Intensive long term monitoring of forest ecosystems


In order to gain a better understanding of the effects of air pollution, climate change and other stress factors affecting UK forest ecosystems, long-term intensive monitoring plots were established in 1995. Ten plots covered three important tree species Sitka spruce, Scots pine and Oak. In 2002 the number of plots was extended to include Beech and Norway spruce. These plots formed part of a European wide ‘Level II’ programme network established under European Union Regulations.

Map showing the locations of intensive long term monitoring (Level II) plots in Britain
Select plot on map or
from list of Level II plots in Britain

Culbin Ardtonish Tummel Loch Awe Rannoch Kelty Coalburn Grizedale Wykeham Lady Bower Clocaenog Wangford Thetford Llyn Brianne Brechfa Savernake Cannonteign Kiddens Covert Wood Alice Holt/Straits Micheldever Rogate

This research complements large-scale surveys of tree health established in Britain by the Forestry Commission, and in many European countries, during the 1980s.

The intensive monitoring programme is a vital resource to detect environmental change in UK forests and to provide the means of explaining changes in forest growth. It has produced valuable data, and considerable insight into the dynamic nature of UK forest ecosystems.

Each plot is 0.5 ha in area and contains a mensuration sampling plot of 0.1ha used to measure growth factors.

A plan of a typical Level II plot (7K)

Plots were established in working forests under normal forest management, so data also document change due to management practices. Data from these plots are being used to support other environmental research programmes, and also to provide information for wider Forestry Commission objectives, namely the protection of Britain’s forests and woodlands, sustainability, and soil and water quality.

Parameters measured and frequency of assessment

The intensive forest monitoring network is supported by detailed measurements of a wide range of variables.

Summary of data collection across all Level II forest monitoring sites

Research objectives

Map showing geographic distribution of Level II plots in Europe
Enlarge map
Map showing geographic distribution of Level II plots in Europe
  • Characterise the UK forests in terms of there relationship to other European monitoring sites.
  • Understand the fate of atmospheric pollutants in a range of managed forest ecosystems; i.e. their accumulation, distribution, patterns of release and leaching.
  • Identify cause-effect relationships which explain the extent to which air pollution and other abiotic (e.g. inter-annual variation in climatic conditions, storms, fire) and biotic (e.g. pest and diseases, newly emerging diseases) stress factors contribute towards observed variations in forest condition.
  • Review the likely impact of future scenarios of climate change, air pollution and other abiotic and biotic stress factors on managed forest ecosystems.
  • Contribute to assessments of net carbon sequestration by European forests. Also, contribute to assessments of the global carbon balance.
  • Determine critical levels/ loads of atmospheric pollutants (SO2, NO2, NH3 and  heavy metals such as Cu, Cr, Zn, Cd, Ni and Pb) for managed forests in the UK under current and predicted climatic conditions.
  • Develop and test indicators that can be used to assess the long-term sustainability of forest ecosystems and shifts in biodiversity.


Publications and presentations related to intensive forest monitoring since 2000.

Funders and partners

Forestry Commission logo EU flag
The programme was jointly funded by the Forestry Commission and the European Union and is now funded solely by the Forestry Commission.

Forestry Commission policy

Under the Convention on Long-Range Transboundary Air Pollution, each country is required to nominate and finance a central agency, known as the National Focal Centre, responsible for:

  • Establishing a network of permanent intensive monitoring plots
  • Collection, organisation, validation and storage national data
  • Data management and analysis at national level
  • Data submission to a central European agency
  • Participation in evaluation and interpretation of data at the European level.

The UK National Focal Centre is based in the Centre for Forestry and Climate Change of Forest Research and its responsibilities are fulfilled with assistance from other parts of Forest Research.


Since 1995, 10 permanent intensive monitoring Level II plots have been installed in Britain in accordance with EU protocols. These represent three important forest species:

  • Sitka spruce (Picea sitchensis (Bong.) Carr)
  • Scots pine (Pinus sylvestris L.)
  • Oak (Quercus spp.).

An additional 10 plots were added in 2002, including a further two important forest species: beech (Fagus sylvatica) and Norway spruce (Picea abies).

Long term monitoring is intended to continue into the next crop rotation.


Project manager:

Sue Benham