Memorandum from the Woodland Trust (AQ06)

 

1. The Woodland Trust welcomes the opportunity to respond to this consultation. We are the UK's leading woodland conservation charity. We own over 1,000 sites across the UK, covering around 20,000 hectares (50,000 acres) and we have 300,000 members and supporters. We have three main aims:

Enabling the creation of more native woods and places rich in trees

Protecting native woods, trees and their wildlife for the future

Inspiring everyone to enjoy and value woods and trees

 

Summary

The extent to which government has recognised the health and environmental impacts risks caused by poor air quality is unclear.

Trees and woodland have a measurable impact in reducing air pollution and reducing the incidence of diseases exacerbated by airborne pollutants. This impact is proportionately greater in urban areas yet tree cover in urban areas is under threat.

Air quality benefits are supplemented by the other benefits of trees and woods in particular relating to management of surface water and reduction in building energy budgets.

There is a need for co-ordination across government departments, particularly within local government to ensure that the overall cost benefits of improved air quality are protected

Urban tree cover should be maintained and increased to intercept airborne pollutants especially particulates.

The conclusions to the Government's National Expert Group on Transboundary Pollution (NEGTAP) 2001 report in relation to trees and woodland focussed on canopy trees and overlooked the threats to the woodland ecosystem posed by nitrogen.

Targeted establishment of new trees and woodland could be used as a buffer to intercept pollutants to the benefit of existing woodland, other habitats and the wider environment.

The extent to which the Government fully understands and has identified the health and environmental risks caused by poor air quality

Health

2. It is unclear to us the extent to which government has recognised the health and environmental impacts risks caused by poor air quality. It is already the case that air quality limits for particulates are exceeded in many urban areas on a regular basis. Air quality can be expected to worsen with climate change.

3. Climate change projections[i], released this year, show that by 2080 London will be between 2oC and 6oC hotter than today. Already the temperature differential between the city centre and surrounding suburbs may be as much as 100C on summer days. Increased temperature combined with pollution from traffic emissions and other sources leads to increases in ground-level ozone. This has an impact both on those with respiratory and chronic lung conditions, and also on children and adults with an active outdoor lifestyle[ii].

4. Airborne pollutants, principally particulate matter of 10 microns (PM10) or less, NO2, SO2, and O3, affect lungs and exacerbate respiratory and heart diseases and PM10 may carry carcinogenic compounds into the lungs. Moderate concentrations of SO2 can result in reduced lung function particularly in people suffering from asthma. O3 irritates the airways of the lungs, increasing the symptoms of those suffering from asthma and lung diseases.

5. A review of the economic benefits of UK trees and woods commissioned by the Woodland Trust earlier this year identified the impact of trees and woodland in reducing air pollution and, stemming from this, the effect trees have in reducing the incidence of diseases exacerbated by airborne pollutants[iii]. An electronic version of this document is included with this submission. This included:

Absorbing gaseous pollutants such as nitrogen dioxide (NO2), sulphur dioxide (SO2), and ozone (O3)

Intercepting particulate matter (PM) such as dust, pollen, and smoke

Releasing oxygen (O2) through photosynthesis

Transpiring water and shading surfaces, thus lowering local air temperatures, thereby reducing O3 levels

6. Airborne concentrations of PM10 increase in urban areas due to increase automobile wind disturbance and eddies formed around buildings. PM10 fall out near the point source. Trees near urban areas therefore tend to capture PM10. The air quality improvement effect of trees is thus proportionately greater in urban than rural areas per unit area of trees, since in urban areas trees are closer to sources of air pollution.

7. Yet the 'Trees in Towns II' report commissioned by DCLG and published in 2008[iv] showed how tree canopy cover in urban areas is under threat, potentially exacerbating existing poor air quality, increasing urban heat island effect and will be amplified by any increase in summer temperatures. This may highlight either a lack of understanding of the impact of tree cover and urban green space, or a lack of co-ordination across departments of government, or possibly both.

Environment

8. We believe there were shortcomings in the conclusions to the Government's National Expert Group on Transboundary Air Pollution (NEGTAP) 2001 report in relation to trees and woodland. Although the report identified that estimated critical loads for nitrogen were exceeded in the vast majority of UK woods, it only considered implications for canopy trees.  Threats to the woodland ecosystem posed by nitrogen and implications for woodland management, as highlighted in a report on the long-term ecological changes to British Woodland produced by Natural England[v], were overlooked. 

9. While the report identified the need to reduce nitrogen pollution, it failed to highlight that targeted establishment of new trees and woodland could be used as a buffer to intercept pollutants to the benefit not just of existing woodland but other habitats and the wider environment (as outlined above for air quality and health).

