06/09/2010 P&Z Packet - Laserfiche WebLink

Home Search

• Attachment 2: Landscaping and Tree Preservation Standards - REVISED May 26, 2010 Page 11 2) Soils: Landscaped areas need high quality soils that retain moisture for plants to use, but drain adequately. Soil shall be uncompacted existing soil, new planting soil or engineered soils designed to allow plant growth. Proper soil preparation helps to ensure long term survival of the plants and to reduce the need for ongoing maintenance, additives, and pest control. If soil compaction exceeds 1400 kPa (200 psi) at the time of planting, the soil shall be loosened. Preexisting soils may be used and should be protected from compaction during construction. 3) Mulch: Mulch helps plant health by keeping the soil moist, protecting soil nutrients, preventing erosion, encouraging infiltration, and inhibiting weed growth. Mulch from decomposing materials such as wood chips enriches the soil over time. Although decomposing mulch needs to be replenished approximately twice a year to maintain adequate thickness, once plants grow together there is often need for little or no mulch. Mulch shall comply with the following requirements: a) Provide mulch at a depth of 3 -4" for wood chips, 4 -6" for shredded bark and 3 -4" for rocks or other non - organic matter. b) Provide a 3' minimum diameter mulch ring at the base of trees. c) Prohibit mounding mulch at the bases of trees, or allowing mulch within 4" of plant stems and trunks, as this will cause them to rot. • d) If used, only water permeable fabric is permitted as a weed barrier. • e) Leave one inch of space from the top of the mulch layer to adjacent hardscape surfaces to prevent spilling. f) The City may limit certain types of mulch in areas where safety or spilling may be an issue. g) Mulch should not be mixed with underlying soil. 4) Fertilizer: When fertilizer is used, organic and slow release fertilizers are recommended. 5) Drainage: Tree planting pits shall drain adequately. Drainage for trees may be accomplished through the use of non - compacted and well draining soils. The City may require the following drainage test: Dig 8" diameter holes 1' deep and fill with water. If the holes do not drain within 24 hours adjust bed design or composition in order to achieve proper drainage. If the underlying soils retain water, the applicant shall provide additional drainage measures. 6) Tree protection after construction: Bollards, barriers, or spacing may be necessary to protect trees from cars. Bike parking should be included to discourage locking bikes to trees. For tree protection during construction see Section Q.15. c. Tree and Infrastructure Placement: Tree placement should be given consideration when locating overhead and underground utilities. Service utilities should be located outside of plant beds where they may conflict with tree plantings. Consider using conduits for buried utilities to allow future work with less disruption to roots. The clearances in the