Minnesota Department of Transportation

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Project development

Environmental process | Environmental review



To ensure early identification of potential construction impacts to functional, protected, culturally important, planted or volunteer vegetation and to minimize spread of invasive plants on existing and proposed right-of-way and adjacent properties.

Early identification of potentially impacted vegetation allows MnDOT to discuss impacts with stakeholders and determine need for additional permanent or temporary right-of-way. Early identification also allows time for additional coordination (if applicable) and language (special provision) can be included in the construction project.

When to use this subject

A project with any of the following threshold criteria will require early review by the MnDOT’s Roadside Vegetation Management Unit (RVMU):

Project will occur along the highways and within the reference posts listed below:

  • Highway 2 – Reference post 35-37 and 42-48
  • Highway 32 – Reference post 35-37, 49-52, 55-58, and 70-74
  • Highway 71 – Reference post 81-83
  • Highway 56 – Reference post 8-16
  • Highway 102 – Reference post 2-6
  • Highway 218 – Reference post 20-44
  1. The locations listed have recorded populations of federally endangered plants growing within the right    of way. A review to determine potential impact, consultation with US Fish and Wildlife Service, and permit (if applicable) will be needed for any work within these areas. Please refer to Threatened and   Endangered Species – Federal guidance page for more information.
  2. Project will cause soil disturbance beyond the inslope. Most of the high value vegetation occurs in the ditch bottom or backslope of the right-of-way.
  3. Project will include soil disturbance under canopy of existing woody vegetation
    • The critical root zone guideline for a tree is typically a radius of one foot for every one inch of trunk diameter measured at 4.5 above ground
      • Although tree roots can extend pass this measurement, minimizing disturbance under the canopy helps the tree through construction
    • The majority of tree roots are in the top 18 inches of soil where oxygen, nutrients, and water are most available
      • Due to the location in the soil, roots are very susceptible to compaction and removal
      • Tree roots grow radially out from the trunk and extend beyond the edge of the tree’s canopy
      • Protecting the root system under the tree canopy is crucial to its survival
      • If soil disturbance needs to occur under the tree canopy additional review/special provisions will be needed
    • Trees growing between sidewalks and curbs have a very limited rooting area
      • Any soil disturbance and root damage under the canopy can be detrimental to tree health
  4. Project is within area of known sensitive vegetation. Areas of known sensitive vegetation include but are not limited to state and federally protected plants, native plant communities, remnant prairies, and specimen trees (see Appendix 1 for species and size).
  5. Project is within area of known high priority weed infestation
    • While all MN State Listed noxious weeds require control on MnDOT right-of-way, some weeds are a higher priority for control than others
      • State listed weeds that pose a human health concern
      • Weeds listed on the MN State Prohibit: Eradicate list
      • Highly invasive species in geographically small populations as determined by the RVMU
        • These may or may not be state listed species
  6. Project will require staging within the right-of-way. Staging of materials and equipment can cause removal of species and compaction. Vegetation review will identify areas within the right-of-way where staging should not be allowed.

See the Vegetation Process for a list of vegetation categories.

For specific process information, see the process, other guidancepages and/or contact the individuals on the contacts page.

Considerations for environmental document preparation

For Class I, II, and III actions, ensure that all mitigation commitments are incorporated into the PS & E package (when appropriate) during detail design.

How this subject fits into the overall project development process

Include vegetation assessment in the predesign phase. Complete it by _____. For Class I, II, and III actions, ensure that all mitigation commitments are incorporated into the PS & E package (when appropriate) during detail design.

Organizations involved