Urban forestry in Sweden from a silvicultural perspective: a review

Landscape and Urban Planning 47 (2000) 1±18

Review

Urban forestry in Sweden from a silvicultural perspective: a review D. Rydberg*, J. Falck Department of Silviculture, Faculty of Forestry, Swedish University of Agricultural Sciences, S-901 83 UmeaÊ, Sweden Received 10 July 1998; received in revised form 12 July 1999; accepted 15 October 1999

Abstract The Swedish urban forests originate mainly from the old production forests and are characterised by the forestry in practice at the time of urbanisation. Forests in the central parts of older urban areas are, therefore, generally old, while forests situated in newly urbanised areas are relatively younger, with proportionately more young stands. During the 1970s and 1980s, recommendations for the management of urban forests were concentrated on recreational forests on the fringes of urban areas. The recommendations proposed more differentiation in silvicultural management; however, the direction to be taken was only weakly emphasised in the urban forestry because it had low priority in the plans of the Swedish local authorities. In the beginning of the 1990s, the ecological aspects of forests in urban areas came more into focus and successively led to parts of the urban forests being given nature conservation status. Based on a classi®cation of the urban forests into ®ve zones, depending on their use and size, future improvements in urban forestry are suggested. The importance of satisfying the urban citizen's needs and demands for urban forestry is emphasised, as is the fact that more research needs to be done on the human aspects, namely, people's perceptions, preferences, expectations, and emotional feelings about urban forests. The regeneration of the urban forest, the management of young forests, the use of coppice with or without standards in urban areas, and the importance of forest edges and glades also give cause for further studies. # 2000 Elsevier Science B.V. All rights reserved. Keywords: Forest management; Multiple use; Visual assessment; Children; Elderly; Wildlife; Recreation; Health; Young stands; Coppice

1. Introduction Among the countries of the world, Sweden is one of those most richly endowed with forests, with more than half of its area forested (56%, or ca. 23 million ha) (Anonymous, 1995) (Fig. 1). Two-thirds of Sweden belongs to the boreal coniferous zone; the southern part belongs to the hemi-boreal forest zone (Ahti *

Corresponding author. Tel.: ‡46-90-786-56-20; fax: ‡46-90786-76-69. E-mail address: [email protected] (D. Rydberg). 0169-2046/00/$20.00 # 2000 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 9 - 2 0 4 6 ( 9 9 ) 0 0 0 6 8 - 7

et al., 1968). Scots pine (Pinus sylvestris L.) is the predominant species in northern Sweden, while Norway spruce (Picea abies (L.) Karst.) is predominant in southern Sweden (Kempe and von Segebaden, 1990). Downy birch (Betula pubescens Ehrh.) and silver birch (B. pendula Roth) predominate among broadleaved tree species (Kempe and von Segebaden, 1990). The commercial use of forests has a long tradition in Sweden, and forestry and its related industries still make up an important branch of Sweden's economic life (Mattsson and Stridsberg, 1981; HytoÈnen and BloÈndal, 1995). In the 1970s, and in the

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Fig. 1. The map on the left-hand side shows the percentage of forestland of total land area, according to the National Forest Survey (Anonymous, 1995). The map on the right-hand side shows the number of inhabitants that can be reached from a point in a circle within a radius of 30 km (Alskogius, 1996).

beginning of the 1980s, an interest in changing from forestry to a more multiple-use concept started (Andersson and Hultman, 1980; HytoÈnen, 1995), and the management of forests adjacent to urban areas for recreation was highlighted (Hultman, 1977); but it was only in the late 1980s that ideas for more multipleuse in forest management, especially those concerning biodiversity, ®rst had a signi®cant effect on Swedish forestry (HytoÈnen, 1995). During the 1990s, multipleuse forestry for social values has been given more attention, and a new interest in the topic of urban forestry in Sweden arose. Urban forestry is most often de®ned as ``the cultivation and management of trees for their present and potential contribution to the physiological, sociological and economic well-being of the urban society'' (Jorgensen, 1974). It is recognised as the management

of the urban forest for sustainable, long-term production of bene®ts that extend beyond simple aesthetics to include environmental amelioration, social enhancement, and production of direct and indirect returns (Collins, 1995). Consequently, urban forests are generally considered to include the total tree population within the entire area in¯uenced and utilised by the urban population (Collins, 1995; Grey, 1997). In Sweden, the de®nition of urban forests used to be restricted to only urban fringe forests (Hultman, 1979; Carlborg, 1991). On this basis, urban forests are estimated to represent more than one percent of the forest land area in Sweden, or around 300 000 ha (Carlborg, 1991). About 60%, or 180 000 ha, of the urban fringe forests are municipal owned (Carlborg, 1991), of which about 67 000 ha are primarily used for outdoor life and nature conservancy (Lidestav, 1994).

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This de®nition excludes arboriculture from urban forestry, and the responsibility for management is mainly laid on foresters (cf. Hultman, 1979). However, Falck (1996) stresses that a wider de®nition of urban forests would be more useful in Sweden in order to increase the professional interdisciplinary relationships in urban forestry and to decrease the differences in the management of urban forests between different administrative departments. Falck's de®nition of urban forests includes all forests on the fringe of, and inside, urban areas (cf. TyrvaÈinen, 1997). In order to separate the urban forests from other urban green spaces with trees, such as gardens, parks, and street trees, the urban forests consist of tree populations with uncultivated ground vegetation. This de®nition corresponds to the European concept of urban forestry that is more concentrated on forests in, and near, urban areas than on urban green space in general (Konijnendijk, 1997). The present article has as its main focus the present conditions, the needs, and the silvicultural methods of urban forestry in Sweden. The objective is to distinguish future improvements to be made in silviculture and areas in which research is needed. The article thus concentrates on the silvicultural part of urban forestry, and maintenance of individual trees, or arboriculture, is hence not included in this review. The paper is divided into the following main topics: Analytical review. The urban forests in Sweden: a description of the urban forest's origin and development up until the present. The main functions of urban forests in Sweden: the most important values urban forests have for the people and the society. The status of urban forestry in Sweden: urban silviculture in the past and present. Discussion. Future improvements in silviculture and suggested research.

2. The urban forests in Sweden During the initial industrialisation of the nineteenth century, small towns and villages started to grow in Sweden, but it was only in the beginning of the

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twentieth century that urbanisation really commenced (Bucht, 1997). With in¯uences from the English and German landscape planning, the buildings of the new urban estates were integrated into the natural landscape (Bucht, 1993). During the 1930s, the ideas of functionalism in shaping the new urban environment led to incorporation of areas of the old farm and forest land as green areas in, and between, urban districts (FlorgaÊrd et al., 1994; Anonymous, 1994a; Bucht, 1997). Woodlands were secured inside, and near, the new estates. The emphasis continued during the 1940s and 1950s, when natural areas were intermixed in the new housing areas and efforts were made to maintain sustainable nature parks in the cities. Smallscale building techniques made it possible to maintain the natural terrain and vegetation, including the standing trees, close to the new houses (Anonymous, 1994a). These ideas of urban planning were totally disregarded in the 1960s and 1970s, when the rapid construction of new, extended suburbs was carried out (Bucht, 1997). The green areas created were believed to be superior to `virgin and raw' nature, and nature was not trusted to `stand the wear' of the urban citizen's recreational use (Bucht, 1993). The new techniques of the development involved enormous alterations of the existing terrain and vegetation, and agricultural land was frequently used for building. The new vegetation often became very unbalanced and arti®cial (FlorgaÊrd et al., 1994), with cultivated lawns and new tree plantations replacing the natural land. Huge green areas of low structural variety consisting of few species were created with a large number of `interspatial' areas (Anonymous, 1994a). These interspaces were not created as the result of human demands or of caring about nature, but as the result of demands for space for verges and roundabouts (Anonymous, 1994a). At the end of the 1970s, ideas from England and the Netherlands for ecological parks and nature-like plantations were implemented in the design of urban areas (Bucht, 1993). Since the beginning of the 1980s, strong efforts had been made to secure adjacent natural tree and ground vegetation when building new housing areas (FlorgaÊrd and Schibbye, 1984). Throughout the last decades, the demand for land for construction of dwellings, of®ces, and other buildings has been very large in Swedish towns. Developers

