Small forest patches (SFPs) are considered as one of the most important landscape elements, enriching the monotonous agricultural areas. Various studies focus on the ecological role of SFPs, however none provides a comprehensive characteristics of the reasons for their occurrence in post-glacial areas. The location of SFPs within field areas is not incidental, and the occurrence is mainly determined by physiographic factors which prevent or hinder the use of such areas for agriculture. To a large extent, the distribution of SFPs is determined by the origin of the given area which, in the case of Europe and North America, is related to ice sheets and their effects over millennia. Therefore, the aim of the present paper was the assessment of the reasons for the occurrence of SFPs within intensely cultivated agricultural post-glacial areas in Western Pomerania of Poland. It was found that the occurrence of SFPs is related to natural abiotic factors, the most important being gradient of a slope, presence of sandy soils and wetlands. Additionally, the significance of these factors, size of SFPs and their spatial characteristics to a large degree are determined by geomorphological variability of the area.