The productive functions (FE/C3)
Increment [m^{3} u.b./year].
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 productive functions (FE/C3). 
Indicator:  The increment. 
Period:  The period between surveys of the NFI1 (2001–2004) and NFI2 (2011–2014). 
Unit of measurement:  Cubic metre underbark per year. 
Population:  The volume of merchantable wood stems which were alive at the time of the next survey and reached the dbh of 7 cm overbark after the previous suvey but at the time of the next inventory survey the latest (it is called recruitment) is included in the estimate of increment. 
Definition:  The mean annual wood increment (of the considered population). The increment relates to the selected period. A merchantable wood volume of a stem is calculated according to the ÚLT volume tables on the basis of the dbh (d13) and total height (h) of stems (trees) included in the calculation. The merchantable wood volume of stems (trees) felled or dead between inventories is deducted from the tables for the dbh measured in the previous inventory, increased by the model increment (GADA model) until the middle of the period between the two surveys (a generally estimated moment of felling or death). The height of the stem (tree) was deducted from the height curve (parametrized for a particular woody species and stand segment) for the already updated dbh. Then it was corrected considering the value of the residue observed within the first inventory  the deviation of the particular stem height from the model curve, found within the first inventory, was carried over to the presumed moment of felling or death. In this way, the increment of between inventories felled or mortality stems (trees) that took place between the previous inventory survey and the moment of their felling or death was considered individually. The evaluation is based on Eriksson‘s methodology (1995). Merchantable wood means all the aboveground, woody parts of a tree that reach a thickness of 7 cm overbark (the thickness is measured perpendicular to the longitudinal axis of the piece). Merchantable wood includes branches or their parts reaching at least a 7 cm thickness o.b. A stump (after possible felling) or a stem’s top under 7 cm o.b. is not considered to be merchantable wood. The coefficients of the conversion of the merchantable wood volume overbark to the volume underbark correspond to Decree No. 84/1996 Coll., i.e. 100/110 for conifers and 100/115 for broadleaves. On individual sample plots, deviations from the nominal length of the period between inventory surveys were considered by recalculating the estimate for one year. 
Area:  Accessible part of the productive forest area within the area which was both in the current and previous inventory identically classified as a forest land category according to the definition of FAO FRA (Forest Resource Assessment). Those inventory plots are considered where it was possible to clearly identify the stems (trees) and assess the status of change in relation to the state of the previous inventory. There are also plots (the area represented by these plots) where it was not possible to identify and assess change at the level of individual stems, but the change status could have been reliably derived from the context. E.g. fully felled inventory plots are also included (all stems registered in the previous inventory have been marked with the change status of "felled") or plots within which the growth phase of a clearcut, plantation or natural seeding (up to 1.3 m tall) has been described and simultaneously no merchantable wood stem has been registered (all living merchantable wood stems registered in the current inventory have received the status of "recruitment"). 
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. 