This dataset contains forest inventory data collected from a network of permanent sample plots across Finland at three time points: 1985-86, 1990-91, and 1995. The network was established in 1985-1986 in conjunction with the 8th National Forest Inventory (VMI). It originally consisted of approximately 3,000 permanent plots designed to monitor long-term changes in forest ecosystems and environmental conditions. The data was gathered using a systematic cluster sampling design that covers the entire country. The sampling strategy varies between two regions: - Southern Finland: Clusters of plots are arranged on a 16 km by 16 km grid. Each cluster contains four sample plots positioned along a south-to-north axis at 400-meter intervals. - Northern Finland (Lapland and Koillis-Suomi): The sampling grid is sparser, with clusters located on a 24 km (south-north) by 32 km (east-west) grid. Each northern cluster consists of three plots, also oriented south-to-north, with a spacing of 600 meters between them. The dataset is structured hierarchically into three levels for each measurement year: 1. Tree Data (lukupuu.csv): Contains measurements for individual trees, including species, diameter, height, age, quality, and any observed damage. 2. Plot Data (koeala.csv): Provides information about each sample plot, such as its unique identifier, geographic coordinates, and measurement dates. 3. Stand/Compartment Data (kuvio.csv): Describes the forest stand containing the plot, with variables for soil and site type, development class, and management history (e.g., drainage, fertilization). The detailed field measurement protocols are documented in the manual Pysyvien koealojen 3. inventoinnin maastotyön ohjeet (1995).

2025