Urban Forestry & Urban Greening 12 (2013) 296–306
Contents lists available at ScienceDirect
Urban Forestry & Urban Greening
journal homepage: www.elsevier.com/locate/ufug
Promoting urban greening: Valuing the development of green infrastructure
investments in the urban core of Manchester, UK
Ian C. Mell a,∗ , John Henneberry b , Sigrid Hehl-Lange b , Berna Keskin b
a
b
Department of Geography & Planning, School of Environmental Science, University of Liverpool, Gordon Stephenson Building, 74 Bedford Square South, Liverpool L69 7ZQ, UK
Department of Town & Regional Planning, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
a r t i c l e
i n f o
Keywords:
Green investment
Economic evaluation
Urban planning
Urban greening
Urban trees
a b s t r a c t
The attribution of economic value to landscape resources is fraught with technical and methodological
difficulties. Little is mandated in UK planning policy explaining how economic value should be established. As a result landscape resources have been undervalued, underfunded and marginalised in favour
of larger grey infrastructure development. The UK NEA however outlined for the first time a national
scale economic evaluation of environmental resources. The Valuing Attractive Landscapes in the Urban
Economy (VALUE) Interreg IVB project examined this issue by establishing a toolkit of economic evaluation methodologies for green investments across North-West Europe. Focussing on the returns that
investments in green infrastructure can deliver to cities and city-regions, the VALUE project identified
economic values that can be used to influence future policy-making. This paper presents an analysis of
VALUE street tree investments in Manchester, UK. Using a contingent valuation survey preferences for
green investments and associated willingness to pay (WTP) for them were generated. Analysis suggests
that willingness to pay is directly related to the size and greenness of the proposed investment and
participant perceptions of added value. 75% of respondents were WTP for investments in green infrastructure. Analysis indicates increased WTP and a marked preference for larger and physically greener
investments. Payment values ranged from £1.46 to 2.33, a 59.5% variance, between the preferred investment option and the status quo. The paper concludes that although green investments vary in size and
function, respondents consider the specific and wider value of green infrastructure resources when asked
how much they willing to pay to fund and maintain such investments.
© 2013 Elsevier GmbH. All rights reserved.
Introduction
The attribution of economic ‘value’ to landscape resources has
been fraught with constraints. Little is mandated in UK planning
policy at a regional or national level explaining how economic value
should be established for ecological resources. As a result landscape resources have historically been underfunded, undervalued
and marginalised in favour of grey infrastructure.
With the release of the UK National Ecosystem Assessment
(UKNEA), the UNEP-WCMC (2011) produced the first comprehensive national guidance establishing the economic value of
landscape resources. Where previous research assessed the value
of specific green investments, such as street trees or local parks, the
UKNEA differs by attributing economic values to a broader range
of both terrestrial and marine resources. Significantly, this process
is applied at a number of scales. By producing guidance the UNEPWCMC and partners have re-positioned the landscape valuation
∗ Corresponding author. Tel.: +44 0151 7943 262.
E-mail address: I.C.Mell@liverpool.ac.uk (I.C. Mell).
1618-8667/$ – see front matter © 2013 Elsevier GmbH. All rights reserved.
http://dx.doi.org/10.1016/j.ufug.2013.04.006
debate to ensure that environmental resources are discussed with
equal attention as other infrastructure development. The guidance
also arrives at an opportune moment where central government,
local authorities (LAs) and environmental organisations in the
UK are making difficult financial decisions regarding current and
future funding for green infrastructure (GI). Green Infrastructure
is defined by Natural England (executive non-departmental public
body responsible to the secretary of state for environment, food and
rural affair) as strategically planned and delivered network of high
quality green spaces and other environmental features. It should
be designed and managed as a multifunctional resource capable of
delivering a wide range of environmental and quality of life benefits
for local communities. Green Infrastructure includes parks, open
spaces, playing fields, woodlands, allotments and private gardens
(2009: 7).
An evaluation framework assessing the economic value of green
investments is a useful tool for landscape professionals. In a
period of austerity the production of economic data that identifies
projected economic returns provides a prudent delivery mechanism for infrastructure planning. Debates though exist within
the planning literature analysing why landscape resources have
I.C. Mell et al. / Urban Forestry & Urban Greening 12 (2013) 296–306
been undervalued. The European Landscape Convention (ELC) also
discussed this issue in legislative terms (CoE, 2007). However,
translating legislation and debate into robust economic data has
proved more difficult. The UKNEA stresses that ‘in the past, the
importance of these [landscape] areas for the health and general
well-being of society was not appreciated and their potential not
realised’ (UNEP-WCMC, 2011: 74). While it would be disingenuous
to suggest that planners are incognisant of the role green investments can play in promoting more liveable and economically viable
urban areas, it can be suggested that these debates are often superficial (Greed, 2011).
Given the constraints of developing robust economic evidence;
identifying discreet projects for evaluation, establishing evaluation parameters and controlling the variables under investigation
(Bateman et al., 2002), this paper examines research that aimed
to establish the economic value of GI in high-density areas. This
reflects the proposition that GI resources provides ecologically,
socially and economically sustainable infrastructure as part of a
strategically orientated approach to landscape management, which
identifies both the policy and practice perceived as most appropriate for investment. However, the grey and academic GI research has
predominately focussed on identifying its characteristics of GI or its
links with other green space planning concepts (Horwood, 2011),
however, within the current economic climate establishing robust
economic data is becoming increasingly important to planners if
they are to balance the conceptual development with the delivery
of GI (UNEP-WCMC, 2011).
