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Home My WebLink AboutStaff Report 420-10CMR:420:10 Page 1 of 5 TO: HONORABLE CITY COUNCIL FROM: CITY MANAGER DEPARTMENT: COMMUNITY SERVICES DATE: NOVEMBER 22, 2010 CMR:420:10 REPORT TYPE: INFORMATIONAL SUBJECT: ELEANOR PARDEE PARK TREE UPDATE This is an informational report and no Council action is required. EXECUTIVE SUMMARY This update provides Council with background information about the condition of sixteen eucalyptus trees at Eleanor Pardee Park that were reported to have spontaneously dropping limbs by park users; their evaluation and diagnosis by the City Arborist and an independent arborist; efforts to reach out to the neighbors and users of the park to keep the community informed of these evaluations; as well as an update on how to move forward with removals of trees that have structural deficiencies and the replanting of replacement trees in the park with input from the public and park users. BACKGROUND In January 2010, shortly after a limb fell from a eucalyptus tree at Eleanor Pardee Park and nearly hit a park visitor, staff began a series of meetings with the public to discuss the safety of the trees, alternatives for making the park safer, findings from the City’s Managing Arborist, and most recently to review the findings of an independent arborist who has evaluated the condition of the remaining trees. On the afternoon of February 24, 2010, members of the City Parks Section, Public Works Tree Section, and managers from the Community Services Department met with a small group of concerned neighbors and park users of Pardee Park to listen to concerns about the safety of the playground, adjoining sidewalks and the area surrounding the sixteen eucalyptus trees lining the southwest corner of the park at Channing Avenue and Center Drive. Staff tried to assure the neighbors and parents that no branches to date had fallen inside of the fence around the playground and that the area was considered by staff to be safe. Staff agreed to close the children’s playground until the City’s Managing Arborist could evaluate the structure of the trees and make recommendations. Staff held a second meeting at the park in the early evening of March 11, 2010 for the benefit of neighbors and park users who were not able to attend the first meeting on February 24th. The City’s Managing Arborist Eric Krebs evaluated the condition of the eucalyptus trees, effects from their prior pruning and their general health. His report dated March 2, 2010, concluded that six of the trees exhibited evidence of internal trunk rot caused by an aggressive wood decay pathogen (sulphur fungus) (Attachment A), and he recommended that these six trees, together CMR:420:10 Page 2 of 5 with a dying redwood tree in another area of the park, be removed. He further recommended that the remaining ten eucalyptus trees be pruned to remove structurally unsound branches. On March 11, 2010, staff from Public Works, Community Services and the City Manager’s Office held an informational meeting at the Lucie Stern Community Center with concerned citizens to review the Arborist’s report and recommendations. Staff explained that because of the aggressive nature of the decay pathogen the six trees with fruiting bodies of sulphur fungus should be removed, as outlined in the March 2nd report showing the greatest extent of trunk cankers be cut down and thoroughly examined. On April 20, 2010, staff met with citizens concerned with saving the remaining eucalyptus trees and received a petition from Mr. Keith Nicholls signed by nearly 400 people asking the City to refrain from any tree removals. In the meeting staff stressed the urgent need to examine the core of the trunks of the most severely affected trees and to proceed with the pruning of the remaining trees. City Manager Keene sent a memo to Council on May 9, 2010 (Attachment B), providing notice of the eminent removal of six trees. Three of the most severely affected trees would be removed first and examined. The examination of the three trees that were removed in May showed conclusively that the sulphur fungus had indeed caused extensive rotting of the core of the three trees. Staff advertised a public meeting to be held at the Stern Community Center on June 8, 2010, to discuss the findings from the examinations of the trunks of the removed trees. There was a large turn-out of concerned neighbors, parents and park users at this meeting. The public was informed that the final three of six trees would be removed from the park as soon as possible. Dave Muffley, an arborist hired by a group of concerned park users, expressed his opinion that the other ten remaining trees were structurally unsound and that despite the plan to prune the trees, the trees would still be subject to spontaneous limb failure. He and some members of the audience urged the City to hire an independent arborist to examine the trunks of the removed trees and all of the remaining trees for their health, safety and structural integrity. During the month of July, the services of Torrey Young, an arborist from the firm of Dryad, LLC, were contracted by the City. Mr. Young examined impacts of the tree pruning conducted by the City tree crews in the 80’s, the recent limb pruning by West Coast Tree Services, the condition of trunk cores of the removed trees, and the trunks of the remaining trees. His report dated August 5, 2010 (Attachment C), concluded that in spite of the recent pruning of the ten remaining trees, the structural integrity of the branches had been so severely compromised because of past tree pruning or the presence of sulphur fungus spores, as well as severe soil compaction around the roots of the trees caused by vehicles, that the trees could not be effectively rehabilitated. His conclusion was that all of the eucalyptus trees should be removed to prevent additional limb drop or whole tree failure around the playground. Mr. Young presented his findings at a fifth public meeting held at the Stern Center on September 23, 2010. Mr. Young answered questions from the audience and concluded that because of the proven structural damage to the trees, the trees posed an unacceptable safety risk to park visitors. He stressed that CMR:420:10 Page 3 of 5 even with annual inspections of the remaining trees and systematic cycle pruning, the structural defects of the trees pose too great of a risk to public safety and welfare. DISCUSSION Concluding that all of the eucalyptus trees will either need to be removed at one time or in phases, staff has hired Landscape Architect Edward Chau to develop conceptual plans for the replanting of trees at the southwest corner of the park. His plans are to be designed to both complement the olive, oak and other ornamental trees around the playground and provide a relatively safe and attractive canopy along Channing Avenue and Center Drive. In developing his conceptual plans, Mr. Chau has also taken recommendations from Mr. Krebs, Mr. Young, members of the park staff and representatives from Canopy for the species and spacing of trees in this area. Staff intends to extensively advertise a sixth public meeting for the evening of December 1, 2010, to present two different conceptual renderings for the restoration of the park corner. Mr. Young will attend the December 1st meeting and will be able to answer questions about the recommended trees and to make suggestions. Comments, suggestions and concerns will be gathered from the meeting participants. After the December 1st meeting, Mr. Chau will incorporate comments from meeting participants into a revised conceptual plan. Staff intends to then review this revised conceptual plan at another public meeting scheduled for Wednesday, December 8, 2010. Mr. Chau will outline what suggestions from the first meeting have been incorporated into the second plan. Once Mr. Chau and staff have helped the public reach consensus on the tree replacement plan at the two December meetings, Mr. Chau will develop engineer’s cost estimates for the removal of the remaining trees, grinding of tree stumps, installation of irrigation systems to sustain the newly planted trees, pathways, fencing and other necessary park amenities for the area. Three principal factors bear on whether to replace the remaining ten eucalyptus trees at one time, or through a phased approach: 1. Public safety; 2. Liability to the City; and 3. Cost. While discussions on what to do with the remainder of the eucalyptus trees will continue, staff plans to proceed with the removal of the sixth diseased eucalyptus tree that was identified in the initial report by the City Arborist in April. This tree would have been removed with the other severely affected trees in June, however, three bird nests were observed in the tree which required staff to postpone removal of the tree until the bird nests were abandoned. The dying redwood tree in the center area of the park, which was also identified in the initial report, will also be removed. Public Safety and Liability to the City: Although staff has taken appropriate measures to extensively prune the remaining ten trees, all three of the arborists who have evaluated the trees agree that the trees have significant structural CMR:420:10 Page 4 of 5 defects due to past pruning and that additional pruning will not be able to completely mitigate for the damage caused by heading and topping cuts. New branches will continue to sprout from these cuts and the new branches will be more vulnerable to spontaneous limb failure than normally forming branches. The independent consulting arborist also asserts that because of the presence of sulphur fungus in the six severely affected trees, and because of stress to the trees caused by compaction of the soil around the base of the trees by vehicles over time, the remaining trees are highly susceptible to developing trunk rot. The presence of wood rot pathogens significantly increases the odds of additional limb failure or total tree failure in a storm. Although a continued regimen of cycle pruning of the limbs is possible, it would be very difficult to accurately assess which individual limbs have the weakest structural support defects and which are apt to fail spontaneously or during wind storms. Similarly, although the City could remove the remaining trees over time, it would be impossible to tell which trees would be most vulnerable to limb or total failure. Since the City has received an independent evaluation of the trees that point to the trees structural defects, in the event that a limb injures or kills a park visitor or pedestrian on the sidewalks under the trees, the City would face direct liability for allowing the trees to stay in place. Replacement Costs: The City could replace the trees at one time in the fall or early winter, or could replace the trees over many years in a phased approach. The cost to remove all of the trees and grind the stumps at one time would be significantly less (approximately $20,000 to $25,000) than removing the trees through a phased approach (approximately $65,000 to $75,000). In addition to having to stage for separate removals, the work would have to be performed in such a manner as to protect newly planted trees and installed irrigation systems. In the phased approach there would also be the on-going annual cost of inspecting and re-pruning all of the branches. The cost of planting trees in separate phases would also be greater due to additional staging costs and the expense of adding irrigation heads during separate phases. The other advantage to replacing all of the trees at once would be the ability to install new fencing along the edge of the tree planting to ensure that vehicles and heavy equipment is kept away from the area around the trees. If staff decides to replace all of the remaining ten trees at one time the costs would be paid from the existing Park and Open Space Emergency Repair CIP (PG-09002). Once the contracted landscape designer has estimated the cost of new trees, soil preparation, new irrigation, fencing, pathways and other park amenities, staff will return to Council with a Budget Amendment Ordinance to allocate additional funds to CIP PG-09002. Timeline: Because of the potential of limb drop during winter storms and because of the prognosis of the trees for additional limb or trunk failure, staff considers this matter to be extremely urgent. CMR:420:10 Page 5 of 5 After the two additional public meetings in December, staff will work closely with Mr. Chau to develop and review final plans and engineer’s estimates for the project. In order to begin replanting at least some of the trees to fill in where trees have been removed, staff will endeavor to finalize the replanting plan (and any associated BAO for additional funds) by mid-January so that trees could be planted by the end of January 2011. RESOURCE IMPACT There are no resource impacts at this time. As plans are developed for the removal of additional trees, grinding of the tree stumps, planting of replacement trees, installation of new irrigation systems, pathways and other park amenities, staff will return to Council with a Budget Amendment Ordinance to add funds to Capital Improvement Project PG-090002 (Park and Open Space Emergency Repairs) for this work. POLICY IMPLICATIONS Development of strategies to evaluate the care or replacement of trees at Eleanor Pardee Park is consistent with the Governance Section of the Comprehensive Plan, Program G-9: “Where feasible, assist residents with neighborhood improvement, beautification, and planting projects,” and with Natural Environment Section of the Comprehensive Plan, Program N-17: “Develop and implement a plan for maintenance, irrigation, and replacement of trees in parks, parking lots, and City rights-of-way.” ENVIRONMENTAL REVIEW The actions summarized in this report do not meet the definition of a “project,” therefore no California Environmental Quality Act (CEQA) review is required at this time. Attachment A: City Arborist’s Report: Eleanor Pardee Park Eucalyptus and Redwood Maintenance Recommendations, E. Krebs, March 2, 2010 Attachment B: City Manager Memo to City Council, May 9, 2010 Attachment C: Independent Arborist’s Report: Evaluation of Ten Eucalyptus Trees, Eleanor Pardee Park, Dryad, LLC (T. Young), August 5, 2010 PREPARED BY: GREG BETTS Director, Community Services Department CITY MANAGER APPROVAL: PAMELA ANTIL ASSISTANT CITY MANAGER March 2, 2010 Eric Krebs eric.krebs@cityofpaloalto.org City of Palo Alto (650) 496-6905 Public Works Managing Arborist Page - 1 - of 12 Eleanor Pardee Park Eucalyptus and Redwood Maintenance Recommendations Report Prepared for: Greg Betts City of Palo Alto Director of Community Services Prepared by: Eric Krebs City of Palo Alto Managing Arborist March 2, 2010 March 2, 2010 Eric Krebs eric.krebs@cityofpaloalto.org City of Palo Alto (650) 496-6905 Public Works Managing Arborist Page - 2 - of 12 Background/Summary In response to safety concerns expressed by Palo Alto residents, I performed an inspection of the Eleanor Pardee Park eucalyptus trees and one redwood tree. My recommendation is to preserve ten of the sixteen eucalyptus trees and to remove six. I am also recommending the removal of one redwood tree that is in very poor condition. The individual tree conditions and supporting rationale are discussed in the Observations portion of this report. My inspection was performed from the ground and this report reflects only the information I noted from this perspective. Most of these trees are very large and it is difficult to provide a thorough evaluation from ground level. If the City adopts my recommendation, a more comprehensive inspection will be performed during climbing/pruning operations. While the need for maintenance is clear, I did not find obvious signs of imminent hazards. The trees are tagged with numbers that correspond to the City’s tree inventory. A map is included for easy reference to individual trees (see Attachment A). Observations Tree #1 Species: Eucalyptus viminalis Size: Diameter at breast height (DBH) = 53” Height (per PWE Survey) = 94’ Canopy spread = average 70’ Past pruning was limited to the more horizontal branching. The remainder of the tree’s structure was left to grow naturally. There are branches with heavy end weights throughout the canopy. No obvious or imminent hazards are noticeable. The most recent maintenance was in September of 2006. Maintenance included pruning and an aerial inspection. The health appears to be good. Recommendations: Safety Prune (See Pruning Recommendations) Tree #2 Species: Eucalyptus viminalis Size: DBH = a multiple of three trunks originating below 4.5 feet (M/3); 31”, 22” and 17.5” March 2, 2010 Eric Krebs eric.krebs@cityofpaloalto.org City of Palo Alto (650) 496-6905 Public Works Managing Arborist Page - 3 - of 12 Height (per PWE Survey) = 31’ Canopy spread = average 25’ This tree was topped in July of 2000. Rapid regrowth of branches at the topping cuts are weakly attached to the parent stems. Fungal fruiting bodies were found on the base of the tree. Field identification indicated a well- known and aggressive wood decay pathogen, sulphur fungus (Laetiporus sulphureus). The most recent maintenance was in September of 2006. Maintenance was limited to an inspection. Recommendations: Due to the aggressive nature of this wood decay pathogen, my recommendation is removal. Tree #3 Species: Eucalyptus viminalis Size: DBH = M/4; 26”, 21”, 19” and 13” Height (per PWE Survey) = 60’ Canopy spread = average 25’ This tree’s natural form has been maintained. Fungal fruiting bodies (L. sulphureus) were found on the base of the tree. The most recent maintenance was in February of 2010. Maintenance included limb pickup and an inspection. Recommendations: Due to the aggressive nature of this wood decay pathogen, my recommendation is removal. Tree #4 Species: Eucalyptus viminalis Size: DBH = M/2; 19” and 16” Height (per PWE Survey) = 47’ Canopy spread = average 25’ This tree’s natural form has been maintained. Fungal fruiting bodies of sulphur fungus (L. sulphureus) were found on the base of the tree. March 2, 2010 Eric Krebs eric.krebs@cityofpaloalto.org City of Palo Alto (650) 496-6905 Public Works Managing Arborist Page - 4 - of 12 The most recent maintenance was in September of 2006. Maintenance included pruning and an aerial inspection. Recommendations: Due to the aggressive nature of this wood decay pathogen, my recommendation is removal. Tree #5 Species: Eucalyptus viminalis Size: DBH = M/3; 49”, 36” and 26” Height (per PWE Survey) = 134’ Canopy spread = average 60’ Past pruning was limited to the lower branches. The remainder