Silvicultural Success

Practical quarry landscaping and restoration in The National Forest

By Robin Truslove, senior forestry consultant with Lockhart Garratt Ltd

Lockhart Garratt Ltd (LGL), forestry, restoration and arboriculture consultants to Hanson Building Products Ltd, have worked at Hanson’s Heather Brickworks site, near Coalville, Leicestershire, since 1995. This article describes the technical challenges encountered in creating manageable priority habitats and screening over the past three years, covering the beneficial creation of a 7.8ha community woodland within The National Forest.

Planning background to Heather Quarry

Clay extraction and brick production at the 45ha site between Ibstock and the river Sence pre-date World War II and planned reserves have been worked under various permissions since 1950. As part of the 2003 Review of Mineral Planning (ROMP) submission, Hanson commissioned an ecological, landscape and visual impact assessment (VIA) of the site to inform the restoration proposals for the next 25 years. LGL progressed this assessment by undertaking the detailed design of pre-landscape planting for the first five years of restoration. The goal was to agree proposals with the mineral planning authority and manage the implementation of the works. The final restoration concept is envisaged to incorporate a large water body (capable of supporting recreational after-uses), neutral flood meadow and broadleaf woodland (map 3).

Woodland design, landscape design and visual impact

The site lies in the shallow valley of the river Sence, which runs south-west from Coalville in Leicestershire to Atherstone in Warwickshire, at 110m asl. The aims of the planting were to provide a green visual screen to the expanding quarry and existing works buildings while simultaneously enhancing the natural character of the river Sence. The area’s assets include belts of willow/alder wet wood-land, well maintained strong hedgerows and mature field trees, principally oak, ash and willow.

The VIA identified the zone of visual influence showing the extent to which the surrounding area was impacted or screened by existing landforms, trees and other developments. The main views affected were from the minor road to the west and from residential properties in Heather village to the north-west.

In some cases a very simple (and often effective) solution is to create a dense and continuous belt of woodland on the ownership boundary. However, this was not appropriate in this case. The river corridor already provided intermittent views across the adjacent arable and pasture land and, in keeping with this character, the planting was structured to retain some glimpsed views from the west. In addition, works could not negatively impact the diversity of habitat along the environmentally sensitive river Sence. The existing 0.5ha native wet woodland (EW1) was therefore extended by 0.25ha in 2005–06 (NW1) and a further three strips of woodland of 0.15ha each (NW2) will be planted in the northern river corridor in 2006–07 (map 2).

While the brickworks itself is outside the ROMP submission area, it does border it and a further 0.25ha of woodland (NW3) will be planted on the northern limit of the site in 2006–07, allowing screening of the loading areas and south elevation of the 8m high building from nearby residential properties.

Adjusting to campaign clay winning

Previously the clay winning had been undertaken on a continuous basis with one operator loading a 25-tonne dumptruck and relaying the material straight from the quarry. In 2005 Heather moved over to campaign stockpiling with the installation of a new haul road to accommodate the annual extraction of 80,000 tonnes of clay by contractors during May–June. The stockpile is located immediately adjacent to the works and presents a significant man-made intrusion to views from the west, extending to 6.5m in height and 150m in width on ground 2–3m higher than the river. Access to the stockpile for construction is from the south, thereby reducing the available space for what, in this case, would most suitably be a curtain of woodland planting. The western edge was therefore fully utilized by the construction of a 3m high sloping bund (1v:2h) in June, to prevent degradation of soil structure in wet conditions. The bund was seeded in mid-August 2005 with a low-maintenance mixture of 75% red fescue and 25% rye grass. This achieved an early green cover and ultimately a low-maintenance sward to suppress broadleaf weed growth. The bund’s western face was densely planted with broadleaf woodland in 2005–06 (NW4) (map 2).

Implementing the first phase of woodland landscaping

Detailed consultation and site meetings were held with the Environment Agency (EA) to ensure they were in acceptance of the planting proposals in the potentially sensitive local floodplain. The EA commented on the structure and layout of the new native woodland planting and agreed 5m stand-offs from the river, allowing plenty of room to plant in the obligatory 30m stand-off (for clay extraction) from the river bank. The presence of hares on site required protection of all stock with 75cm guards to prevent browsing. It was agreed with the EA that Tubex standards would be used with a softwood stake to ensure they were more secure in the ground (over a lighter spiral and cane) and would be less easily washed away in a flood event, causing blockage of drainage systems downstream.

