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[[File:Technical information page image.png|100px|left|alt=image]] | [[File:Technical information page image.png|100px|left|alt=image]] | ||
+ | [[File:Pdf image.png|100px|thumb|alt=pdf image|<font size=3>[https://stormwater.pca.state.mn.us/index.php?title=File:Operation_and_maintenance_(O%26M)_of_tree_trenches_and_tree_boxes_-_Minnesota_Stormwater_Manual.pdf Download pdf]</font size>]] | ||
[[File:Central corridor cross section B.jpg|thumb|300px|alt=schematic cross-section of Central Corridor Light Rail tree system|<font size=3>Cross section of the tree system installed for the Central Corridor Light Rail Transit project in St. Paul, MN. Image courtesy of the [http://www.capitolregionwd.org/ Capitol Region Watershed District].</font size>]] | [[File:Central corridor cross section B.jpg|thumb|300px|alt=schematic cross-section of Central Corridor Light Rail tree system|<font size=3>Cross section of the tree system installed for the Central Corridor Light Rail Transit project in St. Paul, MN. Image courtesy of the [http://www.capitolregionwd.org/ Capitol Region Watershed District].</font size>]] | ||
[[File:Marquette avenue 5.jpg|thumb|300px|alt=photo of completed project, Marquette Avenue, Minneapolis|<font size=3>Completed tree system, Marquette and 2nd Avenue Busways project, Minneapolis, MN. Image Courtesy of The Kestrel Design Group.</font size>]] | [[File:Marquette avenue 5.jpg|thumb|300px|alt=photo of completed project, Marquette Avenue, Minneapolis|<font size=3>Completed tree system, Marquette and 2nd Avenue Busways project, Minneapolis, MN. Image Courtesy of The Kestrel Design Group.</font size>]] | ||
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==Design phase O&M considerations== | ==Design phase O&M considerations== | ||
+ | [[File:Maplewood Mall tree protection.png|300px|thumb|alt=photo of tree protection with signage, Maplewood Mall|<font size=3>Photo of tree protection with signage, Maplewood Mall. Image Courtesy of Barr Engineering Company</font size>]] | ||
+ | |||
Tree trenches and tree boxes have a small footprint and should be designed to treat a relatively small drainage area (0.25 acres or less per tree). Surface area of the tree trench or box and surface area to drainage area ratio are key design characteristics. Design specifications vary based on the selected filter <span title="Engineered media is a mixture of sand, fines (silt, clay), and organic matter utilized in stormwater practices, most frequently in bioretention practices. The media is typically designed to have a rapid infiltration rate, attenuate pollutants, and allow for plant growth."> [https://stormwater.pca.state.mn.us/index.php?title=Design_criteria_for_bioretention#Materials_specifications_-_filter_media '''media''']</span> and filter box manufacturer (most tree trench and box systems are proprietary practices). Properly <span title="Sizing refers to the physical dimensions of a stormwater treatment practice or device needed to meet a water quality or quantity goal. For example, stormwater BMPs may be sized to treat a volume of runoff, a flow rate, or to meet a pollutant removal target."> '''sizing'''</span> and designing the tree box will help prevent O&M issues. Designers should consider | Tree trenches and tree boxes have a small footprint and should be designed to treat a relatively small drainage area (0.25 acres or less per tree). Surface area of the tree trench or box and surface area to drainage area ratio are key design characteristics. Design specifications vary based on the selected filter <span title="Engineered media is a mixture of sand, fines (silt, clay), and organic matter utilized in stormwater practices, most frequently in bioretention practices. The media is typically designed to have a rapid infiltration rate, attenuate pollutants, and allow for plant growth."> [https://stormwater.pca.state.mn.us/index.php?title=Design_criteria_for_bioretention#Materials_specifications_-_filter_media '''media''']</span> and filter box manufacturer (most tree trench and box systems are proprietary practices). Properly <span title="Sizing refers to the physical dimensions of a stormwater treatment practice or device needed to meet a water quality or quantity goal. For example, stormwater BMPs may be sized to treat a volume of runoff, a flow rate, or to meet a pollutant removal target."> '''sizing'''</span> and designing the tree box will help prevent O&M issues. Designers should consider | ||
*minimizing the surface area to drainage area ratio, based on the manufacturer guidelines; | *minimizing the surface area to drainage area ratio, based on the manufacturer guidelines; | ||
