Section 19. Planting trees and shrubs along state highways

The commissioner
  of  transportation,  in  his  discretion,  may  plant  rows or groups of
  suitable trees along the bounds  of  existing  state  highways  at  such
  places  as he may determine and may also plant on the banks of such cuts
  and fills as were made in constructing, reconstructing or improving such
  highways such shrubs as are necessary and suitable to  prevent  or  stay
  erosion thereof. Upon the construction, reconstruction or improvement of
  any  state  highway the commissioner of transportation shall plant along
  such highways rows or  groups  of  suitable  trees,  except  where  such
  highways  pass  through wooded sections of country, and shall also plant
  on the banks of such  cuts  and  fills  as  are  made  in  constructing,
  reconstructing  or  improving such highways such shrubs as are necessary
  and suitable to prevent or stay erosion  thereof.  The  commissioner  of
  transportation  may,  with  the  consent  of  the  owner of the abutting
  premises, enter upon such premises to plant suitable trees or shrubs  as
  he may determine as desirable for reasons of safety and to maintain such
  trees  and shrubs for a period not to exceed two years. The commissioner
  of transportation is not required to plant shrubs and  trees  under  the
  provisions   of  this  section  should  such  plantings  already  be  in
  existence, should the soil in any place be too stony for  such  planting
  or  should  such planting imperil the safety of the public. The work may
  be done by forces in the department or by contract  let  to  the  lowest
  responsible bidder after due advertisement.  Moneys appropriated for the
  construction  and  maintenance  of state highways shall be available for
  any of the work authorized by this section.