Consequences of long-distant transfer of reproductive
material by humans are not necessarily restricted
to plantations. Gene flow from plantations to surrounding
natural forests has unpredictable but potentially
strong implications for patterns of genetic
variation and may severely affect the adaptive properties
of naturally regenerated forests (Ellstrand, 1992).
Forest dieback in Central Europe after the longterm
exposure to anthropogenic stress led to efforts of
soil amelioration by liming and fertilization in order to
partially compensate advanced soil acidification. If
soil melioration is applied after clear cutting to
improve the conditions for artificial regeneration,
these measures are also expected to induce selection regimes substantially different from those for regeneration
material under non-manipulated field conditions
(Starke et al., 1996). Some results are described
in case study 2, where amelioration measures seem to
substantially restrain adaptational processes.