Within this paper GI is identified as providing the physical
context for investment (design and composition) which can subsequently be used to investigate the willingness to pay (WTP) of
residents, business owners and commuters for green investments.
It discusses how WTP differs depending on the attachment and
perceptions of GI utility within urban areas. Using data from a largescale survey conducted in Whitworth Street West, Manchester, this
paper examines how stated preference testing (SPT) can be used to
analyse the relation between GI and willingness to pay (WTP). This
is addressed in three-stages. First, the growth in attention given to
the economic value in GI is considered followed by a discussion of
the economic evaluation process developed to assess the investments in Manchester. This highlights the structure of the economic
valuation tool used to identify the value of GI in the case study
area. Finally analysis of the large-scale survey is presented, indicating how SPT can be used to provide economic evaluations of GI
resources in central Manchester, before assessing the relation with
the wider debate focussing on perceptions of green investments
by local residents, users and businesses. The aim of this paper is to
establish a robust economic case for future investments in urban
GI based on WTP and personal valuations, which can be used to
support business cases promoting future GI developments.
Green investments in urban environments
Demographic change, housing and infrastructure development,
and fiscal constraints all impact upon the value of landscape
resources. Furthermore, as migration to urban areas continues
the capacity of cities to support increased use becomes stretched
(Gill et al., 2007). The pressures being exerted upon ecological
resources support the call of Beatley (2000) to rethink the value,
utility and spatial configuration of urban and assess the proportion of GI compared to other infrastructure. Unfortunately, green
and open spaces have historically been vulnerable to development
pressures due to the under-valuation of ecological resources by
planners and developers, who have placed a far greater value on the
creation or enhancement of grey rather than green infrastructure
(Benedict and McMahon, 2006). Grey infrastructure is classified as
the resources in urban areas that are man-made and do not serve an
297
overt or primary ecological function. Although grey infrastructure
can be ‘greened’ it relates most frequently to buildings, roads and
other transport infrastructure. Mell (2013) presents a more detailed
discussion of the meanings of grey and green infrastructure. The
dominant development native of the UK (and globally) exacerbate
this process as housing and transport infrastructure are deemed
necessities, rather than luxuries, offering greater financial returns
than GI.
Such discussions of GI value come at a pertinent time as the
National Planning Policy Framework (NPPF) in the UK has installed
a presumption within urban planning in favour of economic growth
supported through sustainable development. Economic evaluations of GI could thus be proposed as addressing this issue (DCLG,
2012). However GI is still considered by many as a development luxury or afterthought (Mell, 2009). In an attempt to resolve
this disequilibrium landscape practitioners have called for a more
prominent ecological perspective to be embedded within the process of urban planning (Benedict and McMahon, 2002). However,
balancing the utility, composition and value of landscape resources
is difficult, with many landscape professionals considering funding
for environmental management insufficient (CABE Space, 2004),
and has led to a marginalisation of ecologically focussed management in urban planning (Mell, 2009). In practice this is seen
in changing urban land budgets, which highlight the proportional
decreases in GI and public open space as allocations for housing
and commerce increase. Consequently, the protection of landscape
resources within planning policy, at least in the UK, could be considered as being of secondary importance (Wilson and Hughes,
2011).
To address this challenge planning professionals have engaged
in a global debate of GI assessing its ecological, as well as the economic and social value, alongside discussions of capital costs and
projected economic returns (Kambites and Owen, 2006). Unfortunately, whilst this process occurs the values placed upon ecological
resources are still predominately lower than those identified as economic or social resources (Tyrväinen, 2001). Economic evaluations
have also historically failed to take into account the true value of
landscape resources due to a lack of clarity in assessing the value
(market and non-market) of GI (Stenger et al., 2009; UNEP-WCMC,
2011). Establishing an evaluation framework to address this issue
providing equal consideration to ecological, as well as, economic
and social needs is therefore seen as a prerequisite if a balanced
understanding of GI is to be made (Mell, 2010; Underwood, 2011);
promoting the ‘visibility of GI benefits’ is central to achieving this
(Lorenzo et al., 2000).
Establishing the economic case for investment in GI is important
if LAs and developers are to continue to invest in urban greening.
However, increased awareness is needed of how personal engagement with urban areas influences the rationalising process and
WTP for green investments.
Valuation can be interpreted through examinations of place
attachment (identity and place), which explores the interaction
between physical setting of a landscape and personal interpretations of that place (Proshansky, 1978). Subsequently, use of GI
supports the view that through interaction spaces become imbued
with deeper meanings and become places (Tuan, 1974), values are
endowed and place valuation or dependency can develop (Brown
and Raymond, 2007). The relationship people have with urban
landscapes though are also influenced by its physical composition,
utility and psychological meaning. Consequently, the economic
value of a place is constructed through a combination of social and
ecological understandings and how it is situated in the surrounding environment (Winter and Lockwood, 2004). Investments in
urban greening therefore modify the physical, ecological and social
structure of a place and may reshape the relationships between
landscape preferences, WTP and GI.
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A further issue facing LAs investing in GI is balancing social
or ecological needs with economic viability. Whilst new parks,
gardens and greenways provide functional resources, residents
and developers are occasionally less aware of the on-going
maintenance costs (Defra, 2011). Users understand that capital construction costs are incurred, however, they are less aware that
sustained revenue is needed to support on-going management
(Hebbert, 2008). In the UK LAs have attempted to highlight the proportion of local taxes used to fund green space management (MCC,
2011). The analogous nature of urban landscapes thus provides
a platform where evaluations of landscape design and management can be made. A review of the benefits of GI suggests that
it could hold a central role to play in supporting economic growth
(Kambites and Owen, 2006). Benefits include, but are not limited
to, increased access to nature, sports/recreation facilities, increased
biodiversity, improvements in landscape and communal aesthetic
and well-being (Benedict and McMahon, 2006; Mell, 2009). It also
includes the role of GI in delivering ecosystem and regulatory (air,
water and food) and cultural (cohesion, aesthetics and heritage)
services in urban environments (UNEP-WCMC, 2011).
