The supply systems of various public goods are changing with differences in socioeconomic circumstances.　However, it is necessary to clarify the relationships between the characters, non-excludability and non-competitiveness, of greenery as public goods and their supply to determine how supply and by which sector, public or private, these characters are being changed.　

In this study, we concentrated on the relationships between the existence effects and the supply of private-owned greenery by the public sector.　That is, through examining the descriptions of public documents about private-owned greenery from the view point of the existence effects such as environmental preservation, landscape, recreation and disaster prevention in Saitama City, we considered the relationships between the existence effect and the supply of private-owned greenery to the public sector.　

As a result, various existence effects are described to explain the necessity of public supply for private greenery.　Particularly, the description numbers for excludability and competitiveness greenery were higher than others.　There is more description of “landscape” in supply to management than installation, and the description number for regulation is higher than for other means.　

Greenery has exteriority as the existence effect, and is a basis of public supply for private goods.　There are various systems, so descriptions are also various and sometimes vague.　Vagueness may influence the quality of the greenery.　Therefore, it is necessary for descriptions in public documents to be consistent.

JEL Classifications: H41, H23, R59