CITY COUNCIL SPECIAL MEETING AGENDA PACKET 8-11-26

Sam Oakley 231 Old Bernal Avenue Tree Inventory, Valuation, and Construction Guidelines 9/13/2024 7 PO BOX 2412 PISMO BEACH, CA 93448 (415) 407-6995 SAM@OAKLEYGROUP.ORG WWW.OAKLEYGROUP.ORG Trees can be damaged or killed by a wide variety of construction activities. Some injuries, such as broken branches or torn bark, can be easily avoided. However, the worst damage often remains unseen. Roots are one of the most vital parts of a tree. They are responsible for nutrient and water uptake, energy storage, and anchoring of the plant. Because they are so important, it is critical that you protect roots that lie in the path of construction. Trees are never the same shape below ground as they are above, so it is difficult to predict the length or location of their roots. An easy rule to follow is that approximately ninety to ninety-five (90-95) percent of a tree's root system is in the top three (3) feet of soil, and more than half is in the top one (1) foot, which extends radially from the trunk to the dripline of the tree. The part of this root system in which construction damage should be avoided is called the Critical Root Zone (CRZ). Preconstruction Contractor Meeting Prior to ground break a preconstruction meeting shall be held with the Project Arborist, Project Superintendent and other parties associated with the project that may encounter a subject tree during construction to discuss the guidelines included in this report. Soil Cut or Fill within Root Zones One of the most important guidelines to be followed when construction occurs near trees is: Do not disturb the ground surface within the CRZ of any tree proposed to be retained. Disturbing the ground includes heavy equipment, over-watering, trenching, excavating, or any other activity, including foot traffic, within the specified area. When adding new fill to any root zone, care should be taken to assure that it is no deeper than six (6) inches. This fill should not be compacted or placed within three (3) feet of any trunk. If compaction is necessary, sixty to seventy (60-70) percent should be the maximum pore space allowed in the soil. In addition, any change in the natural grade should provide drainage away from rather than towards the tree. It is important to remember that the removal of any soil within the drip line could do serious damage. If soil must be removed, no more than four (4) inches should be allowed. This soil removal work must be done by hand or “AirSpade” (see below). If roots two (2) inches or greater in diameter are encountered, root severance guidelines must be followed. Root Excavation Guidelines Ninety (90) percent of all roots are in the top eighteen (18) inches of soil. Proper excavation of roots in this area is critical to a tree’s successful recovery. The top twenty- four (24) inches of soil should be removed with the assistance of an AirSpade and assisting hand tool, trenching at a pressure of four- to six hundred (400 to 600) pounds per square inch. Page 341 of 373