The species structure and planting layout have varied where the planting will serve differing screening functions. The river corridor planting was created as new native wet woodland (NVC W6). Drifts and clumps of trees were used to create uneven patches of open ground, mirroring the more varied structure of natural woodland, as though regenerated from seed. Random spacing can lead to higher maintenance costs but this was overcome by first marking curvi-linear parallel planting rows at 2m spacing and then varying the spacing between plants (within rows) by 0.5–4m. Retaining the row structure allowed access for weed control and inter-row flail mowing by compact tractor. Average density was 2,250 trees per hectare. The species mixture followed the National Vegetation Classification (NVC) W6 type (Rodwell, 1998) with: willow 25%, alder 10%, birch 35%, oak/ash 15% and shrubs 15%. Planting was with 40–60cm transplants in single- and mixed-species clumps. This is the most cost-effective method of establishing good-quality new woodland. Larger, pot-grown stock are often used for development screening but are expensive and prone to a higher mortality rate.

The stockpile face planting used a wide range of fast-growing native broadleaves suited to the local area and, most importantly, a high proportion of shrubs for an early dense cover: oak 5%, birch 15%, ash 5%, alder 5%, rowan 5% and shrubs 65%. In addition to the forestry transplants, 10 standard trees (3m tall) were used for instant impact. This planting was spaced at 1.5m producing 4,500 trees per hectare.

All areas are under a three-year planting and maintenance contract, which places the obligation on the contractor to maintain 85% weed-free 1m wide planting rows/spots and 100% stocking through annual replacement of losses for three years, and to straighten and secure guards as required. Weed-control prices are agreed from the outset and paid for quarterly, provided the weed-free regime is achieved. This removes the risk of mis-timed or ineffective herbicide application and encourages job ownership by the contractor. The weed-control regime was discussed in detail with the EA. The use of residual (pre-emergent) herbicides was not possible given the potential for leeching into watercourses, but application of glyphosate (Round-Up) was acceptable. A requirement to obtain the WQM1 licence for ‘Use of Herbicides to Control Weeds in or Near Water’ was incorporated into the maintenance contract conditions.

Managing existing assets

The enhancement of existing woodland features was important. The existing riparian woodland (EW1) already contained willow tits and an otter habitat. The wood was, however, experiencing failure of over-mature alder coppice stools and the next generation of seedlings in the understorey was being out-competed by bramble and nettle. A programme of coppicing and bramble clearance was initiated and planting of 100 crack willow, grey sallow, alder and hazel plants undertaken. In addition, a new native hedgerow was planted on the eastern margin to create a favourable edge structure to buffer this resource from the quarrying activity.

Some 500m of existing hedgerows will be retained on site. These are being restored by the clearance of weed vegetation from gaps together with rotavation to allow planting with native hawthorn, blackthorn, hazel, guelder rose and holly at five plants per metre.

Assessment of 16 mature boundary trees in 2004 emphasized that their large healthy crowns were a major contributor to screening. A programme of pruning was undertaken in 2006 to prevent collapse and to ensure dangerous branches were removed over public footpaths. Proposals were first reviewed with an ecologist and it was agreed that retention of dead wood was also beneficial for the biodiversity of the site in providing a standing dry habitat for invertebrates as well as nesting/roosting opportunities for bats and owls. The nature conservation benefits were balanced against the health and safety of public access, resulting in hollow stems and large dead limbs being retained only in ‘low risk’ areas.

During the clay- and earth-moving processes it was also necessary, in order to minimize root damage through trafficking of machinery, to mark a minimum stand-off equal to 12 times the diameter of the stem (BS 5837:2005).

Community woodland creation through the National Forest Tender Scheme

Lockhart Garratt are responsible for a substantial number of new farm woodland sites in The National Forest, funded through the Tender Scheme (TS). This scheme has been run annually by The National Forest Company (NFC) since 1995. One aim of The National Forest is to increase woodland cover (map 1) to 33% (comparable to the well wooded Surrey Hills landscape area). Woodland cover is currently 17% and increasing at a rate of between 400–500ha each year (Williams, 2006). Under the Tender Scheme, detailed woodland designs are submitted in March and judged by the NFC Board in July. Schemes are judged against key criteria covering: price, public access provision/facilities, scheme size, creation of BAP (Biodiversity Action Plan) habitats, community involvement/support, interpretation, silvicultural innovation/commitment and contribution to the local economy.

