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250 Grant Street Redwood Assessments250 Grant Street APN: 279-41-053 Coast Redwood Assessment July 30, 2018 July 30, 2018 Stephen Rose Associate Planner City of Campbell Community Development Department 70 N. First Street Campbell, CA 95008 Summary The proposed excavation is outside six times the trunk diameter distance in feet from the adjacent redwoods (Sequoia sempervirens). Both the ISA Best Management Practices: Root Management, 2017 and ISA Best Management Practices: Managing trees during construction, second edition, 2016 indicate linear cuts should be beyond six times the trunk diameter distance. I do not expect the trees to be highly impacted by this project or caused to be removed because the distances from the trees are sufficient. Because the neighbor fence is in place at the required distance there is no need for tree protection fence. Introduction Assignment, Limits, Purpose and Use •Provide tree protection specifications/guidelines and expected impact ratings. •Document the current conditions including any relevant photographs. •The information in this report is limited to the condition of the trees and site during my inspection on July 27, 2018. •Provide advice on appropriate excavation methods and protective measures to minimize damage to offsite trees (i.e. cutting roots due to excavation) and thresholds of significance (i.e. root size) which, if encountered, would require the basement to be redesigned to avoid significant damage to offsite trees. The report is to be used by the property owner, their agents, and the City of Campbell as a reference for existing tree conditions and to provide guidance for protection during the construction process. Monarch Consulting Arborists LLC - P.O Box 1010, Felton, CA 95018 831.331.8982 - rick@monarcharborist.com Page of 1 10 250 Grant Street APN: 279-41-053 Coast Redwood Assessment July 30, 2018 Observations There are three coast redwoods originating on the adjacent site with two closest to the proposed construction. The closest tree (#1) is eight feet from the edge of the existing neighbor fence and has a trunk diameter of about 16 inches. The next closest tree (#2) is about 16 feet from the edge of the existing neighbor fence and has a trunk diameter of about 24 inches. Tree number one is about 45 feet tall with an asymmetric and suppressed crown that spreads about 10 to 12 feet radially and over the property boundary. Tree number two is about 75 feet tall with a more upright form and symmetrical spread about 12 to 15 feet and is sandwiched between two trees. Both trees have normal foliar color, size, and density. The plans do not provide any information regarding limits of excavation but it has been discussed that a basement will be dug. The concern is whether the basement excavation and light well will damage the trees. The light well will be located about one and one half feet from the boundary. Image 1: Coast redwoods in close proximity to property boundary.  Table 1: Tree Characteristics Tree Species Number Trunk Diameter (in.) ~ Height (ft.)~ Canopy Diameter (ft.) Distance to property boundary (ft.) Coast redwood 1 16 45 20 to 25 8 Coast redwood 2 24 75 25 to 30 16 Monarch Consulting Arborists LLC - P.O Box 1010, Felton, CA 95018 831.331.8982 - rick@monarcharborist.com Page of 2 10 250 Grant Street APN: 279-41-053 Coast Redwood Assessment July 30, 2018 Discussion Linear Trenching Near Trees Both the ISA Best Management Practices: Root Management, 2017 and ISA Best Management Practices: Managing trees during construction, second edition, 2016 indicate linear cuts should be beyond six times the trunk diameter distance. Both the ANSI Standard Part 8 and the ISA Best Management Practices: Root Management (2017) suggest “selective" root removal is preferred over “non-selective” removal. Selective root removal requires pre-excavation, typically by hand or with a pneumatic excavating equipment. Selective removal allows for the roots to be exposed prior to cutting at the appropriate locations. It is suggested roots greater than one inch in diameter should be pruned rather than left torn or crushed (Costello, L., Watson, G., Smiley, E. T.. 2017). Non-selective root removal is more likely to occur during this type of construction but roots should still be “cut clean to a flat surface with all surrounding bark intact.” My assessment included reviewing the site conditions and trees to make a determination as to whether or not the proposed excavation would encroach within six times the trunk diameter