The article contains a literature review about the spatial order of plants and a description of the small-scale experiments with corn. The literature is primarily of German origin. The question of the spatial conditions of trees in forest is important for practice of silviculture. The first part of the article illustrates based on the literature the importance of roots and root concurrence for the development of plants or forest stands. The second and third part deepens the methodological knowledge on root research. Fourth part is the field experiments with corn. There are no clear relation to be found between yield and the number of plants.