = x stipularis 5 = S. viminalis x caprea x aurita R eifenweide d = S. viminalis Mullatin 6 = S. viminalis 683 e = S. viminalis x caprea x cinerea 7 = S. viminalis Mullatin = x dasyclados
ESTABLISHMENT
The site was ploughed in autumn 1988, and a deer fence erected. After a delay due to snow, the site was planted in early April 1989. Planting was followed by a knapsack application of amitrole and simazine (Primatol SE 500L @ 18l/ha), which kept weeds to a minimum and allowed all the plots to establish strongly. The trial was cut-back in March 1990 and the plots were beaten-up using 300-400mm setts. W eeds were sprayed off with amitrole (W eedazol TL), and propyzamide (R apier) as a residual application. Cycloxidin (Laser) was also applied to control grasses.
MANAGEM ENT
Weed Control
Vigorous coppice growth and minimal pest or disease pressure has resulted in good natural suppression of weed growth and meant minimal chemical control has been required. Post harvest treatments of amitrole and simazine (W eedazol TL @ 20l/ ha & simazine @ 4l/ ha) were sufficient to allow good regrowth of the stools and prevent early competition from weed species. The open areas around the plots have been mown twice annually during summer to facilitate plot access and reduce the ingress of weeds to the plots. The increased severity of rust infection during the second rotation lead to the premature defoliation of S. x stipularis and S. x dasyclados, allowing light to penetrate the canopy of the crop and allowing weeds, particularly willow herb to germinate within the plots. The problem was not considered severe enough to warrant remedial action and the weeds will be addressed following the next scheduled harvest in winter 1998/ 99.
Nutrition
No mineral fertiliser was added to the site at Brahan, although it is thought that run-off from the coniferous plantation on the hill above the trial, has increased the fertility of the soil.
Pests and Diseases
The incidence of pest and disease at Brahan throughout the project has been minimal. Of the clones in the production trial only S. x stipularis and S. x dasyclados have shown any significant susceptibilityto Melampsora spp. leaf rust. During summers 1996 and 1997 both clones were severely infected, the infection causing up to 70% premature defoliation, reducing plant growth and allowing weeds to establish within the plots.
During phase 2 and 3 of the project, the trial provided data for the national disease survey: results and analysis are given in Royle et al (1992). No serious insect pests were noted during the project.
HARVESTING
The first harvest took place in February 1993 using an unmodified 2m wide reciprocating hedge cutter mounted on a Unimog. Lack of directional felling meant that the cut shoots had to be collected by hand, before they could be fed into a small tractor mounted chipper (30bhp double bladed TP). It was concluded that the system was slow and inefficient with little commercial value. A full report on the operations is given in Mitchell et al (1994). The second harvest of the crop took place in N ovember 1995 and was accomplished using the Salix Maskiner Bender II. The direct cut and chip machine operated successfully, coping well with all clones except S. candida whose basal form caused the chipper feed to repeatedly block. The site slope restricted operation to one-way working in some areas but in general the operation was efficient and problem free. A full report of the work is given Mitchell (1997).
Clone Productivity
Prior to both harvests at Brahan the screening and production plots were destructively sampled to assess yield. The figures given in Table _seq t braprod_17_ are based on actual stool survival.
Table 17 Productivity of Salix clones at Brahan. _Productivity (odt/ ha/ yr)__ H arvest 1_H arvest 2 Production plots______candida_4.9_3.7 __ viminalis "Bowles Hybrid”_7.6_9.2 __ x stipularis_3.5_2. 1__ viminalis "Mullatin"_5.0_4.4 __ x dasyclados_7.1_6.6 __MEAN_5.6_5.2_____ Screening plots______viminalis "C ampbell"_3.9_5 . 1__ spaethii_2.6_5.6 __ viminalis "Gigantea"_2.6_3.5 __ burjatica "Germany"_2.8_2.1__ viminalis x caprea x aurita "R eifenweide"_5.1_5.7 __ viminalis "683"_5.4_4. 1__ viminalis "Mullatin"_4.3_3.1__ Despite good weed control, and low incidence of pest and disease, the yields recorded at Brahan are not high. It was anticipated that second rotation yields would be significantly higher than those recorded at the first harvest, this was not however the case. With one exception, Bowles Hybrid, the productivity of the production trial clones was lower in the second rotation than the first, reflected in a drop in site mean from 5.6 to 5.2 odt/ ha/ yr. This maybe explained by a combination of increased disease pressure and physiological stress induced by the poor quality of the first harvest.
Current Status
The site has remained in good condition throughout the project and it is anticipated that the crop will remain in the ground past its third harvest in winter 1998/ 99, providing the potential for continued study.
MARKINGTON
This trial was established in 1991 as part of an extension to Phase 2 of the trials programme, aiming to find the potential for using poplar clones in more northerly latitudes. Using plant material from the production and screening plots at Swanbourne, ten clones were planted in pure blocks, and the more promising clones also included in mixed plots. The layout is illustrated in Figure _seq f marklay_12_.
SITE CHARACTERISTICS
Location Ingerthorpe Hall Farm Markington Harrogate North Yorks Long. & Lat. 1O35'W 54O 05'N O S National Grid R ef. SE 290 663 Altitude 107m
Climate Average of data from 1989 to 1997 Average annual rainfall (mm) 662.6 Mean max. daily temperature 13.2 OC Mean min. daily temperature 5.4 OC For more details see Appendix _ seq a climate _3_.
Soils Soil type Medium loams Solid Geology Permian-Lower Magnesian limestone Drift Geology Glacial Till Soil Association Salop & Wick Previous Land Use Arable
Figure12. Layout of Markington Populus Trial
ESTABLISHMENT
Time restrictions meant that site preparation did not commence until April 1992, followed immediately by planting. This rushed operation, combined with low quality cuttings resulted in very poor establishment with plant survival rates of between 20 and 60%. After planting the site was sprayed with a three-way herbicide mixture of simazine (Gesatop at 2.5l/ha), metazachlor (Butisan S at 3l/ha) and pendimethalin (Stomp 400SC at 5l/ha). This stopped the majority of weed species, but willow herb seemed to be resistant and had invaded most of the site by August, along with patches of thistles and grasses. The site was cut back in February 1992, sprayed with amitrole (W eedazol TL at 10l/ ha), before being beaten up in April with setts from Swanbourne. The site was then sprayed with a mixture of metazachlor (Butisan S at 2.5l/ha) and isoxaben (Flexidor at 0.3l/ha) to protect against new flushes of weeds.
MANAGEM ENT
Weed control
Poor initial site preparation created a perpetual weed problem in the three years following establishment. Thistles and willow built up both within the plots and in the alleys and rides, which were controlled in June 1993 with an treatment of glyphosate (Roundup at 3.5l/ha) applied using a knapsack sprayer fitted with a tree guard. Kerb was applied in January 1994 and combined with mechanical weed control this finally allowed the crop to establish a good canopy cover in spring 1994 and facilitated natural weed suppression. No further weed control was required until the first harvest in February 1997.
Nutrition
No fertiliser has been applied to the plots.
Pests and Diseases
No pest or disease problems were noted during the first 5 years of the trial but in September 1996 two clones, Beaupre and Boelare, became infected with Melampsora spp. leaf rust. Although infection was only light and no defoliation resulted, the increased susceptibility of two of the most widely used poplar clones in the UK at this northerly latitude, is of concern.
Harvesting
The first harvest of the plots was carried out in February 1997 using motor manual methods. The single stem poplars were felled using chainsaws and the stems were extracted using a small articulated forwarder. The cut material was then transported using a conventional timber truck to a location near Penrith where it was baled using a Swedish designed (Bala Press A.G.) baling machine. The material baled well, forming bales of approximately 480kg, which are thought to offer potential storage, handling and transport advantages over chips or whole shoots. A full report is given in Hudson, 1997.
Clone Productivity
Prior to harvest the plots were destructively sampled to assess yield. The figures given in table 18_ are based on actual plant survival rates. Table18. Productivity of Populus clones at Markington. Clone No._Clone_Survival rate (%)_Productivity (odt/ ha/ yr)__ 2_T richobell_8 9_6 .9__ 3_76.028/ 5_79_4.7__4_75.028/ 3_75_4.9__5_69.03 9/ 4_90_6. 1__ 6_71.009/ 1_92_4.5__7_71.015/ 1_89_7.5__8_Dorskamp_88_6.6__9_Fritzi Pauley_85_8.2 __ 10_Beaupre_88_6.4 __ 11_Boelare_85_6.6 ___ Mixed plot of 8,9,10,11_68_3. 1___ Site Mean_84_5.9__
Despite the initial establishment problems, the yield and plant survival figures from the plots are comparable with those achieved at Swanbourne in the first rotation. Although there are no particularly outstanding clones, all plots achieved a moderate yield and with a mean plant survival rate of 84% it was anticipated that the crop would have achieved a significantly higher productivity rate during the second rotation.
Crop removal and site restoration
Unfortunately due to a demand for land, it was necessary to remove the trial following its first harvest in winter 1996/ 97.
Operation
A small area (0.2ha) was required for immediate planting in spring 1997 and the stumps were removed from this area in February 1997 using a JCB. The area was then ploughed, disked and planted in April. The growth of the newly planted coppice was weak with high stool mortality. This can be attributed, at least in part, to late and inadequate ground preparation prior to planting.
The proposed work plan was to allow the remainder of the crop to regrow and to spray off the new growth with glyphosate when it reached 150 - 200mm in height. The ground was to be left throughout summer 1997 without further treatment and ploughed if possible in autumn 1997 or spring 1998.
Unfortunately, uneven regrowth meant that whilst some clones reached 200mm by April 1997 others had not yet put on sufficient leaf area to allow an effective application of the contact herbicide, glyphosate. The farmer took the decision to delay the application, preferring to wait until all clones had sufficient leaf area to ensure an effective overall kill. However, by the time that all the plots had achieved sufficient growth, the adjacent, newly planted willow crop was considered to be vulnerable to spray drift and the work was unable to proceed. Consequently, by late September, the majority of the remaining poplar plots had reached 2-3 m in height.
The project time scale did not afford a second opportunity to cut the stools, spray off the stumps and plough out the crop. The remainder of area (0.7ha) was therefore cleared of stumps using a JCB during winter 1997/ 8.
Results The JCB had little trouble in removing the large poplar stumps from the site. The stumps were piled and burnt in summer having first been allowed to air dry. Ideally ground preparation prior to the planting of SRC should commence with ploughing in autumn the year before planting takes place. The removal of the stumps in spring did not facilitate any site preparation until two weeks before planting resulting in incomplete ground preparation and the subsequent poor establishment of the willow crop.
PARBOLD
This site is twinned with the Buckfast site (Section 1.11), both planted within ten days, using the same clones from the same cutting source, and the same plantation design. The aim of these two trials was to enablethe effects of different climate, soils and latitudes on the production of willow clones to be assessed. Five clones are used in the production plots and an additional 5 willow and 4 poplar clones were planted in a smaller screening trial.
The layout is illustrated in Figure 13.
SITE CHARACTERISTICS
Location Fairhurst Farm Parbold Nr Wigan Lancs Long. & Lat. 3056'W 54O37'N O S National Grid Ref. SD 485 125 Altitude 10m
Climate Average of data from 1979 to 1997: Average annual rainfall (mm) 832.6 Mean max. daily temperature 12.6 OC Mean min. daily temperature 6.6 OC For more details see Appendix _ seq a climate _3_.
Soils Soil type Sandy gley Solid Geology Carboniferous Millstone Grit and Culm Measures Previous Land Use Arable
Figure13. Layout of Parbold Salix Trial (not available electronically)
Salix production plots A = S. viminalis Mullatin B = Mixed plot (all 5 clones) C = S. burjatica Germany D = S. viminalis x caprea x cinerea = x Dasyclados E = S. viminalis Bowles Hybrid F = S. caprea x (aurita x viminalis) = x stipularis
Salix screening plots S. x sericans Niginians Pruinifolia (1) S. viminalis Gigantea (2) S. viminalis Campbell (3) S.candida (4) S. viminalis x triandra SQ 83 (7) Mixed Salix plot (5 prod. clones) (8)
Populus screening plots P. trichocarpa x deltoides Beaupre (5) P. trichocarpa x deltoides Boelare (6) P. deltoides x nigra Dorskamp (9) P. trichocarpa Fritzi Pauley (10) Mixed Populus plot (all 4 clones) (11 ESTABLISHMENT
Site preparation began in autumn 1990 when the ground was ploughed and harrowed. Following planting in April 1991, the site was capped with a three-way herbicide mixture of simazine (Gesatop 500L at 2.5l/ha), metazachlor (Butisan S at 3l/ha) and pendimethalin (Stomp at 5l/ha).
A dry summer caused soil cracking and despite the residual herbicide, weeds became a problem necessitating manual control in year 1. At cut back in January 1992, mean plant survival rate was 85%. The plots were beaten up and amitrole (W eedazol TL at 10l/ha) was applied to the whole site in May to prevent further weed growth. MANAGEM ENT
Throughout the project the health of the crop at Parbold has been poor. Dry summers and prolonged waterlogging in winter and spring have made effective weed control extremely difficult. This, combined with intense disease and pest pressure, has resulted in low crop yield and plant survival rates.
In spring 1995, fields adjacent to the willow trial became severely flooded, resulting in the loss of 2 hectares of newly planted barley. After investigation, is was discovered that a transitional drain running beneath the trial had become blocked by the root system of the crop. The unsealed, ceramic pipe set at a depth of 1m, had been penetrated by the fine root system creating a 100mm root mat in the base of each pipe section, trapping silt in the pipe and eventually preventing the flow of water completely. It was decided that the only solution was excavate the blocked section of pipe and replace it with a double skinned, sealed plastic pipe. The work meant the loss of a small section of the production trial and three of the screening plots.
Weed Control
The site and climate conditions resulted in a serious weed problems, necessitating an intensive regime of chemical and manual control throughout the first rotation of the crop. A second post cut back application of amitrole (Lazer @ 2.5l/ha) in August 1992, two applications of Kerb in February 1993 and 1994, and a further application of amitrole (Weedazol TL @ 20l/ha) in May 1993 were required to keep weed growth in check. Following the first harvest of the plots in December 1994 an application of amitrole and simazine (20l/ ha & 4l/ ha respectively) was sufficient to allow a healthy regrowth of the stools and facilitate natural weed suppression. With the exception of a few small patches of thistles, the plots remained weed free throughout the second rotation.
Pests and Diseases
Infection by Melampsora spp. leaf rust was a serious problem throughout the project. The most seriously infected clones were x stipularis, Mullatin and Bowles Hybrid all of which suffered moderate levels of premature defoliation, exacerbating the weed problems by allowing light to penetrate the crop canopy. The remaining two clones, x dasyclados and Germany, although infected, did not defoliation as a result of the rust. In September 1997, three of the four poplar clones in the screening trial (Beaupre, Boelare and Fritzi Pauley) suffered a light infection of Melampsora spp. rust. Although there was no associated premature defoliation, the increased susceptibility of ‘disease resistant’ poplars to the leaf rust represents a worrying trend.
In summers 1994 to 1997, the crop was infested with high numbers of brassy beetles (Phyllodecta spp.). Both the larvae and adult beetlescaused a substantial degree of leaf damage and were considered to pose a serious additional threat to crop health. Harvesting
The production plots at Parbold were harvested for the first time in December 1994 by the FA/TDB using 3 different cut and chip machines: John Deere with an unmodified Kemper header, Class Jaguar and the Salix Maskiner Bender I. The work is reported fully in Deboys 1996.
The second harvest of the plots was carried out motor-manually using chainsaws in February 1998. The cut shoots were gathered byhand and chipped using a small tractor mounted unit.
Clone Productivity
Prior to both harvests the production and screening plots were destructively sampled to assess yield. The figures given in Table _seq t pbscreen_19_ are based on actual stool survival.
In addition to the pre-harvest assessments, four of the clones in the production plots (Mullatin, Bowles Hybrid, Germany and x dasyclados) were assessed annually to chart the variation in crop growth throughout the 3 year cutting cycle. These annual growth patterns are discussed fully in Appendix _ seq a growthmod _2_.