*properly sizing the tree box or tree trench to manage an appropriate surface area based on local precipitation patterns; | *properly sizing the tree box or tree trench to manage an appropriate surface area based on local precipitation patterns; | ||
*selecting regionally appropriately species that are tolerant to the soil and growth media (see [https://stormwater.pca.state.mn.us/index.php?title=Design_guidelines_for_tree_quality_and_planting_-_tree_trenches_and_tree_boxes Design Guidelines for Tree Quality and Planting]); and | *selecting regionally appropriately species that are tolerant to the soil and growth media (see [https://stormwater.pca.state.mn.us/index.php?title=Design_guidelines_for_tree_quality_and_planting_-_tree_trenches_and_tree_boxes Design Guidelines for Tree Quality and Planting]); and | ||
− | *selecting species that will grow in the limited space provided by the filter box see | + | *selecting species that will grow in the limited space provided by the filter box (see [https://stormwater.pca.state.mn.us/index.php?title=Design_guidelines_for_tree_quality_and_planting_-_tree_trenches_and_tree_boxes Design Guidelines for Tree Quality and Planting]). |
Designers should also consider the maintenance schedules and tasks when locating tree trenches or tree boxes on their site. The small surface area of tree boxes makes them versatile. However, they should be placed within areas that are easily accessible to ensure proper maintenance. Maintenance of tree trenches and tree boxes does not require large or heavy equipment, but routine maintenance should be expected once or twice a year. Designers can incorporate solutions to facilitate the following maintenance activities. | Designers should also consider the maintenance schedules and tasks when locating tree trenches or tree boxes on their site. The small surface area of tree boxes makes them versatile. However, they should be placed within areas that are easily accessible to ensure proper maintenance. Maintenance of tree trenches and tree boxes does not require large or heavy equipment, but routine maintenance should be expected once or twice a year. Designers can incorporate solutions to facilitate the following maintenance activities. | ||
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*Specifying the optimized soil <span title="Engineered media is a mixture of sand, fines (silt, clay), and organic matter utilized in stormwater practices, most frequently in bioretention practices. The media is typically designed to have a rapid infiltration rate, attenuate pollutants, and allow for plant growth."> [https://stormwater.pca.state.mn.us/index.php?title=Design_criteria_for_bioretention#Materials_specifications_-_filter_media '''media''']</span> composition and depth to effectively trap or <span title="to remove or withdraw"> '''sequester'''</span> nutrients (phosphorus in particular), and that can also support the desired species | *Specifying the optimized soil <span title="Engineered media is a mixture of sand, fines (silt, clay), and organic matter utilized in stormwater practices, most frequently in bioretention practices. The media is typically designed to have a rapid infiltration rate, attenuate pollutants, and allow for plant growth."> [https://stormwater.pca.state.mn.us/index.php?title=Design_criteria_for_bioretention#Materials_specifications_-_filter_media '''media''']</span> composition and depth to effectively trap or <span title="to remove or withdraw"> '''sequester'''</span> nutrients (phosphorus in particular), and that can also support the desired species | ||
*Site-specific species selections that take into account sun exposure, shade, proximity to traffic corners (visibility issues), salt-tolerance, etc. | *Site-specific species selections that take into account sun exposure, shade, proximity to traffic corners (visibility issues), salt-tolerance, etc. | ||
− | *Providing educational signage to increase public awareness | + | *Providing educational signage to increase public awareness |
*Installing measures like low fencing to prevent damage from pedestrian foot traffic | *Installing measures like low fencing to prevent damage from pedestrian foot traffic | ||
− | Designers should consult and include any local requirements regarding green infrastructure. O&M considerations often depend on whether the practice is located on public land, private land, or in the public right of way. For example, plantings in the public right of way that conflict with any traffic safety considerations could require increased O&M, such as pruning or complete removal. | + | Designers should consult and include any local requirements regarding <span title="Green stormwater infrastructure is designed to mimic nature and capture rainwater where it falls. Green infrastructure reduces and treats stormwater at its source while while also providing multiple community benefits such as improvements in water quality, reduced flooding, habitat, carbon capture, etc."> '''green infrastructure'''</span>. O&M considerations often depend on whether the practice is located on public land, private land, or in the public right of way. For example, plantings in the public right of way that conflict with any traffic safety considerations could require increased O&M, such as pruning or complete removal. |