Variations in GI size, composition and location have all been proposed as major advantages of investments in urban greening. This
has been articulated predominately through social values in the UK
and ecological values in North America (Benedict and McMahon,
2006; Mell, 2010). There is a less well-defined debate regarding
economic value (Wilson and Hughes, 2011). Consequently, there
is a need to move away from the perceived fragmented approach
of urban green space planning in order to adopt a more coherent framework for investment based on an understanding of the
principles of GI: multi-functionality, connectivity, integrated management, strategic investment and economic value (Mell, 2009).
The development of a database of evidence supporting the value
of green investments could be used to address this issue; the EU
Interreg IVB project Valuing Attractive Landscapes in the Urban
Economy (VALUE) is one programme directly engaging this debate.
Interreg provides funding for interregional cooperation across
Europe. It is implemented under the European Community’s territorial co-operation objective and financed through the European
Regional Development Fund (ERDF). VALUE was a multi-partner
project, bringing together academic and delivery organisations in
Amersfoort (NE), Bruges (BE), Manchester (UK), Sheffield (UK),
Stuttgart (GE) and Liege (BE).
Valuing Attractive Landscapes in the Urban Economy (VALUE)
The central aim of VALUE was to address the lack of economic
data associated with GI development. Issues of scale, investment
type, the availability of funding and opportunities to implement GI
projects were all addressed. The challenge of VALUE was to establish a toolkit of economic assessment techniques to enable LAs
across North-West Europe to identify locations for future investments. These locations needed to deliver the greatest economic
benefit, whilst ensuring that high quality GI resources remain integral to functional and attractive urban environments. This was
articulated in the project’s objectives:
• To promote transnational actions that enhances the economic
and social performance of cities, towns and rural areas; including
the economic potential of local and regional assets.
• To identify and develop collective actions that will improve the
environmental quality and attraction of towns and cities including the sustainable use of the cultural heritage, tourism, the
creative economy and sustainable and innovative energy practices.
Fig. 1. Whitworth Street West – status quo.
One of the central assumptions proposed by VALUE was that, as
stated in the ELC, all investment in urban greening has an economic
value in spite of variation in size, function or location; a view sometimes undermined in evaluations of GI (Benedict and McMahon,
2006). Approaching VALUE within a multi-agency structure made
it possible to develop a theoretical understanding of the constraints
placed upon GI development, whilst generating economic data that
could be used to support future investments in GI.
Case study: Manchester
Two VALUE projects were undertaken in England, one in
Sheffield (Mell et al., 2012b) and one Manchester (Mell et al.,
2012a). The Manchester research was conducted in conjunction
with Community Forest North West/Red Rose Forest (CFNW-RRF).
This paper discusses street tree investments in Manchester, which
tested Lorenzo et al.’s assumption that: ‘urban and community
forests have become widely recognised as an important component
of the infrastructure of urban communities’, thus people become
attached to places and are subsequently WTP to support green
investments (2000: 319). The street tree investments were located
on Whitworth Street West, which was identified as an area of GI
deficiency (see Fig. 1). The installation of street trees tested CABE
Space’s (2004) assumption that residents and users prefer to live
and use streetscapes with a higher proportion of trees. It also shows
similarities to research undertaken by Soares et al. (2011) in Lisbon
and Tyrväinen (2001) in Finland, highlighting the social, as well as
the economic value of urban street trees.
The VALUE project aimed to establish comparable economic
values for investments in Manchester to research conducted by
Tyrväinen and Väänänen (1998) who identified respondent WTP,
174FIM (approximately £29/D 32) per year for access to areas with
a greater visible proportion of tree cover. Lorenzo et al. (2000) also
found that residents in Mandeville (LA, USA), would pay $6–12 per
year to protect/enhance urban woodlands. Consequently, developing a better understanding of the economic value of GI would
enable planners to locate investments where they can promote
greater economic returns. In a UK context this could form part of
the £2.2–3.0 billion per year that GI can add to the UK economy
(UNEP-WCMC, 2011).
The VALUE project in Manchester holds an additional importance for CFRW-RRF and Manchester City Council (MCC) following
the UK Comprehensive Spending Review (CSR) in 2010. In the
2011–2012 financial year MCC made £109 million worth of operational savings rising to £170 million in 2012–2013, a budgetary
saving of 23%. As a result funding for GI and public open space,
which is currently less than 5.5% of the environmental services budget, is expected to decrease significantly (MCC, 2011). In practice
the outcome of the CSR will mean that services are being subjected
I.C. Mell et al. / Urban Forestry & Urban Greening 12 (2013) 296–306
to increasingly stringent economic tests assessing capital spend
against revenue received. In light of this the aims of the VALUE
project in Manchester were:
299
Table 1a
Breakdown of Whitworth Street West respondent population categories.
Category
Interviews
achieved
(a) To generate a robust economic evidence base for street tree
investment that CFRN-RRF could use to support further green
investment in the city;
(b) To examine how GI can promote a better sense of place and
increased well-being through an assessment of different qualitative characteristics.
