Media release 20.09.2005
In 2004, the mean defoliation, i.e. premature loss of needles and leaves, was 7.9% for Scots pine, 18.5% for Norway spruce and 9.3% for broadleaved trees growing on peatlands. On mineral soils the corresponding figures were 9.1%, 19.2% and 12.5%, respectively. Compared with the figures from the previous year, the defoliation of Scots pine has slightly decreased, while that of Norway spruce and deciduous trees has increased on mineral soils.
Only slight variation can be seen in the annual defoliation levels and, compared to the level in the rest of Europe, coniferous forests in Finland have suffered less defoliation than those in most other countries. Defoliation in Finland is mainly due to stand aging, unfavourable climate and weather conditions, and damage caused by fungi and insects.
This information was reported in the Annual Forest Condition Monitoring report, published by UNECE/ICP Forests. Since 1985, Finland has participated in the pan-European Forest Condition Monitoring Programme (ICP Forests) under the international Convention on Long-Range Transboundary Air Pollution of the United Nations Economic Commission for Europe. Since 1995, forest condition monitoring activities in EU member states have been funded and coordinated by the EU under e.g. the Forest Focus monitoring programme (2003-2006).
The objective of the programme is the long-term monitoring of the condition of European forests in a broadly-based, consistent and comprehensive manner. The programme focuses especially on monitoring the impact of air pollutants on forests. In Finland Metla is responsible for the co-ordination and implementation of the programme. The National Focal Centre of the programme in Finland is located at the Parkano Research Station. The NFC is responsible for establishing and maintaining both the extensive and intensive observation plot networks, performing the monitoring work, and verifying and delivering the monitoring data to the European and international information centres and databases.
In 1986, approximately 400 observation plots in stands growing on mineral soils (Level I) were selected from the 8 th National Forest Inventory network for annual crown condition monitoring. The network has since been supplemented with ca. 100 mineral soil and 100 peatland plots and, currently, the assessments are carried out on 11,000 trees on approximately 600 plots. In addition to the annual crown condition assessments, soil condition and foliar chemical composition have also been determined on a smaller number of plots. Tree stand measurements and vegetation mapping have been made on the plots, and sampling for the determination of heavy metal concentrations in forest mosses has been carried out at five-year intervals.
The intensive monitoring plot netweork (Level II, currently 31 plots) was established in the late 1990,s. The network is used to monitor the functioning of forest ecosystems, and the data are used to investigate the processes underlying possible changes in forest condition observed on the Level I plots.
The pan-European results are published annually in “The Condition of Forests in Europe, Executive Report”, which is available at: http://www.icp-forests.org/Reports.htm
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