(a) Purpose. The City Council recognizes that preservation and replanting of trees is important on new single-family residential development sites in order to maintain a healthy and desirable community. The City Council also recognizes that a certain amount of tree loss is an inevitable consequence of the residential development process. The City Council finds that these tree preservation regulations help to establish a balance between an individual's rights to develop his or her property and the needs of the community to protect the natural environment. The purpose of these tree preservation regulations includes, but is not limited to:
(1) Prevention of soil erosion and sedimentation;
(2) Improved air quality;
(3) Reduced noise pollution;
(4) Energy conservation through windbreaks and shading;
(5) Control of the urban heat island effect;
(6) Increased property values;
(7) Protection of privacy by maintaining and establishing buffers between conflicting land uses;
(8) Enhanced aesthetics;
(9) Providing habitat for wildlife; and
(10) Support stormwater management.
(b) Applicability. The regulations contained in this section apply to all proposed single- and two-family residential lots for which a plat application was received after August 31, 2006, with the exception of plats that create only lot line adjustments and do not alter the number of lots. The regulations continue to apply for a period of two years after the date the plat was recorded with the county.
(c) Definitions. The following definitions supplement those in § 19.03 and apply only to this section of this code.
CRITICAL ROOT ZONE. The area within a radius surrounding the tree trunk of one foot per one inch DBH of tree diameter. For example, a 20 inch DBH tree has a CRITICAL ROOT ZONE with a radius of 20 feet.
DBH. Diameter at breast height. The diameter of a tree measured four and one-half feet above grade level.
DISTURBANCE ZONES. That part of a site disturbed by tree clearing, grading, trenching or any other construction activities.
HEALTHY TREE. Any significant tree except those deemed diseased by a licensed tree inspector or the City Forester.
NONNATIVE BENEFICIAL. Plant species or varieties that historically originate from outside the local ecosystem and provide benefits to or do not pose a significant threat to native biodiversity, ecosystem function, or human interests.
SIGNIFICANT TREE. Any healthy deciduous hardwood tree or healthy coniferous tree of specific DBH inches as identified in the following table. For the purposes of this § 21.301.14, a prohibited tree species identified in § 18.03 may be considered a significant tree, unless otherwise specified.
Category | Tree Types | Size |
Deciduous Hardwood (General) | All species except Prohibited and Exceptions are Significant when meeting the following size | 12" DBH or greater |
Deciduous Hardwood (Exceptions) | Oak, sugar maple, ironwood, hickory are Significant when meeting the following size | 6" DBH or greater |
Deciduous Hardwood (Prohibited) | Willow, boxelder, aspen, silver maple, multiple stem cottonwood are prohibited | Prohibited |
Coniferous (General) | All species except Prohibited are Significant when meeting the following size | 8" DBH or greater |
Coniferous (Prohibited) | Multiple stem white cedar is prohibited | Prohibited |
TREE TRUNK. The stem portion of a tree from the ground to the first branch thereof.
(d) Removal threshold.
(1) Removal or disturbance of significant trees on lots or proposed lots in the R-1, R1-A and RS-1 Zoning Districts beyond 50% of the total inches DBH of significant trees on the lot or proposed lot requires reforestation as specified in this section. The following trees are not counted toward the calculation of significant trees:
(A) Trees within existing or proposed conservation and protective easements;
(B) Trees within 100-year floodplains;
(C) Trees within wetlands;
(D) Trees on slopes greater than 25%; and
(E) Trees deemed diseased by a licensed tree inspector or the City Forester.
(2) Significant trees within existing conservation and other protective easements, floodplains, wetlands or on slopes greater than 25% must be preserved and may only be removed upon issuance of a permit from the City Forester.
(e) Reforestation requirement. When reforestation is required, the landowner is required to prepare a reforestation plan and must mitigate the loss of significant trees by planting 1.25 caliper inches of replacement trees for each inch DBH of significant trees removed beyond the removal threshold.
