Threats to historical parks have various origins. There are three main types regarding their kind and scale: internal threats resulting from outside conditions of a given park facility, internal ones related directly to the area occupied by the garden and general threats. Nowadays an adverse tendency of realization of quite frivolous modernization activities in historic parks is clearly noticeable. It leads to the degradation of specific park forms, and at the same time it leads to an introduction of new, often stylistically alien, forms. Restoration works require an individual approach as each park has its own characteristic features, independent from the features typical for the particular epoch – the features that were determined both by regional specifics and by the designers of the most important elements of its spatial makeup. Identification of threats is an important element in development of the appropriate methods for protection of historic gardens.