In 2004 LGL identified a 10ha area of land at the south of the site that had been restored to agricultural grassland in 1996. The TS rules state that, in contrast to the England Woodland Grant Scheme, planting cannot be used to fulfil planning conditions. However, as the previous planning permission was for restoration to agricultural grassland and not woodland, this allowed the land to be considered for the Tender Scheme. The site landlord was the Crown Estate, whose lease to Hanson had 16 years to run. All parties were therefore consulted and agreed to submit a TS application. The application was successful in securing funding under Round 10 of the Tender Scheme and site development and planting took place during winter 2004–05. The award was presented to Richard Ford of Hanson by the Rt Hon John Gummer MP (the Minister responsible for originally setting up The National Forest project).

Good ground preparation is vital in restoration to woodland. The land lay wet and in combination with clay soils had the potential to restrict tree rooting and establishment. It was therefore decided to implement de-compaction by ripping with a flat-lift subsoiler to 500mm depth across the main slope. In October 2004 a Cat D6 was used to rip the ground to ensure breaking/shattering of the soil above the submerged plates. To improve the overall drainage of the site and further scarify the soil the area was mole ploughed to 750mm working down the slope. This greatly improved drainage and, while it is still early days, the ash has now extended a very encouraging 90cm by the middle of its second season.

The planting was tendered to five reputable contractors and won by Three Shires Ltd. It was agreed, following excellent results in 2003–04, to use a tracked planting machine. This opens the ground with a leading v-shaped tool, allowing an operator to place the transplant into the resulting channel, and then firms the soil back around the roots using two steel wheels. This smooth motion can plant 2,500 trees a day, not only reducing the storage time of stock and minimizing root desiccation but also providing a very consistent plant in terms of soil firming, level of cultivation and plant spacing.

The main broadleaved mixtures followed NVC W8 (Rodwell,1998) and were aimed at timber production. Increasing proportions of ash were planted on the lower, wetter ground and oak on the drier upper slopes. A more colourful mixture of rowan, red oak and whitebeam followed the main public path and birch-willow mixtures were planted around three new wetland habitat scrapes. The woodland is also under a three-year maintenance contract.

Community involvement was welcomed by Hanson as a way to involve the locals. A hard-working team of 15 pupils and teachers from Heather Primary School planted 300 trees on a cold morning in January 2005. Hanson, LGL and the NFC hosted a quarry visit in February 2005 to present the Tender Scheme opportunity at a CPD event. Other quarry operators, surveyors and planners working in The National Forest attended and Chris Brown of Wardell Armstrong (agent to the
Crown Estate) planted a 3m oak tree to mark the opening of the wood.

In order to interpret the link between the history and future of the site, a signboard has been installed at the main viewpoint over the working quarry from the woodland edge. The aim is not to isolate the public from the quarry but to explain the work taking place and that the final restoration of the site will lead to a more diverse landscape with high potential for public access. Security fencing has been installed on the steep quarry edge but simple line wires were used and a hedge was planted adjacent to it to make it unobtrusive.

Summary

Practical solutions and good liaison have been central to the landscaping and restoration of the Heather site. Success in the creation of Heather Brickworks Wood was centrally a triumph of partnership working. Hanson have worked with statutory organizations, the UK’s foremost woodland-based initiative, ecological and environmental consultants/contractors and the local public/stakeholders to deliver a community resource that the company is committed to long term. The project has released capital from the land to assist a holistic restoration that will greatly contribute to the environment.

References

RODWELL, J.S.: British Plant Communities (Vol. 1) – Woodlands & Scrub, 1998, Cambridge.

WILLIAMS, H.: Land management & incentives officer, National Forest Company, Pers. comm., June 2006.

British Standards Institute, British Standard 5837: Trees in Relation to Construction – Recommendations, 2005.

National Forest Company (2004), The National Forest Strategy – 2004–2014.

Footnote

Hanson and Lockhart Garratt Ltd would welcome any feedback on the works undertaken at Heather Quarry. Contact: Robin Truslove, senior forestry consultant, Lockhart Garratt Ltd, 8 Melbourne House, Corbygate Business Park, Weldon, Corby, Northants NN17 5JG; tel: (01536) 408840; or Richard Ford, minerals planning manager, Hanson Building Products Ltd, Stewartby, Beds MK43 9LZ; tel: (08705) 258258.