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ŠUMARSKI LIST 13/2011 str. 150     <-- 150 -->        PDF

I. Pilaš, Š. Planinšek: OBNOVAVODNOG REŽIMANIZINSKIH ŠUMAKAO POTPORAPOTRAJNOM ... Šumarski list – Posebni broj (2011), 138-148

species such as the common oak (Quercus roburL.), field ash (Fraxinus excelsior
Vahl.), common hornbeam (Carpinus betulus L.) and softwood species
such as black alder (Alnus glutinosa(L.) Geartn.), poplars (Populussp.) and
willows (Salixsp.). For the biological diversity of lowland forests and attached
wetlands is strongly important specific combination of hydrology and
soils. The development of these forests in history was determined by regular
seasonal alternations of groundwater tables (hydro period) and periodic flooding.
This paper presents the possibilities for the re-establishment of the water
regime of lowland forests as one option to reduce the impact of climate change
in the future. To reduce negative impacts of anthropogenic alternations in the
groundwater regime from the past and to attenuate slow down future very possible
prolongation of droughts and water scarcity in the lowlands, various forest
managerial and engineering practices could be considered. Basically,
there are potentially two main contrasted measures of soil water balance manipulation:
drainage of soils (through drainage ditches and channels) which
contribute to decreasing the groundwater tables and forest management i.e.
(tendering and thinning) which contribute to increased soil water content and
increase in the groundwater level. Through these water table management
practices, the amount of soil water required for the survival of lowland forests
could be maintained to some degree to attenuate the negative hydrologic
trends and natural hazards such as droughts. The comprehensive methodological
review of activities that must precede such reconstruction activities are
presented. As the initial segment all the major components of floodplain ecosystems
– the morphology of the terrain, hydrography, soils stratigraphy, vegetation
and anthropogenic influences – should be assessed. As a next step
methodological options towards how to obtain the knowledge of the natural
water regime prior anthropogenic hydrotechnical activities which caused the
creation of the ecosystem in its current form are presented. For this purpose
the morphology of hydromorphic soils i.e. relict indicators of natural water
regime in lowland habitats are assessed. The next step includes the spatial determination
of critical areas or hot spots, threatened by excessive falls in the
groundwater level on which specific measures can be applied to return to natural
water regime conditions (i.e. water retention in dry riverbeds).

Key words:Lowland forests, water regime, groundwater, relict indicators,
soil morphology, hydro-technical measures