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became insistent in their demands to condense (that is, to be allowed to build on land that had been earmarked for other purposes, such as playgrounds, sports, and recreation) (Grahn, 1991). This has resulted in a decrease in the proportion of green area in the total urban area from 45 to 38% between 1970 and 1990 (Anonymous, 1994a). Today, when 83% of the Swedish population is urbanised and the efforts of the Swedish municipalities are increasingly concerned with local resources as a consequence of the Rio declaration, the functions of urban green areas have been highlighted (Anonymous, 1994a). The urban forests in Sweden originate mainly from the production forests (cf. TyrvaÈinen, 1997) and are, therefore, characterised by the forestry and silviculture in practice at the time of urbanisation. Urban forests on the estates built before the 1960s consist frequently of old production forests in late succession stages (cf. Falck, 1994). The forests were often old at the time of urbanisation, and the trees have since aged another 50 to 100 years. Newly reforested clear-felled areas and afforested farmlands planted with Norway spruce or different broad-leaved species have successively been incorporated into the house plots of new suburbs and villages constructed after the 1970s (cf. Gustavsson and IngeloÈg, 1994). Abandoned farmland, interspaces, and different kinds of wastelands have also gradually been naturally afforested (cf. FlorgaÊrd et al., 1994). As a result, the forests situated in the central parts of urban areas are generally old, while the forests in the urban periphery, often newly commercially managed, are comparably younger, consisting of proportionately more young stands (cf. Falck, 1994; Tallhage LoÈnn, 1994). 3. The functions of urban forests in Sweden 3.1. Forests for amenity and beauty Swedes are known to be lovers of nature and trees (cf. SundbaÈrg, 1911; SoÈrlin, 1992; Uddenberg, 1993; Linnell and LoÈfgren, 1995), and even if this is not true of all Swedes, the majority do enjoy a wood or a forest close to their homes and of®ces. A great deal of the consumption of amenity and beauty is made from indoors through a window or from a car or bicycle (cf. Bucht et al., 1996; Lindhagen, 1996). Those who

are lucky enough to have their own garden or a balcony are pleased to have their estate surrounded by trees or, preferably, a forest. Visual variation is often stressed as being crucial for aesthetic experiences (KellomaÈki, 1975; Hultman, 1983a; Pukkala et al., 1988; Axelsson Lindgren, 1995). Trees are, because of their size, shape, colour, seasonal changes, and importance in the landscape, the natural living element most visible and, therefore, the one most people care for (Olembo and de Rham, 1987). Seasonal changes are especially obvious in Swedish forests, with dramatic differences between summer, winter, spring, and autumn. 3.2. Urban forests for recreation The common Swede estimates that she or he visits a forest for recreational purposes about once a fortnight, which means about 200 million forest visits per year in Sweden in total (Kardell, 1985a). Between 80 and 90% of all Swedes visit a forest at least once a year (Lindhagen, 1996). About 55% of all visits are estimated to be made in urban forests (Kardell, 1985a), which implies that the everyday forest for the majority of Swedes is located in an urban area. Any activity that refreshes the mental attitude of an individual can be regarded as recreation (Douglass, 1982). Recreation is a wholesome activity that is engaged in for pleasure, which includes among other things, exercise, relaxation, social contacts, natural studies, and aesthetic pleasure. The most common recreational activity is walking (Lindhagen, 1996). Jogging and orienteering during the snow-free periods and cross-country skiing during the winter are other popular outdoor activities in Sweden (cf. Sùndergaard Jenesen, 1995). Recreational activities could be performed as short promenades close to home or as long walking tours to areas of wilderness, but most often, forest recreation takes place close to home (Lindhagen, 1996). Elderly people's outings to nature have two aims: to experience beauty and to get exercise (NordstroÈm and Gora, 1995). Their walks for exercise are mainly taken in forests, and urban forests are of special importance since elderly people commonly have low mobility and may need assistance in visiting more remote forests (cf. Berglund et al., 1985; Grahn, 1991; Sùndergaard Jenesen, 1995).

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The distance to the forest proved to be a very important factor in choosing among different forests for recreational purposes (Kardell, 1982; Lindhagen, 1996). The distance must not exceed a normal walking distance (1±1.5 km) from home if the forest is to be frequently used (Kardell, 1985b). Recreational frequency is also in¯uenced by the occurrence of different physical barriers, such as streets with heavy traf®c and railways and by the recreational quality of the urban forest (Anonymous, 1994a). Sweden is one of the Nordic countries in which the right of public access is recognised (Kardell, 1985b). This means that citizens have the right to free access to outdoor areas, including the right to pick wild berries and mushrooms on private land. On average, about 80% of all Swedes pick berries at least once a year (Hultman, 1983b), and one out of three Swedes picks about 2.5±3.5 kg of mushrooms annually (Kardell and Eriksson, 1983). Mattsson and Li (1993) stated that the consumptive use value provided by picking berries and mushrooms is especially important to rural people, while non-consumptive use value of forests derived from hiking, camping, and so on is more important to urban people. However, in the urban areas, picking berries and mushrooms is an enjoyable pastime for people, and it provides them with exercise and the opportunity to satisfy their own appetite for berries and mushroom (Salo, 1984). Hultman (1983b) found that people in the central and northern parts of Sweden were more active in picking berries than were those in the southern and more urbanised parts, but the population of southern Sweden is more active in collecting mushrooms. 3.3. Urban forests for children It has been emphasised that the quality of playing rooms in childhood has a great in¯uence upon problem-solving ability, preferences, and ethics in adulthood (Uddenberg, 1993). Living close to nature and verdure makes it possible for urban children to discover and to understand the relationship of humans to nature (Tallhage LoÈnn, 1994). Children do not need much space for their play, but they seem to prefer places that are not de®ned by adults (Bettelheim, 1982; Grahn, 1991). Structurally diverse natural places have been stressed as being more inspiring and imaginative, even compared to a well-organised

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playground (cf. Berglund et al., 1985; Grahn et al., 1997). Grahn (1991) suggests, therefore, that the outdoor environment for children should represent the borderland between the closed forest and the open meadow. Preference studies from North America have shown that attitudes towards the environment seem to differ between children, teens, and adults (Kaplan and Kaplan, 1989). Balling and Falk (1982) argued that young children, with overall less experience, are more likely to reveal some innate predisposition to Savannah-like settings. The older the person, the more likely he or she will show the effect of experience (Searles, 1960). Youths seem to appreciate the wild, dense, and hidden forest more than they do the cultivated and open forest (Grahn, 1991). Adults and children appear to value the open-forest landscape more than they do the dense forest (Kaplan and Kaplan, 1989; Ribe, 1989). It seems, however, that children search for the Savannah and that adults want a structured, cultivated landscape with easily identi®able trees (Balling and Falk, 1982), but knowledge is still lacking. Day nurseries based on the `Outdoor-in-allWeather' educational philosophy have been started all over Sweden since 1985 (Grahn et al., 1997). The basic idea is that personnel and children allocate the majority of all activities to the outdoors in nature. The intentions are to teach the children how to perform in nature and to be careful with living beings and to improve the children's individual development. Grahn et al. (1997) found that children from an `Outdoor-inall-Weather' day nursery were less sick, had better powers of concentration, and had better motor activity than did children from a usual city day nursery. Grahn et al. (1997) stress the importance of nature in making children's play imaginative and varied, which gives the children opportunities for relating to the environment in different ways. Innovative teachers take their pupils to nature and to forests in order to make education more realistic and motivating (cf. Kellert, 1996). To make a 40-min outdoor lesson possible, the forest has to be adjacent to the school (Grahn and Sorte, 1985). Lindholm (1995) found that access to forests stimulated outdoor educational activities and that children in school yards with close access to woods took part in a greater number of activities than did children in school yards without access to woods. The forest is a considerable