The designer should also provide a site-specific O&M plan that includes the following. | The designer should also provide a site-specific O&M plan that includes the following. | ||
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==Post-construction phase O&M== | ==Post-construction phase O&M== | ||
Post-construction maintenance is performed on tree trenches and tree boxes to maintain proper infiltration, filtration, and to promote healthy vegetation. Immediately after construction, short-term maintenance goals include efforts to establish and keep the tree healthy. Not all trees are guaranteed to survive the establishment phase, so care should be taken to inspect the health following construction. Important post-construction considerations are provided below. | Post-construction maintenance is performed on tree trenches and tree boxes to maintain proper infiltration, filtration, and to promote healthy vegetation. Immediately after construction, short-term maintenance goals include efforts to establish and keep the tree healthy. Not all trees are guaranteed to survive the establishment phase, so care should be taken to inspect the health following construction. Important post-construction considerations are provided below. | ||
− | *A site-specific '''''Operations and Maintenance Plan''''' should be prepared by the designer prior to putting the stormwater practice into operation. This plan should provide any operating procedures related to the practices. The plan should also provide clear maintenance expectations, activities, and schedules. Include photos if possible. Be clear who is responsible for maintenance and the type of expertise needed for distinct O&M activities. The O&M plan should include an anticipated budget for O&M activities. The O&M plan should also include an example O&M inspection checklist and an example maintenance report. Example O&M plans are provided here and a schedule of general maintenance activities is provided in the adjacent table. | + | *A site-specific '''''Operations and Maintenance Plan''''' should be prepared by the designer prior to putting the stormwater practice into operation. This plan should provide any operating procedures related to the practices. The plan should also provide clear maintenance expectations, activities, and schedules. Include photos if possible. Be clear who is responsible for maintenance and the type of expertise needed for distinct O&M activities. The O&M plan should include an anticipated budget for O&M activities. The O&M plan should also include an example O&M inspection checklist and an example maintenance report. Example O&M plans [https://stormwater.pca.state.mn.us/index.php?title=Operation_and_maintenance_(O%26M)_of_tree_trenches_and_tree_boxes#Maintenance_Training_Documents_and_Videos are provided here] and a schedule of general maintenance activities is provided in the adjacent table. |
*A legally binding and enforceable maintenance agreement should be executed between the practice owner and the local review authority. Example maintenance agreements [https://stormwater.pca.state.mn.us/index.php?title=Operation_and_maintenance_(O%26M)_of_tree_trenches_and_tree_boxes#Maintenance_Training_Documents_and_Videos are provided here]. | *A legally binding and enforceable maintenance agreement should be executed between the practice owner and the local review authority. Example maintenance agreements [https://stormwater.pca.state.mn.us/index.php?title=Operation_and_maintenance_(O%26M)_of_tree_trenches_and_tree_boxes#Maintenance_Training_Documents_and_Videos are provided here]. | ||
*Inspection and maintenance activities are distinct and can be done as separate activities or together. Inspection will typically assess the practice for any O&M issues, whereas maintenance will address the O&M issues identified by the inspection. A dedicated inspection effort on a large number of BMPs can help prioritize maintenance activities. | *Inspection and maintenance activities are distinct and can be done as separate activities or together. Inspection will typically assess the practice for any O&M issues, whereas maintenance will address the O&M issues identified by the inspection. A dedicated inspection effort on a large number of BMPs can help prioritize maintenance activities. | ||
