Application of cartographic sources, satellite imagery Landsat 7ETM+ and GIS technology to spatial analysis of windthrows in Bory Tucholskie Forest

Abstract

The spatial distribution of wind-induced damages was analysed in the forest complex of Komorza, situated in the Woziwoda Forest Inspectorate, the region of Bory Tucholskie Forest, northern Poland. The discussed damages were caused by a windstorm on the 22 nd of June 2000 in the forest fragment neighbouring agricultural grounds. The present study aimed at answering two questions: 1 does closer location of forest in relation to field-forest borderline increase damages in the standing timber? 2 – do windinduced damages occur more often and are more severe in the secondary forests restored on the formerly arable lands than in the forests, the development of which was not interrupted by temporary agricultural land use after cutting of trees? In order to define changes in forest and farming grounds in the study area, and as well as to identify secondary forests, old and temporary topographic maps were used, forest economic maps and satellite image Landsat 7ETM+ dated year 2000. Information derived from the above sources and also from the forest stock-taking and direct field measurements carried out with application of GPS receiver were organised in the geographic information system. Statistical analysis conducted according to GIS technology with application of computer programs: MicroStation/Bentley, ESRI ArcView3.2 and Idrisi32, proved that factors like the neighbourhood of large non-forested areas and the temporary use of forest soils for farming purposes do indeed increase range and frequency of damages caused by strong wind in the canopy of forest ecosystems.