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part of Swedish culture (cf. Gunnarsson, 1988), and as the schools are becoming more internationalised, it may be important to use the forest as a bearer of the Swedish culture (cf. Andersson and Hultman, 1980; Uddenberg, 1993; Komulainen, 1995). Since, 1983, Swedish forest companies have allocated a share of their pro®ts to the `Forest-in-School' programme in order to help teachers educate their pupils about the great economical and environmental value of the Swedish forest (LoÈfquist et al., 1994). Several hundred school forests have been established for training pupils at the Swedish junior and intermediate levels in practical forestry and for studies of ecology (LoÈfquist et al., 1994). In 1998, the `Forest-inSchool' project received the IPRA Golden World Award of the United Nations. 3.4. Urban forests for health and environmental amelioration Research, especially from North America, shows that human interaction with natural environments has potential health and stress-reducing effects (cf. Kaplan and Kaplan, 1989; Parsons, 1991; Ulrich et al., 1991; Ulrich, 1993). Hartig and Stokols (1994) claim that nature areas to which people have access have great in¯uence on people's mental health. Swedes not only appreciate nature, but also channelise many strong emotions through nature and through experiences of nature (NordstroÈm, 1994). The timelessness of the trees in nature seems to give the Swedes peace and relaxation in moments of despair (cf. Ottosson, 1997). NordstroÈm and Gora (1995) emphasise that old forests with large trees could give people the opportunity to revive memories and thus to regain con®dence. The opportunity to rediscover previously discovered types of environments is stressed as being important, especially for the elderly (Grahn, 1991). The signi®cance of vegetation in improving the climate is well known (Anonymous, 1994a). Trees improve the air, reduce the wind, level the temperature, increase the atmospheric humidity, and provide cooling shade (Miller, 1988; Lawson, 1996). Wellmanaged forests around estates reduce the wind's cooling effects and, thus, energy consumption and the production of atmospheric carbon dioxide (Miller, 1988). Meanwhile, the trees and bushes sequestrate carbon dioxide from the air through photosynthesis

(Rowntree, 1989). Furthermore, the wind-sheltering effect of forests near gardens increases the charm of outdoor activities, supports pollinating insects, and shelters temperature-sensitive plants (cf. Gustavsson and IngeloÈg, 1994). Urban areas are heavily subjected to air pollution, but urban vegetation acts as an effective sink for air pollutants and can signi®cantly reduce their levels (McCurdy, 1978; Miller, 1988; McPherson et al., 1994). The trees and bushes of urban forests catch air pollution, both in suspension in water drops and as aerosols in small particles (McPherson et al., 1994). 3.5. Wildlife and nature conservation Encounters with wildlife increase the quality of life, and urban forests are surprisingly rich in wildlife. The roe deer (Capreolus capreolus L.) is today a very ordinary urban mammal in southern and central Sweden (FlorgaÊrd et al., 1994). The moose (Alces alces L.) is seasonally a rather common guest, and hares (Lepus sp.), hedgehogs (Erinaceus europaeus L.), squirrels (Sciurus vulgaris L.), weasels (Mustela sp.), foxes (Vulpes vulpes L.), and badgers (Meles meles L.) nest and breed regularly in most urban forests (FlorgaÊrd et al., 1994). All kinds of birds frequently breed in all kinds of wooded urban areas (cf. Hansson, 1992; WireÂn, 1994). The biological diversity is often high in urban forests and the biodiversity is often believed to be better maintained, if the forests are measured with accurate silvicultural methods, than in many rural environments of the commercial agriculture and forestry landscape (LoÈfvenhaft and Ihse, 1998). All types of water tend to be reduced in urban areas. Surface water is put into culverts, and wetlands are drained. Today, water is being reintroduced into urban green areas in some Swedish municipalities (FlorgaÊrd et al., 1994; Tallhage LoÈnn, 1994). New ponds, brooks, and wetlands are being created and old ones are being recreated in order to prolong the time surface water spends on its way to the sea, which increases the uptake of nitrogen by vegetation and, thus, reduces the amount of nitrogen leaking away with the surface water. In urban areas, coppices are recommended as vegetation ®lters to remove nutrients from municipal waste and surface water (Perttu, 1993). The introduction of water will enrich the urban green areas as habitats and will also increase their recreational value (cf. Grahn, 1992).

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4. Status of urban forestry in Sweden During the 1970s and 1980s, recommendations for management of urban forests were concentrated on recreational areas adjacent to urban areas (Hultman, 1976; Kardell, 1974, 1985b). Kardell (1985b) proposed that recreation forests should be maintained with one single objective: ``that of providing the public with an attractive and beautiful piece of wood.'' It was, therefore, suggested that the proportion of old forest should be increased through longer rotation periods within the clear-cutting system (Kardell, 1974). A transformation of the recreational forest by moving from the clear-cutting regime to more old-fashioned selective systems was also believed to be desirable (Kardell, 1980, 1985b). Selective precommercial thinnings to enrich the beauty of the young stands were further suggested (Kardell, 1980). The proportion of various broad-leaved tree species was recommended to constitute 30% of the standing volume (Kardell, 1980). The proportion should not be larger because during the long winter in Sweden, wintergreen conifers are considered to be more pleasant than naked broad-leaved trees (Kardell, 1985b). The importance of creating and maintaining well-organised path systems was stressed, since about 90% of all forest visits are believed to involve the use of paths (Hultman, 1983c). A good passage was accentuated as being essential for recreation (Hultman, 1976). All of these management recommendations for recreational forests have had an effect on the directions for managing the urban forests given by the Swedish National Forestry Board (Carlborg, 1991); however, the directions have only partly been emphasised in the urban forestry of the Swedish municipalities. Lidestav (1994) stated that many of the Swedish local authorities did not have any pronounced objective for their forestland. Outdoor life and nature conservation had low priority in the plans of the municipality (Arnell et al., 1994; Lidestav, 1994). The responsibility for the management of the urban forest was often divided between different departments of the local authority, depending on the location of the forest in the urban area (Arnell et al., 1994). Commercially orientated entrepreneurs regularly managed the urban fringe forest, while the park department staff managed the forest inside urban

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areas. The responsibility for the management was also divided between different landowners. The municipalities are the major landowners, but other landowners of signi®cance are the county councils, the government, the Church, the National Road Administration, and private landowners (Anonymous, 1994a). Up until 1990, most of the `urban silviculture' comprised, therefore, either the silviculture of commercial forestry on a slightly smaller scale or the urban forest, measured without any planned management (cf. FlorgaÊrd et al., 1994). Recent studies have shown that the recommendations for recreational functions of the 1970s and 1980s are still valid (Mattsson and Li, 1994; Lindhagen, 1996). Using group selection to regenerate Norway spruce forests can reduce the negative effect of outdoor activity better than clear-cutting can (Kardell et al., 1993). A more extensive use of seed trees, advanced growth, and single-tree selection systems is considered desirable (Mattsson and Li, 1994). A change in the composition of tree species to one containing more broad-leaved trees is also urged (Lindhagen, 1996). Fallen trees and branches on the ground are generally disliked and should be removed to increase passability (Lindhagen, 1996). These recommendations for how to manage recreational forests correspond well with directions from other countries in Europe and North America (Ribe, 1989; Hummel, 1992; Axelsson Lindgren, 1995). The importance of actively creating new natural urban woods was ®rst highlighted during the 1970s, when about 60% of all house building was performed on agricultural land (Gustavsson, 1982). Afforestation with nature-like plantations of trees and shrubs with associated herbaceous plants was a method often used to introduce nature into urban areas (Gustavsson, 1982; Gunnarsson and Gustavsson, 1989). These plantations were an alternative to traditional park planting (Anonymous, 1994a), but the stand dynamics of these plantations implied that the design process continued into after-care (Tregay, 1986). Since the beginning of the 1990s, the ecological aspects of forests have come more into focus (Asplund and Rudberg, 1990, 1992; Anonymous, 1994a; Emanuelsson, 1997). The City of Stockholm stated several times the importance of biodiversity, and the threats against biodiversity were stressed (Asplund and Rudberg, 1990, 1992). In January 1995, the area of

