Reliability of growing stock estimation using tariffs in case of a spruce treein forest with varied micro site conditions

Reliability of growing stock estimation using tariffs in forest with varied micro site conditions was analysed in case of high karst fi r-beech forest fora spruce tree. Reference bole volumes were calculated with Swiss's three parametric volume functions. Adequate tariffs were selected with standard method, using mean tree diameters and heights, which were calculated from adapted height curves. Adequate tariffs for single sampling plots are different for up to 3 tariff's classes. Difference between growing stock calculated by tariffs and reference growing stock for a spruce tree's stand is-2.8%, whereas for single sampling plots the differences are greater, from -7.0 to 8.6%. The hitherto used tariffs underestimated growing stock by -18.1%in the presented case. Our conclusion is that if tariff for a defi ned area (forest stand or compartment) is representative, with correct method used, the reliability of growing stock estimation is good regardless the varied micro site conditions. Representative selection of tariffs is provided for with measuration on sampling plots that well represent the defi ned area