Rozmieszczenie przestrzenne i wielkość szkód spowodowanych przez wiatr w lasach wybranych obszarów Pomorza

Abstract

The study presents the Geographic Information System created to analyse spatial distribution of wind-induced damages in forest stands of the Tuchola Forest, northern Poland. It was used in several forest complexes mainly on the territory of the following Forest Districts in the Tuchola Forest: Woziwoda, Przymuszewo and Czersk, as well as in the Bory Tucholskie National Park.. The damages in Tuchola Forest were caused mainly by hurricanes in 26th of December 1999 and 22nd of June 2000. This work aimed at answering three questions: 1 – Does nearer location of a forest toward field-forest borderline increases the extent of damages? 2 – Does wind-induced damages occur more often and are greater in secondary forests regenerated on formerly arable lands than in forests of which development was not interrupted by temporary soil exploitation for farming purposes after cutting down the trees? 3 – What influence has the geomorphology on the intensity and extent of wind-induced damages? In order to define changes in forest and agricultural acreage in the study area, as well as to identify secondary forests, old and contemporary topographic maps were applied together with forest economic maps, satellite imageries Landsat 7ETM+ from the year 2000 and IKONOS dated 2003. Information coming from those sources as well as from the forest inventory and from the direct field measurements carried out with the GPS receiver was compiled in the Geographic Information System. The statistical analysis performed in the GIS technology using the programs MicroStation/Bentley, ESRI ArcView3.2 and Idrisi 32 proved that factors like vicinity of large deforested areas as big agricultural areas or big lakes inside forest complex and temporary exploitation of forest soils for farming purposes indeed increase the extent and frequency of damages caused by strong wind in the canopy of forest ecosystems. The analyses conducted in GIS and remote sensing technology also indicated that losses in forest area, as well as the canopy of overstory, significantly modify the spatial pattern of the forest landscape.