Both natural and man−made forest areas are subject to many changes, the observation of which is necessary to understand their causes, monitor current processes and precisely forecast further changes. Protected areas with preserved natural forests play a special role in research on long−term changes in forest cover height. The presented research presents the processes of changes in forest cover height over the last 30 years in the area of the Białowieża Primeval Forest, the last of the large, natural forest complexes that once covered the lowland part of Europe. For areas with different degrees of protection, data was obtained representing the spatial arrangement of tree crowns in the period between 1982 and 2012. The historical status was determined on the basis of point clouds obtained by processing panchromatic stereoscopic aerial photos. These data were compared with contemporary datasets resulting from airborne laser scanning measurements. This allowed for a precise definition of the range of changes, their dynamics and the nature of these changes in parts of the forest with different conservation regimes. The research demonstrated the usefulness of the proposed method for determining long−term changes affecting forested areas, including not only the range, but also the height structure of vegetation. This enables the identification of events affecting the structure of the forest, both due to normal forest management and to natural causes, along with the possibility of determining the location and approximate determination of the occurrence of a given event in time.

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