Except as hereinafter provided, the shade tree commission may exercise exclusive control over the regulation, planting and care of shade and ornamental trees and shrubbery now situate or which may hereafter be planted in any public highway, park or parkway of the county, including:
a. The planting, trimming, spraying, care and protection thereof;
b. The regulation and control of the use of the ground surrounding the same so far as may be necessary for their proper growth, care and protection;
c. The moving or requiring the removal of any tree or part thereof, dangerous to public safety;
d. The care and control of the parks and parkways;
e. The encouragement of arboriculture.