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==Maintenance Costs== | ==Maintenance Costs== | ||
− | Maintenance costs | + | Maintenance costs vary depending on a number of factors, including but not limited to the following. |
− | *Size of the practice and its contributing drainage area | + | *Size of the practice and its <span title="The total drainage area, including pervious and impervious surfaces, contributing to a BMP"> '''[https://stormwater.pca.state.mn.us/index.php?title=Contributing_drainage_area_to_stormwater_BMPs contributing drainage area]'''</span> |
*Type of plantings used | *Type of plantings used | ||
*Site visit frequency | *Site visit frequency | ||
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*Staffing needs (number of staff, external vs. internal staff, etc) | *Staffing needs (number of staff, external vs. internal staff, etc) | ||
*Travel time between sites | *Travel time between sites | ||
− | *Efficiencies of scale (single GI vs. a cluster of GI) | + | *Efficiencies of scale (single GI (<span title="Green stormwater infrastructure is designed to mimic nature and capture rainwater where it falls. Green infrastructure reduces and treats stormwater at its source while while also providing multiple community benefits such as improvements in water quality, reduced flooding, habitat, carbon capture, etc.">'''green infrastructure'''</span>) vs. a cluster of GI) |
*Equipment needed | *Equipment needed | ||
− | Maintenance costs for trees and tree boxes should be relatively low compared to other green infrastructure practices, partially due to | + | Maintenance costs for trees and tree boxes should be relatively low compared to other green infrastructure practices, partially due to their size. Routine maintenance can take as little as 30 minutes per unit and does not require any special training, tools, or machinery. Because routine maintenance does not require any specialized training, the range of annual maintenance cost is around $100-$500 ([https://www.crwa.org/uploads/1/2/6/7/126781580/crwa_tree_pit.pdf CRWA]). [https://owl.cwp.org/mdocs-posts/cost-of-maintaining-green-infrastructure/ A study published in 2017] by ASCE describes the annual maintenance cost for a tree planter to be $260 per year, based on 2015 data from Fort Collins, CO ([https://owl.cwp.org/mdocs-posts/cost-of-maintaining-green-infrastructure/ Clary], 2017). |
==Useful Resources== | ==Useful Resources== | ||
Additional Detailed O&M Information | Additional Detailed O&M Information | ||
− | *More detailed information regarding specific maintenance activities are provided | + | *More detailed information regarding specific maintenance activities are provided at [[Operation and maintenance of tree trenches and tree boxes - supplemental information]]. Topics discussed include the following. |
− | **Supplemental | + | **Supplemental watering |
**Pruning | **Pruning | ||
− | **Staking and | + | **Staking and straightening |
− | **Protecting the | + | **Protecting the trunk |
**Mulching | **Mulching | ||
**Fertilizers | **Fertilizers | ||
− | **Checking | + | **Checking tree safety |
− | **Tree | + | **Tree health and troubleshooting guidelines |
− | **References | + | **References |
==Case Studies== | ==Case Studies== | ||
− | * | + | *[https://sustain.ubc.ca/sites/default/files/2018-52%20Application%20of%20Stormwater%20Tree%20Trenches%20in%20the%20City%20of%20Vancouver_Vega.pdf Application of Stormwater Tree Trenches in the City of Vancouver], 2018 |
− | *https://stormwater.pca.state.mn.us/index.php?title=Case_studies_for_tree_trenches_and_tree_boxes | + | *[https://stormwater.pca.state.mn.us/index.php?title=Case_studies_for_tree_trenches_and_tree_boxes Case studies for tree trenches and tree boxes] |
− | ==Maintenance | + | ==Maintenance training documents and videos== |
*International Society of Arboriculture – [https://www.isa-arbor.com/Credentials/ISA-Tree-Risk-Assessment-Qualification Tree Risk Assessment Qualification] | *International Society of Arboriculture – [https://www.isa-arbor.com/Credentials/ISA-Tree-Risk-Assessment-Qualification Tree Risk Assessment Qualification] | ||
*Tree Care Industry Association (TCIA) – [https://www.tcia.org/TCIA/Build_Your_Business/A300_Standards/A300_Standards.aspx ANSI A300 Tree Care Standards] | *Tree Care Industry Association (TCIA) – [https://www.tcia.org/TCIA/Build_Your_Business/A300_Standards/A300_Standards.aspx ANSI A300 Tree Care Standards] | ||
− | *[https://youtu.be/8emNNf3QyWA Shade Tree Maintenance] | + | *[https://youtu.be/8emNNf3QyWA Shade Tree Maintenance] (Youtube video) |
*[https://extension.psu.edu/planting-aftercare-webinar-essential-to-tree-establishment-and-survival Tree planting aftercare] | *[https://extension.psu.edu/planting-aftercare-webinar-essential-to-tree-establishment-and-survival Tree planting aftercare] | ||