distance of the trees. After reviewing the site and the plans there was no indiction this zone of no excavation would be encroached upon. Coast redwoods are considered to have good tolerance to construction damage, expected impacts are only on one side of the trees, and the distance is adequate and outside the maximum encroachment. For the coast redwoods the maximum encroachment distances are eight feet for tree one and twelve for number two. Expected Impact Level Impact level defines how a tree may be affected by construction activity and proximity to the tree, and is described as low, moderate, or high. The following scale defines the impact rating: •Low = The construction activity will have little influence on the tree. •Moderate = The construction may cause future health or structural problems, and steps must be taken to protect the tree to reduce future problems. •High = Tree structure and health will be compromised and removal is recommended, or other actions must be taken for the tree to remain. The tree is located in the building envelope. I do not expect the redwoods to be highly impacted by this project or caused to be removed. The proposed excavation and light well are outside six times the trunk diameter distances and it is unlikely significant roots will be encountered during construction. Monarch Consulting Arborists LLC - P.O Box 1010, Felton, CA 95018 831.331.8982 - rick@monarcharborist.com Page of 3 10 250 Grant Street APN: 279-41-053 Coast Redwood Assessment July 30, 2018 Tree Protection Tree protection focuses on avoiding damage to the roots, trunk, or scaffold branches from heavy equipment. The tree protection zone (TPZ) is the defined area in which certain activities are prohibited to minimize potential injury to the tree. The most current accepted method for determining the TPZ is to use a formula based on species tolerance, tree age/vigor, and trunk diameter (Matheny, N. and Clark, J. 1998) (Fite, K, and Smiley, E. T., 2016). Because the trees can only potentially be impacted on one side the maximum encroachment of six times the trunk diameter distances reduces likelihood of health or stability issues. If roots greater than one inch in diameter are encountered they should be “cut clean to a flat surface with all surrounding bark intact.” All exposed root areas shall be backfilled or covered within one hour when possible or roots will need to be kept moist at the edge of the trench. Roots greater than four inches in diameter should be left intact and only removed as authorized by the project arborist. Conclusion The proposed excavation is outside six times the trunk diameter distance in feet from the adjacent redwoods. Roots from the trees may be encountered during construction but it is unlikely. Both the ISA Best Management Practices: Root Management, 2017 and ISA Best Management Practices: Managing trees during construction, second edition, 2016 indicate linear cuts should be beyond six times the trunk diameter distance. “Selective" root removal is preferred over “non-selective” removal and roots should be “cut clean to a flat surface with all surrounding bark intact” regardless. I do not expect the trees to be highly impacted by this project or caused to be removed because the distances from the trees are sufficient. All roots greater than four inches in diameter should be left intact and only removed as authorized by the project arborist. Because the neighbor fence is in place at the required distance there is no need for tree protection fence. Monarch Consulting Arborists LLC - P.O Box 1010, Felton, CA 95018 831.331.8982 - rick@monarcharborist.com Page of 4 10 250 Grant Street APN: 279-41-053 Coast Redwood Assessment July 30, 2018 Recommendations 1.If roots greater than two inches in diameter are encountered they should be cut clean “cut clean to a flat surface with all surrounding bark intact.” All exposed root areas shall be backfilled or covered within one hour. Roots greater than four inches in diameter should be left intact and only removed as authorized by the project arborist. 2.All tree maintenance and care shall be performed by a qualified arborist with a C-61/D-49 California Contractors License. Tree maintenance and care shall be specified in writing according to American National Standard for Tree Care Operations: Tree, Shrub and Other Woody Plant Management: Standard Practices parts 1 through 10 and adhere to ANSI Z133.1 safety standards and local regulations. All maintenance is to be performed according to ISA Best Management Practices. 