The extent to which the delivery chain for air quality is coherent, integrated, co-ordinated and effective and whether the  bodies with responsibility for managing air quality have appropriate incentives, understand their role and responsibilities, and are adequately resourced

10. The importance and opportunities for urban tree and woodland cover to mitigate pollution and the impacts of climate change in relation to air quality are at odds with their management. Both the Trees in Towns II report for DCLG and an earlier report from the London Assembly - the 'Chainsaw Massacre'[vi] - highlight problems in a deteriorating urban tree cover with the potential for serious impacts on air quality. The reports also make clear the lack of adequate investment in tree management.

11. In order to take full advantage of the opportunities for improving air quality it is essential that co-ordinated action is taken across government at all levels. For instance the role of Green Infrastructure GI) and well targeted tree planting and woodland creation in improving air quality needs to be recognised in plans for climate adaptation by central government and local government. It needs to be integrated into action by planning departments as part of responsible development, in highways departments in the maintenance and development of infrastructure, into housing departments, parks and countryside management, as well as within the business sector in terms of promotion of corporate social responsibility.

12. The importance and the opportunities to support improvements in air quality are supplemented by the other benefits of trees and woods in particular relating to management of surface water and reduction in building energy budgets. These have been highlighted in the recent report on the UK trees and forests in combating climate change[vii].

13. It has been estimated that doubling the tree cover in the West Midlands alone would reduce mortality as a result of poor air quality from particulates by 140 people per year[viii]. On top of which there would be a significant reduction in morbidity resulting in fewer people in doctors' waiting rooms and lower costs in terms of hospital treatment and fewer people on incapacity benefit.

14. The Campaign for Greener Healthcare and the initiative to establish an NHS Forest[ix] illustrate a growing consensus amongst health professionals of the importance of trees to peoples' health and wellbeing. The campaign endorses the role of trees in improving air quality and health outcomes. The importance of that role will increase as the climate changes. Trees provide a critical factor in adaptation relating to health care.

The steps that need to be taken to ensure that air quality targets will be met in the future

15. Whilst clearly reduction at source in pollution provides the best remedy for improving air quality, we strongly believe that there are short-term important aspects of management of tree cover which can contribute. This should include;

Increasing the understanding in government at all levels of the importance of green infrastructure and trees in particular in maintaining and improving air quality in urban areas

Co-ordination across government departments, particularly within local government to ensure that the overall cost benefits of improved air quality are protected e.g. that savings in arboricultural costs don't reappeared magnified as increases in admission and treatment costs in local health services.

Maintaining and increasing urban tree cover to reduce urban heat island effect and the generation of ground-level ozone

Increasing and targeting urban tree cover to intercept airborne pollutants especially particulates

Using targeted woodland creation to buffer existing woodland and other important habitats through the interception of nitrogen and other pollutants

 

9 December 2009

 

References



[i] UKCP09, UK Climate Projections, downloaded at: http://ukcp09.defra.gov.uk/

[ii] Ozone and you health, Airnow, downloaded at: http://airnow.gov/index.cfm?action=static.ozone2

[iii] Crabtree, C.J. (2009) The Value of Benefits arising from Trees and Woods in the UK, CJC Consulting, a report commissioned for the Woodland Trust

[iv] Trees in Towns II, Department for Communities and |Local Government, downloaded at: http://www.communities.gov.uk/publications/planningandbuilding/treesintownsii

[v] Kirby, KJ, Smart, S.M., Black, H.I.J, Bunce, R.G.H., Corney, P.M., Smithers, R.J. (2005), Long-term ecological changes in British woodland (1971-2001), English Nature Research Report Number 653, English Nature, Peterborough

[vi] Chainsaw Massacre - a review of London's street trees, May 2007, London Assembly, downloaded at: http://www.london.gov.uk/assembly/reports/environment/chainsaw-massacre.pdf

[vii] Read,D.J., Free-Smith, P.H., Morison, J.I.L, Hanley, N., West, C.C. and Sowdon, P. (eds) (2009) Combating Climate Change - a role for UK forests. An assessment of the potential for UK's trees and woodlands to mitigate and adapt to climate change, The Stationery Offcie, Edinburgh.

[viii] Stewart, H., Owen S., Donovan R., MacKenzie R., and Hewitt N. (2002). Trees and Sustainable Urban Air Quality. Centre for Ecology and Hydrology, Lancaster University.

[ix] The Campaign for Greener Healthcare, downloaded at: http://www.greenerhealthcare.org/nhs-forest