− | + | {{:Example O&M Plans, Checklists, Reports, and Maintenance Agreements for tree trenches and tree boxes}} | |
==References== | ==References== | ||
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*Clary, J., Piza, H. 2017. [https://owl.cwp.org/mdocs-posts/cost-of-maintaining-green-infrastructure/ Cost of Maintaining Green Infrastructure]. American Society of Civil Engineers (ASCE), Reston, VA. | *Clary, J., Piza, H. 2017. [https://owl.cwp.org/mdocs-posts/cost-of-maintaining-green-infrastructure/ Cost of Maintaining Green Infrastructure]. American Society of Civil Engineers (ASCE), Reston, VA. | ||
+ | <noinclude> | ||
==Related pages== | ==Related pages== | ||
+ | ===Green Infrastructure=== | ||
+ | *[[Green Stormwater Infrastructure (GSI) and sustainable stormwater management]] | ||
+ | *Operation and maintenance of green infrastructure practices | ||
+ | **[[Operation and maintenance of bioretention and other stormwater infiltration practices]] | ||
+ | **[[Operation and maintenance of bioretention and other stormwater infiltration practices - supplemental information]] | ||
+ | **[[Operation and maintenance (O&M) of tree trenches and tree boxes]] | ||
+ | **[[Operation and maintenance of tree trenches and tree boxes - supplemental information]] | ||
+ | **[[Operation and maintenance (O&M) of green roofs]] | ||
+ | **[[Operation and maintenance of green roofs - supplemental information]] | ||
+ | **[[Operation and maintenance (O&M) of swales]] | ||
+ | **[[Operation and maintenance of swales - supplemental information]] | ||
+ | **[[Operation and maintenance (O&M) of filter strips]] | ||
+ | **[[Operation and maintenance of filter strips - supplemental information]] | ||
+ | **[[Operation and maintenance (O&M) of stormwater and rainwater harvest and use/reuse practices]] | ||
+ | **[[Operation and maintenance (O&M) of stormwater and rainwater harvest and use/reuse practices - supplemental information]] | ||
+ | **[[Operation and maintenance (O&M) of stormwater treatment wetland practices]] | ||
+ | **[[Operation and maintenance (O&M) of permeable pavement]] | ||
+ | **[[Operation and maintenance (O&M) of permeable pavement - supplemental information]] | ||
+ | |||
+ | ===General information on trees=== | ||
+ | *[[Overview for trees]] | ||
+ | *[[Types of tree BMPs]] | ||
+ | *[[Plant lists for trees]] | ||
+ | *[[Street sweeping]] - this page provides a summary of an on-going project to develop a street sweeping credit | ||
+ | *[[Street sweeping for trees]] | ||
+ | *[[References for trees]] | ||
+ | *[[Supporting material for trees]] | ||
+ | *[[Neat websites and articles for trees]] | ||
+ | *[[Links to tree ordinances and forest management master plans]] | ||
+ | *[[Green Infrastructure benefits of tree trenches and tree boxes]] | ||
+ | |||
+ | ===Tree trenches and tree boxes=== | ||
+ | *[[Design guidelines for tree quality and planting - tree trenches and tree boxes]] | ||
+ | *[[Design guidelines for soil characteristics - tree trenches and tree boxes]] | ||
+ | *[[Construction guidelines for tree trenches and tree boxes]] | ||
+ | *[[Protection of existing trees on construction sites]] | ||
+ | *[[Operation and maintenance of tree trenches and tree boxes]] | ||
+ | *[[Assessing the performance of tree trenches and tree boxes]] | ||
+ | *[[Calculating credits for tree trenches and tree boxes]] | ||
+ | *[[Case studies for tree trenches and tree boxes]] | ||
+ | *[[Soil amendments to enhance phosphorus sorption]] | ||
+ | *[[Green Infrastructure benefits of tree trenches and tree boxes]] | ||
+ | *[[Summary of permit requirements for infiltration]] | ||
+ | *[[Tree trench/box photo gallery]] | ||
+ | <!-- | ||
+ | *[[Design variants for tree trenches and tree boxes]] | ||
+ | *[[Construction observations for tree trenches and tree boxes]]--> | ||
+ | *[[Fact sheet for tree trenches and tree boxes]] | ||
+ | *[[Requirements, recommendations and information for using trees as a BMP in the MIDS calculator]] | ||
+ | *[[Requirements, recommendations and information for using trees with an underdrain as a BMP in the MIDS calculator]] | ||
+ | |||
+ | ===Urban Forestry=== | ||
+ | For more information on urban forestry, we suggest visiting the following websites. | ||
+ | *[http://www.fs.fed.us/ucf/ Urban and Community Forestry] - USDA Forest Service | ||
+ | *[http://www.phila.gov/ParksandRecreation/aboutus/divisions/Pages/UrbanForestryEcosystemManagement.aspx Urban Forestry & Ecosystem Management] - City of Philadelphia | ||
+ | *[http://www.forestsforwatersheds.org/reduce-stormwater/ Watershed Forestry Resource Guide] - Center for Watershed Protection and US Forest Service - Northeastern Area State & Private Forestry | ||
