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HomeMy WebLinkAboutAttach 4 Ltr from H ScienceFebruary 2, 2004 Mr. Alex Loukianoff 12 Kirk Court Alamo, CA 94507 Subject: Peer review Joseph McNeil's Arborist Report Dear Mr. Loukainoff: You requested that I conduct a peer review of the Arborist Report prepared by Joseph McNeil, Consulting Arborist. The Arborist Report focused on the impacts of construction of a new home at 11299 Rolling Hills Drive in Dublin. I based my review on the Arborist Report from Mr. McNeil dated January 12, 2004, which you provided via electronic mail on January 5, 2004. I visited the site with you on August 18, 2003 to assess tree protection required for your proposed project at that time. I also evaluated the valley oak (Quercus Iobata), tree #353, referred to in Mr. McNeil's report. In addition, HortScience, Inc. prepared a Heritage tree protection plan for Black Mountain Development in February, 2001, which included an assessment of tree #353. This letter summarizes my comments and review. Observations I concur with Mr. McNeil's assessment of the tree's condition as fair to good. In the Heritage tree protection report (HortScience, 2001) tree #353 was rated in good condition. Its condition has changed little since 2001 (see photo). The site plan in Mr. McNeil's report showed tree #353 approximately 18' from the proposed "pop-out", and about 17' from the proposed deck. The dripline extended about 5' over both the "pop-out" and proposed deck. The canopy on the south side of tree #353 extended to within 2'-3' above existing grade. Mr. McNeil recommended removal of the soil that has sloughed downslope and built up around the trunk of tree #353. I agree. Tree #353 in good condition with a full crown as photographed on August 18, 2003. Letter to Alex Loukianoff Peer review, Joseph McNeil HortScience, Inc. Page 2 Evaluation of Impacts I concur with Mr. McNeil that there will be limited impact to the tree's root system from the construction of the house and deck as the design is presented. The 4' "temporary zone of encroachment" that will result from foot traffic to construct the north side of the home will have some impact on the roots of the tree. As suggested by Mr. McNeil this condition can be improved by the placement of mulch in this area after the project is complete. The pruning of several limbs from 2" to 7" to provide construction clearance will likely constitute a greater stress for the tree than impacts to the roots. I agree with Mr. McNeil that the stress related to the construction and pruning is within the tolerances of the tree, assuming the guidelines he provided are followed. Mr. McNeil's guidelines for managing construction impacts are both sound and comprehensive. The sections outlining irrigation, drainage and landscaping requirements for native oaks are especially important. Summary and Recommendations In summary, my assessment of tree condition, impacts, and recommendations concur with Mr. McNeil's. I also recommend the following: Prune the tree after the foundation lines for the house and deck are marked on the ground to provide a visual guide for the limit of clearance pruning. This will limit the need for repeated pruning. 2. Remove existing sloughed soil from around the trunk of tree #353 to a distance of 5'. Monitor annually so the condition does not reoccur. 3. The tree should be inspected annually to monitor health and structural stability. Thank you for the opportunity to prepare this review. Please feel free to contact me with any questions regarding my observations or assessment. Sincerely, Michael Santos Certified Arborist