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Ulriksdal, Haga, Brunnsviken, and DjurgaÊrden in the middle of Stockholm became Sweden's ®rst National City Park (Linder, 1997). The main aim was that the area would be maintained and would support outdoor activities and good recreation for citizens of all ages without harming the area's wildlife and cultural values (WaldenstroÈm, 1993; Linder, 1997). Many municipalities have given parts of their forests a nature conservation status (FlorgaÊrd and Schibbye, 1984; Karlsson, 1994; Avilov, 1996), leaving them to a natural succession with no further silvicultural treatment intended. These nature conservation areas are mainly allocated to the more remote areas of the urban forests. 5. Discussion: future improvements in urban forestry Urban forests differ from those in rural areas in terms of their use and in the high public involvement in urban forests issues (Konijnendijk, 1997). The local

public's commitment to, and its use of, the forests in¯uences the management of urban forests. Aspirations differ greatly between users according to income group, age, sex, and cultural background (Payne, 1983; Gilbert, 1989). Therefore, it is of great importance to look at the status and the use of the individual urban forest and to rank the use priorities when deciding how to manage the forests. Analogous to the zone models presented in FlorgaÊrd and Schibbye (1984), Smith (1984), Moll (1989), and Collins (1994), the Swedish urban forests could be classi®ed into ®ve zones, depending on their use and size: 1. Trees near houses: groups of trees close to houses and gardens (Fig. 2). 2. Neighbourhood forests: relatively small forests within residential areas (Fig. 3). 3. District forests: forests of medium size between two or more quarters of town (Fig. 4). 4. Recreational forests: large forests often on the urban fringe, where people travel for recreation (Fig. 5).

Fig. 2. Trees near houses have high esthetic value and provide windbreak shelter, but often tall trees close to houses and gardens cause discomfort for householders.

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Fig. 3. Neighbourhood forests create opportunities for children's play and public contact with nature close to their homes.

Fig. 4. District forests are frequently used by commuting walkers and bikers passing through the forest, and by others for shorter walks with a pram or a dog.

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Fig. 5. Recreational forests are larger forests, often used for longer walks and exercising.

Fig. 6. Forests for production are forests on the urban fringe, where traditional forestry is practised.

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5. Forests for production: forests on the urban fringe where traditional forestry is practised (Fig. 6). The silvicultural treatments should differ between all of these categories of urban forests in order to create and maintain forest structures adapted to the actual functional use of the forest. This demands a variety of appropriate silvicultural treatments. 5.1. Trees near houses Many people want a natural component close to their homes and of®ces that they can experience on an everyday basis. The pleasures derived include, among others things, beauty, the unexpected event, contact with birds and animals, wind shelter, quietness, and stimulating playgrounds for young children. Gardens and the environment adjacent to gardens are also of great importance for the urban wildlife and for biodiversity (Gilbert, 1989; FlorgaÊrd et al., 1994). However, trees and forests close to gardens frequently cause discomfort for householders. Tall trees obscure the sun and the line-of-sight from communication satellites to dish antennae and could, in stormy weather, even be dangerous (Falck, 1994). Falck (1994), therefore, suggests the creation of `stepshaped' forest edges close to gardens and houses (Fig. 7). Low, dense coppices that screen and provide

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shelter from the wind without obstructing sunlight may be another arrangement (Rydberg and Falck, 1996). The clear-felling phase of traditional coppicing should, however, be altered to more selective felling since clear-felling in urban areas often faces opposition (Rydberg, 1998). An `ever juvenile' forest (cf. Rydberg and Falck, 1998) treated with selective coppicing in which all trees above a certain height are cut could be appropriate. However, there is little experience in coppicing in Swedish urban areas, and knowledge about public perceptions of low forests and of the importance of coppices for the urban biodiversity is still insuf®cient. 5.2. Neighbourhood forests The neighbourhood is becoming more important since certain groups, like children and the elderly, as well as the unemployed and the IT commuters, spend a major part of their day in the house (Bjur and Gavatin, 1997). The most frequent consumers of neighbourhood forests are probably the children (cf. Sundheim et al., 1980). Children show an increasing radius of action with increasing age (BjoÈrklid, 1980), and therefore they need forests of different sizes at different distances from homes, day nurseries, and schools. (Rydberg and Falck, 1996, 1998) show how to use silvicultural treatments to design forests for children

Fig. 7. The step-shaped forest edge has low trees and bushes close to the garden or house and successively higher trees rising toward the surrounding high forest.

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and school forests, although there is a problem in assuming that adult experts could suggest what environments are best for children's play, since knowledge of children's preferences for different forest environments is de®cient. The urban green areas are characterised by fragmentation, which has resulted in many small forests in close connection to houses and a high proportion of forest edges. Since it is of great importance for human aesthetic and visual perception, the forest edge should be a delightful sight, acting as a welcoming entrance into the forest and forming the `walls' of the forest room (cf. Gustavsson and Fransson, 1991; SarloÈv Herlin, 1994). Well-designed forest edges are structurally complex and consist of a mixture of bush and tree species. Structurally complex forest edges have essential biological values as habitats for many plants and animal species, and together with high structural diversity of the accompanying forests, the urban biological diversity could be supported (cf. SarloÈv Herlin, 1994; WireÂn, 1994; Fuller et al., 1995). In addition, small forests have the functional value of screening air from pollution. The most effective and ef®cient part of forests for removing air pollutants is the ®rst 20±25 m of the forest edge (McCurdy, 1978). Stratifying the forest edge, expanding its width, and increasing its density by augmenting species diversi®cation are measures for improving the sink potential of the forest edge (McCurdy, 1978; Nowak, 1994). A considerable part of the new urban green areas have components of young growth, often in need of accurate silvicultural management. The management of young forests establishes the foundation for the forests of the future, which makes the design of the pre-commercial thinnings a very important part of urban forestry. Kardell (1980) suggested increasing amenity values of young forests by selective precommercial thinnings. Experience in adapting precommercial thinning practice to urban conditions is, however, almost non-existent, although Rydberg and Falck (1998) demonstrate that pre-commercial thinning offers a variety of opportunities for changing or strengthening the structure of young stands and, thus, provides good opportunities for transforming stands in order to attain a range of different functional objectives. Gilbert (1989) states, from an English point of view, that nature is often considered untidy and that the most

powerful social argument against ecological landscapes in towns is that they do not ®t in with the expectations of the majority of citizens, who are ignorant of their objectives. Gilbert implies that low-level management is mistaken for neglect and that scruf®ness is not only a source of criticism but can attract dumping of garden refuse. In Sweden, maintenance of biological diversity in urban areas (for example, leaving forests for natural succession) is recommended for areas less frequented by recreational visitors and for areas far from the estates (FlorgaÊrd and Schibbye, 1984; Lindhagen, 1996). However, the importance of biological diversity in urban areas has recently been more stressed (Emanuelsson, 1997), and the need for making citizens more aware of the importance of different biotopes has been emphasised (Anonymous, 1994b). Increased information, or what can be called mental nature conservation (WaldenstroÈm, 1993), could eventually enhance people's preferences for areas left for natural succession. One of the most important factors causing a decline in biodiversity of urban forests is the fragmentation (LoÈfvenhaft and Ihse, 1998). The effects of fragmentation are not linearly related to decline of biodiversity. There are fragmentation thresholds in proportion of suitable habitat that varied across species and landscape (AndreÂn, 1997). Spatial planing based on biotope structural aspects ( Forman and Collinge, 1997) are considered to be one ef®cient way to preserve high biodiversity in urban areas (LoÈfvenhaft and Ihse, 1998) and the development of sound landscape design principles are believed to be essential for biodiversity conservation (Hobbs, 1997). New silvicultural methods that imitate the prehuman forest dynamics are also examined to increase the biodiversity in urban forests. 5.3. District forests During the building boom of the 1960s and 1970s, the residential estates were placed far from the old town centres. The guidelines for planning the towns, which called for sparsely built-up areas and decentralisation, meant that forests of medium size in between two or more estates were saved. These district forests are frequently used by commuting walkers and bikers passing through the forest, by older children, and by others for shorter walks with, for example, a