Resident
Employee
Business owner/senior manager
Commuter
Passing through
Visiting family/friends
Customer of shop/restaurant/other business
Some other reason
140
47
25
91
108
45
45
11
27
9
5
18
21
9
9
2
Methodology
Total (N)
512
100
A contingent valuation (CV) experiment was developed
assessing the WTP of commuters, residents and business owners
for street tree investments on Whitworth Street West. An expanded
discussion of study’s methodology is outlined in Mell et al.’s
(2012a) report to the VALUE project. The experiment focussed
on four main areas; general attitudes to green space; preferences
to tree and landscaping options based on one real image and
four visualisations; WTP; and attitudes towards the LA services
and green spaces provided in Manchester – see Figs. 2–4 (Mell
et al., 2012a). This guided respondents through a series of questions focussing responses on increasingly discreet aspects of urban
greening (personal–communal value; ecological–social–economic
benefits), and finally the development scenarios. Visualisations
were used to present four alternative development scenarios (plus
the current status quo). The use of visualisation in conjunction with
WTP has been considered one of the most appropriate methods
in effectively gauging respondent valuations (Greenspace, 2005;
Laing et al., 2005).
The survey design was derived from an extensive review of the
WTP literature and feedback provided by two focus group events
conducted in Manchester (O’Garra et al., 2007; Stringer, 2010).
The structure of the questionnaire enabled respondents to think
broadly before focusing on their personal uses of green spaces, the
Q2.
% of sample
values of ecological resources in these sites and the utility of GI in
making Manchester a more liveable place. Atkinson et al. (2008),
however, suggested that CV tests are only valid if the constructed
market and payment vehicle are a recognisable representation
of the landscape under investigation. The survey addressed this
by ensuring that sufficient data was available to participants to
support informed choices between the investments under examination. It also provided details of the financial allocations of taxes
to fund environmental services (Mell et al., 2012a). The constructed
WTP market was considered realistic rather than hypothetical, as
comparable greening projects had previously been completed by
CFNW-RRS (Bateman et al., 2002; ODPM, 2006).
Interviews were conducted face-to-face generating a sample of
512 respondents (N: 512). Interviews were conducted on Whitworth Street West by a professional survey team in 32 shifts. The
data collection was undertaken over 23 days (11th April–3rd May
2011); an average of 16 surveys was conducted per shift. A breakdown of the structure of the sample is shown in Tables 1a and 1b.
Cue cards were used to aid responses to attitudinal scales (Likert scales) and the investment options (Tyrväinen and Väänänen,
1998). The economic value (WTP scale) was established using a
constructed market for street trees. The WTP scale was based on
SHOWCARD B (R) Which of the things shown on the card would you say are most
important in making somewhere a good place to live? Just read out the FIVE letters of
the most important things to you. MULTI-CODE UP TO FIVE ONLY
(66)
A
Access to nature
1
B
Activities for teenagers
2
C
Affordable decent housing
3
D
Clean streets
4
E
Community activities
5
F
Cultural facilities
6
G
Education provision
7
H
Facilities for young children
8
I
Health services
9
J
Job prospects
10
K
The level of pollution
11
L
The level of traffic
12
M
Parks and open spaces
13
N
Public transport
14
O
Race relations
15
P
The level of crime
16
Q
Road and pavement repairs
17
R
Shopping facilities
18
S
Sports and leisure facilities
19
T
Wage levels & local cost of living
20
U
Trees
21
Other (PLEASE WRITE IN AND
22
CODE ‘22‘)
Fig. 2. Question 2: Manchester Whitworth Street West questionnaire survey.
(66)
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I.C. Mell et al. / Urban Forestry & Urban Greening 12 (2013) 296–306
Q5.
SHOWCARD D (R) AGAIN I’m going to read out a number of statements about the green
spaces in near your home. For each please tell me how much you agree or disagree with
the statement. READ OUT a) to d). ROTATE ORDER – TICK START. SINGLE CODE ONLY
FOR EACH QUESTION.
a)
b)
c)
d)
The green spaces in my local area are
maintained to a high standard
The green spaces in my local area are of
a high quality
The green spaces in my local area are
useful for local people
The green spaces in my local area make
a difference in tackling climate change
Strongly
agree
Tend to
agree
Neither
agree nor
disagree
Tend to
disagree
Strongly
disagree
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
(1
6)
(1
7)
(1
9)
(2
3)
Fig. 3. Question 5: Manchester Whitworth Street West questionnaire survey.
Q8a
On average each person in a local area pays £2.20 per month for street cleaning and
£1.50 per month to maintain green spaces. This is paid through their council tax. How
much extra each month would you be willing to pay to maintain the street as shown in
the picture? DO NOT READ OUT. SINGLE CODE ONLY. ENCOURAGE ESTIMATE IF
REPSONDENT NOT SURE.
ASK IF NO AT Q7a, OTHERS GO TO NEXT CONCEPT.
On average each person in a local area pays £2.20 per month for street cleaning and
Q9a
£1.50 per month to maintain green spaces. This is paid through their council tax. How
much extra from the council tax do you think should go towards maintaining the
street as shown in the picture? DO NOT READ OUT. SINGLE CODE ONLY.
ENCOURAGE ESTIMATE IF REPSONDENT NOT SURE.