+ | *[http://www.americanforests.org/our-programs/urbanforests/ American Forests] | ||
+ | *[http://urbanforestry.frec.vt.edu/ Urban Forestry] - Virginia Tech University | ||
+ | *[http://water.epa.gov/polwaste/green/upload/stormwater2streettrees.pdf Stormwater to Street Trees: Engineering Urban Forests for Stormwater Management] - U.S. EPA | ||
+ | *[http://greenstep.pca.state.mn.us/bestPracticesDetail.cfm?bpid=16 Green Step Cities]. This page provides a summary of urban forestry practices that cities can implement to help become a [http://greenstep.pca.state.mn.us/bestPractices.cfm Green Step City] and a list of cities that are implementing the practices, including links. | ||
+ | |||
+ | [[Category:Level 3 - Best management practices/Specifications and details/Operation and maintenance]] | ||
+ | [[Category:Level 3 - Best management practices/Structural practices/Tree trench and box]] | ||
+ | </noinclude> |
This page provides guidance for operation and maintenance (O&M) of tree trenches and tree boxes. A tree trench is a bioretention practice that contains one or more trees. Tree trenches and boxes may be designed as infiltration or filtration (underdrained) systems.
Supplemental information can be found on the page called Operation and maintenance of tree trenches and tree boxes - supplemental information. Supplemental information includes the following.
In addition to runoff reduction and stormwater treatment, street trees and tree boxes provide a range of community benefits. Trees contribute to air pollution reduction, carbon sequestration, reduction in heat island effect, habitat creation for wildlife, and can be used as tools for climate adaptation. Green stormwater infrastructure (GSI) trees are often planted in highly visible areas and are subject to public interaction, vandalism, and winter deicing, but trees typically remain resilient with proper maintenance.
O&M of tree trenches and boxes generally requires a low level of effort and expertise, and street trees can have life spans of up to 60 years (Cappiella et al., 2016). Green infrastructure managers do share common issues and concerns related to trees. The most common O&M concerns for tree trenches and tree boxes include
The sections below describe best practices to prevent or minimize these common problems.
Tree trenches and tree boxes have a small footprint and should be designed to treat a relatively small drainage area (0.25 acres or less per tree). Surface area of the tree trench or box and surface area to drainage area ratio are key design characteristics. Design specifications vary based on the selected filter media and filter box manufacturer (most tree trench and box systems are proprietary practices). Properly sizing and designing the tree box will help prevent O&M issues. Designers should consider
Designers should also consider the maintenance schedules and tasks when locating tree trenches or tree boxes on their site. The small surface area of tree boxes makes them versatile. However, they should be placed within areas that are easily accessible to ensure proper maintenance. Maintenance of tree trenches and tree boxes does not require large or heavy equipment, but routine maintenance should be expected once or twice a year. Designers can incorporate solutions to facilitate the following maintenance activities.
Designers should consult and include any local requirements regarding green infrastructure. O&M considerations often depend on whether the practice is located on public land, private land, or in the public right of way. For example, plantings in the public right of way that conflict with any traffic safety considerations could require increased O&M, such as pruning or complete removal.
The designer should also provide a site-specific O&M plan that includes the following.
Additional information that should be included in O&M plans is described in the Post-Construction Phase O&M Considerations section. Example O&M plans are also provided below.
Proper construction methods and sequencing play a significant role in reducing O&M problems. Some key items during the construction phase include the following.
Post-construction maintenance is performed on tree trenches and tree boxes to maintain proper infiltration, filtration, and to promote healthy vegetation. Immediately after construction, short-term maintenance goals include efforts to establish and keep the tree healthy. Not all trees are guaranteed to survive the establishment phase, so care should be taken to inspect the health following construction. Important post-construction considerations are provided below.
See the adjacent tables for a schedule of general maintenance activities and common problems and troubleshooting.