The problems of weed control, disease and pest pressure experienced during the first rotation are reflected in the low yields achieved at the first harvest; site mean of 4.1odt/ ha/ yr. However, an average plant survival rate of approximately 80% and effective weed suppression during the early stage of the second rotation lead to a significant improvement in productivity. With the exception of two willow and one poplar clone, all the plots in both the production and screening trial gave higher yields at the second harvest; site average of 5.3 odt/ ha/ yr. Comparing the mean of the pure production plots with the mixed planting, the figures at both harvests would suggest that mixed planting of the 5 clones did not offer a yield benefit, any reduction in the severity of leaf rust being over shadowed by inter-clonal competition.
Table19. Productivity of Salix and Populus clones at Parbold. _Productivity (odt/ ha/ yr)___ Harvest 1_Harvest 2__ Screening Salix____ x sericans ”N iginians Pruinifolia"_1.0_0.0 __ viminalis "Gigantea"_3.4_4.2 __ viminalis "Campbell_4.9_7.3__ candida_6.7_5.8 __ viminalis x triandra "SQ83"_6.9_7.9 __ Mixed plot (5 production clones)_3.0_n.a. ______Screening Populus____trichocarpa x deltoides "Beaupre"_2.9_9.9 __ trichocarpa x deltoides "Boelare"_9.4_5.6 __ deltoides x nigra "Dorskamp"_3.1_8.0 __ trichocarpa "Fritzi Pauley"_2.5_n.a. __ Mixed plot (4 screening clones)_5.8_n.a. ______Production Salix____ S. viminalis "Mullatin"_3.2_3.9 __ S. burjatica "Germany"_6.2_8.6 __ S. x dasyclado s_4.4_5 .7__ S. viminalis "Bowles Hybrid"_4.6_5.9 __ S. x stipularis_2.0_2.7 __ MEAN_4.1_5.3 __ Mixed (5 production clones)_3.6_4.8 __ n.a. not available due to crop damage during drainage repairs
Current Status
Due to the low yield of the crop and the continued problems of weed control and disease, the site is was not thought to have sufficient research or commercial value to warrant retention. The preferred choice of crop removal was to spray off the regrowth with glyphosate, leave the land fallow during summer 1998 and plough out the dead stools in autumn 1998. The farm is however being entered into an organic farming programme in March 1998, precluding the use of herbicide. Therefore, following the harvest in February 1998, the crop was grubbed out using a tracked excavator.
BUCKFAST
This site is twinned with the Parbold site (Section 1.10), both planted within ten days, using the same clones from the same cutting source, and the same plantation design. The aim of these two trials was to enablethe effects of different climate, soils and latitudes on the production of willow clones to be assessed. Five clones are used in the production plots and an additional 5 willow and 4 poplar clones were planted in a smaller screening trial. The layout is illustrated in Figure 14
SITE CHARACTERISTICS
Location Buckfast Abbey Buckfastleigh Devon Long. & Lat. 3O55W 50O25'N O S National Grid R ef SX 747 683 Altitude 50m
Climate Average of data from 1989 to 1997: Average annual rainfall (mm) 1301.7 Mean max. daily temperature 14.0 OC Mean min. daily temperature 6.6 OC For more details see Appendix _ seq a climate _3_.
Soils Soil type Silty clay Solid Geology Upper Old Red Sandstone Previous Land Use Arable Figure14. Layout of Buckfast Salix Trial (not available electronically)
Salix production plots A = S. viminalis Mullatin B = Mixed plot (all 5 clones) C = S. burjatica Germany D = S. viminalis x caprea x cinerea = x Dasyclados E = S. viminalis Bowles Hybrid F = S. caprea x (aurita x viminalis) = x stipularis
Salix screening plots S. x sericans Niginians Pruinifolia (1) S. viminalis Gigantea (2) S. viminalis Campbell (3) S. candida (4) S. viminalis x triandra SQ 83 (7) Mixed Salix plot (5 prod. clones) (8)
Populus screening plots P. trichocarpa x deltoides Beaupre (5) P. trichocarpa x deltoides Boelare (6) P. deltoides x nigra Dorskamp (9) P. trichocarpa Fritzi Pauley (10) Mixed Populus plot (all 4 clones) (11) establishment
Time constraints meant that ploughing was the only ground preparation carried out prior to planting in April 1991. Heavy and persistent rain in spring 1991 meant that a delayed application of simazine (Gesatop @ 5l/ha) and fluazifop-p-butyl (Fusilade 5 @ 31/ ha) was ineffective, and by mid summer a subsatntial amount of mayweed (Matricaria recutita), grasses and thistles (Cirsium spp.) had developed necessitating an expensive mechanical weeding operation. The site was cut back and beaten up in January 1992. managem ent
It was the intention to manage the Buckfast and Parbold trials under an identical regime in order to minimise management variables and allowing comparison of data from the two trials. However, during the first rotation circumstances dictated a number of changes to be made to the work plan, mainly remedial weed control measures. Following the first harvest in winter 1994/ 95, weeds became far less of a problem at both sites and it was possible to run very similar management programme for each trial.
Weed Control
Following cut back, an extremely wet spring and a further ineffective application of herbicide (simazine and devrinol), created intense weed competition which again required a mechanical, remedial treatment in summer 1992. A further application of amitrole (Weedazol TL @ 20l/ha) to the whole site was sufficient to allow canopy closure and the natural suppression of weeds across the majority of the site during the 1993 growth season. A spot application of amitrole and simazine (@ 10l/ ha & 4l/ ha respectively) in April 1994 was used to treat persistent patches of weed growth. Following the first harvest in winter 1994/ 95, an overall application amitrole and simazine (@ 10l/ha & 4l/ha respectively) was used to prevent weed growth and allow the crop to successfully establish good canopy cover by early summer 1995. No further weed control was required until the second harvest in February 1998.
Pests and Diseases
Throughout the project the leaf rust Melampsora spp. has been the most serious pathogen noted at Buckfast. The severity of infection has varied annually but the general trend has been for an earlier initial occurrence resulting in a more severe level of infection and heavier defoliation. As at Parbold, the worst affected clones were x stipularis, Mullatin and Bowles Hybrid with levels of defoliation up to 70%. Germany and x dasyclados, although infected, retained full canopy cover until natural senescence occurred in autumn. Previously resistant, all four poplar clones in the screening trial became infected with Melampsora spp. during summer 1997. Infection was light on Beaupre, Fritzi Pauley and Dorskamp but Boelare suffered severe infection causing leaf necrosis and approximately 10% premature defoliation by early September. The levels of infection on the poplars were higher than those recorded at Parbold where no adverse effects were noted.
Although no significant insect pest damage were reported throughout the project, large numbers of black stem aphids (Melanoxantherium salicis L.) were regularly noted within the willow crop, particularly on the S. viminalis clones Mullatin and Bowles Hybrid. It is not currently thought that these aphids pose any serious threat to the health or growth of the crop. Low numbers of Brassy beetles (Phyllodecta spp) were noted each year in the willow plots but did not cause the levels of damage recorded at Parbold and are not thought to have impacted significantly on crop growth or health. harvesting
The production plots at Buckfast were harvested for the first time in December 1994 by the FA/TDB using 3 different simultaneous cut and chip machines: John Deere with an unmodif ied Kemper header, Claas Jaguar and the Salix Maskiner Bender I. The work is reported fully in Deboys, 1996.
The second harvest was carried out motor-manually in February 1998 and the cut material fed by hand through a small horticultural tractor mounted chipper. The chips will be used as horticultural mulch by the land owner. clone productivity
Prior to both harvests the production and screening plots were sampled to assess yield. The figures given in Table _seq t bfscreen_20_ are based on actual stool survival.
In addition to the pre-harvest assessments, four of the clones in the production plots (Mullatin, Bowles Hybrid, Germany and x dasyclados) were assessed annually to chart the variation in crop growth throughout the 3 year cutting cycle. These annual growth patterns are discussed fully in Appendix _ seq a growthmod _2_.
The weed problems experienced during the establishment phase are reflected in the low yields achieved in the first rotation at Buckfast; site average of 3.7 odt/ ha/ yr. The average plant survival rate following the first harvest was approximately 80% and combined with effective natural weed suppression during the second rotation, there was a significant improvement in crop productivity; site average of 8.5%. The mixed planting of the 5 willow production clones offered no benefit in terms of yield, the figure of 7.9 odt/ ha/ yr falling below the mean of the pure plantings of the 5 clones. Table 20. Productivity of Salix and Populus clones at Buckfast. _Productivity (odt/ ha/ yr) ___ Harvest 1_Harvest 2 __ Screening Salix ____ x sericans "N iginians Pruinifolia"_ 1.9_n . a. __ viminalis "Gigantea"_7.3_12.5 __ viminalis "Campbell_5.5_n.a. __ candida_8.6_10.2 __ viminalis x triandra "SQ83"_4.2_12.4 __ Mixed plot (5 production clones)_5.6_n.a ______Screening Populus ____trichocarpa x deltoides "Beaupre"_10.4_12.0 __ trichocarpa x deltoides "Boelare"_11.5_10.5 __ deltoides x nigra "Dorskamp"_8.0_14.3 __ trichocarpa "Fritzi Pauley"_8.4_20.3 __Mixed plot (4 screening clones)_5.7_12.1 ______Production Salix ____ S. viminalis "Mullatin"_3.6_10.3 __ S. burjatica "Germany"_4.0_9.4__ S. x dasyclado s_5.4_10.6 __ S. viminalis "Bowles Hybrid"_4.3_9.0 __ S. x stipularis_1.4_4.0 __MEAN_3.7_8.5 __ Mixed (5 production clones)_2.9_7.9 __ n.a. plant survival in plots was too low to allow accurate interpretation of data
Productivity in the poplar screening plots was high, with all but one clone showing an increase from the first to second rotation. The reason for the slight fall in the yield of Boelare is likely to be its infection by Melampsora spp. and resultant premature defoliation. Despite comparable levels of disease infection at Parbold and Buckfast, the yields recorded for the second harvest of the production plots at Buckfast are, on average, approximately 60% higher than at Parbold. Both sites having followed identical management regimes during the second cycle, the differences in yield can be attributed to variation in soil and climatic conditions.
Current status
The high yields and plant survival rates achieved at Buckfast are encouraging and it therefore anticipated that this site will remain in the ground past the conclusion of this project, providing the potential for continued study. Section two: exploitation of results
Initiated in 1986, this project established the first series of field scale trials of SRC for energy in the UK. In total 12 trials were established during phases 1 and 2 of the project covering a wide geographic spread from Inverness-shire, Scotland to Devon, England and Co. Fermanagh, N. Ireland. The sites represented a range of climate and soil types thought to be typical of the land that might be available for future planting of SRC in the UK.
During the 12 year programme, the sites were carefully monitored to gather as much technical and economic data on the growth, development and management of commercial SRC crops as possible. In addition to this routine monitoring, the trials provided the platform for a number of additional studies including: mechanised harvesting techniques (FA/TDB, EU FAIR, WSRG), plantation hydrology (IOH), foliar nutrient analysis (WSRG), weed control strategies (Clay and Dixon), pest control strategies (University of Belfast, LARS), potential damage to drainage systems (W SR G), wildlife and game potential (Game Conservancy Trust) crop removal techniques (WSRG).
These studies are detailed in this, or the proceeding three end of phase reports, or separately by ETSU for the DTI.
The wealth of data recorded throughout this project, has been collated and is presented in this final project report. This section of the report summarises the main findings of the project, highlighting some of the potential problems and suggesting solutions for the successful management of commercial SRC crops for energy. ESTABLISHMENT AND INITIAL WEED CONTROL
The most common cause of low productivity in the early years of plantation development is poor weed control as a result of bad establishment technique. The first sites to be planted, Long Ashton and Swanbourne, used conventional forestry principles modified by results of early Swedish trials, to establish the crops. Building on the successes and failures of these early plantings, improved techniques of site preparation and weed control were developed and applied to the establishment of the remaining 10 trials.
An good example of the problems caused by poor establishment technique can be seen by analysing the Buckfast site history. Time constraints meant that ploughing was the only site preparation carried out prior to planting, and combined with heavy rainfall in spring and delayed herbicide application, this limited site preparation resulted in a variety of aggressive weed species becoming established. Between planting and the first harvest several remedial control treatments were required including: two further overall applications of herbicide, two mechanical weeding operations and a spot application of herbicide. Although eventually successful in controlling weed growth, these intensive operations were costly and considered to be environmentally unfriendly. The plant mortality rate at the first harvest was approximately 20% which can almost entirely be attributed to weed competition, as can the low crop productivity of 3.7 odt/ha/yr.
The mistakes made in the establishment of the first trials highlighted the need for complete ground preparation and effective pre and post-planting weed control, using techniques more akin to agriculture to ensure successful establishment.
Thorough site preparation is therefore recommended and should begin in the autumn prior to planting with an overall application of contact herbicide and deep ploughing. The ground should be left over winter allowing frost action to break up the soil, and then disked and power harrowed in spring to create a fine planting tilth to ensure good soil:root contact. Planting should take place in early spring after the risk of heavy ground frost has passed and should be followed by an overall application of residual herbicide to prevent weed growth. This should be sufficient to allow the cuttings to develop a full crop canopy, facilitating natural weed suppression. However, any emergent weeds should be dealt with by either a spot application of contact herbicide or mechanical control, depending on the nature of the weed problem.
The most effective herbicides will depend on the quantity and species of the weeds present. Clay (1996) recommends a range of chemicals and application techniques suited for use in SRC, based on studies at Swanbourne, Buckfast and other trial sites in the UK. crop managem ent
Continued weed control
Although the most critical period of weed control is during establishment, it is essential to maintain a weed free site throughout a plantation’s lifecycle. Harvesting of SRC crops breaks the canopy cover allowing light to reach the soil, and facilitating the development of weeds. During this project it has been found that a single, post harvest application of a contact residual mixture is effective in killing/ suppressing weed growth sufficiently to allow the cut stools to re-establish a full canopy and naturally suppress competitive weeds. The rate of application and chemicals used will depend on the nature of the weed population at the site. Clay (1996) recommends a variety of chemicals and application methods suited to SRC, based on work at Swanbourne, Buckfast, Parbold and other trial sites in the UK.
The loss of full canopy cover through pest and disease damage in mid-rotation has been a common problem with many of the trials in this project. Expensive remedial control techniques have been used to prevent the development of weed populations within these crops but in general the treatments have met with only limited success. Crops that suffer perpetual defoliation by disease or pests are generally low yielding and it is concluded that these crops do not justify the costs of remedial weed control and should be removed and replaced. site nutrition
Regular removal of large quantities of woody biomass, without the addition of fertiliser, will eventually result in a decline in available soil nutrition. The major growth limiting nutrient of SRC is nitrogen, a reduced availability of this element induces a shif t in the root:shoot ratio as the plant attempts to exploit a larger soil volume (Ericsson et al., 1992) and increases inter-plant competition resulting in a reduction in above ground biomass production and an increase in stool mortality.
Two fertiliser trials were carried out during the project, at Long Ashton and Swanbourne. Both trials were established on arable farmland and pre-planting soil analysis indicated no deficiencies in the macro nutrients nitrogen, phosphorous and potassium (N,P,K) at either site. The trials were divided into two sections, a fertilised and a control, and a standard application of NPK applied following harvest. After three rotations at each site, the data indicated no yield benefit from the fertilised treatment, suggesting that soil nutrient status had not yet become a limiting factor in determining crop growth.
Foliar analysis during phase 3 of the project indicated that the levels of N,P & K in the willow clone S. viminalis Bowles Hybrid and the poplar clone P. trichocarpa x deltoides Beaupre taken from all the trial sites, were well above the critical level and in most cases close to the optimal level for growth (Mitchell et al 1995). The foliar analysis and fertiliser trials indicate that the addition of fertiliser on most site types will not be necessary until a number of harvests have been completed. The eventual timing and demand for fertiliser will depend on soil type, climate and crop growth rate, but of the sites included in this project, no nutrient deficiencies were detected after 10 years or three full rotations.
