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MEMORANDUM <br /> July 24, 1992 <br /> T0: Executive Managers <br /> FROM: Jan Staszewski, Urban Forester <br /> SUBJECT: The Assessment and Plans for the Big Leaf Maples Around City Hall <br /> The informs ion below will appear in the upcoming City Council newsletter. If <br /> <br /> you have an questions, please call me. Thank you. <br /> This past J ne a large limb fell from the Big Leaf maple nearest the City Hall <br /> entrance on 8th Ave. This, along with a history of limb failure and crown <br /> dieback has prompted me to initiate a detailed tree hazard assessment of all <br /> the large m ples around City Hall. <br /> There are f ve. Big Leaf Maples around City Hall, three on 7th Ave. and two on <br /> 8th Ave. T e maple in the middle of the block on 7th Ave. does not have a <br /> history of allure nor does it show signs of decline or structural weakness. <br /> The remaini g trees are the subject of this report. <br /> Detailed ha and assessment reports along with photos of limb cavities are <br /> available f r public inspection at Public Works-Maintenance on 1820 Roosevelt <br /> Boulevard. In brief, the reports and photos clearly show extensive internal <br /> decay. Som cavities are near key branch junctions of live limbs. There is <br /> evidence th t the decay within these limbs exceeds 30 percent, the threshold <br /> for limb failure. The removal of these dead and decayed limbs would leave the <br /> tree withou a crown. Last fall City crews removed a17 dead limbs, yet this <br /> summer an a ditional 30 percent of the remaining crown has died back. In <br /> addition, t e two maples on 8th Ave. have a history of limb failure. <br /> The two maples on 7th Ave. show less decline, however the maple to the west <br /> has diebac along one major limb. Also, a large section of bark on the trunk <br /> has died and fallen off. The crowns of both trees have cavities, but they are <br /> not as extensive as those in the two maples on 8th Ave. J~~ <br /> To minimiz traffic disruption and to accommodate scheduling of equi ment and <br /> personnel he two maples on 8th Ave. will be removed Sunday, August 1992. <br /> Two large anopy replacement trees will be replanted the same day. The City <br /> Hall block of 8th Ave. will be closed for the duration of the removal. <br /> Police, fi e, ambulance, LTD, and the media will be notified of the closure. <br /> In additio in keeping with Department policy the two trees will be posted <br /> for removal a week in advance. The notice wil] inform the public of the date <br /> and reason for the removals. <br /> Lastly, I nticipate that the two maples on 7th Ave. will experience an accel- <br /> erated rat of decline over the next two to three years. I will closely <br /> <br /> monitor th two maples. However, if this decline does occur, I believe these <br /> trees will also need to be removed within the next twenty-four to thirty-six <br /> <br /> months. <br /> For more i formation call the Jan Staszewski, Urban Forester at 687-5359. <br /> <br />