Bundesforschungs und Ausbildungszentrum fur Wald
Bundesforschungs und Ausbildungszentrum fur Wald
Kindermann G.E.,Bundesforschungs und Ausbildungszentrum fur Wald
Austrian Journal of Forest Science | Year: 2016
Several growth functions (e.g. Backman, Bertalan y, Evolon, Fischer, Gomperz, Gram, Grosenbaugh, Hassell, Hill, Hoßfeld, Hyperlogistic, Johnson, Koller, Korf, Kosun, Kövessi, Kumaraswamy, Levakovic, Logit, Maynard, Michaelis-Menten, Michailoff , Mitscherlich, Morgan, Nelder, Peschel, Richards, Ricker, Robertson, Schnute, Schumacher, Siven, Sloboda, Strand, Stannard, Terazaki, Thomasius, Todorovic, Yoshida,Weber,Weilbull) have been compared for their ability to follow observed height developments. Those with two coeffcients might not be exible enough to follow possible growth patterns. Some functions with three and especially those with four parameters can follow a wide range of growth patterns. The differences between most of the four parameter functions are marginal. Choosing one can depend on their behaviour to converge during parameterisation or the direct interpretability of the parameters selection. Overall the function h = c0 ∗ (ln(1 + c2 ∗ t∗ ∗c3))∗∗c1 showed good behaviour and might be one which could be recommended.
Tomter S.M.,Norwegian Forest And Landscape Institute |
Gasparini P.,Italian Agricultural Research Council |
Gschwantner T.,Bundesforschungs und Ausbildungszentrum fur Wald |
Hennig P.,Johann Heinrich Von Thunen Institute |
And 7 more authors.
Forest Science | Year: 2012
Estimates of growing stock in European countries vary mainly by using different thresholds for dbh of sample trees, as well as by the inclusion or exclusion of stump and stem top volume. European national forest inventories use dbh thresholds ranging from 0 to 12 cm in estimating the volume of growing stock. COST Action E43 has agreed to a reference definition for growing stock with a dbh threshold of 0 cm. With use of national volume distributions by dbh classes, models for estimating the proportions of growing stock between the national threshold and the 0-cm threshold were constructed. Models for characterizing growing stock distributions were tested, and their predictive abilities were investigated. Similar comparisons were made with respect to the volume of stumps and stem tops. Examples of estimation methods and the resulting percentages of these tree elements of total growing stock are presented. © 2012 by the Society of American Foresters.
Rogger M.,Vienna University of Technology |
Kohl B.,Bundesforschungs und Ausbildungszentrum fur Wald |
Pirkl H.,Technisches Buro fur Geologie Dr. Pirkl |
Hofer M.,Ingenieurburo Dipl. Ing. Gunter Humer GmbH |
And 5 more authors.
Osterreichische Wasser- und Abfallwirtschaft | Year: 2011
Flood flows of a certain return period are normally determined by use of flood statistics when needed for the purposes of river engineering, but precipitation-runoff models are used for torrent and avalanche control. Since the two methods tend to yield significantly different results, harmonisation is desirable so as to reconcile the difference. This is the reason why the Hydrographic Service of Tyrol and the Forestry Service for Torrent and Avalanche control of Tyrol have launched the HOWATI project with the aim of understanding the reasons why the two methods differ. The project began with a detailed field reconnaissance in ten representative catchment areas to establish in detail the surface runoff patterns and hydro geological situations. The flood flows were then calculated using the Zemokost precipitation-runoff model and statistical long-term simulation (Monte Carlo). The differences between the two methods can mainly be explained by the significance of what plausible precipitation input is selected so as not to overestimate flood values in the use of the runoff model as well as by the fact that the statistical distribution function for regions of great storage capacity may show a knee, which results in much higher flood values than the usual gauge statistics do. The results obtained from the representative catchments have been used as a basis for a region-wide interpretation across the province of Tyrol. © 2011 Springer-Verlag.
Smidt S.,Bundesforschungs und Ausbildungszentrum fur Wald |
Bauer H.,Vienna University of Technology |
Furst A.,Bundesforschungs und Ausbildungszentrum fur Wald |
Jandl R.,Bundesforschungs und Ausbildungszentrum fur Wald |
And 3 more authors.
Austrian Journal of Forest Science | Year: 2011
Deposition of heavy metals may lead to long-term injuries/damages and to complete and irreversible degradation of soils in forest ecosystems. Relevant doses are found not only in the vicinity of emitters but also elsewhere due to long-range transport. In Austria, heavy metals and radionuclides are monitored in the framework of several national and European monitoring networks (National Monitoring Grid, Austrian Bioindicator Grid, UN-ECE/ICP-Monitoring Network, Austrian Soil Monitoring System and BioSoil, respectively, and Radionuclide Monitoring Grid Upper Austria). On the one hand, since the 1980s, the input of heavy metals was significantly decreased due to emission reduction measures. On the other hand, radionuclides are still present in spruce needles and forest soils since the Tschernobyl disaster in 1986. The evaluation showed that in general, Austrian forest ecosystems per se are not endangered by heavy metal and radionuclide deposition. Nevertheless, the accumulation of heavy metals may cause a permanent physiological stress for forest plants, especially at "hot spots".