Site hygiene
The importance of good site hygiene is hard to assess but there is some evidence to suggest that poor site hygiene is a possible contributory factor to increased pest and disease pressure. It is thought that the infestation of S. viminalis Bowles Hybrid with Brassy beetles (Phyllodecta spp.) at Long Ashton, which lead to eventual death and removal of the crop, was in part due to poor site hygiene. It is thought that the large stacks of cut shoots, piled adjacent to the crop, allowed unusually high numbers of adult beetles to successfully overwinter, re-entering the crop in spring. This might suggest that on site storage of cut material would not be advisable in terms of minimising the risk of pest and disease incidence.
The design and management of the open areas around plantations is important to improve site access, increase the habitat diversity and value of a site, and prevent the ingress of weeds to the main crop.
A variety of techniques were used to manage the rides and open space around the trials in this project. Where trials were established on grassland sites (e.g., Swanbourne, Castle Archdale) weeds were generally non-aggressive perennials, providing good wildlife habitat and were easily managed by regular mowing. Trials established on ex-arableland (Markington, Water Eaton, Parbold, Buckfast, Brahan) tended to have more annual weed species and aggressive perennials (creeping thistle and willow herb) which required more intensive management, including chemical control.
It is therefore recommended that where plantations are established on arable farm land, the open spaces are planted with a non-aggressive grass mix to increase the wildlife habitat value of the site and to reduce the management requirement. Sage et al, 1994 suggest a comprehensive set of best practice guidelines for open space planning and management, based on detailed flora and fauna surveys made on the SRC trials in the UK.
QUALITY OF CLONAL MATERIAL
Much of the plant material used in early SRC trials is now considered to be the ‘old clones’. Improvement has been made not only in the productivity of plant stock but in the disease and pest tolerance of the material used. However, although high productivity in breeding trials is a good indication of initial plant vigour, it is not a guarantee of maintained vigour or yield throughout the lifecycle of a plantation.
Disease
Melampsora spp. rust infection is probablythe most serious disease threat to both willow and poplar SRC crops. Many of the willow clones used in early SRC trials were initially disease resistant but have subsequently become susceptible to new pathotypes of the rapidly mutating species M. epitea. Melampsora spp. infection can lead to chlorosis, necrosis, premature defoliation and, in severe cases, the death of the infected plant. The impact on yield is difficult to quantify but dryweight losses of 25-30% are thought to be common in infected plantations (Royle et al 1992). Willow breeding programmes are producing new willow clones that are currently rust resistant. It is hoped that these clones, when planted in intimate mixtures, will provide an effective rust control strategy that can be maintained throughout the life of the plantation.
Until recently, all the poplar clones used in this trial series showed good Melampsora spp. rust resistance. In summer 1994 the first signs of rust infection were seen on the clones Fritzi Pauley and Trichobel at Swanbourne. In 1995, Beaupre and Boelare also developed a slight infection, occurring late in the summer and having no apparent impact on crop health. In summer 1997, several further clones became infected including the remaining three clones in the Swanbourne production trial (75028/3, Rap and Dorskamp) and the Canadian clones at Long Ashton. Infection of Beaupre, Rap and Boelare was classified as being severe causing significant necrosis and defoliation. The reason for this increase in susceptibility is attributed to the constant mutation of the rust, new pathotypes being formed constantly which are capable of infecting previously resistant clones.
As with the willow breeding programme, new clonal releases are being selected to have multi-gene resistance to Melampsora spp. infection. The approval and use of poplar clones in the UK is currently governed by the Forestry Commission under the Forest Reproductive Material Regulations (1977) (Tabbush & Parfitt, 1996). The recent and severe infection of Beaupre and Boelare throughout Europe may lead to their approval for planting in the UK being withdrawn, as is already the case in France and Belgium. pests
Throughout the trial programme, only one insect pest has posed a serious threat to plant health; the brassy willow beetle, Phyllodecta spp. In the worst case, at Long Ashton, a population explosion in two consecutive summers, caused the total premature defoliation of 1.0 hectare of S. viminalis Bowles Hybrid, resulting in stool mortality rates of up to 80 %
Observation throughout the project, suggests that the beetles are always present in low numbers in both willow and poplar crops but generally cause only minimal damage. High levels of damage seem to occur only in crops that are already suffering physiological stress as a result of disease, weed competition or poor harvesting. Poor site hygiene has also been suggested as a contributory factor in beetle epidemics. It is thought that the storage of cut shoots alongside the growing crop may allow greater numbers of adult beetles to successfully overwinter by providing sheltered habitat.
Phyllodecta spp. have been shown to have a feeding preference for S. viminalis clones such as Bowles Hybrid and Mullatin (Liggit, 1994). It is hoped that this preferential feeding pattern can be used in clonal selection to help minimise the risks of crop damage; work is ongoing at Long Ashton Research Station and Belfast University.
Other pests that have been a significant concern during the project are rabbits, hares and deer. Damage is generally limited to the period of establishment when young stools are vulnerable to grazing. At several sites protective fencing had to be erected (Kincardine, Guisachan, Brahan, Water Eaton) prior to planting, which dramatically increased the cost of establishment.
Frost Tolerance
Climatic conditions play a key role in determining annual plant growth. Although a given site will show a steady mean over long periods, annual variation in radiation levels, precipitation and minimum temperatures experienced in a three year cycle can be great. Severe early autumn or late spring frosts can have serious knock-on effects throughout the entire year, dramatically reducing annual growth. Tolerance to frost is therefore a primary selection criterion for both willow and poplar breeding programmes.
In addition to breeding, it is important to carefully select the correct genus and species for the prevailing site conditions. This project has shown that poplar can be successfully used in more northerly latitudes than previously thought without frost damage. The trial at Markington produced an average first rotation yield of 5.9odt/ha/yr, comparable with more southerly trials at Swanbourne and Water Eaton. In addition, it is thought that the harsher winters experienced at Markington have helped reduce the intensity of Melampsora spp. infection, resulting in better overall crop health.
HARVESTING
The trials sites have been used to study the impact of a number of different harvesting technologies during the project. These studies are reported separately by ETSU (Mitchell et al, 1994, Mitchell et al, 1997), the EU (Mitchell, 1997) and FA/TDB (Deboys, 1996) and are referred to, where appropriate, in the site history of each trial in Section 1. Of more relevance to this report is the impact of harvesting on crop growth and site quality. The window of opportunity for harvesting SRC is limited to the winter months when the crop is dormant. This fact, combined with restricted availability of machinery, resulted in many of the trials being mechanically harvested when ground conditions were extremely soft. Consequently harvesters and support machinery caused severe rutting during many of the operations. This damage had a number of serious implications for the future development of the plantations.
One concern is soil compaction which mayresult in reduced soil aeration and water carrying capacityinhibiting plant growth and leading to a decline in site productivity. It is hard to quantify the affect of compaction on crop growth, suff ice to say that it does not improve growth conditions and in combination with the physiological stress induced by cutting leads to a decline in plant vigour and health.
Deep rutting also causes root damage, crushing and exposing structural root systems and occasionally displacing entire stumps. Displaced stumps and suckers, that develop from exposed root sections between rows, cause difficulties for future harvesting operations. As well as displaced stools, rutting creates difficulties with any future mechanised operations. Rutting damage at Swanbourne caused during the February 1993 harvest, created problems at the two subsequent harvests predominatley with the adjustment of cut height. Ideally stools should be cut at 100mm or less above the ground but the uneven surface meant that heights of more than 250mm were set in order to avoid damage to the expensive cutting blades. Machines with automated cut height selection faired slightly better but in order to cope with the undulation, forward speed had to be reduced causing a drop in machine productivity and an increase in unit cost.
The quality of the cutting of the harvesting machines evaluated varied signif icantly. Early machines, using unmodif ied maize headers (e.g., Claas Jaguar with Kemper header at Long Ashton, December 1993) tended to cut high and leave the tops of the shoots shattered. Rough cut or shattered shoots are thought to be more susceptible to attack by pests and pathogens and consequential to suffer a decline in plant vigour. Later machines like the Salix Maskiner Bender III, Austoft and new version Claas with coppice header, were able to produce a much cleaner cut, causing significantly less damage to the stools.
To minimise the potential problems caused by winter harvesting, careful site selection, planning and management is required. Sites with heavy or peaty soils (e.g., Kincardine, Guisachan) or sites prone to winter waterlogging (Parbold, Castle Archdale) should not be used for SRC plantations. Harvesting equipment, including support units should be designed to have low ground pressure to minimise damage. Machine movements on the crop should be kept to a minimum, through careful site design and operational planning. The root structure of SRC has been shown to provide support for heavy machinery. Where sites are likely to have soft ground conditions during harvesting it maybe useful to extend the SRC planting to cover the headlands, and hence reduce the impact of high traffic levels in these areas. If planted, headlands should be established in rows perpendicular to the main crop area to facilitate efficient harvesting. Crop damage on planted headlands is likely to be high and a lower crop yield should be anticipated. PLANTATION PRODUCTIVITY
Yields achieved
Achieving and maintaining a high yield in coppice plantations is essential for the commercial adoption of SRC to energy systems. Tables _ seq t sumyld _21_ and _ seq t sumpopyld _22_ are a summary of the yields from the main production plots at each of the trial sites.
Table21. Summary of yields (odt/ha/yr) for Salix production trials.
Site_La_Ca_Gu_Br_Pb_Bf_mean*_ Clone______Bowles Hybrid_7.6_6.1_3.2_8.4_5.3_6.7_6.2__ x dasyclados__ 7.3_3.4_6.9_5.1_8.0_5.9 Gigantea __ 6.6 ____6. 6_ Reifenweide__4.5_ 1.8____ 1.8_ Campbell___ 5.0 ____ 5 .0_ _x stipularis __ 5.1 __ 2.8_2.4_2.7_2.6_ Mullatin __ 5 .9_2.9_4 .7_3 . 6_7.0_4 .6_ x calodendron__ 6.4 _____ - Germany__ 9.0___ 7.4_6.7_7.1_ Candida____ 4.3___ 4.3__ 683__6.7 _____ -__Q83__9.3 _____ MEAN______4.9__ * Ca figures are not included in the mean due to their assumption of full survival La - Long Ashton, Ca - Castle Archdale, Gu - Guisachan, Br - Brahan, Pb - Parbold, Bf - Buckfast.
Table 22. Summary of yields (odt/ha/yr) for Populus production trials. Site_Sw_We_Mk_mean_ Clone_____ Rap_9. 1___ 9.1__ Fritzi Pauley_2.6_4.0_8.2_4.9__Dorskamp_6.6_4.6_6.6_5.9 __ Beaupre_8.9_6.1_6.4_7.1 __ Boela re_7.1_6.3_6.6_6.7 __ 75028/3_1.6 ___ 1.6__Trichobel__6.8_6.9_6.9__Donk__8.0__8.0__7 6.028/5 ___ 4.7_4.7__ 75.028/3___ 4.9_4.9__69.039/4 ___ 6.1_6.1 __ 71.009/1___ 4.5_4.5__7 1.015/1 ___ 7.5_7.5 __ MEAN____ 6.0 __ Sw - Swanbourne, We - Water Eaton, Mk - Markington. Notes for tables _ seq t sumyld _21_ and _ seq t sumpopyld _22_: i. where more than one harvest has occurred average figures are given ii. where different fertiliser regimes have been applied average figures are given iii. all figures are based on actual stool survival with the exception Ca iv. Ca figures are based on the monoclonal plot yields
The wide range in clone productivity reflects the influence of site, climate and management techniques, experienced at the different trial sites. In general the average yields achieved at the sites are disappointingly low, with the poplar crops performing marginally better than the willow; averages of 6.0 and 4.9 odt/ ha/ yrrespectively.
The low yields recorded can be attributed in part to the experimental nature of the trial work. The plantations were used to develop best practice techniques of plantation establishment and management, often through a process of trial and error. It is anticipated that current management systems will result in increased plant vigour and higher yields. Much of the clonal material planted twelve years ago is now considered obsolete. Breeding programmes have focused on improved disease, pest and frost tolerance, as well as increased productivity, and should result in higher future yields. At the start of the project little was known about plant:site interaction, and it was not always possible to select the most appropriate genera, species and clone for a given trial. Data from this project and other similar work has lead to better understanding of plant:site interaction allowing future plantations to be established using the most appropriate plant material for the prevailing climatic and edaphic conditions.
Sustainability of yield
The trials established and managed under this project are amongst the oldest in the UK, and have proved unique in their ability to generate long term yield data. The productivity figures from up to 4 rotations were analysed to give an indication of the likely pattern of yield that could be expected from a developing SRC plantation. Detail of the analysis methods used are given in Appendix _ seq a sustyld _1_.
In total 102 data sets were included in the analysis, including 14 willow and 13 poplar clones. Rotation periods varied from 2 to 5 years and initial planting density from 5,000 to 20,000 plants per hectare. All the plots had completed a minimum of two, two year rotations, and were of a minimum size of 20 x 20m.
The analysis reavealed that of crops studied, over half (54%) had a decrease in yield from first to second rotation and of those completing three full cycles, 50% achieved a lower yield in the third rotation than the first. It should be noted that the analysis of third rotation data is likely to be biased by the abandonment of many of the poorer yielding sites after the second rotation, and that the true proportion of crops with a decreasing yield is likelyto have been higher than 50% Only 2 plots completed four rotations and both showed a substantial decrease in yield from first to fourth rotation.
To test if crops with differing first rotation yield levels, reacted differently in subsequent rotations the data was classified by first rotation yield and re-analysed. It was found that crops that had low first rotation yield (less than 6.0 odt/ ha/ yr), due primarily to poor establishment and early weed control, showed a marginal increase in yield in the second rotation; means of 4.0 to 4.9 and 3.4 to 3.6 odt/ha/yr for willow and poplar respectively. These yields are still well below what is anticipated as being a commercially acceptable level. Trials that performed well in the first rotation (yields higher than 10.01 odt/ ha/ yr) were expected to take advantage of a good establishment phase and show higher yields in subsequent rotations. This was not however the case for the crops analysed; a reduction in productivity of 2.4 and 3.8 odt/ha/yr for willow and poplar respectively, being recorded.
The data from this project would indicate that an assumption of increasing yield with plantation age might not be valid, with over half the plots showing a decline in productivity with time. The reasons for this decline are unclear. Certainly damage to both plants and soil, caused by winter harvesting, can be cited as a possible explanation at some sites. At others, increased disease, pest and weed pressure may have had a negative impact on yield. However, there are a large number of plots which have been manually harvested, show no increase in disease, pest of weed pressure, maintain high fertility levels, and yet still show a significant decline in yield with time; it is these plots that raise concern. It appears that in these cases, the actual regular cutting of the stools is resulting in a loss of plant vigour. Further substantive data is required from other SRC trials but, if the regular cutting of coppice stools is found to be a primary cause of productivity decline, the suitability of SRC for energy systems will require careful review.
GROWTH MODELLING
There is still much debate over the optimum strategy of plant spacing versus rotation length. High initial plant density offers the advantages of rapid establishment, fast canopy closure and natural weed suppression, and potentially a higher yield at the first harvest. On the down side, high planting rates increase the cost of establishment, induce greater inter stool competition, and generally confer shorter rotations and more frequent harvesting. Harvesting, as well as representing one of the main costs of coppice production, causes physiological plant stress and frequent harvesting eventually leads to a reduction in plant vigour and a decline in crop yield. In order to maximise the yield from any perennial crop, it should be harvested when the mean annual biomass increment is at a maximum. At any given spacing and growth rate the maximum mean annual increment (max. MAI) will be reached after a different time period.
U sing techniques of minimal destructive sampling (MDS) developed during phase 3 of this project (detailed in Mitchell et al, 1995), the crops at two sites (Parbold and Buckfast) were assessed annually to determine annual increment and generate growth models (full detail of the work is given in Appendix _ seq a growthmod _2_.
