Subject to Site, specific changes as required
The objective of the City of Chicago’s Tree Protection requirements is to minimize the negative impacts of construction activities on street trees. With proper planning, many negative impacts on trees can be avoided. For instance, placement of underground utilities and service connections to new buildings should be designed so that the proposed service lines exit the building and are installed as far away from existing trees as possible. The specifications that follow detail minimum distances that the edge of excavation needs to be in order to ensure that there is minimal impact on existing parkway trees.
A Tree Removal Permit shall be issued only in the event the City finds that all reasonable efforts have been undertaken in the architectural layout and design of the proposed development to preserve existing street trees. As a condition of the Tree Removal Permit, replacement trees and/or compensation for lost value may be required. Please refer to the City's Tree Removal and Replacement Guideline.
A) Building Placement and driveway, walkway and parking areas shall be designed in such a way as to avoid unnecessary removal of existing street trees.
B) Proposed placement of all utility services lines shall be shown on the site/landscaping plan. Every effort shall be made to protect existing street trees during the placement of utility service lines including auguring and/or jacking as opposed to open cutting as appropriate.
The tree protection requirements are intended to guide a construction project to insure that appropriate practices will be implemented in the field to eliminate undesirable consequences that may result from uniformed or careless acts, and preserve both trees and property values.
Tree Protection Required
1) An applicant shall protect trees and plants in the public way.
2) An applicant shall submit a landscaping plan incorporating proposed tree protection measures for any existing trees located in the public way and on any site at any project or construction site where improvements are proposed in compliance with these Standards.
3) The landscaping plan shall identify any tree proposed for removal and shall provide explanation for proposed removal.
4) The landscaping plan shall identify any potential detrimental effects to existing trees that might result from construction activities within the dripline of any existing trees located in the public way.
5) The applicant shall notify the City within 24 hours of any suspected damage to trees resulting from construction activities. If damage occurs during construction, the applicant shall have the damaged tree repaired, if possible, or removed if a hazardous or if the tree is irreparably damaged.
Protection of Existing Trees in the Right of Way
At a minimum, any tree greater than 4" D.B.H. that is permanently damaged due to the construction project and not originally marked for removal shall be replaced with a new tree as identified by the Bureau of Forestry and shall have a minimum of 4" caliper B&B. Any damaged tree smaller than 4" caliper measured 5" above the ground shall be replaced in kind, inch for inch.
2. A protection barrier or temporary fence of at least 1.2m (4 feet) in height must be installed around each tree to be protected and preserved. The tree protection shall be installed prior to the actual construction start and maintained for the duration of the project.
Within this protection zone, construction materials shall not be stored, equipment operated and/or temporary storage buildings or work trailers placed.
The protection barrier must be constructed of orange snow fencing securely fastened to fence posts spaced a maximum of 1.5 m (5 feet) on center. Posts are 1.8m (6 feet) in length with 61cm (2 feet) set into the ground and 1.2m (4 feet) extending above ground. The fencing shall be attached to the post with a minimum of four (4) nylon locking ties evenly spaced at each post.
Dimensions of the protection barrier is as follows:
Trees located in Tree Pits:
Where trees are located within Tree Pits, the fencing should be installed at a minimum distance of the inside dimension of the Tree Pit opening with one stake at each corner of the opening.
Trees Located in Parkways:
Small Trees (<9" D.B.H.): Minimum 1.5m (5 feet) from face of tree along the parkway length. In the dimension bordered by the public sidewalk or curb, the fencing shall be the width of the grass parkway with a maximum offset of 30cm (1 foot) from back of curb or edge of sidewalk. In no case shall the closure be less than 61cm (2 feet) from the center line of the tree.
(Example: 6" Tree in a 6' parkway as measured from back of curb to sidewalk. The dimension of the protection fencing would be 1.2m x 3m (4' x 10') with tree in the center). Note: Larger grass parkways (>12') may allow for a ten foot by ten foot (10' x 10'). Thus, the dimension bordered by the sidewalk or curb would not affect fencing distance.