(67)
£0.00
£0.20
£0.40
£0.60
£0.80
£1.00
£1.20
£1.40
£1.60
£1.80
£2.00
1
2
3
4
5
6
7
8
9
10
11
£2.20
£2.40
£2.60
£2.80
£3.00
£3.50
£4.00
£4.50
£5.00
£5.50
£6.00
12
13
14
15
16
17
18
19
20
21
22
£6.50
£7.00
£7.50
£8.00
£8.50
£9.00
£9.50
£10.00
£10.00+
No figure given
Would not pay
extra
23
24
25
26
27
28
29
30
31
32
33
Fig. 4. Manchester Whitworth Street West WTP scale.
an extensive review of existing WTP research studies and used the
work of Bateman et al. (2002) and Atkinson et al. (2008) as specific reference points in its development. Personal communications
with Professor Guy Garrod (Newcastle University) and Professor
Liisa Tyrväinen (Finnish Forest Research Institute) were also sought
to provide additional information to construct the WTP scale. The
Table 1b
Demographic structure of Whitworth Street West respondent population.
Sex
%
Ethnicity
%
Age
%
Male
Female
58
42
White
BME
Other/not stated
78
20
2
<20
20–29
30–39
40–49
50–59
60–69
70>
8
49
17
14
8
4
1
WTP elicitation question was complemented by contextual questions allowing the survey to establish a deeper understanding of
preferences as ‘. . .cost is not ‘just money’: it is an expression of
resources that could be used for all kinds of other, perhaps equally
deserving, purposes’ (Bateman et al., 2002, p. 19).
Two WTP questions were developed; the first asked how much
respondents were WTP in extra taxes for green investments, whilst
the second question posed whether people would be WTP more
from existing council tax payments to meet these costs. The second
question was asked only if respondents had recorded a zero (£0.00)
or ‘no payment’ value to the first question and was used to address
the potential issue of protest zero payments (Mell et al., 2012a).
The WTP elicitation question was framed as a regular monthly
council tax payment. The incremental payment range reflected the
actual costs of investing in street trees shown in previous CFNWRRS research. This was consistent with the argument presented
by Stenger et al. (2009) that trees provide direct ecological and
I.C. Mell et al. / Urban Forestry & Urban Greening 12 (2013) 296–306
301
Fig. 5. Whitworth Street West – small trees.
Fig. 7. Whitworth Street West – large trees.
socio-economic benefits that can be perceived by respondents.
Tyrväinen also suggested that the use of a regular payment mechanism ‘enables the comparison of provision costs and received
benefits both at the land use planning and management level’ when
discussed in conjunction with other aspects of CV surveys’ (2001:
76). A council tax payment vehicle was proposed such a regular
payment method because:
The images used were developed by CFNW-RRF/University of
Sheffield to show realistic investment opportunities but were not
perfect representations of the proposed investment. Despite these
limitations, 98% of respondents found the images useful aids in
attributing WTP values. Analysis focussed on examining respondent preferences for the various options, WTP and their attitudes
to green space in Manchester. This allowed an exploration of the
influence of the design of the different development options and of
personal attitudes towards green spaces on WTP.
1. It is a tax most respondents in Manchester (and England) are
familiar with and pay;
2. It is a cost that people can interpret against their perceptions of
local service provision;
3. It would draw responses, both positive and negative, as respondents are likely to have formed opinions on council tax charges;
4. Regular or monthly payments potentially elicit a more realistic
WTP value than a one off payment.
The constructed market and the WTP questions were used in
conjunction with a set of five 2D visualisations of the proposed
investments. Text based descriptors were not used. Fig. 1 presents
a no change/status quo option, whilst Figs. 5–8 present four
alternative options for street tree and landscaping investments.
Using Visualise2D in combination with Photoshop was an effective technique to present Whitworth Street West with a variety of
street trees planting conditions with and without grass underneath
(Figs. 5–8). See Mell et al. (2012a) for a more detailed description
of how the visualisations were integrated into the survey. Similar research using photomontage simulations were undertaken by
Todorova et al. (2004) highlight methodological similarities to the
VALUE research additional greening options, including different
tree species, floral arrangements or public amenities (i.e. benches)
were considered, however, additional features would have broadened the variables under consideration too widely.
Fig. 6. Whitworth Street West – small trees and grass verges.
Results
The construction of a realistic valuation market based on known
costs for street tree investments facilitated the establishment of
a robust economic value for green investment options on Whitworth Street West. The results indicate that there is a relationship
between the size and type of greenness of an investment and people’s WTP for it. Furthermore, larger or more visible GI investments,
which refer to the level of perceived greenery in each investment option including the size of each element and the wider
composition within the image, elicit higher payment values than
investments perceived as presenting lower levels of visible greenery. Figs. 9 and 10 highlight two different patterns for WTP extra
council tax and WTP more within existing payment values. Firstly,
the results suggest that the majority of respondents (72%) were
willing to support the installation of the proposed green investments with extra financial contributions. Analysis indicates that
only 25% of respondents would pay to maintain the status quo,
whilst approximately 72% of respondents would pay for some
form of additional urban greening.128 respondents were not WTP,
whilst 369 were WTP to support the green investment options, 15
respondents did not answer the question (Mell et al., 2012a). Fig. 9
Fig. 8. Whitworth Street West – large trees and grass verges.
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Fig. 9. Whitworth Street – willingness to pay/not willing to pay and preference.
Fig. 10. Green assessment and willingness to pay – Whitworth Street.
indicates that greener investments, in terms of tree size and visible street greening, return higher payment values, a 59.5% (£0.87)
increase in WTP values is indicated between the status quo and
the preferred option (Fig. 8). This compares to an 11.6% (£0.17)
increase between the status quo and investments in small trees.
This suggests that the perceived size, shape and composition of
an investment have a significant impact on WTP. Fig. 10 proposes
a similar relationship exists between perceived greenness, preferences and increased WTP for them.