(f) Tree preservation standards. To receive credit for preserving existing significant trees, significant trees must be protected from direct and indirect root damage and trunk and crown disturbance. The following preservation standards apply.
(1) Construction activities including parking, material storage, dirt stockpiling, concrete washout and other similar activities must not occur within the critical root zone of any significant tree to be preserved.
(2) There must be no changes to the grade within the critical root zone of any significant tree to be preserved.
(3) A reasonable effort must be made to have utility line trenches and similar uses avoid the critical root zone of any significant tree to be preserved. Due to certain site conditions, where disturbance is unavoidable, the City Forester may approve underground tunneling or directional boring of utilities within the critical root zone of any significant tree to be preserved. Trenching, when approved by the City Forester, must be used only as the last alternative and root pruning equipment specifically designed for that purpose must be used. Pruned roots must be sealed with nontoxic wound sealant.
(4) Where the tree preservation standards apply, prior to issuance of building or grading permits, protective fencing must be installed around the limits of the disturbance zone or around the critical root zone of significant trees to be preserved. Such fences must be at least four feet high and must consist of orange polyethylene safety fencing. Fencing must remain in place until construction is completed or other landscaping has been installed and the City Forester has approved the removal of the fencing.
(5) Owners pruning oak trees between April 15 and July 1 must apply an appropriate nontoxic tree wound sealant to any cut areas.
(g) Tree survey and tree preservation plans. All plat applications that would create one or more new parcels in the R-1, R-1A and RS-1 Zoning Districts must include both a tree survey and a tree preservation plan. Tree survey and tree preservation plans must be prepared and signed by a registered surveyor and must include the following information.
(1) Location, diameter and species of all significant trees on the site as well as significant trees within ten feet of the site that will be impacted by the development.
(2) Plans must be at the same scale as the plat plans and must show the proposed lots, existing and proposed structures, driveways, retaining walls and other construction, existing and proposed utilities, existing topography and proposed grading, existing and proposed easements, slopes over 25%, wetlands, conservation or restrictive easements, 100-year floodplains and setbacks.
(3) Plans must identify which significant trees are:
(A) To be protected, preserved and undisturbed;
(B) To be removed or disturbed; and
(C) Not counted in the calculation as discussed in subsection (d)(1) above.
(4) Plans must identify proposed disturbance zones by cross-hatching or gray colored shading on the plan and must identify areas of clearing, grading, trenching and similar activities.
(5) Plans must identify the location of the critical root zone of any significant trees to be saved within 30 feet of proposed disturbance zone.
(6) Plans must identify the location and dimensions of building pads, construction zones for each lot and proposed street layout and grading contours of the site.
(7) Plans must identify the proposed locations and details of tree protection fencing or other tree protection measures to be installed for all significant trees to be preserved.
(8) Signature and registration number of the registered surveyor preparing the plan.
(9) Calculation of total significant tree inches DBH proposed to be removed or disturbed on the site (excluding exempt tree inches) divided by the total significant tree inches DBH on the site (excluding exempt tree inches); showing the net percentage of removal/disturbance.
(10) Plans must identify the location of trees proposed to meet reforestation requirements.
(h) Reforestation plan. All plat applications that would create one or more new parcels in the R-1, R-1A and RS-1 Zoning Districts must include a reforestation plan if the amount of significant tree caliper inches to be removed or disturbed as shown on the tree survey and tree preservation plans exceeds the removal threshold. The reforestation plan must be prepared and signed by a registered landscape architect or certified arborist and must comply with the following criteria.
(1) The plan must indicate the location and caliper inches or height of all trees to be planted.
(2) No more than one-half of the trees to be planted may be from any one species.
(3) Trees are encouraged to be native to the region; up to one-half of the planted trees may be nonnative beneficial species or varieties.
(4) No more than 15% of the required tree inches may be of ornamental species.
(5) The minimum planting size for deciduous trees is two and one-half caliper inches.
