Stormwater Quality Design Manual (May 2007) - City of Sacramento ...

Runoff Reduction Control Measure Fact SheetInterceptor TreesLong-Term MaintenanceMaintenance recommendations for interceptor trees are provided in Table INT-2. The property owner isresponsible for all costs associated with the maintenance.Trees that are removed or die should be replaced with similar species, or all water quality benefits will belost. Trees should be properly pruned for safety purposes, to protect structures, or for the improvement ofthe health and structure of the tree. The property owner is responsible for all costs associated with thereplacement of interceptor trees.Table INT-2. Inspection and Maintenance Recommendations for Interceptor TreesActivityRemoval of Leavesand Debris:PruningMulchingIrrigationPesticides andFertilizersLawn maintenanceOther ActivitiesRemoval/ReplacementDescriptionFallen leaves and debris from tree foliage should be raked and removed regularly toprevent the material from being washed into the storm water. Nuisance vegetation aroundthe tree should be removed when discovered. Dead vegetation should be pruned from thetree on a regular basis.It is recommended that a certified arborist or similarly qualified professional be retained toprune trees, or the property owner should learn proper pruning methods. A tree shouldnever be topped. Topping is the practice of removing major portions of a large tree’scrown by cutting branches to stubs or to the trunk. Tree topping shortens the life of thetree, creates weakly attached limbs prone to breakage, decay and disfigures the tree. Italso eliminates the interception canopy.Add 4-6 inch deep hardwood mulch around newly planted trees and shrubs (avoidredwood and cedar, it is light and blows away and does not decompose fast enough to bebeneficial to the soil health and tree's growth).An irrigation system should be installed at the time of planting and maintained during theestablishment period or, if necessary to maintain the tree, in perpetuity.Minimize the use of chemicals to only what is necessary to maintain the health of the tree.Consider using mulch around the base of the tree as a substitute to fertilizer. Do not placemulch within six inches of the trunk of the tree.Keep lawn at least 24 inches from trunk of tree.Competition from turfgrass stunts tree growth, and even additional fertilizer and water willnot overcome this effect. A bare area around the trunk also helps prevent injury to the treefrom a mower or string trimmer. Trunk wounds to a young tree can have a severe dwarfingeffect.Plant evergreen shrubs and ground covers around trees when possible. Care should betaken when digging near tree roots. Once tree has become established, planting ofvegetation near base of tree and subsequent watering of such vegetation may result inover-saturation and damage to the tree.See Long-term MaintenanceStormwater Quality Design Manual for the Sacramento and South Placer RegionsMay 2007INT-5