The level of accuracy of the MDS technique was considered high, with adjusted R2 values ranging from 97.2 - 99.3% in year 1 and 96.1 - 99.2% in year 2. The pattern of annual growth shown by the four clones evaluated is more difficult to analyse.
The best examples of what is considered to be a normal growth pattern is displayed by the clones Germany and x dasyclados. In the first growth season following harvest, the plants do not establish a full canopy cover until mid to late summer and are unable to fully utilise the space and light available; growth in this first year is approximately 20% of the total rotation yield. In year 2, full canopy is rapidly established in spring and with little inter plant competition for nutrients, water and light, the stools grow rapidly; year 2 growth is approximately 45% of rotation total. In year 3, canopy cover is rapidly established but growth of the stools starts to become limited by competition for light, water and nutrients; growth is approximately 35% of rotation total. The max. MAI of these two clones during the 3 year rotation was therefore reached in year 3.
The study served to illustrate the anomalies in growth pattern of the S. viminalis clones. At Buckfast both Mullatin and Bowles Hybrid were severely infected by Melampsora spp. in year two which dramaticallyreduced their growth rate in that year, but recovered well in year three to achieve a productivity of more than 17.5 odt/ ha/ yr. A similar high level of infection was seen at Parbold, but in this case occuring in year three, reducing the third years growth and giving the impression that max. MAI would be achieved after only 2 years. In realitythis is unlikely however; max. MAI is normally achieved when crop growth is constrained by inter-plant competition for light, nutrients and water. At Parbold, disease was almost certainly the main growth limiting factor for these two clones. The growth modelling lead to the following conclusions:
At the plant density used at the Buckfast and Parbold trials (10,000 plants per hectare), the max. MAI for the 3 yearrotation was reached after 3 years, suggesting that the selected rotation period of 3 years was the optimum in terms of yield maximisation.
The growth models constructed during the study, highlight the potential impact that the disease Melampsora spp. has on willow growth. Annual variation in the severity of infection causes significant variation in plant productivity.
The study also confirmed the principles and technique of minimal destructive sampling (MDS) developed during phase 3 of the project, which can be successfully used to determine SRC growth mid rotation without affecting the integrity of the crop.
Annual assessment of crop growth using MDS could be used to monitor crop development and evaluate the impact of annual variation in disease severity and climate. This data could be used to adjust rotation period; extending the cycle if an abnormally low yield increment was detected early in the rotation or bringing the harvest forward if crop productivity was higher than anticipated. CROP REMOVAL AND SITE RESTORATION
SRF crops offer a higher degree of management flexibility with substantially shorter rotations than conventional forestry. New clones offer improved growth rates, better form and increased resistance to disease. To take advantage of these improvements or simply to replace or remove plantations that have passed their maximum productivity, it is possible to remove SRF crops. A number of techniques exist but all have to achieve two basic goals: firstly to prevent further coppice growth, and secondly, to remove or allow the decomposition of the root structure facilitating soil cultivation.
During phase 4 of the project, four trial sites, earmarked for abandonment, were utilised to investigate the potential of various techniques of site restoration: Castle Archdale, Enniskillen 2.0 ha Long Ashton, Bristol 1.0 ha Markington, N. Yorks0.9 ha W ater Eaton, W iltshire 2.0 ha
Work at each of the four sites is described separately in the relevant site histories in Section 1, The common start point for each study was a normal, winter post harvest state with freshly cut stools. The end point of each study was land in a condition suitable for the desired subsequent land use.
FACTORS AFFECTING CROP REMOVAL
Based on the work at the four sites, three main factors have been highlighted, which must be considered when determining the suitability of a given method of crop removal.
Crop to be removed
The species and age of the crop will determine the size of the coppice stools. Single stem poplar crops were seen to have larger root structures than willow stands of a similar age and spacing. Older crops have larger, better developed root architecture. The size of the root system, particularly the diameter of the structural roots, along with soil and climate conditions, and species, will determine the rate of decay of the roots and hence the time required for sufficient breakdown to facilitate ground preparation.
Time available
The time available will restrict the techniques available to the manager. N atural breakdown of mature coppice stumps to a point where ploughing can occur is likelyto take a minimum of one season, during which time it is difficult to generate revenue from the land. This forfeited potential revenue must therefore be considered in the costing of any operation.
Subsequent land use or crop. The intended use of the land following crop removal will influence the method employed. Re-planting with SRC or returning the land to an arable crop requires the ground to be fully cultivated and implies almost total breakdown or removal of the existing root structure. At the other extreme if conventional forestry is the intended land use, the stools only need to be killed to prevent further regrowth. A change from SRC to grassland requires the stools to be killed but only the top 50-70 mm of soil to be cultivated to allow grass to be established.
TECHNIQUES OF CROP REM OVAL
Based on the technical and economic data from the crop restoration work, five different methods of site restoration have been described and costed (Table _ seq t rescosts _23_).
Grubbing out
The fastest method of reclaiming land from SRC is by grubbing out entire stumps using a narrow bucket digger (either a JCB or tractor mounted backactor) leaving the ground suitable for complete cultivation and available for arable planting or re-planting with SRC. This technique is particularly suited to older coppice plantations with large stumps. Although an expensive operation, grubbing out has the advantage of almost immediate land availability and no opportunity cost penalty.
Spray-off only
The translocated, foliar acting contact herbicide, glyphosate (most commonly used under the trade name Round-Up), has been shown to be one of the cheapest methods of preventing the re-growth of coppice stools. The harvested stools are allowed to regrow to a height of approximately 150mm or until sufficient leaf area has been establish to enable the contact herbicide to be effective. A maximum dose application of 6l/ ha is then applied using a standard tractor mounted sprayer. If a conventional forestry crop is to be planted this application should be sufficient to make the land available within 2-3 months. During these trials, this first application was shown to achieve a 90% kill of the stools. If the land is to be subsequently ploughed or conditioned, a second lower rate application of 3l/ ha may be required to kill any remaining stools.
Spray-off and plough out
Following the harvest, the stools are allowed to re-shoot in spring until approximately 150 200mm high. Glyphosate is then applied at the maximum rate (6l/ ha) using a standard tractor mounted sprayer. The site is left during summer and any remaining stools killed off with a second, lower dose application of glyphosate (3l/ha) in late August/ September. Dependent on the initial stump size and the rate of decay, the stumps can then be ploughed out either in autumn or spring the following year. The work during this project has shown this technique to work well for established willow plantations, leaving the ground suitable for arable or SRC planting within 10-14 months. It is considered that single stem poplar plantations would require a longer period for the stumps to decay sufficiently to facilitate soil cultivation; 14-20 months.
Spray-off and soil conditioning
Using the same method of killing off the stools as above, this approach is intended to leave the ground suitable for the broadcast sowing of grass within 10-14 months. Following a double glyphosate application in spring and summer to kill the stools, a tractor mounted mulcher/ soil conditioner is used to prepare the top 50-70mm of soil. The site is then levelled and/ or rolled before it is suitable for broadcast sowing to grass. This method was employed at Castle Archdale (Study 4), converting well established willow SRC to quality grassland in 14 months.
Spray-off, establish fodder crop and plough out.
The main drawback of the two previous glyphosate treatments is that both procedures imply a delay of approximately one year between the final harvest of the crop and the availability of the land for further use. The establishment of a fodder crop during this otherwise fallow period offers two advantages; generation of revenue while the land is being reclaimed, and the trampling action of livestock helps facilitate rapid stump breakdown.
Following harvest, the stools are allowed to re-shoot and then sprayed off with glyphosate when the growth has reached 150-200mm. The site is then direct drilled with a fodder crop such as kale or turnips as soon as the risk of frost has passed. This crop can then be used to support cattle or sheep in August/ September. The site can be ploughed out and cultivated in spring the following year.
It was hoped that this technique could be evaluated during the course of this project. However, the area set aside for the work at Castle Archdale, proved to be too severely rutted to allow direct drilling of a fodder crop and, as broadcasting was not considered suitable, the work was abandoned. This technique and the estimated costs and revenues are therefore theoretical, but it does serve to highlight an alternative approach that should be considered in areas of mixed or livestock farming. Total Soil Mulching
This technique pioneered in Sweden uses a modified peat cutter to completely mulch the top 900mm of soil incorporating all the root material into the soil. The main advantage is the speed of the operation; the land being available almost immediately for re-planting with a SRC or an arable crop. The main limitation is that the soil must be virtually stone free to avoid damage to the machinery, a situation rare in most areas of the UK; this system is not included in the cost summary.
Table 23 Crop removal techniques for SRC System_Grubbing out_Spray-off & plough out_Spray-off & plough out_Spray-off & condition_Spray-off only_Spray-off fodder, plough land use potential_arable/ SRC_arable/ SRC_arable/ SR C_grassland_forestry_arable/ SRC __ Suitability_poplar & willow_willow_poplar_willow & poplar_willow & poplar_willow & poplar __ Time _1 mnth_10- 14 mnths_14-20 mnths_10- 14 mnths_2-3 mnths_10- 14 mnths______O perations_hr/ ha_£ / ha_hr/ ha_£ / ha_hr/ ha_£ / ha_hr/ ha_£ / ha_hr/ ha_£ / ha_hr/ ha_£ / ha __ JCB/ backactor_30_450_-_- _- _-_- _- _-_- _- _- __ herbicide 1 (@6l/ ha)_-_-_0.4_114_0.4_114_0.4_1 14_0.4_114_0.4_114 __ herbicide 2 (@3l/ha)_-_-_0.4_63_0.4_63_0.4_63_0.4_63_-_- __ deep plough_-_-_2.3_53_2.3_53_-_-_-_-_2.3_53 __ power harrow_0.9_30_0.9_30_0.9_30_-_-_-_-_0.9_30 __ conditioning ______2.2_33_-_-_-_- __ diskin g_-_-_-_-_-_-_0.8_25_-_-_-_- __ rolling_-_-_-_-_-_-_1_16_-_-_-_- __ drilling turnips______4.5_81 ______Operation cost_ 480__ 260 __ 260 __ 251 __ 177__ 278 __ O pportunitycost/ R ent__ 0__ 110__ 160 __ 110__ 20__ 110 R evenue__ 0__ 0__ 0__ 0__ 0__ 300______Net cost__ 480_ 370__ 420__ 361 __ 199__ 88 __ Notes:Opportunity cost - calculated on a pro rata basis, based on the average annual agricultural land rent for England; £ 120/ha Direct drilling of turnips in two directions is assumed to be required to ensure good coverage, at a rate of 5kg/ha to allow for losses. It is assumed that 1 hectare of turnips keeps 100 lambs for 1 week at 30p each.
Where possible actual costs and timings from experimental work have been used, otherwise standard costs have been assumed; Nix, 1995. CONCLUSIONS
Several techniques of restoring land under coppice have been shown to be effective, the suitability of which are dependant on the crop to be removed, the time available and the desired subsequent land use. The opportunity cost of the taking land out of production during the restoration period will also determine the relative suitability of different techniques.
On high quality land it may be economic to grub out a coppice crop using a JCB or backactor if the opportunity cost or potential revenue foregone by using a slower technique, is more than £ 220/ ha. For the majority of farm land however, the high cost of grubbing out is not justified and a slower method of restoration should be used, appropriate to the subsequent land use. In areas of mixed or livestock farming, it may be possible to decrease the net cost of restoration work by establishing a fodder crop on the coppiced area providing feed for livestock and hence generating revenue.
COSTS OF OPERATIONS
The trials have provided unique data on the cost of operations from site preparation, through planting and tending, to harvesting and eventual crop removal. A detailed breakdown of the management costs incurred at each site are given in Appendix _ seq a sitecosts _4_. Table _ seq t mancosts _24_ outlines the management operations and costs involved in wood fuel production from SRC, based on the technical and economic data gained from the project. The operational timing and productivities, and materials used are taken directly from the detailed management data but to standardise the costs, farm contractor rates are taken from Nix (1996) (Farm Management Pocket-book).
Table24 Management costs of SRC plantations. T iming_O peration_Materials _Cost __ Year_Season __ per ha._(£ / ha.) ______Site preparation____ - 1_autumn_ fencing (rabbit) 1_2 192m @ 1.50_288.00 __ - 1_autumn_ fencing (deer)_2 192m @ 3.50_672.00 __ - 1_autumn_ deep plough __ 45.00 __ - 1_autumn_ weed control_glyphosate @ 5l/ha_56.00 __ 0_spring_ power harrowing __ 30.00 __ 0_spring_ disking __ 16.00______Establishment ____ 0_spring_ planting 3__ 180.00 __ 0_spring_ plant material_10,000 cuttings @ 5p_500.00_ _0_early spring_ weed control_simazine @ 2.2l/ha_20.00 ______Cut-back____ 1_winter_ manual labour_24hrs @ £ 8_192.00 __ 1_early spring_ weed control (mix)_amitrole @ 20l/ha ______simazine @ 2.2l/ha_125.00 ______Pre 1st harvest management ____ 2_late spring_ spot weed control_glyphosate @ 5l/ha_244.00 ______4,7,10,13,__ H arvest ____ 16,19,22_winter_ mechanised 4__ 200.00 ______Ongoing management ____ 4,7,10,13,_early spring_ weed control (mix)_glufosinate @ 5l/ ha ___ 16,19,22 ___ simazine @ 2.2l/ha_67.00 __ all years_summer_ maintenance (mowing) __ 25.00 __ 10,13,_late spring_ fertiliser application_N :P:K @ 80:40:40_60.00 __ 16,19,22 ______22_variable_Crop removal 5 __ 370.00 __1 added to existing stock fence 2 based on a square field of 5.75 hectares - 5 hectares of crop (15% open space) 3 Salix Maskiner Step Planter, planting a twin row system at 10,000 plants per hectare. 4 Claas Jaguar cut and chip harvester, including 500m on-farm transport to storage. 5 Spray off and plough out technique - for detail of operations see section above: Crop R emoval and Site R estoration
N ote: All chemicals are overall and tractor applied unless stated
The costs given in Table 24 are considerably lower in most instances, than those incurred by the project, due primarily to the pioneering nature of the work. The site management costs given in Appendix _ seq a sitecosts _4_ are those charged by local contractors who introduced a significant element of risk/ uncertainty in to their estimates and invoices. In addition, techniques and equipment used during the early stages of the project were developmental and have since been refined and improved as a result of the work.
U sing the operational costs from T able _ seq t mancosts _24_, the projected costs of an SRC plantation’s complete productive life can be modelled to give a base case cost scenario. Assuming that an upgrade of fencing is required (addition of rabbit mesh), the total cost of establishing and managing (including harvesting and crop removal) an SRC plantation on ex-arable land for a period of 24 years (7 full rotations) would be £ 4,768 per hectare. This can be broken down into: establishment (all costs to first harvest) £ 1,821 (38%); ongoing management £ 1547 (32%) or £ 81 per annum; harvesting £ 1,400 (30%).
The projected costs can also be used to generate a Net Present Value (NPV) for the investment and, by discounting crop yield, to calculate a cost per odt for the wood fuel produced (delivered in chip form to on-farm storage). The cost per odt varies considerably dependant on the anticipated yield used. Table _ seq t costodt _25_ shows the effect of crop yield, including those achieved in these trials (4.6 and 6.0 for willow and poplar respectively) on unit cost of production. Both costs and yield are discounted at a conservative rate of 5% to a common point, 1 year prior to planting (year -1). Table 25. Unit cost of wood fuel production from SRC Productivity (odt/ ha/ yr)_Cost (£ / odt) ___ Base_10% reduction_20% reduction_R ent @ £ 111/ha __ 4.6_62.41_56.17_49.93_94.01 __6.0_47.85_43.07_38.28_72.07 __9.0_31.90_28.71_25.52_48.05 __12.0_23.93_21.53_19.14_36.04 __ 15.0_19.14_17.23_15.31_28.83
The discounted costs per odt indicate that the yieldsachieved by the trials in this project would not be acceptable in a commercial plantation. Increasing yield through improved pest and disease management, and improved clonal selection will significantly decrease the unit cost of wood fuel production. In addition it is anticipated that unit costs may be further decreased through a reduction in the cost of management, driven by further improvements in management technique and development of the technology used. Table _ seq t costodt _25_ illustrates the implication of a 10 and 20% reduction in the total cost of plantation management.
