i-Tree Eco Wirral

Forest Research have worked with Wirral Council to undertake a study of the region’s tree population using i-Tree Eco.

The study area covers the whole of the Metropolitan Borough of Wirral, covering an area of 15,700 hectares. 250 sample plots were distributed within a regular grid across the study area to ensure the sample was representative of the different land uses and characteristics present in Wirral. Details of ground cover, land use, shrubs, and trees were recorded in each plot. The i-Tree Eco software was used to extrapolate the field data to estimate the structure and composition of the whole tree population, and the ecosystem services the trees provide.

This study is the first i-Tree Eco project to include measures of social and cultural values of trees. The Urban Forest and Society and Environment research groups worked together to design a data collection methodology that uses data commonly collected during an i-Tree survey, and additional data variables to represent social and cultural values. These include:

• Public visibility of trees
• Public accessibility of trees
• Type of surface of access route to trees

As well as the tree survey, this project included an online questionnaire which was shared with people living in Wirral. The questionnaire asked people about:

• Perceptions of trees
• Preferences for trees
• Management of trees
• Action for trees
• Uses and values of trees

To capture information about the distribution of trees and the benefits they provide in different socio-economic regions in the study area, the sample was stratified according to the Index of Multiple Deprivation (IMD). This is a metric which is widely used to represent the relative deprivation of small areas. IMD is a single number combining seven different measures of deprivation:

• Income deprivation
• Employment deprivation
• Education, skills, and training deprivation
• Health deprivation and disability
• Crime
• Barriers to housing and services
• Living environment deprivation

The study area was divided into five levels of IMD (quintiles), with level 1 being the most deprived and level 5 being the least deprived. An appropriate number of plots was assigned to each quintile to ensure that enough data were collected to enable comparison of the tree population between quintiles.