As a nutrient, nitrogen continues to be a limiting factor in forest growth in Finland. In Southern Finland, the annual nitrogen deposition is 3 to 4 kg/ha and 1 to 2 kg/ha in Northern Finland. In many areas in Central and Southern Europe, nitrogen deposition is significantly higher than in Finland. The largest annual nitrogen deposition loads in Europe exceed 30 kg/ha.
The nitrogen balance of forest ecosystems is usually positive in Finnish background regions. In other words, because the deposition outweighs leaching, the forests’ nitrogen reservoirs are slowly growing. Nitrogen deposition compensates for the nutrient loss that occurs during timber harvesting.
Results from the monitoring of forest health suggest that the air in northernmost Finland is generally clean. Emissions from the heavy metal foundries on the Kola Peninsula appear in the form of elevated copper and nickel concentrations in the natural landscape of northern Lapland.
Spruce and pine stands are being monitored in different parts of Finland
The Natural Resources Institute Finland monitors the condition and functioning of forest ecosystems on 12 (14 in parts) observation plots. Spruce and pine stands in different parts of Finland have been chosen as observation plots. Monitoring on the plots focuses on issues such as air pollution falldown, the condition and growth of trees, indicators related to nutrient circulation and leaching in the ecosystem, and the chemistry of needles and soil. The seasonal rhythm of trees and changes occurring in the undergrowth are also monitored.
The objective is to study and monitor the response of the forest ecosystem to stress factors occurring naturally and as a result of human activity, and to determine the causations of the observed changes. Reliable observation time series are essential to such monitoring; they enable the demonstration of environmental changes and trends.
In addition to research, monitoring assists in official reporting
Intensive monitoring of the condition of the forest ecosystem is based on the UN Economic Commission for Europe’s ICP Forests monitoring programme, launched to enable the monitoring of the impact of the Convention on Long-range Transboundary Air Pollution (CLRTAP). The programme also feeds into the Forest Europe process.
Finland has participated in the international intensive forest monitoring programme since 1995. Data reserves, compiled from different parts of Europe on the basis of uniform methods, can be used to fulfil various information needs that are both politically and scientifically topical – for example, ecologically sustainable forestry, adaptation to climate change, the protection of biodiversity and the impact of air pollution. The ICP Forests data can be requested free of charge from the German coordinator of the programme.
Depending on the definition of the equipment level, there are currently 250 to 800 ICP Forests Level II observation plots in Europe. International and national cooperation is rather lively in the ICP Forests, ICP Integrated Monitoring, LTER and LYNET networks.
Picture on top of the page: Erkki Oksanen, Luke