The base case scenario only includes direct management costs and does not account for farmer profit, land rent or opportunity costs. To assess the impact of land rent on the unit cost of production, an annual rent of £ 111/ ha (agricultural land class 3 in England; N ix, 1996) was added to the system and the discounted costs recalculated. The results in Table _ seq t costodt _25_ show that a land rent of £ 111/ ha would result in an increase in unit cost of approximately 50%. The variation with yield of the unit cost of production for the four scenarios is shown graphically in Figure __ 15_.
Figure 15 . Unit cost of wood fuel production from SRC. _(not available electronically) References
Clay, D. V., Dixon, F. L., 1996. Report on experiments on weed management in coppice. ETSU B/W2/00401/REP/1, ETSU Harwell. Clay, D. V., 1996. Weed management in short rotation coppice: Current status and future requirements. ETSU B/W2/00401/REP/2, ETSU Harwell. Dawson, W. M., McCracken, A. R., 1995. The performance of poly-clonal stands in short rotation coppice willow for energy. In: Biomass and Bioenergy 8(1): 1-3. 1995. Deboys, R., 1996. Harvesting and comminution of short rotation coppice. ETSU B/W2/00262/ REP. Ennion, R., 1988. Assessment of Productivity of a Range of Spacing , Clonal and Coppice Cycle Length Trials. Long Ashton Research Station internal report to ETSU. Unpublished. Ericsson, T., Rytter, L., Linder, S., 1992. Nutritional Dynamics and Requirements of Short Rotation Forests. In: Ecophysiology of Short Rotation Forest Crops, Eds. Mitchell, C.P., Ford-Robertson, J.B., Hinckley, T., Sennerby-Forsse, L., 1992. Elsevier Applied Science. Hudson, J. B., 1997. Britain industry wood fuel baling, management and logistics. ETSU B/U1/ 00549/ 24/ 00. ET SU H arwell. Kendall, D. A., Hunter, T., Arnold, G. M., Liggit, J., Morris, T., Wiltshire, C. W., 1996. Susceptibility of willow clones (Salix spp.) to hebivory by Phyllodecta vulgatissima (L.) and Galerucella lineola (Fab.) (Coleooptera, Chrysomelidae). In: Ann. appl. Biol (1996), 129:379-390. Liggit, J., 1994. The abundance of insect pests in short rotation willow coppice and their relative importance. Submitted for Msc in Crop Protection, University of Bristol, 1994. Mitchell, C.P.; Wightman, A.D.; Ford-Robertson, J.B. and Ennion, R. 1989. Establishment and Management of Large Scale Trials of Short Rotation Coppice for Energy. Final Report on Phase I. Department of Energy Contractor Report ETSU B 1171. 71p. Mitchell, C.P.; Ford-Robertson, J.B. Watters, M.P., 1993. Establishment and Monitoring of Large Scale Trials of Short Rotation Coppice for Energy. Final Report on Phase II. ETSU Contractor Report ETSU B 1255. Mitchell, C. P., Watters, M. P., Culshaw D. C., 1994. Harvesting short rotation coppice crops with existing machinery. Internal report to ETSU, unpublished. Mitchell, C. P., Watters, M. P., Stevens, E. A., Ford-Robertson, J. B., 1995. Establishment and monitoring of large scale short rotation coppice plantations for energy. Phase III ETSU contractors report (University of Aberdeen) No. ETSU B/W2/00126/REP. Mitchell, C. P., 1997. Development of harvesting and storage technologies essential for the establishment of short rotation forestry as an economic source of fuel in Europe. Final technical report: AAIR 3 CT 94 1102. Mitchell, C. P., Stevens, E.A., Watters, M. P., Angus-Hankin, C. A., 1997. Short rotation coppice harvesting: An evaluation of the Salix Maskiner Bender III. ETSU contractors report, In Press. Nix, J., 1996. Farm Management Pocketbook. Wye College, University of London. Royle, D.J., Hunter T., Pei, M.H., 1992. Evaluation of the Biology and Importance of Diseases and Pets in Willow Energy Plantations. ETSU B 1258. Sage, R. B., Robertson, P. A., Poulson, J. G., 1994. Enhancing the conservation value of short rotation biomass coppice - Phase 1 - The identification of wildlife potential. ETSU B/W5/ 00277/REP Sennerby-Forsse, L. (ed). 1986. Handbook for Energy Forestry. Swedish University of Agricultural Sciences, Uppsala. Tabbush, P., Parfitt, R., 1996. Poplar and willow clones for short rotation coppice. Forestry Commission, Research Information Note 278. Wright, L. L., Doyle, T. W., Layton, P. A., Ranney, J. W., 1988. Short Rotation Woody Crops Program: Annual Progress Report 1988. Environmental Sciences Division, Oak Ridge N ational Laboratory, U S. appendix i : sustainability of yield
The trials established and managed under this project are amongst the oldest in the UK, and have proved unique in their ability to generate long term yield data. The productivity figures from up to 4 rotations were analysed to give an indication of the likely pattern of yield that could be expected from a developing SRC plantation.
Methods and Results
Not all the yield data obtained from the trials was considered suitable for inclusion in the analysis. The study was limited to the two main genera used in the project; Salix and Populus. The plots had to have completed at least two full rotations, equal in length and with a minimum duration of two years per rotation. A minimum plot size of 20 x 20m was set, however the majority of plots were substantially larger than this.
As with all the trials established during this project, a detailed record of all management activity was available for each plot, including: year of planting, plant density, fertiliser regimes, pest, disease and weed control. In total 102 acceptable data sets were chosen, including 14 willow and 13 poplar clones. Rotation periods varied from 2 to 5 years and initial planting density from 5,000 to 20,000 plants per hectare. Only 32 data sets are available for evaluation of third rotation yield. Of the total 102 data sets, 40 are not old enough to have completed three rotations and a further 30 were abandoned after 2 rotations due to poor growth and/ or stool survival.
The analysis was approached in two stages.
Stage O ne. To analyse the general pattern of crop development through several rotations the entire data set was pooled and the mean annual growth increment (MAI) achieved in first, second and third rotations were compared. Using the MAI during the first rotation as a base reference, the data was classified by change in MAI in subsequent rotations. Intervals of 20% from - 100 to +100, (changes of >+100 are grouped) were used to group the data by percentage change and the results are displayed graphically for second and third rotations in figures _ seq f rot21 _16_ and _ seq f rot31 _17_. In addition, the MAI during the second rotation was used as a reference to analyse the change in yield in the third rotation in a similar way. The results are displayed graphically in figure _ seq f rot32 _18_.
Figure 16 . Distribution of MAI yield change: first to second rotation.
Figure 17 . Distribution of MAI yield change: first to third rotation. Figure 18 . Distribution of MAI yield change: second to third rotation. _(These figures not available electronically)
The yield change from first to second rotation is distributed around a mean change of+2% with 54% of the plots showing a decrease in yield. Based on the first rotation yield, 50% of the plots show a decrease in yield in the third rotation. Comparing second to third rotation yields, a mean change of +14% with 39% of plots showing a decrease in yield was observed. However, the analysis of third rotation data is likelyto be biased by the abandonment of many of the poorer yielding sites after the second rotation; the number of crops showing a continuing decrease in yield in their third rotation is likely to have been significantly higher than 39%.
Only 2 plots completed four rotations and both showed a substantial decrease in yield from first to fourth rotation.
Stage Two. To test the hypothesis that crops with differing first rotation productivity respond differently to harvest, the data for both willow and poplar were grouped by first rotation MAI into three ranges: R 1<6.0, 6.01
Table 26 .Comparison of MAI in first and second rotation, by genus: Results of a Single Tail Paired t-test. Genus_Range
(odt/ ha/ yr)_No. of obs_R 1 mean yield (odt/ ha/ yr)_R 2 mean yield (odt/ ha/ yr)_D_t value_Inference at 95% confidence __ Salix_All values_52_5.8_5.8_ 0.0_-0.02_No diff ___ R1< 6.0_28_4.0_4.9_+ 0.9_1.81_Diff__ _6.01
Salix The data set for both poplar and willow crops show enormous variation. The MAI of the willow crops included in the study ranges from 1.4 to 11.1 and 1.0 to 12.4 odt/ ha/ yr in the first and second rotations respectively. There is no statistical difference in the mean yield of 5.8 odt/ha/yr achieved in each rotation.
When analysed by group, only the lowest R1 group (0 - 6.0 odt/ha/yr) showed a significant increase in yield. Although not statistically different, the higher R1 groups suggest a decrease in second rotation yield.
Populus The poplar crops included in the study have first rotation MAI ranging from 1.3 to 16.6 odt/ ha/ yr around a mean of 7.9 odt/ ha/ yr. The range achieved during the second rotation is marginally lower at 0.5 to 14.1 odt/ha/yr with a mean of 6.7 odt/ha/yr; a drop of 1.2 odt/ ha/ yr which is statistically different at the 95% level.
The lowest R1 band indicates a very slight increase in yield in the second rotation. The higher two groups both show decreases, with the top group (R 1> 10.0 odt/ha/yr) indicating a drop from a mean yield of 12.6 to 8.8 odt/ha/yr (30% decrease), significant at the 95% level.
Due to the abandonment of many of the poorer yielding trials after only two rotations, it is not possible to compare mean yields achieved during the third rotation.
It is reasonable to assume that poor establishment techniques, particularly initial weed control, at many of the trial sites, is the cause of many of the low MAIs registered in the first rotation. It is also reasonable to assume that having overcome these initial problems, good second rotation weed control would facilitate a sharp yield increase. This is supported to some extent by the data, with the lowest R1 groups of willow and poplar showing second rotation yield increases from 4.0 to 4.9 and 3.4 to 3.6 odt/ha/yr respectively. It should be noted that these yield figures are still well below what is anticipated as being a commercially acceptable level.
Trials that performed well in the first rotation (i.e., R1 = MAI> 10.01 odt/ ha/ yr) were expected to take advantage of a good establishment phase and show higher yields in subsequent rotations. The data does not support this theory, both willow and poplar trials in the top first rotation yield band show a reduction in MAI of 2.4 and 3.8 odt/ha/yr respectively.
Discussion Reliable, high levels of biomass production are essential if SRC is to become an effective component of a wood fuel for energy supply system. The data from this project would indicate that an assumption of increasing yield with plantation age might not be valid, with over half the plots showing a decline in productivity with time. The reasons for this decline are unclear. Certainly damage to both plants and soil, caused by winter harvesting, can be cited as a possible explanation at some sites. At others, increased disease, pest and weed pressure mayhave had a negative impact on yield. However, there are a large number of plots which have been manually harvested, show no increase in disease, pest of weed pressure, maintain high fertility levels, and yet still show a significant decline in yield with time; it is these plots that raise concern. It appears that in these cases, the actual regular cutting of the stools is resulting in a loss of plant vigour. Further substantive data is required from other SRC trials but, if the regular cutting of coppice stools is found to be a primary cause of productivity decline, the suitability of SRC for energy systems will require careful review.
Appendix _ 2_: growth modelling
Introduction
There is still much debate over the optimum strategy of plant spacing versus rotation length. High initial plant density offers the advantages of rapid establishment, fast canopy closure and natural weed suppression, and potentially a higher yield at the first harvest. On the down side, high planting rates increase the cost of establishment, induce greater inter stool competition, and generally confer shorter rotations and more frequent harvesting. Harvesting, as well as representing one of the main costs of coppice production, causes physiological plant stress and frequent harvesting eventually leads to a reduction in plant vigour and a decline in crop yield.
In order to maximise the yield from any perennial crop, it should be harvested when the mean annual biomass increment is at a maximum. At any given spacing and growth rate the maximum mean annual increment (max. MAI) will be reached after a different time period.
U sing techniques of minimal destructive sampling developed during phase 3 of this project, the crops at two sites (Parbold and Buckfast) were assessed annually to determine annual increment and generate growth models.
Methods
The annual growth of four willow clones (Mullatin, Bowles Hybrid, Germany and x dasyclados) in the production trials at Buckfast and Parbold were assessed at the end of each growth season, during the second rotation of the crops. Minimal destructive sampling techniques developed during phase 3 of the project (detailed in Mitchell et al, 1995) were used to estimate annual yield, without affecting the integrity of the growing crops. For each plot to be evaluated, a small non-random destructive sample covering a range of stool sizes was taken. For each shoot on the sample stools, diameter at 100mm above ground, height and fresh weight were measured. A sub-sample of the cut shoots was taken to calculate dry matter content. U sing a P.C. based statistics package (Minitab 9.0 for Windows) an alometric relationship correlating dry stool weight to diameter and height was generated for each plot.
Utilising these relationships, a larger, random non-destructive sample of diameter and height was used to calculate the yield of each plot in odt/ ha, and then adjusted to allow for stool mortality.
At the end of the third growth season, prior to harvest, the plots were randomly destructively sampled. Mean wet stool weight, moisture content and plant survival rate were measured and used to calculate plot yield in odt/ha.
Results The correlations of the alometric relationships generated using the minimal destructive technique were high, with adjusted R2 values ranging from 97.2 - 99.3% in year 1 and 96.1 - 99.2% in year 2, confirming the reliabilityof the MDS techniques developed during phase 3 of the project.
The incremental growth in each of the 3 years are given in Tables _ seq t growthinc _27_ and _ seq t growthincbf _28_ together with the plant survival rates immediately prior to the first and second rotation harvests. The incremental growth patterns at Parbold and Buckfast are displayed graphically in Figures _ seq f annualparb _19_ and _ seq f annualbuck _20_ respectively, together with the relative percentage of total growth in each year.
Table 27 .Annual growth of Salix at Parbold _Year 1_Year 2_Year 3 ___ annual growth_MAI_annual growth_MAI_annual growth_MAI __ Surv ’ start_Surv ’ end__ odt/ ha_odt/ ha_odt/ ha_odt/ ha_odt/ ha_odt/ ha %_% __ x dasyclado s_3 .6_3 .6_6.1_4.9_7.5_5. 7__ 81_81 __Germany_4.9_4 .9_12.0_8.5_9.0_8.6 __ 8 8_84 __Mullatin_3 .9_3 .9_7.4_5 .7_0.5_3. 9__ 7 2_7 2 __ Bowles Hybrid_5.2_5.2_7.0_6. 1_5.5_5.9__86_85 __MEAN_4.4_4.4_8.1_6.3_5.6_6.0__82_81__
Figure 19 .Annual growth of Salix at Parbold _ (not available electronically) Table 28 . Annual growth of Salix at Buckfast _Year 1_Year 2_Year 3___annual growth_MAI_annual growth_MAI_annual growth_MAI__ Surv ’ start_Surv ’ end__ odt/ ha_odt/ ha_odt/ ha_odt/ ha_odt/ ha_odt/ ha %_% x dasyclados_5.4_5.4_14.9_10.2_11.5_10.6__81_80__Germany_4.7_4.7_13.6_9.2_10.0_9. 4__ 87_81 __Mullatin_4 .0_4.0_8.2_6.1_18.7_10.3 __ 7 8_76 __ Bowles Hybrid_7.3_7.3_2.0_4.7_17.6_9.0__85_84 __MEAN_5.4_5.4_9.7_7.6_14.5_9.8 __ 83_80 __MAI - mean annual increment underscored MAI indicates where highest MAI within the 3 yearrotation was achieved
Figure20 . Annual growth of Salix at Buckfast
Discussion
Climate is one of the main determinants of potential plant growth. Quantity and distribution of precipitation, quantity and quality of sunlight, maximum and minimum temperature, occurrence of frost etc., all directly affect plant growth. As well as directly affecting plant growth, climate also determines the development of Melampsora spp. rust populations within the crop and therefore the severity of infection and level of crop damage. Ironically, conditions suitable for rapid willow growth, warm wet summers, also promote rapid rust development.
