DEFINING & MAPPING URBAN GREENSPACES

What is considered an urban area?

Greenkeeper’s 20,000+ urban greenspaces are located within 149 built up areas in England and Wales and 5 localities in Scotland, as defined by the Office of National Statistics. Each of these areas has a minimum of 75,000 usual resident or workday population, as per the 2011 census.

What is considered a greenspace?

The greenspace data layer used by Greenkeeper  is based on Ordnance Survey Greenspaces and OpenStreetMap, which combine to deliver the most comprehensive dataset available. Greenspaces are defined as publicly accessible parks or green areas; from small pocket parks to large regional parks. Greenkeeper maps tree cover using Sentinel 2 imagery and analyses the benefits provided by trees within greenspaces.

What are the size categories for greenspaces Greenkeeper uses based on?

Greenkeeper defines four size groups (pocket park: under 0.4 ha; small open space: between 0.4 ha and 2 ha; local park: between 2 ha and 20 ha; district park or larger: larger than 20ha). The size definitions are based on guidance from the Greater London Authority, which can be found at current London plan. The size categories are used to compare visit numbers and values of benefits of a greenspace within its peer group.

How are greenspace characteristics mapped and compared?

The characteristics Greenkeeper captures and reflects within the analysis are; built features, such as sports facilities and cafes; natural features, such as trees or waterbodies; accessibility, based on public transport and entrances; and air quality, based on pollutants removed. Greenkeeper then provides an overview of the presence of these features compared to other spaces in the same size category.

What about non-urban areas?

Currently only urban greenspaces are mapped within Greenkeeper, however through the offline services, which utilise the model, we are exploring and building resources to support the application of the tool for new settlements and non-urban development proposals. For further information or to discuss this with us, please do contact us.

ESTIMATING VISIT NUMBERS FOR GREENSPACES

What data does Greenkeeper use?

Greenkeeper utilises the most accurate and comprehensive datasets currently available and wherever possible, relies on open data sources to ensure regular updates. Where data is not open, we have secured a commercial use license. The main datasets used in Greenkeeper are:

How are visit numbers to greenspaces estimated?

Greenkeeper bases visitor estimates primarily on Natural England’s annual Monitor of Engagement with the Natural Environment (MENE) survey, an established data source based on greenspace visits made by 45,000 residents aged 16-years+ across England. Our model has been built to then combine this data with exact location demographics, accessibility and characteristics of the greenspace help us estimate visitor numbers of greenspaces, including those for which no survey data exists. It is important to note however, that this estimated visit number, and therefore estimation of benefits for these visitors, does not include tourists or visitors aged 15 or younger.

Who is visiting?

How does Greenkeeper help inform who is visiting? The MENE survey data includes information about the home postcode sectors of greenspace visitors, which can then be linked to demographic and socio-economic information. When estimating visits, Greenkeeper therefore combines this insight with accessibility data to establish where visitors are coming from, which in turn provides insight into the demographic and socio-economic profile of visitors. Greenkeeper does not however cover tourists or visitors aged 15 or younger, due to the datasets utilised.

How reliable is the estimated number of visits?

The MENE survey has been running since 2009 and is currently the best and most representative source of visitor data currently available. Greenkeeper is based on this data, using this insight into people’s past behaviour as a reliable indicator for future behaviour. The model we subsequently developed has then been validated using other sources of visit counts, including mobile phone data, Royal Parks and local authority information. Fundamentally therefore the predicted visitor numbers are based on people’s actual decisions, not on hunches around what any of us may think happens.

What differentiates Greenkeeper from NEVO (formerly ORVal)?

The Natural Environment Valuation Online Tool (NEVO) is a current, widely used tool for estimating green infrastructure’s value. Also developed by the University of Exeter team, this tool exclusively uses travel costs to estimate recreational value. In Greenkeeper, we capture recreational value within our Wellbeing valuation (an approach we believe is more accurate in terms of reflecting the social value of green infrastructure) as well as applying methodologies to calculate physical health, environmental and local value. We therefore believe greenkeeper provides a far broader estimation of a greenspaces comprehensive value.

MEASURING BENEFITS

What benefits does Greenkeeper value?

Greenkeeper values benefits to greenspace visitors, residents living close to greenspaces and global benefits. The benefits valued for visitors are physical health and wellbeing, the benefits for residents are proximity to greenspace, and global benefits are created by carbon sequestration. Other benefits of greenspaces, such as biodiversity, flood risk management or educational benefits are not quantified in Greenkeeper. Location-specific physical models for these benefits have not been developed.

How are physical health benefits valued?

Visitors achieve physical health benefits from undertaking activity in greenspaces, including running, cycling and playing sports. The resulting improvements for individual long-term health outcomes are estimated and measured in terms of improved quality and length of life. The valuation of these improvements is based on Greenbook guidance on the value of an additional year in good health to an individual. The total physical health value of a space is based on the number of visitors and national averages for activity levels in greenspaces, with higher and more frequent activity generally leading to larger physical health benefits.

How are wellbeing benefits valued?

All visitors to greenspace, no matter what activity level, also receive wellbeing benefits, measured in self-reported increases in life satisfaction. We value the increase in life satisfaction by estimating the amount of money a person would need to receive for an equivalent increase in life satisfaction. The total wellbeing value of a space is then calculated based on the visitor estimate for the greenspace.

How are benefits from living close to green infrastructure valued?

People’s preference for living near greenspace is expressed by their willingness to pay more for a property that is located nearby, than they would pay for the same property if it were further away. The higher property prices near greenspaces are used to measure its value as a local amenity and contribution to the attractiveness of a residential area. This methodology is called Natural Capital Accounting and has been developed by Vivid Economics over the last few years and is now widely adopted to understand this specific value of greenspace.

How are benefits from carbon sequestration valued?

Trees in greenspaces capture and store atmospheric carbon dioxide. We calculate tree canopy cover within greenspaces to estimate the amount of carbon sequestered and value the reduction in atmospheric carbon using the price of untraded carbon.

How are air quality benefits measured?

Urban trees and vegetation remove pollutants from the air. Using spatial data on air quality, information on land cover by greenspace and average pollutant removal by land cover types, we estimate the amount of pollutants removed by vegetation in greenspaces each year. Greenkeeper reports pollutants removed; these benefits are not valued in monetary terms.

How can the total value be used?

Greenkeeper provides you with a combined economic, social and environmental total value of greenspace per annum. Costs are often easy to quantify, but being able to quantify benefits allows a more informed value-for-money assessment and can support greenspace management and planning decisions being made by local authorities, developers, managers and consultants every day and in turn ensure limited funding or investment is spent efficiently.

How do I know how my greenspace compares to others?

Greenkeeper has a benchmarking tool incorporated within it, which enables users to understand how a single space is preforming compared to others of a similar size across the UK. This gives you an immediate feel for how one space compares to others. There is then also a function through which you can compare a greenspace with another local similarly sized greenspace, or all greenspaces in this size category.

What about green corridors, green roofs and beaches?

Green corridors add to the greenspace within our urban areas and enhance the opportunities for sustained ‘immersion’ in green environments. Although we would like to extend the tool to cover these, we are currently not able to as they are so varied in their form and quite difficult to accurately map. Green roofs are similarly difficult to accurately map but also generally inaccessible to people, therefore the demand model approach doesn’t work. Beaches are not green spaces and therefore lie out with the scope of this tool.

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