Medium (10" to 15" D.B.H): Minimum of ten (10) feet from face of tree along the parkway length. In the dimension bordered by the public sidewalk or curb, the fencing shall be the width of the grass parkway with a maximum offset of one (1) foot from back of curb or edge of sidewalk. In no case shall the closure be less than two (2) feet from the centerline of the tree.
Large (>15" D.B.H.): Minimum of fifteen (15) feet from face of tree along the parkway length. In the dimension bordered by the public sidewalk or curb, the fencing shall be the width of the grass parkway with a maximum offset of one (1) foot from back of curb or edge of sidewalk. In no case shall the closure be less than two (2) feet from the centerline of the tree.
Trees located in Boulevards:
Trees located in Boulevards shall have tree protection fencing installed out to the drip-line of the tree where the site allows. In proximity to hardscapes such as curbs and sidewalks, the fencing shall go out to the dripline when feasible (sides of tree free of hardscapes) and to the edge of the hardscape with an offset of one (1) foot from the back of curb or edge of sidewalk.
Alternatives to Tree Protection Fencing may be approved and/or be required should existing conditions and/or proposed work warrant it (limited access to property etc.). Examples of alternatives are as follows:
A) Trunk Protection (boards tied around tree trunk) with a constructed bridge over the root system of the tree. Area of bridge will typically adhere to distance described above for small, medium and large trees.
B) Plywood instead of snow fencing may be required on projects with large number of trees and/or where the Bureau of Forestry determines that additional protection is required.
2) Pre-Construction Tree Trimming
Trees within the construction zone, that are to be preserved, shall be pruned to a minimum height of 3.6m (12 fee) and a maximum of 6.1m (20) feet wherever construction equipment is expected to invade the tree crown. All dead branches should be removed to make trees safer for construction personnel.
All tree trimming shall be performed prior to the start of construction to prevent damage to trees being preserved and protected. Tree trimming must be performed so as to maintain natural tree form. CLEAR CUTTING OF LIMBS DIRECTLY ABOVE CURBLINE IS STRICTLY PROHIBITED.
Only tree service companies will be issued permits to work on trees.
3) Root Pruning (prior to excavation)
Where the proposed back of curb, driveway or sidewalk edge is located 1.5 (5 feet) or less from the trunk of an existing parkway tree, root pruning by an approved mechanical root pruning saw shall be used prior to excavation of street/sidewalk, where noted on the plans or as directed by the Bureau of Forestry. All root pruning not specified on the plans shall be at the direction of the Bureau of Forestry. Permits for root pruning shall be obtained from the Bureau of forestry.
Whenever roots of trees to remain are exposed during construction, the damaged root ends are to be removed by being cut off cleanly.
Dimensions of Root Pruning are as follows:
Small Trees (<10"D.B.H.): The root pruning trench shall be located no more than 30cm (12") off the back of the proposed curbline. The length of the trench shall not be less than 1.5m (5 feet) on each side of the centerline of the tree.
Medium to Large Trees (>10" D.B.H.): The root pruning trench shall be located o more than 15cm (6") off the back of the proposed curbline. The length of the trench shall not be less than 3m (10') on each side of the centerline of the tree.
Depth of root pruning shall not exceed the depth required for installation of hardscape (i.e. curb depth ˜24" or sidewalk depth ˜6"). Excavation for new curbline shall not exceed 15cm (6") off the back of the proposed curb. A fine of $500 per inch beyond the 15cm (6") will be imposed for each occurrence adjacent to a preserved and protected tree.
4) Parkway Restoration and Grading
All mechanical grading shall be prohibited within the tree protection zones. Any grading required within the tree protection zone shall be done by hand implements and performed in a manner so as to minimize the excavation required to meet the original grade to the new top of curb. In no case shall the hand excavation extend more than 61cm (2 fee) from the curbside fencing. Grade changes in excess of one (1) inch in three (3) feet shall be reviewed and approved by the Department of Streets & Sanitation, Bureau of Forestry, prior to work being started. Grade changes within the tree protection zone in excess of this minimum, may require ADDITIONAL tree removal.