Finnish Programme for the Intensive Monitoring of
Forest Ecosystems (ICP-Forests/Level II)

Finland has been participating since 1985 in the International Cooperative Programme on the Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) established by the United Nations Economic Commission for Europe (UN/ECE) under its Convention on Long-range Transboundary Air Pollution (CLRTAP).
The Finnish Forest Research Institute (Metla) is responsible for both monitoring the health and vitality of the forests in Finland by carrying out an annual survey of the overall condition of the trees on a permanent network of systematically selected sample plots (Level I, totalling 490 plots) using internationally standardised methods. A survey of needle chemistry on the plots was started in 1987, and a soil survey carried out during 1985-89 (supplemented in 1995).
In order to gain a better understanding of the effects of air pollution and other stress factors on forests, a Pan-European Programme for Intensive and Continuous Monitoring of Forest Ecosystems (Level II) has been implemented in 1995.
Organisation of Finnish programme

Observation plot network

By 1987, 31 intensive monitoring plots had been established in different parts of the country: 27 of the plots on mineral soil sites and 4 on peatlands. 17 of the plots have stands comprising Scots pine and 14 Norway spruce. All the plots, except the four Integrated Monitoring (IM) plots, are located in commercially exploited forest. The IM plots represent natural stands in catchment areas. A number of the plots are located close to background, air quality monitoring stations primarily run by the Finnish Meteorological Institute.

It has been suggested, that the effect of acid fallout on the total amount of base cations and base saturation in peat soils is slight. More important than the total balance of base cations is the potassium balance of the stand and its changes. Also the follow-up of the response of the stand is important in conditions where the nutrient flows that come to the stand, immobilized or leached away, are under control. The follow-up of runoff is seldom carried out on mineral soils, whereas on peat soils it is required for investigating nutrient balance. In order to reach this target all the observation plots on peatlands has been established as a separated catchment area. This has required restrictive ditches which will lead external waterflows past the plots and also V-notched weirs to collect the internal waterflows for follow-up of leaching elements and runoff. This follow-up monitoring will be performed by national resources. The runnoff will be continuously monitored automatically with data-loggers and water samples for element analysis will be collected weekly starting each snow-melt periods in spring.

About 1.5 million hectares of peatland forests have been fertilized in Finland. Presently fertilizations are not being carried out extensively. It is, however, obvious that in order to bring stands to normal final cutting stages, hundreds of thousands of hectares will require at least potassium but also possibly phosphorus fertilizations in the next few decades. Therefore, it has been sensible to set up follow-up plots on two differently treated plots, first on those where a balanced nutrient regime will be maintained by normal fertilizations and secondly on unfertilized areas.

Design of the observation plot and location of the sub-plots

The observation plots proper consist of three sub-plots and a surrounding mantle (sub-plot 4). The sub-plots are square in shape (30 x 30 m). A 5-10 m wide strip has been left between the sub-plots for possible future use in special studies and for additional sampling. Sampling methods that may have a detrimental, long-term effect on the soil or stand, e.g. soil sampling, deposition and soil water collection, needle and litter sampling etc., are concentrated on one sub-plot. One of the other two sub-plots is reserved for vegetation studies, and the other for tree growth measurements.

The centre point of the observation plot, the corners of the sub-plots and the outer edge of the mantle area have been marked with wooden posts. The mantle is surrounded by a buffer zone. The width of the mantle and buffer zones varies from 10-30 m.

Due to the importance of drained peatlands for Finnish forestry and forest industry, four of the 31 permanent Level II observation plots in Finland has been established on peatlands. In order to represent the most typical site types, they has been established on an originally wet and sparsely stocked pine mires. The peat soils of these kind of site types might have low concentrations of mineral nutrients. At the same time nitrogen content of the peat might be very high, which means an unbalanced nutrient regime in the forestry point of view.

Girth band

Basic stand measurements and mapping

All the trees on the observation plot have been numbered at a height of 1.3 m on the side of each tree facing the centre point.

The following parameters have been recorded or measured on each tree: tree species, canopy layer, diameter at 1.3 m, tree height, and length of the living crown. The measurements have been performed on the trees on sub-plots 1 - 3 and those located in the mantle area (sub-plot 4). Twenty additional trees representing different diameter classes have been selected and numbered on the buffer zone (sub-plot 5). In addition to the above measurements, bark thickness has been measured and increment cores taken at 1.3 m height for determining earlier growth and tree age. The forest site type of the observation plot has also been determined.

The location and elevation of all the trees on the observation plots have been mapped using a tachymeter. The exposition and gradient of each sub-plot have also been determined. Care has been taken during the field work to avoid causing unnecessary trampling of the ground vegetation or other forms of damage. Wooden walkways have been laid on the sub-plot used for collecting deposition and soil water.

Monitoring activities

Survey	No of plots	Frequency of assessments

Crown Condition	31	Annual
Soil condition	31	Every 10 years
Needle chemistry	31	Every 2 years
Tree growth	31	Every 5 years
Stem diameter growth	12	Hourly
Deposition	16	Every 4 weeks, but every 2 weeks during summer

Soil solution
- gravity lysimeter	16	Every 2 weeks during the snowfree period
- suction-cup lysimeter	16	Every 2 weeks during the snowfree period

Meteorology	12
- air temperature (13 m & 20 m)		Hourly
- relative humidity		Hourly
- precipitation		Hourly
- wind speed		Hourly
- wind direction		Hourly
- photosynthetically active radiation (PAR)		Hourly
- solar radiation		Hourly
- soil frost (-10, -20, -30, ..... -100 cm)		Hourly

Ground vegetation	31	Every 5 years
Litterfall	13	Every 2 weeks

Database and data evaluation

The database of the Finnish Programme for the Intensive Monitoring of Forest Ecosystems consists of four subsidiary databases: data base I (Original data and measurements), data base II (FIMCI dta), info base and photo base. A review of the results of the individual surveys and the summaries of the pilot projects will be presented each year in the national report. In-depth scientific evaluations of the results will be presented every fifth year.

Cooperation

In 1993, five international organizations - FAO, ICSU, UNEP, UNESCO and WMO - decided to co-sponsor the planning process for a Global Terrestrial Observing System (GTOS). GTOS is intended to provide the data basis and observational framework needed to understand and address the impacts of global change on terrestrial, including freshwater, ecosystems. The Terrestrial Ecosystem Monitoring Sites (TEMS) database, which is an international directory of meta-data about monitoring stations and their activities, has been established to document existing long-term monitoring sites that may be suitable for inclusion in the GTOS network once it has been established. The Finnish ICP level II monitoring plots are included in the TEMS database. The data collected on the monitoring plots in northern Finland will be regularly submitted for inclusion in the database of the Arctic Monitoring and Assessment Programme (AMAP).

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Palaute 26.3.1999