Aim of the study:
The article is devoted to studying the state of preservation, transformations in the compositional and planning structure, and the tree species composition of plantations within parks that are monuments of 18th–19th century landscape gardening art in historic Volyn, located within the Rivne region. This research serves as a scientific basis for developing projects aimed at their revalorization.

Material and methods:
The theoretical foundation of the research is based on the works of Polish and Ukrainian scholars in the fields of park design history. Primary sources (cartographic materials and inventory descriptions) play a crucial role, alongside the accounting documentation of parks classified as historical monuments and data from recent field surveys of park plantations in the Rivne region of Ukraine. The historical-genetic method, comparative analysis, synthesis, route surveys, phytocoenotic analysis, and the determination of the taxonomic composition of the plantations are used.

Results and conclusions:
In the 20th and 21st centuries, significant changes have occurred in the structures of the historical parks in the Rivne region, leading to partial landscape degradation and the loss of stylistic features. Key issues include the reduction of park areas, the introduction of uncharacteristic species or natural self-seeding, which have caused substantial alterations in the parks' compositional structure, the loss of original landscape views, and the overcrowding of plantations. Effective revalorization of historical parks can be achieved through a phased restoration of their environment to a state and appearance as close as possible to their original condition. Such efforts can be integrated into student educational programs, community initiatives, or public outreach projects.