(6) The minimum planting size for coniferous trees is six feet in height.
(7) Trees must be planted a minimum of 15 feet apart from one another and from existing trees, except where approved by City Forester.
(8) Trees to be planted must be from certified nursery stock as defined and controlled by M.S. Chapter 18H, as it may be amended from time to time, the Plant Pest Act.
(9) The plan must include a planting schedule with a tree key, botanical and common tree names, the quantity and size of each tree species to be planted, the total caliper inches of trees to be added and the anticipated heights and spread at maturity.
(10) Unless approved by the City Engineer, trees must not be planted within 15 feet of city curb and gutter or sidewalk, must not be planted in a clear view triangle area and must not be planted in a public utility easement.
(i) Authority of the City Forester.
(1) The tree survey, tree preservation plan and any related reforestation plan must be reviewed and evaluated by the City Forester.
(2) The City Forester has the authority to approve, deny, condition or reject as incomplete a tree survey, tree preservation plan, or reforestation plan.
(3) A tree preservation plan and reforestation plan may be amended after it has been approved. The City Forester has authority to approve amendments, except that a change resulting in removal of more than 10% of the significant tree inches DBH that were shown as preserved on an approved tree preservation plan requires further review by the City Council. As part of any amendment to a tree preservation plan, the required reforestation may be increased or reduced accordingly. Requests for amendments must be submitted prior to removal of any trees shown as preserved on an approved plan.
(4) The City Forester has the authority to establish surety rates.
(j) Surety. When a reforestation plan is required, a reforestation surety must be submitted prior to issuance of a grading permit, or building permit if no grading permit is required, to ensure that proposed trees shown on a reforestation plan are installed as proposed and survive through at least one full growing season lasting one year. The reforestation surety must reflect the average market rates for providing, installing and warranting plant materials that equal or exceed the total required reforestation caliper inches multiplied by the average value per caliper inch of trees as determined by the City Forester. The minimum surety amount is $1,000. The surety must be maintained at the calculated level until one year passes from the time of tree planting and the city has inspected the site for conformance to the plan and authorized a reduction or release. The surety may consist of a bond, an irrevocable letter of credit, cash deposit or other instrument which provides an equal performance guarantee to the city.
(k) Inspection and enforcement of the tree preservation plan.
(1) Field staking and pre-grading inspection. When a tree preservation plan is required, all sites must be staked and fenced for tree preservation pursuant to the approved tree preservation plan prior to removal of any trees and prior to issuance of a grading permit, or prior to commencement of any grading operations if no grading permit is required, or prior to issuance of a building permit if no grading operations are required. A copy of the approved tree preservation plan must be submitted with an application for a grading permit or with an application for a building permit if no grading permit is required. Upon staking of the site and installation of the tree protection fencing, but prior to issuance of any permits or commencement of any grading operations, the landowner or applicant must contact the City Forester to schedule an inspection of the staking and fence installation on the site. No permits may be issued, nor may any grading or grubbing operations commence without first receiving authorization by the City Forester. Tree protection fencing must remain in place until after the permanent certificate of occupancy is issued for the building on the site.
(2) Post grading inspection. Upon completion of the preliminary site grading operations, but prior to any further issuance of permits upon the site, the landowner or applicant must contact the City Forester to schedule a second inspection of the site to verify the preservation of trees as shown on the approved tree preservation plan.
(3) Final inspection. Prior to issuance of a certificate of occupancy, the landowner or applicant must contact the City Forester to schedule a final tree preservation inspection to verify the preservation of significant trees and the planting of any reforestation trees as shown on the approved tree preservation plan.
(l) Violations. Violation of any provision of this section is a misdemeanor. Provisions of this section may be enforced by injunction or other appropriate civil remedy. In the case of a violation of the provisions of this section, additional permits or certificates of occupancy must not be issued for the lot or lots that have violations until the violation is mitigated through reforestation or other appropriate measures.