There are two main approaches to ‘vegetation architecture’ or planting design that can be characterised as follows.
• Physiognomic (textural)—this has been the dominant approach until now, focusing on
individual plant qualities: forms, colours and shapes of flowers, bark and leaves, etc.
• Structural, focusing on vertical and horizontal patterns, stressing the direct links
between vegetation architecture and ecology, and offering an improved knowledge base involving design, longterm development and management principles.
The structural approach allows us to increase our understanding of the relationships between forms and dynamics, and of how these dynamics can be actively used, thereby stressing the fact that natural processes are always part of the design in parks and gardens. Furthermore, it allows us to deepen and sharpen our image of links between cultural expressions and natural processes, rather than dividing the two into separate worlds. To combine trees and shrubs in different patterns means that a certain architecture will be created. If we are to speak truthfully about long-living, sustainable, environment-friendly solutions, there is a need to understand much more about how different species interact, and the resultant expressions in terms of vegetation architecture.
Conventional design traditions sometimes make people sceptical about identifying types because it is said to diminish the world of possibilities and narrow the scope of creativity. However, even if some frames, focus areas and ways of thinking are suggested, this should be seen as open-ended and as a way of stimulating the discovery of other
An overview of different structural types of vegetation dominated by trees and shrubs focussing on high and low woodland types.
1. The dark high woodland;
2. The light high woodland;
3. Multistemmed, one-storied high woodland;
4. Two-storied high woodland with shrubs;
5. Two-storied high woodland with well developed middle layer;
6. Three-storied high woodland;
7. Multi-layered highwoodland;
8. Low woodland types
possibilities other than those presented here. The invention of ‘types’ and ‘sub-types’ on a habitat or stand level, which is chosen here as the main scale area, does not need to end with the identified types. It structures thinking in a way that easily finds combinations and unidentified types as part of a design process. Thereby a tool-box is created, a toolbox from which it is possible to pick and combine in an unending way in order to aid the design of local parks, gardens or other urban semi-natural areas.
Very few attempts have been made through the years to achieve an articulated view of how it may be possible to create the different major characters of vegetation as an essential part of a new woodland creation in the design of parks and gardens, or, broadly, of landscape architecture. The structural vegetation approach, with its spatial interest, developed initially with the ‘Cambridge School’ of botanists and their applications in tropical rain forests. In the 1950s, Dansereau (1951, 1958) and Dansereau and Arras (1959) tried to identify a universal system of structural types of vegetation. Some years later, more incomplete, attempts were also made by forest ecologists, such as Rackham (1975), Kira (1978), Peterken (1996) and Koop (1989), and by foresters like Mayer (1992). Despite these and some other exceptions, very few attempts have been made to identify structural types, and thereby to focus on the architecture and the character of vegetation. No one has so far seen the possibilities to directly link the research of vegetation structure to landscape architecture and city contexts.
These were the main reasons why research at the Department of Landscape Planning in Sweden in the 1970s and 1980s focused on the structure of vegetation as an approach for urban woodland design and long-term management. An overview of the main structural types of vegetation with trees and shrubs was developed, and was presented in a series of practical projects in Sweden as well as in Britain, including the well-known example of Oakwood in Warrington New Town (Tregay and Gustavsson 1983). As a result, a classification scheme was made based on North and Central European vegetation, published in the early 1980s as a series of research reports about naturalistic (nature-like) areas in parks and housing areas, focusing on different kinds of native and ornamental plantations (Gustavsson 1981, 1995; Gunnarsson and Gustavsson 1989). Later the identification of woodland types was taken some steps further, identifying more sub-types that should be regarded as important for practice. More recently, improvement has been made through a better integration of dynamic concepts (Rizell and Gustavsson 1998). In parallel, questions were raised about how frequently these vegetation types were found in the Swedish cities of today, within different time rings in a city development. The original scheme covered 29 identified structural types, including both open and more tree – and shrub-rich characters. Of these, only 10 were commonly used in the investigated Swedish cities, and several of what could be considered as the most interesting were totally missing. The reason for this ‘character poorness’ was mainly thought to be a lack of knowledge of what structural types could possibly be used.
Below, some of the main types have been selected in order to illustrate such aspects as key characteristics, use of nursery species during the first years, species, recommendations for the choice of planting scheme, and other aspects which might be practically relevant. It should be noted that the structural approach includes both indigenous and exotic species, and does not only cover naturalistic characters. Furthermore, there are also important links between the number of layers, dominating trees, light and shadow, and the field layer with its characteristic perennial herbs and grasses.