In contrast, where respondents were not WTP extra but were
willing to allocate a greater proportion of existing payments for GI
an alternative pattern was evident. Analysis indicates that respondents showed preferences for, and were, WTP higher amounts for
visibly and physically smaller investments. The values generated
when asked to allocate additional financial resources from existing
taxes were also substantially lower than those when respondents
were asked to pay additional taxes. This may demonstrate that
respondents include other factors (i.e. assessments of the costs of
maintenance) within their perception of whether they would use
the investments. It may also indicate a reticence to pay for GI as
they were being asked both WTP (extra and additional allocations)
questions.
A relationship is seen between the differences in how people
perceive and interact with the environment, investment preferences and WTP. This is highlighted when assessed against payment
type. Table 2 highlights preferences for visibly larger GI investments in street trees across each of the five user classifications.
The classifications were: resident, business owner, employee (work
on street), commuter and other. Residents, employees and commuters preferred larger trees and grass investment options, whilst
business respondents were less likely to indicate preferences for
this investment; 32% compared to an average of 62%. This suggests a relationship between interpretations of each investment
and how respondents perceive its value in terms of visual and functional factors. Whilst each of the other respondent types presents
a clear investment preference, in contrast, businesses show similar
WTP values for each of the greening investments without identifying a clear preference. This can be compared to Fig. 11 and
Table 2
Preference percentage per user category.
Residents
Status quo
Small trees
Small trees and grass
Large trees
Large trees and grass
Other
a
a
1%
3%
17%
14%
65%b
0%
Business
a
0%
20%
24%
20%
32%b
4%
Lowest preference for each user category.
b
Highest preference for each user category.
Employees
6%
2%a
11%
19%
62%b
0%
Commuters
a
1%
3%
13%
22%
59%b
2%
Other
3%a
6%
15%
13%
63%b
0%
I.C. Mell et al. / Urban Forestry & Urban Greening 12 (2013) 296–306
303
Fig. 11. Characteristics of a high quality environment.
Table 3
Reported factors influencing WTP.
Characteristic
Focus: environmental, economic or social
%
Makes the street attractive
Makes the street cooler
Increases property values
Decreases the level of pollution
Increases local business revenue
Improves water run-off
Encourages dog fouling
Blocks off the light to my home and/or business
Increases bird fouling
Increases leaf drop/makes my car dirty
Makes it harder to see other people
Other
Not stated
Social
Environmental/social
Economic
Environmental
Economic
Environmental
Social/economic/environmental
Social/economic
Social/economic/environmental
Social/economic/environmental
Social/economic
Social/economic/environmental
93
29
25
27
11
5
4
7
5
4
4
3
0
Table 4
WTP/Not WTP by user category.
Willing to pay
Not willing to pay
Resident
Business owner
Work on street
Commuter
Other
£1.88
£0.40
£1.26
£0.80
£1.71
£0.37
£1.76
£0.34
£1.80
£0.47
Table 3, which outline the factors noted by respondents as influencing preferences and WTP. Whilst the analysis does not show a
causal relationship between each characteristic and WTP, Table 3
and Fig. 11 indicate that people assess social (landscape attractiveness, utility), economic (house prices) and environmental (access
to GI, nearby nature) factors when asked to indicate preferences for
GI investments.
Analysis also highlighted the following pattern relating to
‘green’ infrastructure preferences and WTP. Within the investment
options there was a clear preference and related WTP for the scenarios deemed greenest. Fig. 10 is indicative of this showing where
each transition in greening (small to large and no grass to grass)
sees an increase in the respondent perceptions of greenness. When
examined against WTP this supports the view that the greener a
development scenario is perceived the higher the WTP value. With
regards the objectives of VALUE this suggests that a strong relationship exists between WTP, scenario preferences and respondent
perception of greenery.
Table 4 presents comparable data to Fig. 9 with business respondents stating lower monetary values where they were WTP. They
are, however, willing to provide the greatest financial support
from existing taxes compared to the other respondent groups.
Therefore, although business users are WTP significantly lower
additional taxes (minimum difference of −23%) they are WTP proportionally more from current council taxes (minimum difference
+41%). The data indicates that residents (who are likely to have
the closest attachment to the area) are prepared to pay the most
to improve their local environment (£1.88 more per month) with
commuters and employees being WTP 12–15% (£1.60–1.65) less.
This supports the suggestion that residents show greater place
attachment due to their proximity to the study area, and is reflected
in higher WTP values.
A reading of Tables 4 and 5 suggests that residents (who may
or may not be working) were WTP more for green investments
Table 5
WTP, frequency of use of local green infrastructure resources and work status.
Frequent
Regularly
Infrequent/never use
WTP
NWTP
Working
Retired
Not working
Education
59%
29%
11%
£1.84
£0.43
80%
13%
7%
£2.10
£0.26
65%
23%
13%
£2.32
£0.39
47%
41%
12%
£1.62
£0.45
304
I.C. Mell et al. / Urban Forestry & Urban Greening 12 (2013) 296–306
Table 6
Perceptions of GI’s contribution to urban landscape value.
Local green space is maintained to a high standard
Local green space is of a high quality
Local green space provide useful amenities for
local people
Local green spaces make a positive contribution to
climate change control
Discussion
Agree
Disagree
69%
61%
80%
14%
18%
8%
40%
21%
than other users. Thus, we can hypothesise that the monetary value
placed upon street trees and landscaping reflects respondent perceptions of Whitworth Street West in relation to frequency of use,
size and composition of GI resources. Therefore the greater the
perceived amenity value, the higher its reported preference and
the more respondents were WTP. This pattern also appears true
between GI proximity to homes, places of employment and WTP.
