The urban woodlands at Birchwood

Birchwood was constructed on the site of the former Royal Ordnance Fac­tory at Risley, built to supply armaments during the Second World War. Constructed on a largely “green field” site, the factory employed 30,000 people and was operational for just seven years. After the war the 740- hectare site lay disused and derelict for twenty-five years. To the south lay a belt of woodland running alongside the Liverpool to Manchester railway line, and to the south west lay an area of woodland and raised bog known as “Risley Moss”, the remnant of a much larger area of bog that had origi­nally covered the site itself and surrounding area. During this 25 year pe­riod natural succession took over and the site was colonized by Quercus, Fraxinus, Betula and Salix species, amongst others. The factory was de­molished and the settlement of Birchwood was constructed during the 1970’s and early 1980’s. It consisted of three housing areas, “Oakwood”, Gorse Covert, and Locking Stumps, as well as an employment area and shopping centre. By 1991 Birchwood was home to 12,500 inhabitants housed in a mixture of privately owned and rented dwellings (64/35%). The 1991 census returns indicated that 38% of the “heads of household” were employed in “managerial and technical” and 19% in “skilled manual” occupations.

The development at Birchwood was unusual in the sense that it was landscape driven, and the concept for the landscape plan was to use wood­land as the main structuring element. Rather than being confined to iso­lated patches, the woodland was a continuous entity surrounding and flow­ing through the whole development, dividing up parks and green spaces, running alongside roads and footpaths, and creating a matrix into the cells of which the built development was placed.

Early on, a decision was made to retain Risley Moss and its surrounding woodland, as well as the belt of woodland alongside the Liverpool to Man­chester railway line, and other isolated vegetation outcrops. The different vegetation types found in these woodlands were used to develop four basic vegetation mixes, adapted to variations in local conditions such as differ­ences in substrate and the availability of light, which were used to create the woodland structure on site. Thus the newly planted woodlands at Birchwood were in some respects “grown on” to the existing woodlands, and retained much of their character.

There were many aspects of the methods at Birchwood that can be de­scribed as “ecological”, and the whole approach was widely imitated in Britain and became known as “the ecological style” or “the ecological ap­proach”. The ecological woodland approach at Birchwood was inspired partly by contemporary ideas from Europe, particularly from Sweden and the Netherlands, but was in many ways the largest and most uncompromis­ing example of the application of these ideas.

Location on the urban-rural gradient and type of nature

The Birchwood woodlands can be defined as “woodlands in the urban fringe”. In terms of the typology developed by Kowarik (2005) they are a mix of “Nature of the third kind” (planted tree stands in green spaces and other forms of functional greening) and “Nature of the fourth kind” (wood­lands naturally established on specific urban-industrial sites).

In this paper the woodland at Birchwood is frequently described as “naturalistic”. This expression was often used by Birchwood’s planners and designers (Tregay and Gustavsson 1983). Judging by the manner and context in which these expressions were used and by the landscape itself, Birchwood’s new landscape was “nature-like” or “naturalistic” because it was informal, with an organic structure, and made use of ecotones such as woodland edge as transitions between different plant communities and vegetation types; and because it resembled the spontaneously occurring ex­isting woodland and open scrub on and around the site. Thus, whenever the word “naturalistic” is used to describe woodland or vegetation in Birchwood in this paper, these are the characteristics that are implied.