Students from Austria and Brazil (n = 129) were shown 50 photographic images of various trees and asked to judge their size and distance from the viewpoint. The results show that smaller trees are perceived to be larger and more distant than larger trees. Another important factor for the perception of distances was texture: trees with fine texture (small or pinnate leaves, thin branches, etc.) appear to be larger and more distant from the viewer, thus enlarging the spatial impression of a scene. A key for the explanation of these effects is the term familiarity: in the human cognitive system familiar objects are assigned to a certain norm size. Perceived objects not matching this size are automatically rescaled. Although frequently postulated in the literature, the effects of colour could not be generalised as the two test groups from Austria and Brazil showed completely different reactions. Demographic factors (e.g. geographical and social origin, sex) were responsible for a high proportion of statistical variance: females estimated tree sizes smaller and more distant than males, the influence of urban or rural origin of the test subjects depended on the geographical origin (Austria or Brazil).