%0 Research article
%T Equilibrium curves and growth models to deal with forests in transition to uneven-aged structure – application in two sample stands
%A Sterba, Hubert
%D 2004
%J Silva Fennica
%V 38
%N 4
%R doi:10.14214/sf.409
%U https://silvafennica.fi/article/409
%X Stem number distributions in uneven-aged forests are assumed to be  stable, if they follow special functions, e.g. de Liocourt’s reverse  J-shaped breast height diameter distribution. These distributions  therefore are frequently regarded as a target in all-aged forests.  Intending to convert an even-aged forest or any other forest, not yet  exhibiting this sort of equilibrium, towards a steady state forest, the  question rises, how to choose an appropriate equilibrium curve and how  to achieve this stem number distribution by an appropriate thinning and  harvesting schedule. Two stands are investigated: One dominated by  Norway spruce (Picea abies), having developed from a 120 year old  even-aged stand 25 years ago, after several “target diameter thinnings”.  The other one is a mixed species stand of Norway spruce, white fir  (Abies alba), larch (Larix europea), common beech (Fagus silvatica), and  Scots pine (Pinus sylvestris), having lost its typical uneven-aged  structure 20 years ago. These stands were used, together with the  distance independent individual tree growth model PrognAus, to reveal  that 1) there are more than only one equilibrium curve per stand, 2) not  every hypothesised equilibrium can be reached with any stand,  3) an equilibrium in stem number does not necessarily mean a stable  species distribution, and 4) growth models provide an excellent help to  decide between several equilibrium curves and harvesting schedules to  reach them.