Target diameter harvesting - a strategy to convert even-aged forests

The forests of the Schlagl-Monastery in the north-eastern corner of Austria are managed according to Reininger's [Osterreichischer Agraverlag, Vienna, Austria, 163] idea of target diameter harvesting. Twenty years of observat ions in a 3.5 ha Norway spruce stand in Schlagl and the first re-observatio n of a permanent inventory in the nearly 500 ha forest management district (FMD) Sonnenwald are investigated and reveal that indeed small trees make e fficient use of the area they gain from the removal of their larger neighbo urs and that the growth per hectare is not decreased by target diameter har vesting. It seems that over a rather long period in the investigated stand and in all stands above 80 years the number of larger trees removed will be replaced by the growth of smaller ones. comparing the stem number distribu tion with Schutz's [Schweiz. Z. Forstwes. 126 (9) Romandes, 178] equilibriu m model shows that the steady state is not yet achieved but is fast approac hed by target diameter harvesting. Probably the equilibrium stocking volume is somewhat below the current average stocking of 450 m(3) ha(-1). (C) 200 1 Elsevier Science B.V. All rights reserved.