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pram or a dog (cf. NordstroÈm, 1994; Lindhagen, 1996). Often, these forests are the most common forests in urban people's everyday lives. Today, district forests are regularly held as cultivated `pillared halls' with rather evenly aged stand structures created by continuous felling of undergrowth (Falck, 1994). The forest edges and entrances are also often poorly developed. There are reasons to increase the variation in stand structure in order to enrich the visual appeal and the recreational experience (cf. KellomaÈki and Savolainen, 1984; Axelsson Lindgren and Sorte, 1987); however, the occurrence of more densely vegetated wood patches has been questioned because people tend to prefer more open woodlands and forests of the pillared-hall type (Parsons, 1995). The sense of `enclosure', which is the fundamental physical feature of forests, often causes people to feel fear and anxiety (Burgess, 1995); nevertheless, the sense of enclosure is also the main reason people appreciate woodlands. One solution for this dilemma is to create areas that cater to different needs (Burgess, 1995). Rydberg and Falck (1998) demonstrate the creation of multi-functional urban forests of medium size by means of silvicultural thinning techniques. In an urban forest (around 2 ha), they promoted twelve different forest types, where each forest type served a speci®c function. The forest types used were, for example, a rowan forest, a children's forest, glades, a `walk-the-dog' forest, and an unevenly aged spruce forest. Gustavsson and Fransson (1991) propose similar measures (cleaning, thinning, stump clearing, and planting/sowing of woodlands ¯owers and grasses) for a rather trivial forest in the middle of a community in order to achieve a forest of high environmental quality. Alterations in forest structure must be done successively and must not involve drastic changes. Smallscale techniques should also be used to avoid damage to ground vegetation and standing trees (Kardell, 1985b; FlorgaÊrd et al., 1994; Karlsson, 1994). Using horses for wood extracting is a very careful, popular, and rather economical method (Kardell, 1974; Karlsson, 1994). Urban settlements tend to be located on fertile soils, which provides an opportunity to select slow-growing hardwood species for high-quality timber production. The silvicultural measures used should, therefore, promote the growth of trees with good wood quality as well as individual trees with noble and salient features (Kardell, 1988).

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Forest management has to be carried out with empathy for the local people in order to reduce all kinds of con¯icts associated with urban forestry. This makes information and communication between local populations and mangers essential (cf. Karlsson, 1994; Konijnendijk, 1997). Very few efforts have been made to involve local communities and to share responsibilities in the planning and management of Swedish urban forests (cf. Karlsson, 1994; LoÈfquist et al., 1994). Increasing the level of commitment of local inhabitants to urban forestry could make a considerable improvement in Swedish urban forestry. 5.4. Recreational forests Senior citizens are among the most regular visitors to recreational forests (cf. Lindhagen, 1996). Grahn (1991) found that elderly people search for recreational forests with well-drained paths, following softly broken ground and with benches for resting that are always available. The forest should preferable be large, above 60 ha, with softly varying forest types offering a wide diversity of nature experiences, water scenarios, spring ¯owers, berries, mushrooms, and a rich wildlife. These demands correspond well with those of other visitors to recreational forests (Kardell and Lindhagen, 1995; Lindhagen, 1996). Walking and exercising are the most popular activities in recreational forests (Kardell and Lindhagen, 1995; Sùndergaard Jenesen, 1995; Lindhagen, 1996; Kardell, 1998). The presence of forest glades with benches is, therefore, of great importance. The glades are the places where people stop and take a rest, enjoy the solitude of the forest, and feel comfortable in the peacefulness and silence of the soothing forest (cf. Hummel, 1992). Glades are also meeting places for adults and playrooms for children. Creation of dynamic glades (ca. 0.5 ha) has been suggested as a method to enhance habitat diversity in relatively uniform areas and to increase the amenity value of forests (Gilbert, 1989). Small areas of clear-felling, cleaned from slash, could temporarily act as glades in the forests. Ribe (1989) states that the greater the proportion of trees removed, the lower the resulting scenic value. This means that when a forest is to be regenerated, patches of clear-cuts are preferred to larger ones, but are less attractive than shelterwood cuts (Ribe, 1989).

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A shelterwood system with periods of partially twostoried stand structure is, therefore, of interest as a method for increasing beauty during the period when the tree generations are altered (Falck, 1992). This method differs from the common shelterwood system in the respect that the over-storey is maintained during a longer part of the undergrowth youth. Hence, a varied stand structure is attained, and the future wood quality of the undergrowth is formed (Falck, 1992). However, there is a need to study the method using partially two-storied stands more carefully, especially with different broad-leaved species. Single-tree selection of unevenly aged stands is another regeneration method of interest for the urban forest. This method is believed to attain forests of great beauty that are wellsuited for outdoor activities (Ammer and ProÈbstl, 1991). However, a study of how the environmental values of the forest are affected by different forest management practices shows that people's preferences varied a lot and that natural regeneration using seed trees gives a higher value than does single-tree selection (Mattsson and Li, 1994). 5.5. Forest for production Most of the encounters with larger wildlife, in particular, and a major part of the wild berries and mushrooms picked in urban areas take place in forests for production (Falck, 1994). The commercial management of these forests is limited by the new forest policy approved by the Swedish parliament in May 1993. Its main principles are the following: ``The forests shall be managed so that the needs for both, a high timber production and other functions of the forests are satis®ed . . . This is a multiple-use approach to forest management'' (Anonymous, 1994c). 6. Concluding remarks and suggested research Just like a park, a forest has to be managed appropriately if it is not to degrade, with the difference that the forest is much cheaper to keep in an attractive condition. If the forest is not too small, the revenue from timber sold will at least cover the cost of management over the long run. Thus, management can maintain traditional forest structures, create and maintain structural diversity, and maintain open-space

habitats and young growth, while also contributing timber, wood, amenities, recreation, and good landscape to society. This article has focussed on the importance of satisfying the urban citizen's needs and demands for the management of urban forests. This management should be uniformly performed irrespective of administration boundaries, but silviculture applications ought to be adapted to local uses and needs. It is, therefore, important for forest managers to be familiar with people's requirements and preferences. Children's and adult's needs for different green areas, such as urban woodlands, have been carefully studied during the last decades, but during recent years, the importance of green areas for youths has attracted much attention. To better understand and predict the demands of youths for urban forests, a better understanding of youths' preferences for forests is needed. Furthermore, when looking at the uses of urban forests, it is of interest to understand why people do not use urban forests. Often, fear of forests obstructs their use. Understanding people's fears and concerns about problems associated with trees and forests is essential, and solutions must be looked into. Perhaps fears and problems would decrease if local co-operation in the management of urban forests were increased. The possibility of increasing local community involvement in urban forestry needs to be further investigated. Today, signi®cant parts of the urban forests of Swedish municipalities are left for natural succession in order to increase their biological diversity; however, there are apprehensions that the urban forests will lose value and degenerate as recreational forests. Targeted information leading to a better awareness is often put forward as a way of increasing general acceptance of nature conservation. There is a need to more carefully study people's perception and preference of forests left for natural succession compared with forests under silvicultural practice, and to evaluate the importance of information for people's preference for maintenance of biodiversity. There are also essential to develop reliable landscape design principles and silvicultural methods to increase the biodiversity. Another important issue to be addressed is how to regenerate urban forests. It is desirable for the tree generations to partially overlap each other when urban forests are regenerated; however, the method using partially two-storied stands needs to be further

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evaluated experimentally, especially with different broad-leaved species. The public's perceptions of shelterwood systems and single-tree selection in urban forests ought to be more closely studied. The importance of young forests, coppices with or without standards, forest edges, and glades in urban areas gives cause for further studies on improving silvicultural treatments and management. At present, we lack important information on the best silvicultural measurements for providing bene®ts, such as stress reduction and urban wildlife, or for creating particular sights, sounds, or smells. In conclusion, Sweden is richly endowed with established urban forests, and the people feel, traditionally, a strong relationship with trees and forests. This makes the prospects for urban forestry in Sweden extremely good, but the managers and planners of the urban forests need to inspire people with con®dence in their work. Research on, and management of, urban forests requires teamwork among representatives from many professional disciplines and an increased local involvement. Managers and planners of urban forests must learn about the many psychological, social, and cultural needs that forests ful®l for urban areas, and they need to be empathetic and humble towards people's reactions. Acknowledgements The Swedish Council for Building Research, Movium, and the Swedish Council for Forestry and Agricultural Research ®nanced this work. Our sincere thanks go to Dr. Anders Karlsson and Associate Professor Erik Valinger for useful comments on the manuscript. Erich Schultz of Proper English Ltd has checked the English language. References Ahti, T., Hamet-Ahti, L., Jalas, J., 1968. Vegetation zones and their sections in north-western Europe. Annales Botanici 5, 168±211. Alskogius, H., 1996. Living conditions and life patterns. In: Helmfrid, S. (Ed.), The Geography of Sweden. National Atlas of Sweden, SNA Publishing, Stockholm, pp. 134±167. Ammer, U., ProÈbstl, U., 1991. Freizeit und Natur Verlag Paul Parey, Hamburg (in German).