Comparing the two sites, the mean, maximum daily temperature at Buckfast throughout the rotation was approximately one degree higher than at Parbold. Total annual rainfall at Buckfast was approximately 1300mm, twice that recorded at Parbold (see appendix _ seq a climate _3_ for detail). This was reflected in the mean site productivities; the plots at Buckfast yielding approximately 60% more dry matter per hectare than at Parbold.
At each site, however, the annual variation in temperature and rainfall was minimal during the study period and is considered to have been relatively constant in determining in annual growth.
The best examples of what is considered to be a normal growth pattern is displayed by the clones Germany and x dasyclados. In the first growth season following harvest, the plants do not establish a full canopy cover until mid to late summer and are unable to fully utilise the space and light available; growth in this first year is approximately 20% of the total rotation yield. In year 2, full canopy is rapidly established in spring and with little inter plant competition for nutrients, water and light, the stools grow rapidly; year 2 growth is approximately 45% of rotation total. In year 3, canopy cover is rapidly established but growth of the stools starts to become limited by competition for light, water and nutrients; growth is approximately 35% of rotation total. The max. MAI of these two clones during the 3 year rotation is therefore reached in year 3.
Figures _ seq f annualparb _19_ and _ seq f annualbuck _20_ illustrate the anomalies in growth pattern of the S. viminalis clones. In year 2, both Mullatin and Bowles Hybrid at Buckfast were severely infected by Melampsora spp. rust which resulted in low growth rates. Despite the premature loss of approximately70% of the foliage, these clones recovered well, achieving growth rates of more than 17.5 odt/ ha in the third year.
The same two clones were also affected by rust at Parbold. However, at this site, the most severe infection occurred in the 3rd year, reducing growth and giving the impression that, at the spacing used, max. MAI would be achieved after only 2 years. In reality this is unlikely however; max. MAI is normally achieved when crop growth is constrained by inter-plant competition for light, nutrients and water. At Parbold, disease was almost certainly the main growth limiting factor for these two clones.
Conclusions
At the plant density used at the Buckfast and Parbold trials (10,000 plants per hectare), the max. MAI for the 3 yearrotation was reached after 3 years, suggesting that the selected rotation period of 3 years was the optimum in terms of yield maximisation.
The growth models constructed during the study, highlight the potential impact that the disease Melampsora spp. has on willow growth. Annual variation in the severity of infection causes significant variation in plant productivity.
The study also confirmed that the principles and technique of minimal destructive sampling (MDS) developed during phase 3 of the project, can be successfully used to determine willow coppice growth mid rotation without affecting the integrity of the crop.
Annual assessment of crop growth using MDS could be used to monitor crop development and evaluate the impact of annual variation in disease severity and climate. This data could be used to adjust rotation period; extending the cycle if an abnormally low yield increment was detected early in the rotation or bringing the harvest forward if crop productivity was higher than anticipated. appendix___3_: CLIMATE DATA
Means of 24 hour Maximum Temperature (24 hrs from 09GMT) 1991 Site Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Long 6.3 5.0 11.1 11.6 14.9 15.3 20.4 21.0 19.2 12.9 9.7 7.0 Ashton Swanbourn 6.0 4.5 11.6 12.3 14.6 16.5 22.1 23.1 20.1 13.3 9.5 7.2 e Castlearchd 5.9 6.0 10.4 11.1 16.0 15.0 19.4 19.0 17.7 11.7 9.3 7.2 ale Kincardine 4.4 3.7 9.6 10.1 12.9 13.5 19.5 19.0 15.4 10.9 7.5 6.4 Guisachan 5.1 5.1 9.9 10.8 14.3 14.9 18.7 19.0 16.9 11.1 8.0 7.7 Water 5.8 4.3 11.1 11.6 15.0 15.7 21.2 21.9 19.6 12.8 9.1 6.9 Eaton Brahan 5.4 4.7 10.1 11.5 14.4 14.8 19.5 19.9 16.8 11.3 9.5 8.0 Markington 5.4 4.7 10.6 11.0 13.9 15.4 21.3 21.6 18.6 12.6 9.2 7.6 Buckfast 5.4 5.5 11.3 11.7 14.6 16.0 19.8 21.5 19.9 12.9 9.7 8.1 Parbold 5.7 5.2 10.9 11.6 14.0 15.1 21.0 20.4 18.8 12.9 9.6 7.6
Means of 24 hour Maximum Temperature (24 hrs from 09GMT) 1992 Site Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Long 5.7 8.6 10.0 11.7 17.9 20.5 19.5 18.3 16.5 10.9 11.0 6.5 Ashton Swanbourn 6.0 8.8 10.8 13.0 19.4 20.9 21.1 20.3 17.8 10.8 10.5 6.3 e Castlearchd 7.3 8.7 9.6 10.6 15.9 19.1 18.2 16.4 14.4 10.5 9.5 6.3 ale Kincardine 6.5 7.2 8.0 10.3 17.3 18.8 17.6 16.7 14.8 8.6 7.2 4.5 Guisachan 6.8 8.1 8.5 10.8 16.7 18.0 17.4 16.6 14.4 9.4 7.9 5.1 Water 5.4 8.1 10.3 12.3 18.4 21.1 19.9 19.1 16.7 10.7 10.3 5.9 Eaton Brahan 7.8 9.2 9.0 11.0 17.8 18.3 17.8 17.2 15.2 10.0 8.7 4.9 Markington 6.6 8.8 10.0 11.9 17.3 20.0 19.4 18.7 15.8 10.3 10.2 6.0 Buckfast 6.3 9.1 11.2 12.5 18.4 21.2 20.9 18.8 16.1 11.3 11.6 7.1 Parbold 6.1 8.7 9.8 11.8 17.7 19.6 19.1 17.9 16.0 10.2 10.2 6.1 Means of 24 hour Maximum Temperature (24 hrs from 09GMT) 1993 Site Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Long 9.5 7.2 10.1 12.2 15.2 19.0 18.6 18.4 15.8 11.3 7.9 8.7 Ashton Swanbourn 9.2 6.5 10.7 13.0 16.5 20.0 20.4 20.2 16.1 11.8 7.7 8.2 e Castlearchd 8.5 8.5 9.4 12.3 14.9 16.8 16.3 16.4 15.3 10.6 8.3 7.3 ale Kincardine 5.4 7.4 8.4 11.7 12.7 16.7 16.9 15.8 14.1 8.6 6.4 3.4 Guisachan 6.4 8.1 9.1 11.3 12.2 15.7 16.4 16.1 14.8 9.4 7.2 4.4 Water 8.9 6.3 10.0 12.3 15.8 19.6 19.4 19.2 15.9 11.1 7.4 7.9 Eaton Brahan 7.7 9.3 9.9 11.7 12.8 15.8 16.6 17.1 15.0 10.3 7.0 4.5 Markington 8.3 7.7 9.9 12.0 14.4 18.4 18.5 18.0 15.2 10.6 6.3 7.2 Buckfast 9.6 7.6 10.5 13.2 14.7 19.8 19.6 19.8 16.1 11.4 8.8 9.0 Parbold 8.6 7.1 9.5 12.8 15.1 18.0 17.1 17.2 15.3 11.3 6.9 7.4
Means of 24 hour Maximum Temperature (24 hrs from 09GMT) 1994 Site Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Long 8.3 6.8 10.4 11.3 14.2 18.0 21.8 19.2 15.7 14.0 12.8 7.1 Ashton Swanbourn 8.3 6.4 11.4 12.0 14.7 19.9 24.6 21.4 16.3 13.6 12.3 7.4 e Castlearchd 7.4 5.8 9.5 10.7 13.8 16.4 19.9 18.6 15.1 12.2 10.1 6.9 ale Kincardine 4.7 4.2 6.6 9.6 13.3 16.3 20.6 17.3 14.2 11.4 10.5 5.4 Guisachan 5.9 5.4 7.2 9.7 13.4 15.0 19.1 17.5 14.3 11.4 11.5 6.2 Water 7.8 6.3 10.4 11.5 14.5 18.9 23.3 19.9 16.0 13.9 12.1 6.5 Eaton Brahan 6.3 5.5 8.0 10.8 13.6 16.4 20.1 17.5 15.4 12.0 11.6 4.9 Markington 7.1 4.7 10.2 11.8 13.7 18.4 22.5 18.8 15.3 12.5 11.7 7.2 Buckfast 8.6 7.7 11.2 12.0 13.6 19.2 22.4 19.4 16.2 13.2 12.8 8.4 Parbold 7.4 5.4 9.8 11.3 14.3 16.8 20.9 18.6 15.2 13.4 12.1 7.2
Means of 24 hour Maximum Temperature (24 hours from 09GMT) 1995 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Long 8.5 9.7 9.5 13.0 16.7 19.6 23.1 25.5 17.4 16.8 11.5 4.9 Ashton Swanbourn 7.7 9.4 9.8 13.8 17.2 18.7 24.7 25.4 17.4 17.2 10.5 3.8 e Castle 9.2 10.0 8.6 12.8 13.7 19.0 20.6 23.3 17.2 15.0 10.6 7.1 Archdale Water 7.7 9.3 9.2 12.8 16.4 19.0 23.8 25.7 17.4 16.3 10.6 3.9 Eaton Markington 6.9 9.1 8.6 12.3 16.2 17.9 23.3 23.6 17.1 16.1 10.2 4.4 Brahan 6.5 7.0 7.5 12.2 14.9 18.0 21.2 22.9 15.5 14.8 10.1 3.1 Buckfast 8.8 9.9 9.8 13.7 15.8 19.8 22.7 25.2 17.5 16.0 11.2 6.6 Parbold 7.5 8.9 8.4 12.1 15.4 18.0 22.6 23.7 16.8 16.1 10.5 4.6
Means of 24 hour Maximum Temperature (24 hours from 09GMT) 1996 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Long 6.8 6.0 8.1 12.6 13.3 19.4 21.5 21.1 17.6 14.9 9.8 5.5 Ashton Swanbourn 5.6 5.4 7.5 13.3 13.7 21.0 22.4 21.9 17.9 15.3 9.0 5.0 e Castle 7.9 7.2 7.6 12.6 13.3 17.8 19.0 18.3 18.2 13.9 8.8 6.1 Archdale Water 5.9 5.3 7.5 12.6 13.2 19.9 22.2 21.3 17.6 14.6 8.9 4.7 Eaton Markington 5.0 5.7 5.8 11.9 12.8 18.7 20.7 20.9 16.5 14.6 8.3 5.2 Brahan 6.8 5.7 7.5 12.1 12.3 17.6 18.9 19.8 17.4 13.8 7.4 5.1 Buckfast 7.4 6.3 8.4 12.4 13.6 19.0 21.9 19.9 17.0 14.1 9.5 5.4 Parbold 6.2 5.5 7.1 12.2 12.9 17.6 19.2 20.1 17.3 14.3 8.8 5.5 Means of 24 hour Maximum Temperature (24 hoursfrom 09GMT) 1997 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Long 5.3 10.1 12.7 13.9 16.4 18.1 21.0 19.8 18.5 14.3 11.9 9.2 Ashton Swanbourn 4.7 9.9 12.5 13.8 17.0 18.3 22.1 19.7 19.4 14.5 11.4 8.2 e Castle 6.7 9.4 11.5 13.2 15.7 16.6 19.2 16.8 16.6 12.3 10.7 8.4 Archdale Water 4.5 9.3 12.1 13.8 16.4 17.9 21.5 18.6 18.5 14.3 11.3 7.5 Eaton Markington 5.5 9.6 11.8 12.8 16.0 16.4 21.1 19.9 17.2 13.0 10.4 8.6 Brahan 5.7 8.4 10.9 12.5 13.9 16.6 20.2 18.9 16.3 13.2 14.0 7.4 Buckfast 4.2 9.7 11.8 14.4 15.4 16.6 20.9 21.4 - 14.4 11.6 9.1 Parbold 5.5 9.5 11.0 12.2 15.9 17.0 20.1 19.4 16.8 - - -
Means of 24 hour Minimum Temperature (24 hrs from 09GMT) 1991 Site Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Long 1.4 -1.0 5.3 4.8 8.0 9.2 13.7 13.1 11.0 7.7 4.4 2.1 Ashton Swanbourn 0.5 -2.4 4.2 3.3 6.0 8.3 12.3 11.2 8.9 6.0 3.6 0.2 e Castlearchd 0.2 -0.5 4.0 4.5 6.8 7.4 12.5 11.3 8.5 4.8 2.5 2.1 ale Kincardine -3.4 -3.5 -0.3 1.5 5.0 5.7 10.4 8.6 4.8 3.5 1.0 -1.5 Guisachan -0.2 -1.4 2.6 3.6 6.6 7.5 12.7 11.4 7.6 5.4 2.4 1.7 Water 0.4 -2.3 4.3 3.5 6.9 8.2 12.9 12.4 10.4 6.9 3.6 1.3 Eaton Brahan -2.1 -2.7 1.7 3.0 6.7 6.8 12.5 10.9 6.6 4.1 1.6 0.3 Markington -0.9 -1.0 3.5 3.6 6.5 7.6 12.1 11.2 8.1 6.4 3.0 0.6 Buckfast 1.3 -0.6 4.5 3.8 7.2 8.5 12.0 11.9 11.2 6.9 4.5 3.5 Parbold 0.7 -0.6 4.9 4.6 7.3 8.7 13.9 13.0 10.5 8.1 4.4 3.3 Means of 24 hour Minimum Temperature (24 hrs from 09GMT) 1992 Site Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Long 1.8 2.4 5.2 5.5 9.0 11.0 13.3 12.6 10.7 5.0 4.9 2.0 Ashton Swanbourn 0.6 1.7 4.1 4.3 7.0 9.4 12.5 11.5 9.8 4.4 4.1 0.3 e Castlearchd 2.0 1.5 3.9 4.3 7.3 10.0 10.7 9.4 7.4 3.9 3.9 1.3 ale Kincardine -0.6 0.5 1.4 2.2 5.5 7.8 9.1 7.2 6.0 1.1 0.7 -1.8 Guisachan 1.2 2.4 3.1 3.3 6.9 9.7 10.0 9.3 8.0 2.9 1.9 -0.1 Water 0.8 1.1 3.9 4.6 8.2 10.6 12.5 11.6 9.9 4.4 4.3 0.8 Eaton Brahan 0.9 1.6 2.5 3.1 7.7 9.6 9.6 8.1 7.3 2.3 1.0 -1.7 Markington -0.5 1.7 3.4 4.7 7.1 9.9 11.5 10.3 8.8 3.8 3.0 0.4 Buckfast 1.7 2.5 4.1 4.6 8.4 10.3 12.7 11.5 9.9 5.1 5.4 2.4 Parbold 1.7 3.2 4.3 5.6 8.9 11.2 12.2 11.5 10.3 4.8 4.6 1.3
