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Arborist Report_15.pdfu sne 193 NORTHWEST LANDSCAPE MAINTENANCE COMPANY 283 KINNEY DRIVE SAN JOSE CALIFORNIA 95112 February 12, 2018 Cupertino Roundtree HOA C/O: Community Management Services, Inc. 1935 Dry Creek Road, Suite 203 Campbell, CA 95008 RE: Arborist Report Problem 21060 Red Fir Court, Cupertino: Resident is concerned that the Liquidambar tree in front is displacing the hardscape and possibly the building foundation. Water, now, drains toward and stands at front door. Observation • Tree (#162): 63" circumference/20" diameter • One side had roots cut within 5' of trunk to facilitate concrete patio replacement. • Two other sides of this tree are bordered with concrete sidewalks. One sidewalk is within 12" of trunk and the other within 36". • Both sidewalks are cracked and displaced. (408) 298-4720 FAX (408) 298-1761 Discussion • Pruning of roots closer than 3X trunk diameter is not recommended. R Pruning of roots on more than one side a year is not recommended. • To facilitate concrete replacement, roots will need to be pruned closer to trunk than recommended- ■ The closer tree roots are cut, the larger the amount of root volume and anchorage ability lost. • The roots would have to be cut on at least two sides of the trunk. Roots on the third side were cut in the past to repair the hardscape in patio. Conclusion • Trees with the roots severed close to trunk have a high potential to fail. Recommendation Remove tree. Replace with (2) 24" box Cercis canadensis (Redbud) trees. Replacement trees to be planted in a more suitable location on this site. RESPECTFULLY SUBMITTED, 691 WC -5728A Warren Nakamura REFERENCES: "Evaluation of Hazard Trees in Urban Areas", 2nd Edition, Methany & Clark, 1994 "Arboriculture", Prentice -Hall, Richard W. Harris, 1983 "Reducing Infrastructure Damage By Tree Roots', WCISA, L. S. Costello & Katherine Jones, 2003 =�� 19 3 NORTHWEST LANDSCAPE MAINTENANCE COMPANY 283 KINNEY DRIVE SAN JOSE CALIFORNIA 95112 February 12, 2018 Cupertino Roundtree HOA C/O: Community Management Services, Inc. 1935 Dry Creek Road, Suite 203 Campbell, CA 95008 Problem 21076 Red Fir Court, Cupertino: Resident is concerned that the (2) Liquidambar trees in front are damaging his fence and patio. Observation • Tree 'A' (#157): Size= 61" circumference • Tree 'B' (#156): Size= 51" circumference. • Roots have been pruned within 18" of trunk to facilitate concrete patio replacement. • The trees have been side trimmed to clear patio. • Evidence of major limb failure in the past. • Resident claims that Tree 'A' has started to list. (408) 298-4720 FAX (408) 298-1761 Discussion • Pruning of roots closer than 3X trunk diameter is not recommended. • Side trimming has left trees with unbalanced canopies. • Listing (lean) could be an indicator of root/ground failure. • Trees are in a narrow planter that may restrict root volume. ■ Should tree(s) fail, the most likely 'Target' is a main driveway. Conclusion • These trees with the severed roots close to trunk have a high potential to fail. • The unbalanced crowns with the weight on the opposite side of the severed roots are a contributing factor that increases their potential to fail. Recommendation These trees should be considered hazardous and removed. Replace with (3) 24" box Lophostemon confertus(Tristania) and (1) 24"box Tilia cordata 'Greenspire' (Linden). Replacement trees to be planted in a more suitable location on this site. RESPECTFULLY SUBMITTED, 19. 1 J 1 Vj; WC -5728A Warren Nakamura REFERENCES: "Evaluation of Hazard Trees in Urban Areas", 2nd Edition, Methany & Clark, 1994 "Arboriculture", Prentice -Hall, Richard W. Harris, 1983 "Reducing Infrastructure Damage By Tree Roots', WCISA, L S. Costello & Katherine Jones, 2003