Whilst use and place attachment appear to influence WTP the
length of respondent tenure (owner occupied, social tenant, private
tenant and student housing) did not show a significant relationship
with WTP. Although resident WTP was highest; average WTP varied (£1.50–1.99). None of the Chi2 calculations were found to be
significant at the 95% confidence level (0.05) as a result the tabulations are not reported in this paper. A closer relationship can
however be identified if WTP, frequency of use and work status are
assessed. Table 5 indicates that people who are retired or not working visit green and open spaces most frequently and are also WTP
more for them. This supports Tyrväinen and Väänänen (1998) view
that valuation is closely linked with frequency of use. Research by
CABE Space (2006) also suggested that specific social and ethnic
groups, including the retired and unemployed are more likely to
make use of green spaces because they are not subject to the same
constraints (time or financial) as other people.
Further analysis suggests that respondent characteristics and
attachment to Whitworth Street West influence WTP. It is however
important to assess whether the preferences identified can also
be supported though respondent discussions of landscape quality.
Fig. 11 and Table 3 presents a number of characteristics identified
by respondents as influencing perceptions of a high quality environment. When analysed alongside WTP, the breadth of respondent
reasoning suggests that valuation is based on interpretations of a
combination of social, ecological and economic variables. Fig. 11
and Table 3 both show a number of issues including street cleaning, access to nature, employment and crime, which supports the
research of CABE Space (2006) arguing that these characteristics
affect the ways in which people perceive the value of urban street
scenes. It could also be suggested that although ‘green’ influences
(public and open space: 39%, access to nature: 20% and trees: 22%)
are not the most prominent factors (clean streets: 48%: crime: 40%
and transport: 43%), they do influence the process of value attribution.
Respondents were also asked to rate their local environment in
terms of value, quality and utility (Table 6) to enquire whether WTP
could be linked to positive perceptions of other GI resources. Analysis indicates that there is a positive interpretation of the local GI,
69% reported it being maintained to a high standard, 61% being of a
high quality and 80% proposing GI as useful resources for local communities. When reviewed alongside an assessment of respondent
interpretations of local authority services the analysis indicates that
59% of respondents felt that their LA provided high quality services
and a further 47% value for money (63% (No. 323) of respondents
lived within an MCC controlled LA area). Thus, there appears to be
consistent positive view for WTP, interpretation of the local environment and respondent perceptions of the LAs ability to manage
high quality GI resources.
The analysis of the VALUE survey demonstrates that residents,
businesses and commuters are all WTP for green investments in
urban areas. This supports the research of CABE Space (2004) and
Benedict and McMahon (2002) who stated that the development
of a functional, attractive and visibly greener urban environment
is fundamental in establishing WTP values for greening projects.
However, payment values and the preferred mechanism, extra
council tax or an additional percentage of existing council tax, to
fund vary among user groups. The findings of the Manchester case
study though compare favourably with the research of Gensler and
Land Use Institute (2011) who reported that 95% of European planners and developers would be WTP a 3% increase in taxes or rent for
GI development. Scarpa et al. (2000) though sounded a note of caution, reporting that there are issues to comparing stated WTP values
(potential future payments) against the actual economic costs of
implementation or maintenance. Thus, whilst WTP surveys provide
indications of potential revenue returns that can be used by LAs to
build business cases for GI investments, it may prove difficult to
use this information for funding for development.
Participants in the VALUE survey concurred with the CABE
Space view stating that in highly urbanised locations, with high
proportions of grey infrastructure investments in GI provides are
attributed higher WTP values. CABE Space extends this arguments suggesting this is due to GI providing greater personal or
communal benefits within environments perceived as being ecologically restrictive (CABE Space, 2006). Analysis presented in this
paper support this highlighting the relationship between visibly
larger investment in street trees, preferences and WTP extra for
such investments. However, when respondents were reluctant or
perceived lower utility values, smaller investments (i.e. small trees)
were the preferred investment option. Throughout investments in
GI were seen as preferable to the status quo. This variation reflects
a number of issues (size, utility and cost), therefore this analysis and the existing practitioner research literature proposes that
respondents may identify that investments in urban greening act
as an improvement to the physical landscape; although smaller
green investments could provide more cost-effective returns to
local residents and businesses than larger projects. Moreover, Irwin
(2002) noted that increased distance from a GI resource has a negative impact on WTP, whereas a residential view of high quality
GI increases WTP. Thus the development of GI in highly urbanised
locations could have a proportionally greater impact for local communities due to the increased population density. A view reinforced
in the Whitworth Street West survey. Willis and Garrod (1992)
and CABE Space (2006) also proposed that the type of GI (tree and
landscaping species, size, design and relative greenness) influenced
WTP.
To highlight the value of WTP data a process of grossing up was
undertaken based on the generated WTP values to extrapolate the
potential economic value of GI at a ward and city scale. This was
conducted as a theoretical exercise to highlight the potential revenue returns for MCC. A basic calculation methodology was used
and the figures presented should be considered indicative; a more
extensive appraisal would be needed for these figures to be applied.
Based on ward and citywide demographic data (MCC, 2011) it was
possible to estimate potential yearly increases in council tax payments of between £43,540 and £190,361 from residents in the City
Centre Ward, where Whitworth Street West is located, using the
WTP values of £0.43–£1.88 (scenario averages) (Table 7). At a city
scale (151,659 eligible households) additional council tax returns
would range from £564,171 to £3,057,445 a year (Table 8).