Overview and schedule of general maintenance activities for tree trenches and tree boxes
Link to this table
Activity | Frequency | Time period | Level of effort | O&M benefita |
---|---|---|---|---|
Check that there is no ponding within the box or trench. | At least twice after storm events > 0.5 inches | Within the first 6 months | 1-2 hours | 1,5 |
Check for evidence of clogging in the media. | At least twice after storm events > 0.5 inches | Within the first 6 months | 1-2 hours | 1 |
Supplemental watering, during drier periods, particularly if keeping stormwater offline trees are established. | 1/week initially | During first two months of the growing season | 1-2 hours | 2,3,4,5,6 |
As needed | First growing season | 1-2 hours | 2,3,4,5,6 | |
Remove any weeds present | As needed | First growing season | 1-2 hours | 2,3,4,5,6 |
Remove any trash or debris | As needed | First growing season | 1-2 hours | 1,2,3,4,5,6 |
Add mulch if layer is less than 3 inchesb | As needed | First growing season | 1-2 hours | 4,5 |
Clean root collar | Annually | During growing season | 1-2 hours | 1 |
Remove stakes | As needed | End of growing season | 1-2 hours | 5 |
Inspect tree health | Biannually and after large storms | First growing season | 1-2 hours | 1,2,5,6 |
Activity | Frequency | Time period | Level of effort | O&M benefita |
Check that there is no ponding within the box or trench. | Biannually | Any time when ground is not frozen | 1-2 hours | 1,5 |
Check for evidence of clogging | Biannually | In spring and fall | 1-2 | 1 |
Supplemental watering during drier periods | As needed or when soil is dry 3 inches below the surface | Dry periods until roots are established | 1-2 hours | 2,3,4,5,6 |
Remove any weeds present | As needed | During growing season | 1-2 hours | 2,3,4,5,6 |
Remove any trash or debris | As needed | Any time | 1-2 hours | 1,2,3,4,5,6 |
Add mulch if layer is less than 3 inches | Annually | During growing season | 1-2 hours | 4,5 |
Remove stakes (if still present) | Once | End of second growing season | 1-2 hours | 5 |
Prune excess growth |
|
End of winter or early spring | 1-2 hours | 2,5,6 |
Inspect tree health and safety | Biannually and after large storms | During growing season | 1-2 hours | 1,2,5,6 |
Activity | Frequency | Time period | Level of effort | O&M benefita |
After long term operation of the practice, some occasional and infrequent maintenance activities might be required, such as tree or media replacement. | As needed | As needed | Could be significant depending on the activity | 1,2,3,4,5,6 |
aKey to Maintenance Benefits:
|
Common problems and how to troubleshoot them for tree trenches and tree boxes
Link to this table
Symptom | Possible causes | Solution |
---|---|---|
Standing water within the infiltration area for more than 48 hours | This might be because a pretreatment is no longer working, or there are excessive sediment loads due to erosion or high sediment loads from the contributing area. |
|
Rainwater does not appear to flow to the infiltration/filtration area | Leaves, sediment, trash, or plant debris may be blocking the flow path to the inlet | Remove these materials on a regular basis |
Tree is not growing or shows signs of poor health during inspections |
|
Consult with an arborist. Check that plants are suited to the local conditions. |
Erosion or scouring around the inlet | Flow is obstructed by debris or improper grading | Correct for drainage and flow path issues to make sure flows are evenly distributed. Make sure the flow paths are unobstructed |
Maintenance costs vary depending on a number of factors, including but not limited to the following.
Maintenance costs for trees and tree boxes should be relatively low compared to other green infrastructure practices, partially due to their size. Routine maintenance can take as little as 30 minutes per unit and does not require any special training, tools, or machinery. Because routine maintenance does not require any specialized training, the range of annual maintenance cost is around $100-$500 (CRWA). A study published in 2017 by ASCE describes the annual maintenance cost for a tree planter to be $260 per year, based on 2015 data from Fort Collins, CO (Clary, 2017).
Additional Detailed O&M Information
Example O&M Plans, Checklists, Reports, and Maintenance Agreements for tree trenches and tree boxes
Link to this table
Symptom | Possible causes |
---|---|
Operation & Maintenance Plan | City of Redding, CA: Instructions to Inspect and Maintain Tree Box |
Construction phase inspection checklist | District of Columbia Department of Energy and Environment, Construction Inspection Checklists |
O&M inspection checklist | |
Maintenance Agreements |
For more information on urban forestry, we suggest visiting the following websites.
This page was last edited on 9 February 2023, at 16:12.