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Andersson, B., Hultman, S-G., 1980. Skogens vaÈ rden Ð skogsbrukets roll. SLU/LTs foÈrlag, Kristianstad (in Swedish). AndreÂn, H., 1997. Habitat fragmentation and changes in biodiversity. Ecologic. Bull. 46, 171±181. Anonymous, 1994a. MiljoÈ och fysisk planering. Statens offentliga utredningar, Stockholm 1994, pp. 36 (in Swedish). Anonymous, 1994b. MaÊngfald i taÈtortslandskapet. In: Bernes (Ed.), Biologisk maÊngfald i Sverige. Monitor 14, pp. 232±242 (in Swedish). Anonymous, 1994c. Sweden's new forest policy. The National Board of Forestry, JoÈnkoÈping. Anonymous, 1995. Statistical yearbook of forestry. National Board of Forestry, JoÈnkoÈping (in Swedish, with charts and summary in English). Arnell, A., Eckerberg, K., Lidestav, G., 1994. Kommunernas utmaningar (in Swedish). Skog Forskning 1, 38±48. Asplund, E., Rudberg, J., 1990. Stockholms groÈna baÈlte. Stockholms stadsbyggnadskontor, Stockholm (in Swedish). Asplund, E., Rudberg, J., 1992. Storstockholms groÈna kilar. Stockholm stadsbyggnadskontor, Stockholm (in Swedish). Avilov, A., 1996. Values and use of an urban forest in the coastal region of south-western Sweden Ð The area of KaÊsjoÈ. Dept. of Silviculture, Swedish University of Agricultural Sciences, UmeaÊ, Report 5 (in Swedish, with English summary). Axelsson Lindgren, C., 1995. Forest aesthetics. In: HytoÈnen, M. (Ed.), Multiple-Use Forestry in the Nordic Countries. METLA, The Finnish Forest Research Institute, Helsinki, pp. 279±289. Axelsson Lindgren, C., Sorte, G., 1987. Public response to differences between visually distinguishable forest stands in a recreation area. Landscape Urban Planning 14, 211±217. Balling, J.D., Falk, J.H., 1982. Development of visual preference for natural environments. Environ. Behav. 1, 5±28. Berglund, U., Jergeby, U., Kreutzfeldt, U., 1985. Ute till vardags. Statens raÊd foÈr byggnadsforskning, R101, Stockholm (in Swedish). Bettelheim, B., 1982. Den tomma faÈstningen. WahlstroÈm and Widstrand, Stockholm (in Swedish). Bjur, H., Gavatin, M., 1997. Research and development in spatial planning and urban management. In: Guinchard, C.G. (Ed.), Swedish Planning towards Sustainable Development. Swedish Society for Town and Country Planning, GaÈvle, pp. 149±154. BjoÈrklid, P., 1980. Ut och lek. BostadsomraÊdets utemiljoÈ ur miljoÈoch utvecklingspsykologisk synvinkel. Statens raÊd foÈr byggnadsforskning, R65, Stockholm (in Swedish). Bucht, E., 1993. GroÈnplanering. In: Berg, P.G. (Ed.), Biologi och bosaÈttning. Natur och Kultur, Stockholm, pp. 201±232 (in Swedish). Bucht, E., 1997. Public parks in Sweden 1860±1960. The planning and design discourse. Acta Universitatis Agriculturae Suecia Agraria 56, Swedish University of Agricultural Sciences, Alnarp. Bucht, E., PaÊlstam, Y., Widgren, C., 1996. Tra®kupplevelse paÊ vaÈg. Stad and Land 142, Alnarp (in Swedish). Burgess, J., 1995. Growing in con®dence. Country Commission, London. Carlborg, N., 1991. TaÈtortsnaÈra skogsbruk. The National Board of Forestry, Report 1, JoÈnkoÈping (in Swedish).

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D. Rydberg, J. Falck / Landscape and Urban Planning 47 (2000) 1±18

Collins, K.D., 1994. Urban forestry in the Republic of Ireland. A review and case study. Thesis, National University of Ireland, Dublin. Collins, K.D., 1995. A strategy for urban forestry in Ireland. ECO, Report, Dublin. Douglass, R.W., 1982. Forest Recreation. Pergamon Press, New York. Emanuelsson, U., 1997. VarfoÈr naturhaÈnsyn? RaÈcker inte haÈnsyn? (in Swedish). Skog & Forskning 3(4), 6±10. Falck, J., 1992. New aspects of multiple-use in education and research at the Department of Silviculture in Sweden. Nor. J. Agric. Sci., Suppl. 8, 25±29. Falck, J., 1994. SkogsskoÈtsel i taÈtortnaÈra skog (In Swedish). Skog & Forskning 1, 4±12. Falck, J., 1996. Pre-commercial thinning in urban forests. In: Randrup, T.B., Nilsson, K. (Eds.), Urban Forestry in the Nordic Countries. Proceedings of a Nordic workshop on urban forestry held in Reykjavik, Iceland, 21±24 September, pp. 28±31. FlorgaÊrd, C., Schibbye, B., 1984. Naturmark. En kursbok om skoÈtsel, anlaÈggning och skydd av naturmark vid bebyggelse. Stad och land/Special, Alnarp (in Swedish). FlorgaÊrd, C., MoÈrtberg, U., Wallsten, M., 1994. VaÈxter och djur i stadsnatur. ByggforskningsraÊdet Tl: 1994, Stockholm (in Swedish). Forman, R.T.T., Collinge, S.K., 1997. Nature conservation in changing landscapes with and without spatial planning. Landscape Urban Planning 37, 129±135. Fuller, R.J., Gough, S.J., Marchant, J.H., 1995. Bird populations in new lowland woods: landscape, design and management perspectives. In: Ferris-Kaan, R. (Ed.), The Ecology of Woodland Creation. Wiley, Chichester, pp. 163±182. Gilbert, O.L., 1989. The Ecology of Urban Habitats. Chapman and Hall, London. Grahn, P., 1991. The meaning and signi®cance of urban parks. Dissertation, Swedish University of Agricultural Sciences, Department of Landscape Planning, Alnarp, Stad and Land 93 (in Swedish, with English summary). Grahn, P., 1992. MaÈnniskors behov av parker - amerikansk forskning idag. Stad and Land 107 (in Swedish). Grahn, P., Sorte, G.J., 1985. How is the park being used? A survey on organized groups usage of public green areas. Part 1. Stad och land/Rapport 39, Alnarp (in Swedish, with English summary). Grahn, P., MaÊrtensson, F., Lindblad, B., Nilsson, P., Ekman, A., 1997. Outdoor at day nursery. Stad and Land 145, Alnarp (in Swedish, with English summary). Grey, G.W., 1997. The Urban Forest. Wiley, New York. Gunnarsson, A., 1988. TraÈden och maÈnniskan. RabeÂn and SjoÈgren, Stockholm (in Swedish). Gunnarsson, A., Gustavsson, R., 1989. Etablering av loÈvtraÈdsplantor. Stad and Land 71, Alnarp (in Swedish). Gustavsson, R., 1982. Nature-like parks and open space in housing areas in Sweden. In: Ruff, A.R., Tregay, R. (Eds.), An Ecological Approach to Urban Landscape Design. University of Manchester, pp. 119±134. Gustavsson, R., Fransson, L., 1991. Furulunds Fure - en skog i samhaÈllets centrum. Stad and Land 96, Alnarp (in Swedish).

