Ústav pro hospodářskou úpravu lesů Brandýs nad Labem

The biodiversity (FE/C4)

Woody species composition [%].

NFI more detailed results are available here.


Region
Geographical domain
Category
Sorting criterion
Point estimate
The most probable value
Standard deviation
Point estimate standard deviation
Variation coef. %
Procentual expression of the standard deviation since the point estimation values
Sample size
Sample size
Min. sample size
Min. sample size
Interval estimation
Interval estimation


Table information

Topic: The biodiversity (FE/C4).
Indicator: Woody species composition.
Period: The NFI2 survey period, between 2011 and 2015.
Unit of measurement: Percent.
Population: Only living regeneration stems are considered within the total productive area. Regeneration stems are all non-merchantable wood individuals (tall ≥ 10 cm, dbh < 7 cm overbark) of the artificial origin (planting, sowing) and non-merchantable wood stems of the natural origin which occur in suitable stand conditions and whose woody species, spatial distribution and density create preconditions for formation of a subsequent stand.
Definition: This estimate of woody species composition in regeneration is the proportion of the estimate of the regeneration forest area of a certain group of woody species and the estimate of the total regeneration forest area within the considered territory. Stand gaps are excluded from the total of the regeneration forest area, i.e. cases where no living regeneration stem has been registered on the sample plot. The productive forest area includes forest stands, cleared boundary lines up to 4 m, unpaved roads up to and including 4 m traffic lane width, watercourses up to 4 m in channel width, seedbeds and clearcuts belonging to the forest land category according to the FAO FRA (Forest Resource Assessment) definition. A regeneration forest area is a subset of a productive forest area. It is determined by the presence of one of the following growth stages: an unestablished or established plantation, natural seeding, advance growth, young growth or small pole stage (mean dbh up to 7 cm overbark), or it is alternatively determined by the presence of regeneration stems. Regeneration stems are all non-merchantable wood stems (high 10 cm and more, dbh up to 7 cm overbark) of the artificial origin (planting, sowing). There are included also non-merchantable wood stems of the natural origin which occur in suitable stand conditions and whose woody species, spatial distribution and density create preconditions for establishment of a new forest stand. Within the individual sample plots, the contribution to the (local density) estimate of a regeneration forest area (excluding clearcuts and stand gaps) is divided among the considered groups on the basis of their contribution to the (local density) estimate of the total production area of regeneration. The production area is generally identified at the level of a stem with the area of its crown projection (to the horizontal plane), which is directly measured for the second-level samplers of non-merchantable wood (measuring the length of major and minor half-axes of an ellipse approximating a crown projection of a stem). Regarding the other, registered, non-merchantable wood stems, the crown projection area is predicted by a dendrometric model (a classical regression model with fixed effects) using a height category of a non-merchantable wood stem, measured in a field. The second-level samplers were selected among non-merchantable wood stems with an unchangeable probability of 0.21 (Bernoulli’s selection during registration within the non-merchantable circles). The purpose of the second-level samplers is to compensate for errors in the dendrometric model used to predict the crown projections (identified with the production area). The principle of compensation is to estimate the total error of predictions of the dendrometric model (the concept of generalised local density, see Mandallaz 2007). A relatively small number of registered regeneration stems (and even fewer second-level regeneration samplers with actually measured crown projections) led to instabilities in the estimation of woody species composition within forest regeneration in some geographical domains (regions) and for woody species groups with fewer stems. Finally, the second-level, non-merchantable wood samplers (of regeneration) and the related estimation methodology were not used for this reason.
Area: Accessible part of the regeneration forest area within the whole area of interest (geographical domain). The forest land category corresponds with the definition of FAO FRA (Forest Resource Assessment).
Confidence interval: The confidence interval is constructed at a 95% confidence level (significance level alpha = 0.05).
Geographic domain type: Nomenclature of Territorial Units for Statistics, level 0 + 1 – state.; Nomenclature of Territorial Units for Statistics, level 3 – region.
Attribute domain: The group of conifers or broadleaves.

Attribute graph category selection: