ARBORIST REPORT. Carondelet Athletic Complex Walnut Creek, CA. Attachment 11

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1 Attachment 11 ARBORIST REPORT Carondelet Athletic Complex Walnut Creek, CA PREPARED FOR BkF Engineers 1646 N. California Blvd., Suite 400 Walnut Creek, CA PREPARED BY 325 Ray Street Pleasanton, CA May 2016

2 Arborist Report Carondolet Sports Complex, Walnut Creek CA Executive Summary BKF Engineers is coordinating development application materials for the Carondolet Sports Complex, in Walnut Creek. was asked to prepare an Arborist Report for project to meet the City of Walnut Creek requirements per their Tree Preservation Ordinance Descriptions of each tree are found in the Tree Assessment Form and locations are plotted on the Tree Assessment Plan (see Exhibits). A total of 93 trees were assessed, including trees along the southern, western and northern property boundaries. The 93 trees included 10 species, with Coast redwood, Canary Island pine and callery pear representing over 90% of the population. The most common species encountered was Coast redwood (62 trees). Coast redwoods were young to mature in form and development, with trunk diameters between 9 and 38. The species is not native to the interior valleys and these trees exhibited moderate to extensive dieback associated with drought stress. Callery pears (11 trees) were in fair condition but had been poorly pruned over the years, producing trees with poor structure. Canary Island pines (10 trees) had performed well, with 9 trees in good condition. The City of Walnut Creek defines certain native species with diameters of 9 or greater, as Highly Protected. Two trees, including on-site valley oak #49 and off-site coast live oak #93 qualified as Highly Protected. The plan proposes to construct a new sports field in the area of the existing tennis courts, expand the existing pool and construct a new sidewalk connecting to Valley Vista Rd. to the north. Based on the Grading Plan prepared by BKF Engineers (dated May 5, 2016), 33 trees are proposed to be removed to accommodate the sports court and sidewalk. The majority of removals are proposed along the southern property line, where the new sports court will expand toward the property line. Sixty (60) trees are proposed for preservation, including both of the Highly Protected trees. Minor pruning of trees along the entry may be required to provide vertical clearance for construction vehicles. Preservation of trees is predicated on adhering to the Tree Preservation Guidelines provided at the end of this document (page 11).

3 Arborist Report Carondelet Athletic Complex, Walnut Creek Table of Contents Page Introduction and Overview 1 Survey Methods 1 Description of Trees 2 Suitability for Preservation 4 Evaluation of Impacts and Recommendations 5 Appraisal of Value 8 Tree Preservation Guidelines 11 List of Tables Table 1. Tree condition and frequency of occurrence. 3 Table 2. Suitability for preservation 5 Table 3. Recommendations for action 6 Table 4. Appraised value of trees recommended for removal 8 Table 5. Appraised value of trees recommended for preservation 9 Exhibits Tree Assessment Form Tree Assessment Plan

4 BKF Engineers, May 2016 Page 1 Introduction and Overview BKF Engineers are coordinating development application materials for the proposed development of the Carondelet Athletic Complex property located on Valley Vista Rd., in Walnut Creek. The property currently contains the Club Sport facilities, including tennis courts, a pool and associated landscaping. was asked to prepare an Arborist Report for the sites for review by the City of Walnut Creek. This report provides the following information: 1. A survey of trees within and immediately adjacent to the proposed project area. 2. An assessment of the impacts of constructing the proposed project on the trees. 3. Recommendations for tree preservation and removal. 4. The appraise value of all surveyed trees using the techniques described in the Guide for Plant Appraisal, 9 th edition (International Society of Arboriculture). 5. Guidelines for tree preservation during the design, construction and maintenance phases. Assessment Methods Trees were assessed on April 6 and 28, All trees 9 or greater in diameter, within the project area or with portions of their crowns extending into the project area, were included (per Walnut Creek Ordinance No. 1966). The assessment procedure consisted of the following steps: 1. Identifying the tree as to species; 2. Tagging each tree with an identifying number and recording its location on a map; 3. Measuring the trunk diameter at a point 54 above grade; 4. Evaluating the health and structural condition using a scale of 1 5: 5 - A healthy, vigorous tree, reasonably free of signs and symptoms of disease, with good structure and form typical of the species. 4 - Tree with slight decline in vigor, small amount of twig dieback, minor structural defects that could be corrected. 3 - Tree with moderate vigor, moderate twig and small branch dieback, thinning of crown, poor leaf color, moderate structural defects that might be mitigated with regular care. 2 - Tree in decline, epicormic growth, extensive dieback of medium to large branches, significant structural defects that cannot be abated. 1 - Tree in severe decline, dieback of scaffold branches and/or trunk; most of foliage from epicormics; extensive structural defects that cannot be abated. 5. Rating the suitability for preservation as high, moderate or low. Suitability for preservation considers the health, age and structural condition of the tree, and its potential to remain an asset to the site for years to come. High: Trees with good health and structural stability that have the potential for longevity at the site. Moderate: Trees with somewhat declining health and/or structural defects than can be abated with treatment. The tree will require more intense management and monitoring, and may have shorter life span than those in good category. Low: Tree in poor health or with significant structural defects that cannot be mitigated. Tree is expected to continue to decline, regardless of treatment. The species or individual may have characteristics that are undesirable for landscapes, and generally are unsuited for use areas.

5 BKF Engineers, May 2016 Page 2 Description of Trees Ninety-three (93) trees were assessed, representing 7 10pecies (Table 1, following page). Two off-site trees with portions of their canopies extending over the development site were included in the assessment (#92 and 93). Descriptions of each tree are found in the Tree Assessment Form and locations are plotted on the Tree Assessment Plan (see Exhibits). Vegetation at the site was primarily located along the perimeter of the tennis courts and pool, with approximately 18 of the trees located on the interior, between the tennis courts, club house and pool. There were many trees with diameters below the 9 threshold for inclusion. Sixty-six (66) coast redwoods had been planted on the property, with the majority concentrated along the southern and western property lines. The trees were young to mature in form and development, with trunk diameters between 9 and 38. Condition varied widely among the individual trees, with most showing some amount of dieback associated with drought stress (Photo 1). Seven of the coast redwoods were in poor condition, 34 were in fair and 21 were in good. Photo 1: Looking southwest at coast redwoods #48-58, growing along the western property boundary. Most of the coast redwoods at the Carondelet Sports Complex site were exhibiting some amount of branch dieback associated with drought-stress. Eleven (11) callery pears had been planted on the site, with 8 located between the tennis courts and adjacent to the club house, and the 3 located along the southern property line. Callery pears were semi-mature to mature, with diameters between 9 and 19. One (1) was in poor condition, 6 were in fair and 4 were in good. Several of the trees had been topped or poorly pruned producing trees with poor form and structure. Ten (10) Canary Island pines had been planted along the drive entry and adjacent to the pool. These were mature, with diameters between 18 and 26. The species had performed well on the site and provided a stark contrast to the coast redwoods. Nine (9) of the Canary Island pines were in good condition and 1 was in fair. Few of the trees showed any indication of drought stress. Four (4) olives were assessed, all of which were located in the southwestern corner of the site. All 4 were multi-stemmed from the base, with diameters between 4 and 10, and all 4 were in good condition.

6 BKF Engineers, May 2016 Page 3 The remaining 6 species were represented by individual trees and included: Purple-leaf plum #16 was located in a landscape area just south of the eastern tennis courts. It was 9 in diameter and in good condition. Italian stone pine #28 was located along the southern property line. It was young, at 11 in diameter and in good condition. Valley oak #49 was located along the western perimeter, among the coast redwoods. It was young, with trunks measuring 7 and 12 in diameter. It was in good condition but the chain link fence in this area had become embedded in the trunk. Hackberry #71 was located northeast of the pool. It was in fair condition and had been suppressed by the larger coast redwoods in this area and was very onesided to the south. Siberian elm #89 was located near the entry on Valley Vista. It was young and multi-stemmed from the base, with trunks measuring 7, 8, and 9 in diameter. It too had been suppressed by its larger neighbors and was very one-sided to the west. Off-site coast live oak #93 was located just north of the existing club house. It was mature, with an estimated diameter of 24. It had a moderate amount of twig and branch dieback in the canopy. Average tree condition for the site was fair, with 44 trees or 47% of the population. Fortyone (41) trees were in good condition (44%) and 8 trees was in poor (49). Table 1 provides a summary of condition by species. Walnut Creek Ordinance No defines certain native species with diameters of 9 or greater as Highly protected. Based on this definition, all valley oak #49 and off-site coast live oak #93 qualified as Highly protected. Highly protected trees are identified in the Tree Assessment Form (see Exhibits). Table 1. Tree condition and frequency of occurrence. Carondelet Athletic Complex, Walnut Creek Common Name Scientific Name Condition Rating No. of Poor Fair Good trees (1-2) (3) (4-5) Hackberry Celtis occidentalis Olive Olea europaea Canary island pine Pinus canariensis Italian stone pine Pinus pinea Purple-leaf plum Prunus cerasifera 'Atropurpurea' Callery pear Pyrus calleryana Coast live oak Quercus agrifolia Valley oak Quercus lobata Coast redwood Sequoia sempervirens Siberian elm Ulmus pumila Total % 47% 44% 100%

7 BKF Engineers, May 2016 Page 4 Suitability for Preservation Before evaluating the impacts that will occur during development, it is important to consider the quality of the tree resource itself, and the potential for individual trees to function well over an extended length of time. Trees that are preserved on development sites must be carefully selected to make sure that they may survive development impacts, adapt to a new environment and perform well in the landscape. Our goal is to identify trees that have the potential for long-term health, structural stability and longevity. For trees growing in open fields, away from areas where people and property are present, structural defects and/or poor health presents a low risk of damage or injury if they fail. However, we must be concerned about safety in use areas. Therefore, where development encroaches into existing plantings, we must consider their structural stability as well as their potential to grow and thrive in a new environment. Where development will not occur, the normal life cycles of decline, structural failure and death should be allowed to continue. Evaluation of suitability for preservation considers several factors: Tree health Healthy, vigorous trees are better able to tolerate impacts such as root injury, demolition of existing structures, changes in soil grade and moisture, and soil compaction than are non-vigorous trees. Structural integrity Trees with significant amounts of wood decay and other structural defects that cannot be corrected are likely to fail. Such trees should not be preserved in areas where damage to people or property is likely. Species response There is a wide variation in the response of individual species to construction impacts and changes in the environment. In our experience, for example, drought-stressed trees are more sensitive to construction impacts, while Canary Island pine and healthy coast redwoods are tolerant of site disturbance. Tree age and longevity Old trees, while having significant emotional and aesthetic appeal, have limited physiological capacity to adjust to an altered environment. Young trees are better able to generate new tissue and respond to change. Invasiveness Species which spread across a site and displace desired vegetation are not always appropriate for retention. This is particularly true when indigenous species are displaced. The California Invasive Plant Inventory Database ( lists species identified as being invasive. Walnut Creek is part of the Central West Floristic Province. Olive and purple-leaf plum are both listed as having Limited invasiveness. Each tree was rated for suitability for preservation based upon its age, health, structural condition and ability to safely coexist within a development environment. Table 2, following page, provides a summary of suitability ratings. Suitability ratings for individual trees are provided in the Tree Survey Forms (see attachments).

8 BKF Engineers, May 2016 Page 5 We consider trees with high suitability for preservation to be the best candidates for preservation. We do not recommend retention of trees with low suitability for preservation in areas where people or property will be present. Retention of trees with moderate suitability for preservation depends upon the intensity of proposed site changes. Table 2: Tree Suitability for Preservation Carondelet Athletic Complex, Walnut Creek High These are trees with good health and structural stability that have the potential for longevity at the site. Seven (7) trees were highly suitable for preservation including 3 Canary Island pine, 3 olives and coast redwood #1. Moderate Trees in this category have fair health and/or structural defects that may be abated with treatment. Trees in this category require more intense management and monitoring, and may have shorter lifespans than those in the high category. Sixty-eight (68) trees were of moderate suitability for preservation, including 49 coast redwoods, 7 callery pears, 6 Canary Island pines, and 1 each of olive, coast live oak, hackberry, Italian stone pine, purple-leaf plum and valley oak. Low Trees in this category are in poor health or have significant defects in structure that cannot be abated with treatment. These trees can be expected to decline regardless of management. The species or individual tree may possess either characteristics that are undesirable in landscape settings or be unsuited for use areas. Eighteen (18) trees had low suitability for preservation, including 12 coast redwood, 4 callery pears, Canary Island pine #82 and Siberian elm #89. Evaluation of Impacts and Recommendations Appropriate tree retention develops a practical match between the location and intensity of construction activities and the quality and health of trees. The Tree Assessment was the reference point for tree condition and quality. Potential impacts from construction were evaluated using the Grading Plan prepared by BKF Engineers (dated May 5, 2016). The project proposes to construct a new sports court complex, expand the existing pool and construct a new sidewalk connecting to Valley Vista Rd. to the north. The majority of the sports court complex would be constructed where the existing tennis courts are located, except where it would expand toward the southern property line. The pool footprint would be expanded to the north in the area where the existing concrete pool deck is located. The plan showed the limits of grading and accurate trunk locations, but drainage and utilities were not included. Using the proposed plan, potential impacts from construction were estimated for each tree. Since the majority of the trees were located along the perimeter of the site, they can be preserved. The exception is where the sports court would expand to the south.

9 BKF Engineers, May 2016 Page 6 Based on my assessment of the Plans, I recommend removal for 33 trees, 30 of which would be within or impacted by the grading for the sports court complex and 3 of which would be within or impacted by the sidewalk work. Of the 30 trees recommended for removal, 4 were of low suitability for preservation and none qualified as Highly Protected. Table 3 provides the recommended action for each tree along with a description of the impacts. The remaining 60 trees can be preserved under the current design, including both of the Highly Protected trees (#49 and 93). Neither of the Highly Protected trees will require a dripline encroachment permit issued by the City of Walnut Creek. Preservation of trees is predicated on adhering to the Tree Preservation Guidelines provided at the end of this document (page 11). Pruning of trees, especially those along the entry drive may be required to provide construction vehicle clearance. Pruning guidelines are provided in the Tree Preservation Guidelines (Page 11). Table 3. Recommendations for action. Carondelet Athletic Complex, Walnut Creek Tree Common Trunk Highly Action No. Name Diameter Protected? 1 Coast redwood 20 No Remove, within grading 2 Callery pear 9 No Remove, within grading 3 Callery pear 9 No Remove, within grading 4 Callery pear 9 No Remove, within grading 5 Callery pear 19 No Remove, within grading 6 Callery pear 17 No Remove, within grading 7 Callery pear 17 No Remove, within grading 8 Callery pear 11 No Remove, within grading 9 Coast redwood 15 No Remove, within grading 10 Coast redwood 15 No Remove, within grading 11 Coast redwood 13 No Remove, within grading 12 Coast redwood 15 No Remove, within grading 13 Coast redwood 15 No Remove, within grading 14 Coast redwood 10 No Remove, within grading 15 Coast redwood 33 No Remove, within grading 16 Purple-leaf plum 9 No Preserve, outside impacts 17 Callery pear 11 No Preserve, outside impacts 18 Callery pear 9 No Preserve, outside impacts 19 Callery pear 10 No Preserve, outside impacts 20 Coast redwood 20 No Preserve, outside impacts 21 Coast redwood 13 No Preserve, outside impacts 22 Coast redwood 13 No Preserve, outside impacts 23 Coast redwood 14 No Preserve, outside impacts 24 Coast redwood 15 No Preserve, outside impacts 25 Coast redwood 15 No Preserve, outside impacts 26 Coast redwood 15 No Remove, within grading 27 Coast redwood 15 No Remove, within grading 28 Italian stone pine 11 No Preserve, 15' S. of grading 29 Coast redwood 15 No Remove, within grading 30 Coast redwood 11 No Remove, within grading 31 Coast redwood 24,18,15 No Remove, within grading 32 Coast redwood 22 No Remove, within grading (Continued, following page)

10 BKF Engineers, May 2016 Page 7 Table 3. Recommendations for action, continued. Carondelet Athletic Complex, Walnut Creek Tree Common Trunk Highly Action No. Name Diameter Protected? 33 Coast redwood 31 No Remove, impacted by grading 34 Coast redwood 28 No Remove, impacted by grading 35 Coast redwood 10 No Remove, within grading 36 Coast redwood 12 No Remove, within grading 37 Coast redwood 9 No Remove, within grading 38 Coast redwood 28 No Remove, within grading 39 Olive 10,8,7,6 No Remove, within grading 40 Olive 9,9,7,6 No Remove, impacted by grading 41 Coast redwood 24 No Remove, within grading 42 Coast redwood 28 No Preserve, outside impacts 43 Olive 9,9,6,5,4 No Preserve, outside impacts 44 Coast redwood 29 No Preserve, outside impacts 45 Olive 9,6,5,5,4,4 No Preserve, outside impacts 46 Coast redwood 29 No Preserve, outside impacts 47 Coast redwood 24,6 No Preserve, outside impacts 48 Coast redwood 25 No Preserve, 10' W. of seating 49 Valley oak 12,7 Yes Preserve, outside impacts 50 Coast redwood 26 No Preserve, 8' W. of seating 51 Coast redwood 29 No Preserve, 8' W. of seating 52 Coast redwood 33 No Preserve, 10' W. of seating 53 Coast redwood 19,11 No Preserve, 10' W. of seating 54 Coast redwood 31 No Preserve, outside impacts 55 Coast redwood 38 No Preserve, outside impacts 56 Coast redwood 37 No Preserve, outside impacts 57 Coast redwood 38 No Preserve, outside impacts 58 Coast redwood 23 No Preserve, outside impacts 59 Coast redwood 27 No Preserve, outside impacts 60 Coast redwood 31 No Preserve, outside impacts 61 Coast redwood 14,8 No Preserve, outside impacts 62 Coast redwood 11,8,6 No Preserve, outside impacts 63 Coast redwood 11,11,10,9,7,7,6 No Preserve, outside impacts 64 Coast redwood 10 No Preserve, outside impacts 65 Coast redwood 10 No Preserve, outside impacts 66 Coast redwood 15 No Preserve, outside impacts 67 Coast redwood 16 No Preserve, outside impacts 68 Coast redwood 14 No Preserve, outside impacts 69 Coast redwood 12 No Preserve, outside impacts 70 Coast redwood 19 No Preserve, outside impacts 71 Hackberry 10 No Preserve, outside impacts 72 Canary island pine 23 No Preserve, outside impacts 73 Canary island pine 26 No Preserve, outside impacts 74 Callery pear 14 No Preserve, outside impacts 75 Coast redwood 14 No Preserve, 3' W & N. of sidewalk 76 Coast redwood 10 No Remove, within sidewalk 77 Canary island pine 19 No Remove, within sidewalk 78 Canary island pine 23 No Preserve, 4' W. of sidewalk 79 Canary island pine 18 No Preserve, 9' W. of sidewalk 80 Canary island pine 22 No Remove, impacted by sidewalk (Continued, following page)

11 BKF Engineers, May 2016 Page 8 Table 3. Recommendations for action, continued. Carondelet Athletic Complex, Walnut Creek Tree Common Trunk Highly Action No. Name Diameter Protected? 81 Canary island pine 24 No Preserve, outside impacts 82 Canary island pine 18 No Preserve, outside impacts 83 Canary island pine 19 No Preserve, outside impacts 84 Canary island pine 23 No Preserve, outside impacts 85 Coast redwood 10,6 No Preserve, outside impacts 86 Coast redwood 19 No Preserve, 5' W. of sidewalk 87 Coast redwood 13 No Preserve, outside impacts 88 Coast redwood 19,18 No Preserve, outside impacts 89 Siberian elm 9,8,7 No Preserve, outside impacts 90 Coast redwood 25 No Preserve, 3' W. of sidewalk 91 Coast redwood 22 No Preserve, outside impacts 92 Coast redwood 10 No Preserve, off-site 93 Coast live oak 24 Yes Preserve, off-site Appraisal of Value As part of the submittal requirements, Contra Costa County requires that the value of all of the surveyed trees be established prior to development. To accomplish this, I employed the standard methods found in Guide for Plant Appraisal, 9th edition (published in 2000 by the International Society of Arboriculture, Savoy IL). In addition, I referred to Species Classification and Group Assignment (1992), a publication of the Western Chapter of the International Society of Arboriculture. These two documents outline the methods employed in tree appraisal. The value of landscape trees is based upon four factors: size, species, condition and location. Size is measured as trunk diameter at 54" above grade. The species factor considers the adaptability and appropriateness of the plant in the inland valley of the East Bay Area. The Species Classification and Group Assignment lists recommended species ratings and evaluations. Condition reflects the health and structural integrity of the individual, as documented in my October 2012 assessment. The location factor considers the site, placement and contribution of the tree in its surrounding landscape. The appraised value of the 33 trees recommended for removal was $81,750 (Table 4). The appraised value of the 60 trees recommended for preservation was $172,750 (Table 5, following page). Table 4. Appraised value of trees recommended for removal. Carondelet Athletic Complex, Walnut Creek Tree Common Name Size Appraised No. (in.) Value ($) 1 Coast redwood 20 2,100 2 Callery pear 9 1,000 3 Callery pear 9 1,000 4 Callery pear Callery pear 19 6,000 (Continued, following page)

12 BKF Engineers, May 2016 Page 9 Table 4. Appraised value of trees recommended for removal, continued. Carondelet Athletic Complex, Walnut Creek Tree Common Name Size Appraised No. (in.) Value ($) 6 Callery pear 17 3,450 7 Callery pear 17 4,800 8 Callery pear 11 2,050 9 Coast redwood 15 1, Coast redwood 15 1, Coast redwood Coast redwood 15 1, Coast redwood 15 1, Coast redwood Coast redwood 33 3, Coast redwood 15 1, Coast redwood 15 1, Coast redwood 15 1, Coast redwood Coast redwood 24,18,15 4, Coast redwood 22 1, Coast redwood 31 3, Coast redwood 28 3, Coast redwood Coast redwood Coast redwood Coast redwood 28 3, Olive 10,8,7,6 9, Olive 9,9,7,6 3, Coast redwood 24 2, Coast redwood Canary island pine 19 5, Canary island pine 22 7,500 Total 81,750 Table 5. Appraised value of trees recommended for preservation Carondelet Athletic Complex, Walnut Creek Tree Common Name Size Appraised No. (in.) Value ($) 16 Purple-leaf plum Callery pear 11 2, Callery pear 9 1, Callery pear 10 1, Coast redwood 20 2, Coast redwood Coast redwood Coast redwood 14 1, Coast redwood 15 1, Coast redwood 15 1, Italian stone pine 11 1, Coast redwood 28 1, Olive 9,9,6,5,4 6, Coast redwood 29 3, Olive 9,6,5,5,4,4 4,050 (Continued, following page)

13 BKF Engineers, May 2016 Page 10 Table 5. Appraised value of trees recommended for preservation Carondelet Athletic Complex, Walnut Creek Tree Common Name Size Appraised No. (in.) Value ($) 46 Coast redwood 29 3, Coast redwood 24,6 2, Coast redwood 25 3, Valley oak 12,7 5, Coast redwood 26 2, Coast redwood 29 3, Coast redwood 33 4, Coast redwood 19,11 2, Coast redwood 31 5, Coast redwood 38 5, Coast redwood 37 5, Coast redwood 38 5, Coast redwood 23 2, Coast redwood 27 2, Coast redwood 31 3, Coast redwood 14,8 1, Coast redwood 11,8, Coast redwood 11,11,10,9,7,7,6 1, Coast redwood Coast redwood Coast redwood Coast redwood Coast redwood Coast redwood Coast redwood 19 1, Hackberry Canary island pine 23 7, Canary island pine 26 9, Callery pear 14 2, Coast redwood Canary island pine 23 8, Canary island pine 18 5, Canary island pine 24 8, Canary island pine 18 3, Canary island pine 19 5, Canary island pine 23 8, Coast redwood 10, Coast redwood Coast redwood 13 2, Coast redwood 19,18 1, Siberian elm 9,8, Coast redwood 25 2, Coast redwood 22 1, Coast redwood Coast live oak 24 6,350 Total 172,750

14 BKF Engineers, May 2016 Page 11 Tree Preservation Guidelines The goal of tree preservation is not merely tree survival during development but maintenance of tree health and beauty for many years. Trees retained on sites that are either subject to extensive injury during construction or are inadequately maintained become a liability rather than an asset. The response of individual trees will depend on the amount of excavation and grading, the care with which demolition is undertaken, and the construction methods. The following recommendations will help reduce impacts to trees from development and maintain and improve their health and vitality through the clearing, grading and construction phases. Design recommendations 1. Have the vertical and horizontal locations of all the trees identified for preservation established and plotted on all plans. Forward these plans to the Consulting Arborist for review and comment. 2. Any plan affecting trees should be reviewed by the Consulting Arborist with regard to tree impacts. These include, but are not limited to, improvement plans, utility and drainage plans, grading plans, landscape and irrigation plans and demolition plans. 3. Tree Preservation Guidelines prepared by the Consulting Arborist should be included on all plans. 4. A TREE PROTECTION ZONE must be established for trees to be preserved, in which no disturbance is permitted. TREE PROTECTION ZONES for trees identified for preservation are provided in the following table. No grading, excavation, construction or storage of materials shall occur within that zone. Specific Tree Protection Zones Tree No. TPZ #48, 52 and 53 10' E., DL in all other directions= #50 and 51 8' E., DL in all other directions #75 3' E. & S., DL in all other directions #78 4' E., DL in all other directions #79 9' E., DL in all other directions #86 5' E., DL in all other directions #90 4' E., DL in all other directions 5. No underground services including utilities, sub-drains, water or sewer shall be placed in the TREE PROTECTION ZONE. To minimize impacts to trees, locate underground services to provide as much room as possible from trees identified for preservation. 6. Any herbicides placed under paving materials must be safe for use around trees and labeled for that use. 7. Irrigation systems must be designed to avoid trenching within the TREE PROTECTION ZONE. 8. Do not apply lime to soil for stabilization within 25 of trees to be preserved. Lime is toxic to tree roots.

15 BKF Engineers, May 2016 Page Maintain the existing irrigation system. If the existing irrigation system is not functional, have a temporary system installed (using soaker hoses or pvc laid on the ground and covered with mulch) as soon as possible to supply the coast redwood trees with water and help them recover from drought and prepare them for impacts associated with the demolition and construction process. Pre-construction treatments and recommendations 1. The construction superintendent shall meet with the Consulting Arborist before beginning work to discuss work procedures and tree protection. 2. Fence all trees to be retained to completely enclose the TREE PROTECTION ZONE prior to demolition, grubbing or grading. Fences shall be 6 chain link held in place with rebar staples as required by the City of Walnut Creek. Fences are to remain until all grading and construction is completed. 3. Any grading within the TREE PROTECTION ZONE specified in the above table shall be performed by hand and under direct supervision of the Consulting Arborist. 4. Installation of the pervious pavers within the TREE PROTECTION ZONE of trees #31, 35 and 36 will require temporarily moving the Tree Protection Fencing. All work within the TREE PROTECTION ZONE shall be approved and monitored by the Consulting Arborist. 5. Prune trees to be preserved to clean the crown and to provide clearance. All pruning shall be done by a State of California Licensed Tree Contractor (C61/D49). All pruning shall be done by Certified Arborist or Certified Tree Worker in accordance with the Best Management Practices for Pruning (International Society of Arboriculture, 2002) and adhere to the most recent editions of the American National Standard for Tree Care Operations (Z133.1) and Pruning (A300). 6. All tree work shall comply with the Migratory Bird Treaty Act as well as California Fish and Wildlife code to not disturb nesting birds. To the extent feasible tree pruning and removal should be scheduled outside of the breeding season. Breeding bird surveys should be conducted prior to tree work. Qualified biologists should be involved in establishing work buffers for active nests. Recommendations for tree protection during construction 1. Prior to beginning work, the contractors working in the vicinity of trees to be preserved are required to meet with the Consulting Arborist at the site to review all work procedures, access routes, storage areas and tree protection measures. 2. No grading, construction, demolition or other work shall occur within the TREE PROTECTION ZONE. Any modifications must be approved and monitored by the Consulting Arborist. 3. Any root pruning required for construction purposes shall receive the prior approval of, and be supervised by, the Consulting Arborist. 4. If injury should occur to any tree during construction, it should be evaluated as soon as possible by the Consulting Arborist so that appropriate treatments can be applied.

16 BKF Engineers, May 2016 Page No excess soil, chemicals, debris, equipment or other materials shall be dumped or stored within the TREE PROTECTION ZONE. 6. Any additional tree pruning needed for clearance during construction must be performed by a Certified Arborist and not by construction personnel. Maintenance of impacted trees Trees preserved at the Carondelet Sports Complex site may experience a physical environment different from that pre-development. As a result, tree health and structural stability should be monitored. Occasional pruning, fertilization, mulch, pest management, replanting and irrigation may be required. John Leffingwell Board Certified Master Arborist WE-3966B Registered Consulting Arborist #442 Exhibits: Tree Assessment Form Tree Assessment Plan

17 Tree Assessment Carondelet Athletic Complex Walnut Creek, California April 2016 TREE SPECIES SIZE HIGHLY CONDITION SUITABILITY COMMENTS No. DIAMETER PROTECTED 1=POOR FOR (in inches) 5=EXCELLENT PRESERVATION 1 Coast redwood 20 No 4 High Good form and structure; twig dieback; minor browning of needles. 2 Callery pear 9 No 3 Low Codominant trunks at 4'; topped at 10'; dieback in upper crown. 3 Callery pear 9 No 3 Low Multiple attachments at 6'; topped at 10'; leans N.; decay at base. 4 Callery pear 9 No 2 Low Topped at 10'; moderate dieback. 5 Callery pear 19 No 4 Moderate Multiple attachments at 6'; buried in planter box; moderate dieback. 6 Callery pear 17 No 3 Moderate Multiple attachments at 10'; history of branch failures; moderate dieback. 7 Callery pear 17 No 4 Moderate Multiple attachments at 10'; good form; moderate dieback. 8 Callery pear 11 No 4 Moderate Codominant trunks at 7'; leans N.; dieback. 9 Coast redwood 15 No 4 Moderate Good form and structure; twig dieback; browning of needles. 10 Coast redwood 15 No 4 Moderate Good form and structure; twig dieback; thinning of upper canopy. 11 Coast redwood 13 No 4 Moderate Good form and structure; twig dieback; thinning of upper canopy. 12 Coast redwood 15 No 4 Moderate Good form and structure; twig dieback; thinning of upper 13 Coast redwood 15 No 4 Moderate Good form and structure; twig dieback; thinning of upper canopy. 14 Coast redwood 10 No 4 Moderate Good form and structure; dieback & thinning of upper 15 Coast redwood 33 No 3 Moderate Good form and structure; extensive dieback; very thin canopy Page 1

18 Tree Assessment Carondelet Athletic Complex Walnut Creek, California April 2016 TREE SPECIES SIZE HIGHLY CONDITION SUITABILITY COMMENTS No. DIAMETER PROTECTED 1=POOR FOR (in inches) 5=EXCELLENT PRESERVATION 16 Purple-leaf plum 9 No 4 Moderate Multiple attachments at 6'; narrow attachments. 17 Callery pear 11 No 4 Moderate Multiple attachments at 8'; pruned N.; minor fireblight & dieback. 18 Callery pear 9 No 3 Moderate Topped at 10'; pruned W.; fireblight & dieback. 19 Callery pear 10 No 3 Moderate Multiple attachments at 8'; topped at 15'; fireblight & dieback. 20 Coast redwood 20 No 4 Moderate Good form and structure; pruned S. for overhead utilities; dieback. 21 Coast redwood 13 No 4 Moderate Good form and structure; pruned S. for overhead utilities; dieback in upper canopy. 22 Coast redwood 13 No 4 Moderate Good form and structure; pruned S. for overhead utilities; dieback in upper canopy. 23 Coast redwood 14 No 4 Moderate Good form and structure; pruned S. for overhead utilities; dieback in upper canopy. 24 Coast redwood 15 No 4 Moderate Good form and structure; pruned S. for overhead utilities; dieback & browning in upper canopy. 25 Coast redwood 15 No 4 Moderate Good form and structure; pruned S. for overhead utilities; dieback & browning in upper canopy. 26 Coast redwood 15 No 4 Moderate Good form and structure; pruned S. for overhead utilities; dieback & browning in upper canopy. 27 Coast redwood 15 No 4 Moderate Good form and structure; pruned S. for overhead utilities; dieback & browning in upper canopy. 28 Italian stone pine 11 No 4 Moderate Crowded & one sided S.; beneath overhead utilities. 29 Coast redwood 15 No 4 Moderate Good form and structure; pruned S. for overhead utilities; dieback & browning in upper canopy. Page 2

19 Tree Assessment Carondelet Athletic Complex Walnut Creek, California April 2016 TREE SPECIES SIZE HIGHLY CONDITION SUITABILITY COMMENTS No. DIAMETER PROTECTED 1=POOR FOR (in inches) 5=EXCELLENT PRESERVATION 30 Coast redwood 11 No 4 Moderate Good form and structure; pruned S. for overhead utilities; dieback & browning in upper canopy. 31 Coast redwood 24,18,15 No 3 Moderate Multiple attachments at base; two stems topped for overhead utilities; dieback in upper canopy. 32 Coast redwood 22 No 3 Moderate Good form and structure; dieback; thin canopy. 33 Coast redwood 31 No 3 Moderate Good form and structure; pruned S. for overhead utilities; moderate dieback & browning. 34 Coast redwood 28 No 3 Moderate Good form and structure; pruned S. for overhead utilities; very thin canopy; dieback. 35 Coast redwood 10 No 3 Moderate Crowded; asymmetric form; very thin canopy; dieback. 36 Coast redwood 12 No 3 Moderate Crowded; one sided N.; very thin canopy; dieback. 37 Coast redwood 9 No 3 Moderate Crowded; one sided S.; very thin canopy; dieback. 38 Coast redwood 28 No 3 Moderate Good form and structure; pruned S. for overhead utilities; very thin canopy; dieback. 39 Olive 10,8,7,6 No 4 High Multiple attachments at base; pruned N.; one sided S. 40 Olive 9,9,7,6 No 4 Moderate Multiple attachments at base; one stem split at base; one sided S. 41 Coast redwood 24 No 3 Low Topped at 20' for overhead utilities; very thin canopy; dieback. 42 Coast redwood 28 No 2 Low Pruned S. for overhead utilities; all but dead. 43 Olive 9,9,6,5,4 No 4 High Multiple attachments at base; crowded; narrow form. 44 Coast redwood 29 No 3 Low Good form and structure; very thin upper canopy. 45 Olive 9,6,5,5,4,4 No 5 High Multiple attachments at base; spreading form. 46 Coast redwood 29 No 3 Moderate Good form and structure; very thin canopy. 47 Coast redwood 24,6 No 3 Moderate Good form and structure; very thin canopy. 48 Coast redwood 25 No 4 Moderate Good form and structure; thin canopy. Page 3