Gustavsson, R., IngeloÈg, T., 1994. Det nya landskapet: kunskaper och ideÂer om naturvaÊrd, skogsodling och planering i kulturbygd. Skogsstyrelsen, JoÈnkoÈping (in Swedish). Hansson, L., 1992. Requirements by the Great Spotted Woodpecker, Dendrocopos major for a suburban life. Ornis Svecica 2, 1±5. Hartig, T., Stokols D., 1994. Toward an ecology of stress and restoration. Man and Nature, Odense University, Working paper 53. Hobbs, R., 1997. Future landscapes and the future of landscape ecology. Landscape Urban Planning 37, 1±9. Hultman, S-G., 1976. Impact of forestry on outdoor recreation environment. Statens NaturvaÊrdsverk, SNV PM 706, Stockholm (in Swedish, with English summary). Hultman, S-G., 1977. Urban forestry in the USA Ð description and lessons for Sweden. SST 75, pp. 299±321 (in Swedish, with English summary). Hultman, S-G., 1979. Interpretation for recreation and wood production in urban forests. Arboric. J. 3, 483±489. Hultman, S-G., 1983a. Public judgement of forest environments as recreation areas. 2. A national survey. Dissertation, Swedish University of Agricultural Sciences, Section of Environmental Forestry, Uppsala, Report 28 (in Swedish, with English summary). Hultman, S-G., 1983b. How Many Berries and Mushrooms do we Actually Pick? VaÊr FoÈda 35, pp. 284±297 (in Swedish with English summary). Hultman, S-G., 1983c. Skog foÈr friluftsliv. Skogsfakta, Swedish University of Agricultural Sciences, Uppsala, No. 4 (in Swedish). Hummel, F.C., 1992. Aspects of forest recreation in Western Europe. Forestry 65, 237±251. HytoÈnen, M., 1995. History, evolution and signi®cance of the multiple-use concept. In: HytoÈnen, M. (Ed.), Multiple-Use Forestry in the Nordic Countries. METLA, The Finnish Forest Research Institute, Helsinki, pp. 43±65. HytoÈnen, M., BloÈndal, S., 1995. Timber production and the forest industry. In: HytoÈnen, M. (Ed.), Multiple-Use Forestry in the Nordic Countries. METLA, The Finnish Forest Research Institute, Helsinki, pp. 81±116. Jorgensen, E., 1974. Towards an urban forestry concept. Prepared for the 10th Commonwealth Forestry Conference, Ottawa, Canada. Kaplan, R., Kaplan, S., 1989. The Experience of Nature. A Psychological Perspective. Cambridge University Press, Cambridge. Kardell, L., 1974. RekreationsskogsskoÈtsel. Skogsfakta, SkogshoÈgskolan, Stockholm, No. 4 (in Swedish). Kardell, L., 1980. Skog foÈr fritid. ALA - Arbetsgruppen lantbruk och samhaÈlle, Swedish University of Agricultural Sciences, Uppsala, No. 5 (in Swedish). Kardell, L., 1982. Hur LinkoÈpingsborna utnyttjar sina stadsnaÈra skogar. Sveriges lantbruksuniversitet, avdelningen foÈr landskapsvaÊrd, Uppsala, Rapport 23 (in Swedish). Kardell, L., 1985a. Rekreationen, skogen och svenskarna. Statens naturvaÊrdsverk, Stockholm (in Swedish). Kardell, L., 1985b. Recreation forests Ð a new silviculture concept? Ambio 14, 139±147.

D. Rydberg, J. Falck / Landscape and Urban Planning 47 (2000) 1±18 Kardell, L., 1988. Tankar kring friluftsskogen i JoÈnkoÈpings laÈn. Sveriges lantbruksuniversitet, institutionen foÈr skoglig landskapsvaÊrd, Uppsala, Rapport 38 (in Swedish). Kardell, L., 1998. Anteckningar om friluftslivet paÊ Norra DjurgaÊrden 1975±1996. Sveriges lantbruksuniversitet, institutionen foÈr skoglig landskapsvaÊrd, Uppsala, Rapport 75 (in Swedish). Kardell, L., Eriksson, L., 1983. SkogsbaÈr och skogsskoÈtsel. SkogsskoÈtselmetodernas inverkan paÊ baÈrproduktionen. Sveriges lantbruksuniversitet, avdelningen foÈr landskapsvaÊrd, Uppsala, Rapport 30 (in Swedish). Kardell, L., Lindhagen, A., 1995. FoÈraÈndringar i VaÈxjoÈbornas friluftsliv mellan 1975 och 1992. Sveriges lantbruksuniversitet, institutionen foÈr skoglig landskapsvaÊrd, Uppsala, Rapport 59 (in Swedish). Kardell, L., Eriksson, L., Lindhagen, A., 1993. LuckblaÈdningsfoÈrsoÈk i Uppsalatrakten 1976-1990. Sveriges lantbruksuniversitet, institutionen foÈr skoglig landskapsvaÊrd, Uppsala, Rapport 54 (in Swedish). Karlsson, S., 1994. TaÈtortsnaÈra skogsbruk i Uppsala (in Swedish). Skog & Forskning 1, 50±53. Kellert, S.R., 1996. The Value of Life. Biological Diversity and Human Society. Island Press/Shearwater Books, Washington, DC. KellomaÈki, S., 1975. Forest stand preferences of recreationists. Acta Forestalia Fennica 146. KellomaÈki, S., Savolainen, R., 1984. The scenic value of the forest landscape as assessed in the ®eld and the laboratory. Landscape Planning 11, 97±107. Kempe, G., von Segebaden, G., 1990. What do the forests look like? In: Nilsson, N.E., Wastenson, L. (Eds.), The Forests. National Atlas of Sweden, SNA Publishing, Stockholm, pp. 56± 69. Komulainen, M., 1995. Landscape management in forestry. In: HytoÈnen, M. (Ed.), Multiple-Use Forestry in the Nordic Countries. METLA, The Finnish Forest Research Institute, Helsinki, pp. 295±320. Konijnendijk, C.C., 1997. A short history of urban forestry in Europe. J. Arboric. 23, 31±39. Lawson, M., 1996. Vegetation and sustainable cities. Arboric. J. 20, 161±172. Lidestav, G., 1994. Municipal forests - extent, use and planning. Dissertation, Department of Operational Ef®ciency, Swedish University of Agricultural Sciences, Garpenberg (in Swedish, with English Abstract). Linder, P., 1997. The ®rst National City Park in Sweden. In: Guinchard, C.G. (Ed.), Swedish Planning towards Sustainable Development. Swedish Society for Town and Country Planning, GaÈvle, pp. 126±129. Lindhagen, A., 1996. Forest recreation in Sweden. Four case studies using quantitative and qualitative methods. Dissertation, Swedish University of Agricultural Sciences, Department of Environmental Forestry, Uppsala. Lindholm, G., 1995. The school yard Ð adult's pictures, the child's environment. Dissertation, Swedish University of Agricultural Sciences, Department of Landscape Planning, Alnarp, Stad and Land 129 (in Swedish, with English Abstract).