3.Required tree pruning must be performed by a licensed contractor with a C-61/D-49 California Contractors License. Pruning specification shall be provided in writing according to ANSI A300 Part 1 (Pruning) 2017 standards and limitations. All tree pruning shall be performed in accordance with ISA Best Management Practices: Tree Pruning 2008. 4.Refer to Appendix B for general tree protection guidelines including recommendations for arborist assistance while working under trees, trenching, or excavation within a trees drip line or designated TPZ/CRZ. 5.Provide a copy of this report to all contractors and project managers, including the architect, civil engineer, and landscape designer or architect. It is the responsibility of the owner to ensure all parties are familiar with this document. 6.Arrange a pre-construction meeting with the project arborist or landscape architect to verify tree protection is in place, with the correct materials, and at the proper distances. Monarch Consulting Arborists LLC - P.O Box 1010, Felton, CA 95018 831.331.8982 - rick@monarcharborist.com Page of 5 10 250 Grant Street APN: 279-41-053 Coast Redwood Assessment July 30, 2018 Bibliography American National Standard for Tree Care Operations: Tree, Shrub and Other Woody Plant Management : Standard Practices (Management of Trees and Shrubs During Site Planning, Site Development, and Construction)(Part 5). Londonderry, NH: Secretariat, Tree Care Industry Association, 2012. Print. Costello, Lawrence, Gary Watson, E. Thomas Smiley, 2017. Best Management Practices: Root Management International Society of Arboriculture, Print. Fite, Kelby, and Edgar Thomas. Smiley. Managing trees during construction, second edition. Champaign, IL: International Society of Arboriculture, 2016. Matheny, Nelda P., Clark, James R. Trees and development: A technical guide to preservation of trees during land development. Bedminster, PA: International Society of Arboriculture1998. Smiley, E, Matheny, N, Lilly, S, ISA. Best Management Practices: Tree Risk Assessment: International Society of Arboriculture, 2017. Print Monarch Consulting Arborists LLC - P.O Box 1010, Felton, CA 95018 831.331.8982 - rick@monarcharborist.com Page of 6 10 250 Grant Street APN: 279-41-053 Coast Redwood Assessment July 30, 2018 Appendix A: Tree Location and Site  Monarch Consulting Arborists LLC - P.O Box 1010, Felton, CA 95018 831.331.8982 - rick@monarcharborist.com Page of 7 10 Redwoods 250 Grant Street APN: 279-41-053 Coast Redwood Assessment July 30, 2018 Appendix B: Tree Protection Guidelines Pre-Construction Meeting with the Project Arborist Tree protection locations should be marked before any fencing contractor arrives. Prior to beginning work, all contractors involved with the project should attend a pre construction meeting with the project arborist to review the tree protection guidelines. Access routes, storage areas, and work procedures will be discussed. Monitoring Any trenching, construction or demolition that is expected to damage or encounter tree roots should be monitored by the project arborist or a qualified ISA Certified Arborist and should be documented. The site should be evaluated by the project arborist or a qualified ISA Certified Arborist after construction is complete, and any necessary remedial work that needs to be performed should be noted. Restrictions Within the Tree Protection Zone No storage of construction materials, debris, or excess soil will be allowed within the Tree Protection Zone. Spoils from the trenching shall not be placed within the tree protection zone either temporarily or permanently. Construction personnel and equipment shall be routed outside the tree protection zones. Root Pruning Root pruning shall be supervised by the project arborist. When roots over two inches in diameter are encountered they should be pruned by hand with loppers, handsaw, reciprocating saw, or chain saw rather than left crushed or torn. Roots should be cut beyond sinker roots or outside root branch junctions and be supervised by the project arborist. When completed, exposed roots should be kept moist with burlap or backfilled within one hour. Boring or Tunneling Boring machines should be set up outside the drip line or established Tree Protection Zone. Boring may also be performed by digging a trench on both sides of the tree until roots one inch in diameter are encountered and then hand dug or excavated with an Air Spade® or similar air or water excavation tool. Bore holes should be adjacent to the trunk and never go directly under the main stem to avoid oblique (heart) roots. Bore holes should