20 Tree Assessment Carondelet Athletic Complex Walnut Creek, California April 2016 TREE SPECIES SIZE HIGHLY CONDITION SUITABILITY COMMENTS No. DIAMETER PROTECTED 1=POOR FOR (in inches) 5=EXCELLENT PRESERVATION 49 Valley oak 12,7 Yes 4 Moderate Upright form; fence embedded in trunk. 50 Coast redwood 26 No 3 Moderate Slight sweep from base; good form and structure; thin canopy. 51 Coast redwood 29 No 3 Moderate Good form and structure; very thin canopy. 52 Coast redwood 33 No 3 Moderate Good form and structure; very thin canopy. 53 Coast redwood 19,11 No 4 Moderate Codominant trunks at base; narrow form; thin upper canopy. 54 Coast redwood 31 No 4 Moderate Good form and structure; thin upper canopy. 55 Coast redwood 38 No 3 Moderate Good form and structure; very thin canopy. 56 Coast redwood 37 No 3 Moderate Good form and structure; very thin upper canopy. 57 Coast redwood 38 No 3 Moderate Good form and structure; very thin canopy. 58 Coast redwood 23 No 3 Moderate Good form and structure; very thin canopy. 59 Coast redwood 27 No 3 Low Good form and structure; very thin canopy; extensive dieback & browning. 60 Coast redwood 31 No 3 Moderate Good form and structure; very thin upper canopy. 61 Coast redwood 14,8 No 3 Low Codominant trunks at base; poor form; very thin canopy. 62 Coast redwood 11,8,6 No 1 Low All but dead. 63 Coast redwood 11,11,10,9,7,7,6 No 2 Low Multiple attachments at base; extensive dieback. 64 Coast redwood 10 No 3 Low Good form and structure; moderate dieback. 65 Coast redwood 10 No 2 Low Good form and structure; extensive dieback. 66 Coast redwood 15 No 3 Moderate Good form and structure; moderate dieback. 67 Coast redwood 16 No 3 Moderate Good form and structure; moderate dieback. 68 Coast redwood 14 No 3 Moderate Good form and structure; moderate dieback. 69 Coast redwood 12 No 4 Moderate Good form and structure; minor dieback. 70 Coast redwood 19 No 3 Moderate Good form and structure; dieback in upper crown. 71 Hackberry 10 No 3 Moderate Multiple attachments at 7'; one sided S.; twig dieback. Page 4

21 Tree Assessment Carondelet Athletic Complex Walnut Creek, California April 2016 TREE SPECIES SIZE HIGHLY CONDITION SUITABILITY COMMENTS No. DIAMETER PROTECTED 1=POOR FOR (in inches) 5=EXCELLENT PRESERVATION 72 Canary island pine 23 No 4 Moderate Good form; fair structure; a little one sided SW. 73 Canary island pine 26 No 4 High Good form and structure; long lateral limbs SW. 74 Callery pear 14 No 3 Low Multiple attachments at 7'; poor form and structure; dieback. 75 Coast redwood 14 No 3 Moderate Good form and structure; moderate dieback. 76 Coast redwood 10 No 3 Moderate Good form and structure; moderate dieback. 77 Canary island pine 19 No 4 Moderate One sided S. 78 Canary island pine 23 No 4 High Good form and structure; long lateral limbs N. & E. 79 Canary island pine 18 No 4 High Good form and structure; a little one sided S. 80 Canary island pine 22 No 4 Moderate Codominant trunks at 25'; upright, narrow form. 81 Canary island pine 24 No 4 Moderate Codominant trunks at 20'; upright, narrow form. 82 Canary island pine 18 No 3 Low Lost top; poor form and structure. 83 Canary island pine 19 No 4 Moderate Crowded; one sided S. 84 Canary island pine 23 No 4 Moderate Crowded; good form and structure; long lateral limbs. 85 Coast redwood 10,6 No 2 Low Codominant trunks at base; extensive dieback. 86 Coast redwood 19 No 2 Low Good form and structure; extensive dieback. 87 Coast redwood 13 No 3 Moderate Good form and structure; very thin canopy. 88 Coast redwood 19,18 No 3 Moderate Codominant trunks at base; good form and structure; thin canopy. 89 Siberian elm 9,8,7 No 3 Low Multiple attachments at base; very one sided W. 90 Coast redwood 25 No 3 Moderate Good form and structure; thin canopy. 91 Coast redwood 22 No 3 Moderate Good form and structure; thin canopy. 92 Coast redwood 10 No 2 Low Group of three off-site trees, no tag; moderate to extensive dieback. 93 Coast live oak 24 Yes 3 Moderate Off-site, no tag; multiple attachments at 7'; narrow attachments; moderate dieback. Page 5

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