Means of 24 hour Minimum Temperature (24 hrs from 09GMT) 1993 Site Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Long 3.9 2.9 3.3 6.6 7.9 11.2 11.9 11.1 8.8 5.1 2.8 3.7 Ashton Swanbourn 2.6 2.0 2.5 5.7 6.9 9.5 10.8 9.7 8.6 5.1 1.5 2.6 e Castlearchd 2.6 4.4 3.5 5.2 6.0 10.4 10.6 8.6 8.0 3.7 2.8 2.1 ale Kincardine -0.2 2.1 0.9 2.2 3.6 8.3 8.3 7.8 5.0 1.7 -1.3 -2.5 Guisachan 1.3 4.0 2.6 4.3 5.4 9.7 9.8 9.0 7.0 3.3 1.2 -0.5 Water 2.6 1.7 2.7 5.6 6.7 10.6 11.2 10.3 8.5 4.9 1.7 2.5 Eaton Brahan 0.1 3.7 1.7 3.9 5.3 9.1 9.5 8.7 5.6 3.6 -1.9 -2.0 Markington 1.7 2.7 2.0 5.4 6.2 9.3 11.1 9.6 7.3 3.8 1.3 2.0 Buckfast 3.8 2.8 3.5 6.3 6.8 10.4 11.1 10.4 8.9 5.1 3.3 2.7 Parbold 3.0 2.9 3.6 6.2 7.2 10.9 11.5 10.4 9.3 5.1 2.1 2.8 Means of 24 hour Minimum Temperature (24 hrs from 09GMT) 1994 Site Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Long 3.3 1.3 5.8 5.3 7.7 10.6 13.4 12.7 10.1 7.0 8.9 2.4 Ashton Swanbourn 2.3 0.2 4.0 4.3 6.4 9.2 12.3 11.7 9.4 6.0 6.8 1.4 e Castlearchd 1.6 1.2 3.6 3.6 5.8 7.5 10.4 9.8 8.3 5.8 5.4 1.2 ale Kincardine -0.9 -1.7 0.5 1.6 2.2 7.5 9.4 8.3 5.5 3.3 4.2 -0.8 Guisachan 1.0 0.8 1.7 3.1 4.0 7.9 10.8 9.3 7.5 5.2 5.3 0.4 Water 2.5 0.4 4.3 3.8 6.9 9.9 12.7 11.9 9.3 6.3 7.9 1.1 Eaton Brahan -0.4 -1.6 0.7 2.9 4.2 8.6 10.4 9.6 6.2 3.8 4.3 -0.9 Markington 1.7 -1.1 3.8 4.3 5.8 9.5 11.4 11.0 8.0 5.5 5.8 0.9 Buckfast 3.2 1.7 4.7 3.8 6.6 9.6 12.3 12.1 9.5 8.8 8.1 3.2 Parbold 2.7 0.7 4.5 4.7 7.0 10.6 13.0 12.4 9.6 7.7 8.0 2.1
Means of 24 hour Minimum Temperature (24 hours from 09GMT) 1995 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Long 2.7 4.5 4.3 5.2 7.1 10.3 13.9 14.1 10.3 10.6 4.8 0.5 Ashton Swanbourn 1.1 3.2 2.6 4.4 5.6 9.0 12.6 12.0 9.3 9.1 4.2 -0.8 e Castle 2.8 2.9 3.8 5.1 6.6 9.9 12.9 13.0 8.9 8.7 4.9 1.9 Archdale Water 1.5 3.4 2.8 4.5 7.0 9.3 13.1 13.4 9.7 9.7 4.9 -0.2 Eaton Markington 0.5 2.7 2.5 3.4 5.8 8.8 13.0 11.6 8.9 8.0 3.9 -0.5 Brahan -0.9 -0.3 2.4 3.7 4.2 8.1 10.6 10.5 8.5 5.9 2.6 -3.9 Buckfast 2.3 3.7 3.5 4.8 7.5 9.8 12.1 13.0 10.1 9.9 5.0 1.2 Parbold 1.8 3.8 3.6 5.4 7.7 9.9 14.0 14.1 10.2 9.9 5.1 0.5 Means of 24 hourMinimum Temperaure (24 hours from 09GMT) 1996 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Long 3.4 0.3 2.2 5.0 5.9 9.6 12.3 12.5 10.1 9.0 3.3 1.0 Ashton Swanbourn 1.8 -1.3 0.8 3.3 4.0 8.0 10.6 11.5 9.1 7.4 2.1 -0.5 e Castle 3.6 -0.4 2.3 4.4 3.8 9.0 11.5 11.9 9.5 8.2 2.1 0.8 Archdale Water 2.3 -0.7 1.3 4.1 4.9 9.5 11.8 12.0 9.5 88.1 2.3 -0.1 Eaton Markington 2.2 0.0 1.6 3.6 4.4 8.6 10.8 11.1 8.4 6.6 1.6 -0.3 Brahan 2.0 -2.1 1.3 4.0 3.6 7.8 9.4 10.7 7.6 5.9 -0.5 -1.2 Buckfast 3.3 0.4 2.1 4.4 4.7 9.3 11.0 11.2 9.5 8.5 3.8 0.9 Parbold 3.0 -0.3 2.1 4.9 5.1 9.3 11.7 12.7 9.8 9.5 1.4 0.4
Means of 24 hour Minimum Temperature (24 hours from 09GMT) 1997 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Long 0.0 4.1 6.4 5.2 7.2 11.0 12.0 12.4 10.8 7.0 6.1 3.5 Ashton Swanbourn -1.7 3.1 4.1 2.6 5.3 10.2 11.2 9.6 9.7 5.1 5.1 2.8 e Castle 1.9 2.5 5.0 5.6 6.7 9.5 12.1 9.6 9.1 5.7 5.5 3.2 Archdale Water -0.9 3.3 4.5 4.0 6.8 10.4 11.7 10.4 10.0 6.3 5.6 2.7 Eaton Markington -1.7 3.1 3.2 2.9 4.9 9.4 12.8 11.1 9.1 5.5 5.0 - Brahan -1.6 1.1 3.7 3.4 5.4 8.4 10.7 9.0 6.4 3.7 - 0.2 Buckfast 0.2 4.0 4.8 4.9 7.3 9.7 11.7 14.2 - 8.3 6.5 3.9 Parbold 0.3 3.4 4.8 5.1 7.4 10.2 12.7 12.1 11.0 - - - 1991 Rainfall (mm) Site Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Annu al Long 135.2 41.8 70.4 86.6 8.5 148.1 95.0 19.9 44.6 105.3 119.2 33.2 907. Ashton 8 Swanbour 54.7 44.4 30.2 68.5 12.8 87.9 72.4 15.9 90.6 31.1 66.3 12.1 586. ne 9 Castlearch 111.5 62.8 119.5 127.6 13.7 114.4 67.1 59.8 60.3 111.1 143.2 65.1 1056 dale .1 Kincardine 51.1 28.4 61.8 46.2 55.8 142.3 40.0 37.4 45.2 78.0 95.7 48.0 729. 9 Guisachan 162.1 58.4 79.6 111.1 31.5 85.8 72.5 40.7 164.6 151.9 180.8 128.3 1267 .3 Water 94.3 32.1 65.7 66.0 8.3 90.2 74.0 11.9 38.1 61.7 71.1 20.5 633. Eaton 9 Brahan 56.3 22.7 69.8 36.3 16.4 142.7 55.4 29.0 79.2 88.9 113.9 75.4 786. 0 Markington 80.5 78.0 65.0 48.7 12.6 69.8 19.9 7.5 34.4 69.7 86.0 37.8 609. 9 Buckfast 241.7 80.1 163.8 96.3 14.0 142.9 65.5 23.8 107.3 143.9 112.7 50.0 1242 .0 Parbold 52.8 46.3 53.5 41.0 5.4 60.3 53.9 34.9 52.9 74.0 92.3 52.3 619. 6
Site Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Annu al Long 53.0 41.0 113.1 172.8 41.2 48.6 97.7 181.3 71.1 56.6 209.1 84.8 1170 Ashton .3 Swanbour 49.7 14.9 47.2 59.1 69.1 45.5 93.0 102.4 115.3 76.6 100.5 42.2 815. ne 5 Castlearch 65.1 103.2 160.0 129.5 57.3 61.7 111.1 223.3 104.0 85.2 155.7 81.0 1337 dale .1 Kincardine 107.3 54.3 113.1 67.0 68.5 32.6 39.4 114.7 118.7 88.5 126.3 104.8 1035 .2 Guisachan 248.2 173.9 166.0 68.5 61.8 25.6 48.8 170.5 161.8 90.3 253.0 192.9 1661 .3 Water 39.8 26.0 44.4 55.6 35.6 51.2 71.4 124.2 59.8 47.2 130.8 70.8 756. Eaton 8 Brahan 82.4 74.0 106.7 51.5 62.3 33.9 21.0 110.3 85.4 62.3 134.9 88.7 913. 4 Markington 45.4 36.4 83.7 48.6 61.9 30.2 58.3 101.9 101.7 64.2 102.5 61.0 795. 8 Buckfast 52.3 83.1 66.2 101.1 24.4 28.6 42.3 176.0 95.5 85.0 260.6 196.8 1211 .9 Parbold 49.4 53.6 80.0 50.9 53.3 26.0 41.4 115.6 80.1 143.2 111.0 85.9 890. 4
1993 Rainfall (mm) Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Annu al Long 173.5 9.2 29.0 77.0 69.0 71.9 95.6 38.5 130.1 134.8 70.1 179.0 1077 Ashton .7 Swanbour 81.6 8.8 23.2 96.2 64.8 79.1 51.2 40.2 84.5 103.3 63.4 98.4 794. ne 7 Castlearch 153.5 45.9 68.8 145.8 79.4 89.5 120.4 82.4 91.2 23.1 51.1 224.1 1175 dale .2 Kincardine 335.6 40.2 55.1 25.4 92.8 47.4 43.7 44.3 43.1 119.5 24.3 134.5 1005 .9 Guisachan 425.6 50.0 94.0 40.0 94.8 32.2 50.5 42.2 39.5 97.6 40.8 193.3 1200 .5 Water 97.2 5.8 35.6 61.0 67.6 60.0 57.6 27.8 73.0 95.8 46.3 113.2 740. Eaton 9 Brahan 177.8 14.9 47.1 40.5 52.9 52.1 30.0 26.1 30.8 117.8 18.3 122.3 730. 6 Markington 86.8 19.1 12.5 108.3 91.1 35.0 66.5 84.7 125.6 70.5 48.2 110.0 858. 3 Buckfast 226.9 19.1 37.5 127.6 165.1 58.0 62.6 28.1 205.6 141.4 124.8 331.4 1528 .1 Parbold 80.2 12.0 16.0 73.4 87.5 48.9 77.7 76.1 66.2 54.2 47.8 172.2 812. 2 1994 Rainfall (mm) Site Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Annu al Long 109.6 73.4 70.0 71.7 87.1 23.1 20.5 70.8 102.1 99.8 79.5 72.1 879. Ashton 7 Swanbour 71.5 55.3 43.3 54.3 65.6 31.9 9.2 47.2 72.1 65.8 34.8 84.5 635. ne 5 Castlearch 173.8 97.2 175.7 103.9 42.0 35.4 48.2 35.1 98.0 78.1 98.2 80.7 1066 dale .3 Kincardine 143.6 56.5 219.5 103.5 14.2 57.0 18.5 47.1 66.8 70.3 81.1 54.6 932. 7 Guisachan 206.6 43.7 376.8 102.3 23.6 89.5 25.4 103.4 73.3 56.0 111.9 145.6 1358 .1 Water 94.8 63.3 60.4 44.8 65.0 30.8 37.4 52.6 83.8 80.0 59.8 66.2 738. Eaton 9 Brahan 94.7 68.6 167.3 57.4 19.5 55.3 28.0 72.1 38.7 51.0 88.8 78.2 819. 6 Markington 87.3 63.1 49.6 50.4 46.6 18.4 41.3 49.6 95.6 61.9 100.2 89.5 753. 5 Buckfast 200.4 256.2 117.3 82.9 145.9 31.1 44.1 122.6 123.5 86.5 124.3 58.7 1393 .5 Parbold 86.9 47.6 91.6 62.9 48.6 47.2 76.2 97.8 96.5 150.6 82.2 88.8 976. 9 Totals of 24 hour Rainfall (24 hours from 09GMT") 1995 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annu al Long 175. 54.9 52.7 29.5 59.1 12.3 12.7 7.1 145. 74.2 99.7 97.5 820. Ashton 0 9 6 Swanbour 103. 64.6 18.8 18.5 28.5 15.7 36.6 1.9 148. 29.1 65.2 85.1 615. ne 3 3 6 Castle 178. 181. 38.7 18.4 66.0 27.0 84.6 7.4 62.4 171. 130. 40.6 1006 Archdale 4 6 2 0 .3
Water 132. 66.1 30.8 16.4 47.6 12.0 12.4 1.8 104. 54.4 89.0 94.5 661. Eaton 1 4 5 Markington 107. 85.6 28.9 17.7 39.9 8.9 18.0 5.4 110. 22.1 45.9 62.7 553. 5 9 5 Brahan 137. 113. 32.2 33.2 36.8 25.3 28.4 17.4 197. 76.7 71.0 22.7 792. 9 7 6 9 Buckfast 275. 222. 78.2 42.4 82.1 5.6 74.3 7.4 140. 137. 157. 170. 1393 0 5 0 7 8 2 .2
Parbold 144. 104. 38.0 19.3 61.7 23.1 46.5 15.0 128. 24.8 50.8 31.1 687. 3 7 0 3 Totals of 24 hour Rainfall (24 hours from 09GMT") 1991 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annu al Long 57.5 72.3 60.0 65.6 74.8 17.5 34.5 85.5 41.8 108. 129. 30.8 778. Ashton 0 9 2 Swanbour 37.3 58.5 23.2 30.7 24.0 26.1 42.3 60.3 15.0 40.1 81.9 27.3 466. ne 7 Castle 57.6 87.6 51.0 86.0 112. 72.2 90.2 131. 23.2 141. 118. 58.0 1028 Archdale 4 2 2 2 .8 Water 39.6 55.2 40.2 44.4 37.8 16.2 27.6 56.8 21.4 53.8 87.0 26.2 506. Eaton 2 Markington 41.8 60.7 33.7 41.4 58.9 43.5 36.3 86.3 21.6 55.4 90.9 86.7 657. 2 Brahan 21.1 72.8 31.1 65.2 39.4 20.4 41.6 49.4 31.7 116. 95.5 42.4 626. 2 8 Buckfast 216. 171. 102. 81.8 100. 45.3 25.0 108. 50.6 130. 185. 57.1 1276 7 6 8 8 6 3 5 .1 Parbold 19.3 55.5 31.5 62.9 47.9 39.4 40.7 64.1 48.2 108. 125. 50.3 692. 0 1 9 Totals of 24 hour Rainfall (24 hours from 09GMT") 1997 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annu al Long 10.5 133. 32.5 24.8 87.9 18.1 46.2 202. 36.0 66.5 100. 104. 863. Ashton 1 5 9 5 5 Swanbour 13.7 54.5 7.8 11.0 60.3 18.3 35.6 108. 18.0 60.8 65.2 52.0 506. ne 9 1 Castle 29.2 139. 44.0 42.8 78.2 16.6 11.8 81.6 23.6 55.0 90.4 135. 748. Archdale 8 6 6 Water 6.2 80.4 18.8 20.8 57.4 17.9 29.4 167. 9.4 48.4 85.0 69.6 610. Eaton 6 9 Markington 8.0 103. 15.6 17.7 74.6 16.4 50.5 60.1 13.7 39.2 85.0 107. 591. 0 2 0 Brahan 33.6 140. 93.3 39.5 125. 16.6 42.3 87.2 43.9 23.8 - 65.6 711. 8 2 8 Buckfast 44.6 207. 49.0 27.4 84.9 16.6 29.8 162. - 117. 243. 203. 1188 9 9 6 6 8 .1 Parbold 3.9 92.6 40.1 22.4 102. 17.0 101. 97.5 47.3 - - - 525. 6 9 3 appendix 4 : MANAGEMENT COSTS
bu HC&S^I
Spring 1986 Site Preparation Mar-86 5,6,7,8 (0.93) Plough / rotivate @ £86/ha 15,000 Fountain 79.98 86.00 22738 Mar-86 5,6,7,8 (0.93) Glyphosate @ £90/ha Fountain 83.70 90.00 22738
Planting Apr-86 5,6,7,8 (0.93) materials 9300 Fountain 702.50 755.38 22738 5,6,7,8 (0.93) labour 2.45 Man days @ £77 20 21 9.82 192.50 206.99
Weed 0 Apr-86 5,6,7,8 (0.93) simazine by tractor @ £41/ha Fountain 38.13 41.00 22738
May-86 5,6,7,8 (0.93) roundup 10L @ £16.80 Fountain 168.00 180.65 22738 labour 2.5 man days @ £77 20 22 9.63 192.50 206.99 Aug-86 5,6,7,8 (0.93) roundup 2.5l @ £16.80 Fountain 42.00 45.16 23111 labour 1 man days @ £77 8 9 9.63 77.00 82.80 Oct-86 5,6,7,8 (0.93) roundup 2.5l @ £16.80 Fountain 42.00 45.16 23111 labour 1 man days @ £77 8 9 9.63 77.00 82.80
Winter 1986/87 Cut back and beat up Dec-86 5,6,7,8 (0.93) labour 3 man days @ £77 24 26 9.63 231.00 248.39
Spring 1987 Weed 1 Apr-86 5,6,7,8 (0.93) overall Paraquat tractor @ £30/ha 27.90 30.00 S01699 Apr-86 5,6,7,8 (0.93) overall Simazine tractor @ £30/ha 27.90 30.00 S01699 May-87 5,6,7,8 (0.93) roundup 2.5L @ £16.80 42.00 45.16 25272 labour 1 man days @ £80.25 8 9 10.03 80.25 86.29 May-87 5,6,7,8 (0.93) mechanical 4.5 man days @ £60 36 39 7.50 270.00 290.32 May-87 5,6,7,8 (0.93) 2.75 man days @ £60 including 25272 aminotriazol 165.00 177.42 Fertiliser May-87 6,7 (0.47) NPK 60:30:80 33.95 36.50
