Agroforestry systems support all categories of ecosystem services (ESs). In providing the regulating category of ESs, these systems have become an important strategy used to attenuate drought impacts and biodiversity losses on agricultural landscapes. Within the agroforestry design process aimed at ES provision, one of the agroforestry types used is tree belts (TBs). Unfortunately, due to the inappropriate spatial arrangement of TBs, agricultural landscapes often become too shaded or too sunny. In existing agricultural models of the TB impact on light conditions, only the average values of all TB parameters are considered. Moreover, these models can only be used for whole study plots, or a given plot can be divided into several zones parallel to the TB. Therefore, we developed the QGIS plugin to design TB simulations on a spatially continuous scale for more effective estimation of their impact on potential insolation. The design process is based on the user library containing the tree and shrub species, soil data, parcel-based layout, and digital surface model. In this study, we tested our plugin and its outcomes in terms of predicting changes in potential insolation.