Trees in Urban Enviroment

Issues of sustainable development, liveable cities, green infrastructure, and urban ecosystem services currently receive attention from researchers and decision-makers. Furthermore, the benefits to public wellbeing and health of high quality open spaces and green areas are now undisputed (e.g. Simson, 2008; Booth, 2005, 2006). However, with increasing pressure on urban landscapes for competing uses like housing-development green-spaces are under threat. Furthermore, austerity-driven cuts to local authority budgets mean loss of core services and skills relating to openspace management and planning. Some local authorities such as Newcastle City Council are withdrawing all expenditure on parks and community spaces. With major challenges in providing good quality urban green-spaces, the loss of most local authority countryside management services from 2008 onwards, reflects bigger problems (see Rotherham, 2014, 2015 for example). Within this wider scenario has been the growing importance of Public Private Partnerships (PPP) to deliver core environmental and green-space services in many urban areas. These have been seen as possible fixes for the current waves of austerity cuts and many local authorities such as Sheffield City Council have gone down this route. Nevertheless, real costs (financial and otherwise) of Private Finance Initiatives (PFIs) are now emerging (Syal, 2018). There are also issues of public access to information once contracts become 'commercially sensitive' and of profit-driven delivery of core 'public benefit' services. These changes threaten 'local environmental democracy' as part of a wider shift in democratic processes (Flinders, 2012, 2017). This paper examines wider issues of austerity-driven cuts to green-space services, of PFI projects, and of local environmental democracy. It takes the Sheffield streettrees initiative as an exemplar case-study to interrogate the broad concerns.

Urban areas profoundly alter the local atmosphere, hydrology
and biology, usually for the worse. Increasing the vegetative cover in
urbanised areas is considered an effective way of offsetting many of
the undesirable outcomes of urbanisation and is often incorporated as
Green Infrastructure into urban development plans. In this paper we
present a first assessment of the green cover in Irish city centres (Belfast,
Cork, Derry, Dublin, Galway, Limerick and Waterford) and evaluate the
environmental benefits of trees for air quality using the i-Tree Canopy
software. This online software is used to conduct a spatial sample of the
urban landscape and estimate tree canopy cover from which potential air
quality benefits are calculated. The results show significant differences
between and within city centre areas in terms of vegetative (and tree)
cover; Belfast and Dublin, with less than 10% vegetative cover are in
marked contrast to other cities where the average is close to 30%. Based
on the findings we discuss place-based policies for improving green
infrastructure in Irish cities and the evidence needed to support policies.