Cal. Government Code § 25635

In any county where a county board of forestry has been created and appointed, it is unlawful for any person except the county board of forestry or its employees to trim, prune, cut, deface, destroy, or remove any shade or ornamental tree or hedge growing upon any public road, highway, ground, or property or to paint, place, attach to, or put upon such trees, hedges, shrubs, lawns, or flowers, any sign, notice, advertisement, or advertising device, or to plant any tree or hedge on any such road, highway, ground, or property without the consent in writing of the board of forestry first obtained. This article does not give the county board of forestry any jurisdiction over any fruit or nut trees which on August 10, 1913, were growing along such roads, highways, grounds, or property, except that such trees may not be removed without the consent of the board of forestry. The violation of any provision of this section is a misdemeanor.