06-13-2012 Council Agenda - Laserfiche WebLink

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LLF[RIHG - 41SSO(IATZS Memo [ UEUUkTA TO: Mayor Biesener & Members of the City Council FROM: Lee Elfering, City Engineer DATE: June 6, 2012 RE: Dianna Lane Island Tree Replacement In the 1980's after the original construction of Dianna Lane the residents adjacent to the end cul -de -sac approached the City with a request to add a center island to the cul -de- sac. The City allowed the island to be constructed, but the construction and landscaping of the island was paid for by the adjacent residents. The maintenance and upkeep of the island landscaping was also the responsibility of the adjacent property owners. The island was landscaped with two pine trees, a clump river birch tree, and wood mulch on top of fabric. The island was preserved with the reconstruction project based on input from the residents, but the street around the island was fully reconstructed along with the curb around the island. When the street was reviewed early this spring the trees in the island showed signs of stress, likely due to the construction. However, due to the dry weather last fall and the winter we felt the trees may come back with normal precipitation. We reviewed the condition of the trees again last week and even with the above average rainfall this spring the trees have not recovered and it does not appear that they wilt Therefore, we would recommend that the trees be removed before the final wear course is paved and new landscaping be installed in the island. Due to the small size of the island, approximately 25 feet across, we would recommend that only a single pine tree be planted in the middle of the garden and rock be used instead of wood mulch. At maturity a Colorado Blue Spruce tree can be 20 -25 feet wide, nearly covering the entire island. We spoke to Mr, Desai regarding the island tree replacement and the fact that we were proposing to replace the existing trees with only a single tree. He was a strong advocate of the initial island and is one of the properties that paid for its initial construction and landscaping. He agreed that it may be best to only plant a single tree and allow it to mature. We discussed utilizing rock instead of wood mulch in the island and he was acceptable to that change as well. We have spoke to Public Works Staff and they would be able to remove the trees and stumps from the island and we could have the contractor install the rock as a bid item is provided for in the project. The tree would need to be purchased from a nursery or landscape contractor and the installation could be done by either Public Works Staff or a Contractor depending on the size of tree installed. A larger tree (8 -feet) would provide more of an initial impact, but smaller trees (4 -5 feet) acclimate to a new location faster and therefore begin to grow at a normal pace before a larger tree. We would ask for some direction on the size of the tree that should be planted. If you have any questions please feel free to call me at 763 - 780 -0450 Ext. 3. 10062 Flanders Court NE — Blaine, MN 55440 — (763) 780 -0450 fax (763) 205-2341 C. 1Users\kathy.glanzeMppData \ocal \ Microsoft \windows\Temporary Internet Files \OLKD636 \Memo- 060612 -CC- Island Tree Replacemenl.doc 1