Fungicide May-88 5,6,7,8 (0.93) Calirus, tractor (@ £20.64/pmh) 25,000 4 4 20.64 83.70 90.00 S02240
Spring 1990 Weed 3 5,6 (0.47) Primatol and weedazol, tractor 25,000 2 5 20.64 51.15 110.00 (@ £20.64/pmh) Date Comp Operation Machine Quantity of Total HRS/ha Contractor Actual Total Total Cost (area ha) excluding materials Capital Cost materials hours Cost/hr actual cost/ha reference (£) L, kg,t cost
Insecticide 5,6 (0.47) Dursban 0.47L 15.81 34.00
Spring 1992 weed 5 5,6,7,8 (0.93) simazine 4.65L 29.76 32.00
Fertiliser 6,7 (0.47) NPK 20:10:10 392 kg 43.71 94.00
Spring 1993 Weed 6
Apr-93 5,6,7,8 (0.93) chemical control 275.00 295.70
Ste clearance Feb-96 7,8,9 (0.70) tractor hedge flail 35,000 20 29 IACR 16.24 324.80 464.00 7,8,9 (0.70) chain saw fell of os trees 400 8 11 IACR 9.16 73.28 104.69 7,8,9 (0.70) clearing of large lying material labour 8 11 IACR 7.50 60.00 85.71 tractor and trailer 25,000 4 6 IACR 7.50 70.00 42.86
Feb-96 5,6 (0.47) Dutzi flail of crop 48,000 4 9 IACR 30.00 120.00 255.32 Apr-96 5,6,7,8,9 (1.16) Dutzi re-flail of crop 48,000 4 3 IACR 30.00 120.00 103.45
Apr-96 5,6,7,8,9 (1.16) Kill of stumps glyphosate @3.3l/ha 4l @ £9 IACR 34.45 29.70 lapplication 3 3 IACR 35.70 107.10 92.33 Jun-96 5,6,7,8,9 (1.16) re-kill roundup @ 5l/ha 5.5l @ £8 IACR 44.00 37.93 application 3 2 IACR 35.70 89.25 76.94 Aug-96 5,6,7,8,9 (1.16) re-kill roundup @ 3l/ha 3.5l @ £8 IACR 28.00 24.14 application 3 2 IACR 35.70 89.25 76.94
Apr-97 5,6,7,8,9 (1.16) Dutzi - soil conditioning 54,000 4 3 IACR 50.00 200.00 172.41 Autumn 1986 Weed -1 Aug-86 all rows (1.82) overall glyphosate Fountain 163.80 90.00 30570
Ground prep. Sep-86 all rows (1.82) plough and disc (4WD tractor) 25,000 9 5 Fountain 20.64 191.10 105.00 30570 (@ £20.64/pmh)
Oct-86 all rows (1.82) Fencing 728m Fountain 2138.50 1175.00 28950
Spring 1987 all rows (1.82) Planting Mar-87 materials 12170 1148.42 631.00 labour @ £37/1000 78 43 Fountain 5.72 445.90 245.00 30570
Weed 0 Apr-87 all rows (1.82) simazine @ 6L/ha 11L labour 16 9 Fountain 109.20 60.00 31759 Jul-87 all rows (1.82) glyphosate 4L labour 36 20 Fountain 252.98 139.00 31759
Winter Cut back and beat up 1987/88 Dec-87 all rows (1.82) labour @ £51 40 22 5.73 229.32 126.00 all rows (1.82) labour @ £40 15 8 4.97 74.62 41.00
Spring 1988 Weed 1 Apr-88 all rows (1.82) roundup 11.5L labour 72 40 Fountain 609.70 335.00 34251 Apr-88 all rows (1.82) overall simazine Fountain 89.18 49.00 Fertiliser rows 29-60 (0.9) NPK 80:40:40 120.60 134.00 Spring 1991 rows 1-46 (0.9) Weed 4 May-91 simazine 5L J&M Fremantle and Son 136/4/91 labour and machinery @ £14.10/hr 5 5 14.10 63.90 71.00
Jun-91 Fertiliser rows 29-60 (0.9) Enmag 12:18:18:17 (N:P:K:Mg) Fountain 850.50 945.00 16696
Date Comp Operation Machinery Quantity of Total HRS/ha Contractor Actual Total Total Cost (area ha) excluding materials capital cost materials hours Cost/hr actual cost/ha reference (£) L, kg, t cost
Weed 6 Jul-93 rows 47-90 (0.9) simazine application Fountain 102.50 113.89 O25370 Jul-93 all rows (1.82) cutting rides Fountain 55.00 30.22 O25370
Weed 7
Sep-94 all rows (1.82) cutting rides Fountain 55.00 30.22 14064
Fertiliser Sep-94 rows 29-60 (0.9) N:P:K 69:46:60 Fountain 230.00 255.56 14064 Weed 8
Apr-95 rows 47-60 (0.9) amitrole (Weedazol TL @ 20l/ha) 20l J&M Fremantle and Son 100.80 112.00 simazine (@ 4.5l/ha) 4.5l J&M Fremantle and Son 12.15 13.50 application by tractor 2 2 J&M Fremantle and Son 35.00 52.50 58.33 044/07/95
Weed 9
Apr-97 all rows (1.82) amitrole (Weedazol TL @ 20l/ha) 40l J&M Fremantle and Son 201.60 224.00 simazine (@ 4.5l/ha) 9l J&M Fremantle and Son 24.30 27.00 application by tractor 3 3 J&M Fremantle and Son 35.00 87.50 97.22 044/10/97
0.72 hectares
Autumn 1987 Weed -1 Aug-87 0.72 overall glyphosate 4L Guisachan Farm 81.00 112.50 0.72 labour @ £10.50/ man day 3 4 10.50 31.50 43.75
Ground prep
Nov-87 0.72 disc 15,000 Guisachan Farm 84.00 116.67 Sep-87 0.72 plough 15,000 Guisachan Farm 115.50 160.42
Fence (deer) 0.72 material 1671.29 2321.24 Mar-88 0.72 labour @ £37/ man day 112 156 Guisachan Farm 4.58 513.00 712.50 GUI 001 Spring 1988 Planting Mar-88 0.72 Materials @12p &10p 7200 Dept of Agriculture 858.00 1192.00 Mar-88 0.72 labour @ £50/man day 48 67 6.25 300.00 416.67 Travel 64.80 64.80
Aug-88 Weed 0 Aug-88 0.72 paraquat and simazine 70.96 98.56 0.72 labour @ £48.64/man day 42 59 Strathspey woodlands 6.08 258.00 358.33 Winter 1988/89 Cut back and Beat up Nov-88 0.72 labour @ £41.12 16 22 5.13 82.08 114.00
Weed 1 May-89 0.72 Primatol 175.68 244.00
Weed 4 Aug-92 0.72 Roundup 5L Guisachan farms 60.00 83.33 Wills O5b (tractor application) 1 2 Guisachan farms 20.00 27.78 Wills O5b
Weed 5 Apr-93 0.72 Weedazol @ £5.2/L 20L Arbor services 104.00 144.44 953355 labour (knapsac) Arbor services 150.00 208.33 953355 HI Autumn 1988 Ground prep. 1.0 ploughing 15,000 2 2 Brahan Farms 15.88 25.00 25.00
Spring 1989 1.0 Fence (deer) Brahan Farms 2217.00 2217.00
Planting 1.0 labour @ £40/man day 64 64 Brahan Farms 5.00 320.00 320.00 1.0 materials @ £4.50/100 427.00 427.00
Weed 0 1.0 materials 96.00 96.00 1.0 labour @ £7/man hr 24 24 Brahan Farms 7.00 168.00 168.00
Cut back and Beat up Mar-90 1.0 labour @ £35.75/man day 48 48 Brahan Farms 4.47 214.50 214.50
Weed 1 May-91 1.0 rapier,weedazol Brahan Farms 437.00 437.00
Weed 4 Apr-93 1.0 Weedazol TL + labour Brahan Farms 95.00 95.00
Weed 5,6
Aug-94,95 1.0 mow rides (tractor) @ £15/hr 18,000 3 3 Brahan Farms 15.00 45.00 45.00
Weed 7 Apr-96 1.0 weedazol @ 10l/ha 10l
amitrole @ 4l/ha 5l
total including application Brahan Farms 307.85 307.85 Aug-96 1.0 mowing rides 18,000 3 3 Brahan Farms 15.50 46.50 46.50 Weed 8 Aug-97 1.0 mowing rides 18,000 2 2 Brahan Farms 15.50 31.00 31.00 Autumn 1990 Weed -1 1.5 parable @4L/ha 6L 129.00 86.00
Ground Prep. 1.5 Mole Ploughing 15,000 9 6 15.88 144.00 96.00
1.5 Fencing (rabbit) 700m wire net P. Trowbridge 988.50 659.00 78 235 fence stakes
Winter 1991 Planting Jan-91 1.5 material @ 15p 6000 Coppice Green Nursery 900.00 600.00 15 labour @ £40 96 64 P. Trowbridge 5.00 480.00 320.00 76
Weed 0 Apr-91 1.5 simazine and aminitriazole P. Trowbridge 154.50 103.00 88 1.5 hand weeding P. Trowbridge 1296.00 864.00
Winter 1991/92 Cut back and Beatup Feb-92 1.5 labour (beat up) 32 21 P trowbridge 5.63 180.00 120.00 74
Weed 1 Jul-92 1.5 hand weeding P. Trowbridge 670.00 446.67 Jul-92 1.5 mow rides P. Trowbridge 55.00 36.67 Jul-92 1.5 chemical application P. Trowbridge 357.00 238.00
Weed 2 Aug-93 1.5 Mowing rides (machinery) Mr C. Nicholls 77.00 51.33 labour Mr C. Nicholls 60.00 40.00
Weed 3 Jan-94 2.0 Kerb Southern Forestry 784.90 392.45 1865 Mar-94 0.6 weedazol & simazine Southern Forestry 344.15 573.583 1917 Sep-94 1.5 mow open space Southern Forestry 180.00 120.00 1944 Crop removal Mar-97 1.5 grubbing out with JCB 35,000 56 37 Home Farm 15.00 840.00 560.00 Spring 1991 Ground prep. 1.00 plough 15,000 2 2 15.88 32.00 32.00 1.00 harrow 15,000 1 1 15.88 23.00 23.00
Planting material @ 7p 4500 315.00 315.00 Mar-91 1.00 labour @ £68/day 54 54 Working Woodlands 8.50 459.00 459.00 AG/143
Weed 0 1.00 simazine @5L/ha 5L 1.00 stomp @ 2.5L/ha 2.5L 1.00 butisan @ £3L/ha 3L 1.00 manual weeding @ £37.75 16 16 71.50 71.50
Winter 1991/92 1.00 Cut back/ Beat up
Weed 2 Jun-93 1.00 roundup @ 3.5L/ha 3.5L 70.00 70.00 WSRG/360 labour to apply @£9/hr 35 35 Working Woodlands 9.00 315.00 315.00 WSRG/360 Jul-93 1.00 manual weed (strim) 41 41 Working Woodlands 9.00 369.00 369.00 WSRG/360
Weed 3 Jan-94 1.00 Kerb as required 1 bag 82.50 82.50 WSRG/409 labour @ £9/hr 10 10 Working Woodlands 9.00 90.00 90.00 WSRG/409 Hl^l ■m Autumn 1990 Ground prep. 0.9 ploughing 15,000 2 2 M. Ainscough Farms 15.88 28.80 32.00 MAF 1 0.9 harrow 15,000 1 1 M. Ainscough Farms 15.88 20.70 23.00 MAF 1
Spring 91 Planting 0.9 material @ 5p 9500 cuttings 475.00 527.78 Mar-91 0.9 labour @ £68 56 62 Working Woodlands 8.50 476.00 528.89 AG/142
Weed 0 May-91 0.9 simazine @ 5L/ha 4.5L @ £8.84 May-91 0.9 stomp @2.5L/ha 2.3L @ £2.41 May-91 0.9 butisan @ 3L/ha 2.7L @ £25.75 Working Woodlands 123.30 137.00 AG /175 0.9 manaul weeding @ £68 80 89 8.50 612.00 680.00
Cut back/ Beat up
Jul-92 0.9 labour @ £8.50/hr 17 19 Working Woodlands 8.50 146.63 162.92 AG/274
Weed 1 Aug-92 0.9 lazer 2L Working Woodlands 79.00 87.78 AG/274 labour @ £8.50/hr 8 9 Working Woodlands 8.50 68.00 75.56 AG/274
Weed 2 Feb-93 0.9 Kerb Flo 3L Working Woodlands 75.58 83.98 AG/286 labour @ £8.50/hr 8 9 Working Woodlands 8.50 70.00 77.78 AG/286 Jun-93 0.9 Weedazol 10L Working Woodlands 41.00 45.56 WSRG 359 labour @ £9/hr 18 20 Working Woodlands 9.00 162.00 180.00 WSRG 359
Weed 3 Feb-94 0.9 Kerb 1 bag Working Woodlands 82.50 91.67 WSRG 409 labour 6 7 Working Woodlands 9.00 54.00 60.00 WSRG 409
Weeds 4 Apr-95 0.9 amitrole (Weedazol TL) 10l @ £5.80 Working Woodlands 52.20 58.00 WSRG/698 simazine (Gaestop) 5l @3.60 Working Woodlands 16.20 18.00 WSRG/699 application by knapsac 12 13 Working Woodlands 9.90 118.80 132.00 WSRG/700
Site maintenance Aug-95 0.9 clearance of poorly cut shoots labour 27 30 Working Woodlands 9.00 243.00 270.00 WSRG/670 tractor & chipper 20,000 12 13 Working Woodlands 11.67 140.00 155.56 WSRG/671 ■ HH IB Autumn 1990 Ground prep. 0.9 ploughing 15,000 2 2 15.88 28.80 32.00
Spring 1991 Planting Apr-91 0.9 materials @ 5p 9500 475.00 527.78 labour @ £40 48 53 Buckfast Abbey 240.00 266.67 436
Weed 0 Jun-91 0.9 fusilade 5 /simazine 10L Gesatop @ £4.90 Elliott Bros 247.00 274.44 611 3L Fusilade @ £50.87 Jul-91 0.9 manual weed @ £38 220 244 J. Dodd 4.75 1045.00 1161.11 78/88
Winter 1991/92 0.9 Cut back Beat up labour @ £40/day 32 36 5.56 177.78 160.00
Weed 1 Jun-92 0.9 Chemicals gesatop @ £5/L Elliott Bros 20.00 22.22 75 Jun-92 0.9 devrinol @ £25/L Elliott Bros 125.00 138.89 756 labour Elliott Bros 60.00 66.67 756
Weed 2
May-93 0.9 weedazol & simazine Fountain 411.00 456.67 O24820
Weed 3
Jan-94 0.9 Kerb to alleys Fountain 200.00 222.22 11089
Apr-94 0.9 weedazol & simazine Fountain 411.00 456.67
Weed 4 (underatken by Avon Vegetation Research)
Weed 5 Mar-96 0.9 weedazol & simazine Fountain 384.00 426.67 23749