Naslov
Trends and Seasonality of Groundwater Tables in Croatian Lowland Forest

Autori
Pilaš, Ivan ; Vrbek, Boris

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, ostalo

Izvornik
Water Management through Forest Management / Wang Yan-Hui, Xu Li-Hong - Peking, 2007, 81-81

Skup
Water Management through Forest Management

Mjesto i datum
Peking, Kina, 12-1710.2007

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
Lowland oak forest; groundwater table; Forest decline; tree stem diameter changes

Sažetak
The remnants of Central Europena lowland hardwood forest present important areas for forestry production, flood reduction, recharging groundwater reserves, as well as filtering pollutants. Due to excesive urbanization and the spread of agriculture, the total area of these forest has been significantly reduced and now presents one of the most disturbed ecosystems in Europe. theirdevelopment is mostly determined by discharge of groundwater and periodic flooding that provides sufficient availability of soil water adequate for tree species such as the common oak (Quercus robur L.), field ash (Fraxinus excelsior Vuhl.), common hornbeam (Carpinus betulus L.) and black alder (Alnus glutinosa (L.) Geartn.). In the past decades the natural conditions regarding the surface and groundwater regime have changed cignificantly due to hydro-technical activities including river canalization, internal forest drainage networks and the construction of artificial flood containment areas, the results of which is cignificant forest decline. In order to gather information regarding graundwater resourses of these forest under changing environmental conditions, a network of piezometric stations was established. The graundwater data series has been gathered for more than decade up to now from 120 piezometric stations all over the lowland forest aresa and is a very good basis for analyzing the trends sesonality of graundwater tables. In addition to permanent graundwaqter monitoring, some additional site oriented studies were provided from which indices of disturbance of stand water and mass transport (radial increment, crown condition, stem changes, sapwood chemistry andelectric resistance of cambia zone) as a result of changes of groundwater tables can bedetermined. In this work the results of GIS analysis of spatial groundwater data was linked to point orientated studies on various plots related to the monitoring network. The gathered groundwater data in general confirms that especially in the last decade, a significant decreasing trend of groundwater as result of climate change and global warming is very evident over the lowland forest region in Croatia. This can be assessed from GIS interpolated data layers. The seasonal characteristics of the groundwater series shows a spatially specific pattern influenced mostly by differences in soil properties (texture) and climate characteristics (total amount of precipitation) of different lowland forest regions. A major threat to the forest is periodic episodes of drought in which an extremly strong drop of groundwater tables occurs. Episodes of drought werw determined from 1990 to 1993 and even more intensively from 2000 to 2007. During these episodes the lack of regular periodic groundwater discharge and more intensive fall of graundwater especially at the beginning of the vegetation season caused a disturbance of water and mas transport of oak forest stands. this is evident through a decrease in the tree radial increment and significantly smaller seasonal alternations of tree diameter changesč. The disturbance of oak forest stand helth condition showed significant changes in sapwood chemistry and transport of elements in trees what is evident through decreasing fluxes of N and icreasing fluxes of Mn, Fe and Mg.

Izvorni jezik
Engleski

Znanstvena područja
Šumarstvo

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