be a minimum of three feet deep. Monarch Consulting Arborists LLC - P.O Box 1010, Felton, CA 95018 831.331.8982 - rick@monarcharborist.com Page of 8 10 250 Grant Street APN: 279-41-053 Coast Redwood Assessment July 30, 2018 Qualiﬁcations, Assumptions, and Limiting Conditions Any legal description provided to the consultant is assumed to be correct. Any titles or ownership of properties are assumed to be good and marketable. All property is appraised or evaluated as though free and clear, under responsible ownership and competent management. All property is presumed to be in conformance with applicable codes, ordinances, statutes, or other regulations. Care has been taken to obtain information from reliable sources. However, the consultant cannot be responsible for the accuracy of information provided by others. The consultant shall not be required to give testimony or attend meetings, hearings, conferences, mediations, arbitration, or trials by reason of this report unless subsequent contractual arrangements are made, including payment of an additional fee for such services. This report and any appraisal value expressed herein represent the opinion of the consultant, and the consultant’s fee is not contingent upon the reporting of a specified appraisal value, a stipulated result, or the occurrence of a subsequent event. Sketches, drawings, and photographs in this report are intended for use as visual aids, are not necessarily to scale, and should not be construed as engineering or architectural reports or surveys. The reproduction of information generated by architects, engineers, or other consultants on any sketches, drawings, or photographs is only for coordination and ease of reference. Inclusion of said information with any drawings or other documents does not constitute a representation as to the sufficiency or accuracy of said information. Unless otherwise expressed: a) this report covers only examined items and their condition at the time of inspection; and b) the inspection is limited to visual examination of accessible items without dissection, excavation, probing, or coring. There is no warranty or guarantee, expressed or implied, that structural problems or deficiencies of plants or property may not arise in the future. Monarch Consulting Arborists LLC - P.O Box 1010, Felton, CA 95018 831.331.8982 - rick@monarcharborist.com Page of 9 10 250 Grant Street APN: 279-41-053 Coast Redwood Assessment July 30, 2018 Certiﬁcation of Performance I Richard Gessner, Certify: That I have personally inspected the tree(s) and/or the property referred to in this report, and have stated my findings accurately. The extent of the evaluation and/or appraisal is stated in the attached report and Terms of Assignment; That I have no current or prospective interest in the vegetation or the property that is the subject of this report, and I have no personal interest or bias with respect to the parties involved; That the analysis, opinions and conclusions stated herein are my own; That my analysis, opinions, and conclusions were developed and this report has been prepared according to commonly accepted Arboricultural practices; That no one provided significant professional assistance to the consultant, except as indicated within the report. That my compensation is not contingent upon the reporting of a predetermined conclusion that favors the cause of the client or any other party, nor upon the results of the assessment, the attainment of stipulated results, or the occurrence of any other subsequent events; I further certify that I am a Registered Consulting Arborist® with the American Society of Consulting Arborists, and that I acknowledge, accept and adhere to the ASCA Standards of Professional Practice. I am an International Society of Arboriculture Board Certified Master Arborist® and Tree Risk Assessor Qualified. I have been involved with the practice of Arboriculture and the care and study of trees since 1998. Richard J. Gessner ASCA Registered Consulting Arborist® #496 ISA Board Certified Master Arborist® WE-4341B ISA Tree Risk Assessor Qualified CA Qualified Applicators License QL104230 Copyright © Copyright 2018, Monarch Consulting Arborists LLC. Other than specific exception granted for copies made by the client for the express uses stated in this report, no parts of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, recording, or otherwise without the express, written permission of the author.Monarch Consulting Arborists LLC - P.O Box 1010, Felton, CA 95018 831.331.8982 - rick@monarcharborist.com Page of 10 10