The attribution of value to green investments should be considered as a nuanced process. As discussed throughout this paper there
is a relationship between the visible greenery in specific urban
I.C. Mell et al. / Urban Forestry & Urban Greening 12 (2013) 296–306
305
Table 7
Estimated grossing-up based on 8438 eligible households for council tax in Manchester City Centre ward.a
Manchester City Centre ward population: 8438
SQ
ST
ST&G
LT
LT&G
Total WTP
Average (sample size 140)
£60.00
£157.20
£183.80
£238.20
£268.20
£0.43
£1.12
£1.32
£1.71
£1.88
Per month WTP
£3628.34
£9450.56
£11,138.16
£14,428.98
£15,863.44
Per year WTP
£43,540.08
£113,406.72
£133,657.92
£173,147.76
£190,361.28
a
This uses the total household figure of 9427 and withdraws 637 properties noted as ‘void’ by Manchester City Council and a further 352 households that receive council
tax benefits.
Table 8
Estimated grossing-up based on total number of eligible households for council tax in Manchester Metropolitan area: 151,659.a
Manchester City Centre ward population: 151,659
SQ
ST
ST&G
LT
LT&G
Total WTP
Average (sample size 323)
Per month WTP
Per year WTP
£99.30
£347.30
£392.50
£500.90
£541.10
£0.31
£1.08
£1.22
£1.55
£1.68
£47,014.29
£163,791.72
£185,023.98
£235,071.45
£254,787.12
£564,171.48
£1,965,500.60
£2,220,287.70
£2,820,857.40
£3,057,445.40
a
The total number of households in the Manchester Metropolitan area is 215,251, however, Manchester City council note that 63,592 households received council tax
benefits or are exempt from this charge.
Table 9
Results of previous studies of WTP of urban greening.
Location
Investment type
Average monthly WTP
(current prices)
Yorkshire Dales National Park
Willis and Garrod (1992)
North Carelia, Finland Tyrväinen
and Väänänen (1998)
New York Peper et al. (2007)
Guangzhou Jim and Chen (2006)
London Olympics Atkinson et al.
(2008)
National Park resources and
visitor facilities
Urban trees/forests
£2.19 (residents)
Urban/street trees
Urban greenspace and trees
Olympic games venues,
greenspace and infrastructure
UK Botanical Gardens Garrod et al.
(1993)
Access and maintenance of
botanical gardens
£0.34–0.67
£1.70
London – £1.83
Manchester – £1.00
Glasgow – £0.92
Edinburgh – £1.29
Sheffield – £1.12
Cambridge – £0.86
Westonbirt – £2.23
environments, preferences for GI investments and WTP. Additional
benefits including alleviating crime, improving health, increasing biodiversity and supporting economic development were also
attributed to GI in the research literature but were not analysed
in-depth in this study (Tuan, 1974; Benedict and McMahon, 2006).
Furthermore, an extensive range of benefits were discussed in the
studies outlined in Table 9, indicating that the WTP values calculated for the VALUE investments compare favourably to previous
studies. Although the survey focusses primarily on establishing
economic values for street trees, Tables 3 and 6 illustrate that additional value was identified for the ecological characteristics of the
site. The objective of this research though was not to develop an
assessment of the ecological benefits of investments in street trees
but to show whether economic values are supported by positive
perceptions of a sites ecological and social context. Respondents on
Whitworth Street West also highlighted that the process of valuation is based on a number of personal and communal preferences
and the nature of the investment. Thus, WTP for GI can be proposed as reflecting the complexity of evaluating physical landscape
characteristics alongside the principles of place attachment and
discussions of the social and economic value (Proshansky, 1978;
Winter and Lockwood, 2004).
£1.6 (visitors)
£2.42
Conclusion
The impacts of green investment in urban areas are many.
Reports from two focus groups held prior to the WTP research in
Manchester made reference to improvements in health, well-being,
additional recreation spaces and tackling climate change as benefits of GI. The analysis presented in this paper supports a number
of these issues, as respondents noted clean streets, reduced crime,
climate control and less pollution as reasons to financially support
investment in GI. The data also suggests that the physical size of
a resource is not necessarily as important as its function, relative
level of additional greenery or payment type. Overall a perceived
increase in the proportion of GI has been shown to attract higher
WTP values. Investments in urban greening though appear to be
evaluated against the physical characteristics, i.e. greenery, of an
investment site. Street tree investments should therefore be considered as economically viable, in terms of investment options, as
larger public parks. However, they potentially offer greater benefits at a local scale. Economic evaluations of GI investments should
be encouraged as planners are attempting to identify implementation mechanisms to integrate multi-functional GI in urban areas.
This view meets the proposals of the EEA who stated that ‘Green
306
I.C. Mell et al. / Urban Forestry & Urban Greening 12 (2013) 296–306
infrastructure is an important part of territorial identity and capital’
and should be used to enhance the urban landscape (EEA, 2012:20).
In urban locations where land availability is limited, open space
needs to be thought of in creative terms so that street greening
and new forms of public space meet local needs. The analysis for
the VALUE research highlights that residents and users are WTP
for green development; although the level of financial commitment varies responses were predominately positive. What is clear
is that a greener environment is viewed more favourably than an
urban area with low levels of accessible and visible GI. The VALUE
research in Manchester also provides evidence to support funding
applications for investment in GI by identifying potential council
tax returns. The development of GI should therefore not be limited
by the quality of the existing urban environment but should be
developed with an understanding of how it is distributed and its
functions endow meaning and economic value.
Acknowledgements
This paper is based on work undertaken for an international, collaborative research programme on ‘Valuing Attractive Landscapes
in the Urban Economy’ (VALUE) funded by the European Regional
Development Fund (ERDF) under its INTERREG IVB, North-West
Europe, Community Initiative concerning Promoting Strong and
Prosperous Communities at Transnational Level 2007–2013.
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