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Linnell, B., LoÈfgren, M., 1995. Svenska krusbaÈr. En historiebok om Sverige och svenskar. Bonniers Alba, Stockholm (in Swedish). LoÈfvenhaft, K., Ihse, M., 1998. Biologisk mlngfald och fysisk planering. Department of Physical Geography, Stockholm University, Research Report No. 108. LoÈfquist, S., Enander, K-G., Gustafsson, B., 1994. Skogen i skolan. Skogsstyrelsen, JoÈnkoÈping (in Swedish). Mattsson, L., Li, C-Z., 1993. The non-timber value of northern Swedish forests: an economic analysis. Scand. J. For. Res. 8, 426±432. Mattsson, L., Li, C-Z., 1994. How do different forest management practices affect the non-timber value of forests? Ð an economic analysis. J. Environ. Manage. 41, 79±88. Mattsson, L., Stridsberg, E., 1981. Skogens roll i svensk markanvaÈndning Ð en utvecklingsstudie. Swedish University of Agricultural Sciences, Department of Forest Economics, UmeaÊ, Report 32 c (in Swedish). McCurdy, T., 1978. Open space as an air resource management strategy. Proceeding National Urban Conference Washington, DC, pp. 306±319. McPherson, E.G., Nowak, D.J., Rowntree, R.A., 1994. Chicago's urban forest ecosystem. USDA Forest Service Gen. Tech. NE 186, Radnor, PA. Miller, R.W., 1988. Urban Forestry. Planning and Managing Urban Greenspaces. Prentice Hall, NJ. Moll, G., 1989. In search of an ecological urban landscape. In: Moll, G., Ebenreck, S. (Eds.), Shading Our Cities: A Resource Guide for Urban and Community Forests. Island Press, Washington, DC, pp. 13±24. NordstroÈm, M., 1994. VaÊrt behov av groÈnska: aktuella miljoÈpsykoloiska forskningsresultat. Statens raÊd foÈr byggforskning, R14, Stockholm (in Swedish). È ldres liv och naÈra omgivning. NordstroÈm, M., Gora, M., 1995. A Stad and Land 133, Alnarp (in Swedish). Nowak, D.J., 1994. Understanding the structure. J. For. 92(10), 42± 46. Olembo, R.J., de Rham, P., 1987. Urban forestry in two different worlds. Unasylva 155(39), 26±35. Ottosson, J., 1997. Naturens betydelse i en livskris. Stad and Land 148, Alnarp (in Swedish). Parsons, R., 1991. The potential in¯uences of environmental perception on human health. J. Environ. Phychol. 11, 1±23. Parsons, R., 1995. Con¯ict between ecological sustainability and environmental aesthetics: conundrum, canaÈrd or curiosity. Landscape Urban Planning 32, 227±244. Payne, B.R., 1983. Urban woodlands and their recreational uses. In: Trees in the 21st Century, Based on the First Arboricultural Conference, A B Academic Publishers, Oxford, pp. 77±85. Perttu, K.L., 1993. Biomass production and nutrient removal from municipal wastes using willow vegetation ®lters. J. Sustainable For. 1, 57±70. Pukkala, T., KellomaÈki, S., Mustonen, E., 1988. Prediction of the amenity of a tree stand. Scand. J. For. Res. 3, 535±544. Ribe, R.G., 1989. The aesthetics of forestry: what has empirical preference research taught us? Environ. Manage. 13, 55±74. Rowntree, R.A., 1989. Urban forestry, carbon dioxide and global climate change. Forestry on the frontier, Proceedings of the

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D. Rydberg, J. Falck / Landscape and Urban Planning 47 (2000) 1±18

1989, Society of American Foresters National Convention, pp. 429±433. Rydberg, D., 1998. Urban forestry in Sweden from a silvicultural perspective focused on young forests. Doctor's thesis. Acta Universitatis Agriculturae Sueciae, Silvestria, No. 73. Rydberg, D., Falck, J., 1996. Den maÊngsidiga skottskogen. Fakta skog, SLU, Uppsala, No. 8 (in Swedish). Rydberg, D., Falck, J., 1998. Designing the urban forest of tomorrow Ð pre-commercial thinning adapted for use in urban areas in shaping tomorrow's urban forest. Arboric. J. 22, 147± 171. Salo, K., 1984. The picking of wild berries and mushrooms by the inhabitants of Joensuu and SeinaÈjoki in 1982. Folia For. 598 (in Finnish, with English summary). SarloÈv Herlin, I., 1994. Woodland edges in the agricultural landscape. Studies of structural characteristics as a base for management, new construction and conservation. Proceedings SNS Multiple Use Group Meeting and Excursion in Vejle, Denmark, 23±25 May, 1993, pp. 29±36. Searles, H.F., 1960. The Nonhuman Environment. International Universities Press, New York. Smith, D.M., 1984. Silviculture at the urban/forest interface. In: Bradley, B.A. (Ed.), Land Use and Forest Resources in a Changing Environment at the Urban/Forest Interface. University of Washington Press, Seattle, WA, pp. 101±108. SundbaÈrg, G., 1911. Det svenska folklynnet. P. A. Norstedt and SoÈners foÈrlag, Stockholm (in Swedish). Sundheim, L., Bennet, R., Elvestad, R., 1980. NearmiljoȱFritid± Rekreasjon. Sampl. Stiftelsen Samfunn-MiljoÈ-planlegging. Geograf®sk institutt. Universitetet i Bergen, Bergen (in Norwegian). Sùndergaard Jenesen, F., 1995. Forest recreation. In: HytoÈnen, M. (Ed.), Multiple-Use Forestry in the Nordic Countries. METLA, The Finnish Forest Research Institute, Helsinki, pp. 245±278. SoÈrlin, S., 1992. Frihetens hemman paÊ jorden (in Swedish). Skog & Forskning 4, 46±57. Tallhage LoÈnn, I., 1994. Stadens parker och natur. Boverket, Rapport 12, Karlskrona (in Swedish). Tregay, R., 1986. Design and ecology in the management of naturelike plantations. In: Bradshaw, A.D., Goode, D.A., Thorp, E.H.P. (Eds.), Ecology and Design in Landscape. Blackwell Scienti®c Publications, Oxford, pp. 275±284. TyrvaÈinen, L., 1997. The amenity value of the urban forest: an

application of the hedonic pricing method. Landscape Urban Planning 37, 211±222. Uddenberg, N., 1993. Ett Djur bland alla andra? Nya Doxa, Nora (in Swedish). Ulrich, R.S., 1993. Biophilia, biophobia and natural landscapes. In: Kellert, S.R., Wilson, E.O. (Eds.), The BIOPHILIA Hypothesis. Island Press/Shearwater Books, Washington, DC, pp. 73±137. Ulrich, R.S., Simons, R.F., Losito, E., Miles, M.A., Zelson, M., 1991. Stress recovery during exposure to natural and urban environments. J. Environ. Psychol. 11, 201±230. WaldenstroÈm, H., 1993. Ekoparken. Stockholms groÈna lunga. In: Berg, P.G. (Ed.), Biologi och bosaÈttning. Natur och Kultur, Stockholm, pp. 155±174 (in Swedish). WireÂn, M., 1994. Fauna and vegetation in urban parks. ByggforskningsraÊdet, Stockholm, R18 (in Swedish, with English abstract). D. Rydberg is a specialist in forestry at the County Forestry Board in Kristianstad. He was formerly employed as a researcher and project leader at the Department of Silviculture at the Swedish University of Agricultural Sciences (SLU) at UmeaÊ. In the early 1980s, he studied biology and chemistry at the University of LinkoÈping, in 1988 he graduated from SLU with an M.Sc in forestry, and, in 1998, he gained his Ph.D. in forestry at SLU. The thesis focussed on silvicultural aspect on urban forestry. His professional interests are mainly urban forestry, silviculture focussing on young forests, broad-leaved trees, coppice and shelterwood, forest landscape planning, nature conservation, forest management, and forest pathology. J. Falck is a lecturer in silviculture at the Forestry Faculty at the Swedish University of Agricultural Sciences (SLU) at UmeaÊ. He has held this position since 1974. In 1961, he took an M.Sc in statistics, geology, genetics, and botany at the University of Stockholm, an M.Sc in forestry in 1967 and a Ph.D. in forestry in 1982 at SLU. Under his supervision, Lars Lundqvist made the first study in Sweden on single-tree selection for a Ph.D degree (1985). During the 1990s, he headed a research project concerning sustainable use of virgin jungle in Borneo. The project led to a Ph.D. studentship in `Tropical Rain Forest Silviculture' in 1996. His other main interest is in international and local urban forestry, and under his supervision Dan Rydberg attained his Ph.D. in 1998. Jan Falck is one of the authors of the textbook Plantation Silviculture in Europe, Oxford University Press 1997.