Scope of collected data
The system of forest resource assessment saw several changes as years passed with sample collection becoming more uniform, the scope of collected data broadening (dead wood, stumps, coverage of shrubs and herbaceous vegetation and the description of game browsing damage), while other components that do not lend themselves to effective research have been eliminated. Sampling is not limited to stand characteristics, it also cover site specific parameters and the geographic position of sampling plots, which are also studied.
Experts used a piece of software called Field-Map Data Collector during field work and the scope of collected data are arranged in line with the distribution of layers in the software, which also adds a map layer to show recorded sample trees, dead wood and stumps.
The general data taken include sampling point status, metered GPS coordinates and GPS accuracy, name of sample taker, date and circumstanced of recording, the geographic position of sampling plots (topography, inclination/location, altitude above sea level), site characteristics (climate, hydrology, degree of water management, genetic soil type, thickness of topsoil, physical soil type and soil damage). The method of tree utilisation observed at the sampling plot and the estimated year of utilisation are also entered here.
Additional concentric circles with varying diameter limits have been laid out inside each fixed radius sampling circle, but the general description of a sampling plot must always pertain to the area of the full circle.
Depending on sampling plot status, actual and potential forest community, structure of layers and canopy closure are also captured. It is this layer of the software that records the shrubbery and herbaceous plants in the sampling circle, the coverage with dead branches and the volume of accumulated dead wood. Since 2011, increment core data have also been captured in this layer.
As regards sample tree specimens, basic descriptive data such as species, origin and age are supplemented with records taken of height and diameter at breast height information, social status and data pertaining to the general health status of the specimen (condition of crown, stem quality).
Small trees in forest covered areas must always be recorded. These include trees with diameter at breast height below 7 cm in a circle with a radius of 3 meters drawn around the centre point of a sampling plot. These small trees are recorded by height group, and broken down by species, the number of trees of a certain species, number of specimens with apical buds subject to browsing damage and the estimated diameter of the average specimen.
Lying dead wood must be at least 10 cm in diameter over at least 1 m to be recorded. The diameters measured at the two ends, the full length, the degree punkiness and the distinction between deciduous/coniferous of lying dead wood are also recorded.
As regards stumps with a diameter at or above 20 cm, height and diameter records are supplemented with data about degree of punkiness and a distinction between deciduous/coniferous.
Any pests requiring quarantine are also recorded if observed.
The Appendix, List of Codes presents content which is deemed to be important for the interpretation of completed statistics.