of the tree’s structure was left to grow naturally. There are branches with heavy end weights throughout the canopy. No obvious or imminent hazards are noticeable. The most recent maintenance was in September of 2006. Maintenance included pruning and an aerial inspection. The health appears to be good. Recommendations: Safety Prune (See Pruning Recommendations) Tree #6 Species: Eucalyptus viminalis Size: DBH = 57” Height (per PWE Survey) = 90’ Canopy spread = average 40’ Past pruning was limited to the lower branches. The remainder of the tree’s structure was left to grow naturally. There are branches with heavy end weights throughout the canopy. No obvious or imminent hazards are noticeable. The most recent maintenance was in September of 2006. Maintenance included pruning and an aerial inspection. The health appears to be good. Recommendations: Safety Prune (See Pruning Recommendations) March 2, 2010 Eric Krebs eric.krebs@cityofpaloalto.org City of Palo Alto (650) 496-6905 Public Works Managing Arborist Page - 5 - of 12 Tree #7 Species: Eucalyptus viminalis Size: DBH = 48” Height (per PWE Survey) = 31’ Canopy spread = average 20’ This tree was topped in July of 2000. Rapid regrowth of branches at the topping cuts are weakly attached to the parent stems. Fungal fruiting bodies (L. sulphureus) were found on the base of the tree. The most recent maintenance was in November of 1995. Maintenance included pruning and an aerial inspection. Recommendations: Due to the aggressive nature of this wood decay pathogen, my recommendation is removal. Tree #8 Species: Eucalyptus viminalis Size: DBH = 64” Height (per PWE Survey) = 62’ Canopy spread = average 50’ This tree was topped in July of 2000. Rapid regrowth of branches at the topping cuts are weakly attached to the parent stems. Fungal fruiting bodies (L. sulphureus) were found on the base of the tree. Recommendations: Due to the aggressive nature of this wood decay pathogen, my recommendation is removal. Tree #9 Species: Eucalyptus viminalis Size: DBH = 56” Height (per PWE Survey) = 125’ Canopy spread = average 40’ March 2, 2010 Eric Krebs eric.krebs@cityofpaloalto.org City of Palo Alto (650) 496-6905 Public Works Managing Arborist Page - 6 - of 12 Past pruning was limited to the more horizontal branching. The remainder of the tree’s structure was left to grow naturally. There are branches with heavy end weights throughout the canopy. No obvious or imminent hazards are noticeable. The most recent maintenance was in September of 2006. Maintenance included pruning and an aerial inspection. The health appears to be good. Recommendations: Safety Prune (See Pruning Recommendations) Tree #10 Species: Eucalyptus globulus Size: DBH = 42” Height (per PWE Survey) = 122’ Canopy spread = average 35’ Fungal fruiting bodies (L. sulphureus) were found on the base of the tree. The most recent maintenance was in July of 2000. Maintenance included pruning and an aerial inspection. Recommendations: Due to the aggressive nature of this wood decay pathogen, my recommendation is removal. Tree #11 Species: Eucalyptus globulus Size: DBH = 37” Height (per PWE Survey) = 72’ Canopy spread = average 35’ Past pruning was limited to the more horizontal branching. The remainder of the tree’s structure was left to grow naturally. There are branches with heavy end weights throughout the canopy. No obvious structural defects are noticeable. The most recent maintenance was in September of 2006. Maintenance included pruning and an aerial inspection. The health appears to be good. Recommendations: Safety Prune (See Pruning Recommendations) March 2, 2010 Eric Krebs eric.krebs@cityofpaloalto.org City of Palo Alto (650) 496-6905 Public Works Managing Arborist Page - 7 - of 12 Tree #12 Species: Eucalyptus globulus Size: DBH = 40” Height (per PWE Survey) = 113’ Canopy spread = average 30’ Past pruning was limited to the more horizontal branching. The remainder of the tree’s structure was left to grow naturally. There are branches with heavy end weights throughout the canopy. No obvious or imminent hazards are noticeable. The most recent maintenance was in September of 2006. Maintenance included pruning and an aerial inspection. The health appears to be good. Recommendations: Safety Prune. (See Pruning Recommendations) Note: Special attention should be given to the limbs that are oriented towards and located above the playground. Tree #13 Species: Eucalyptus globulus Size: DBH = 41” Height (per PWE Survey) = 96’ Canopy spread = average 35’ Past pruning was limited to the more horizontal branching. The remainder of the tree’s structure was left to grow naturally. There are branches with heavy end weights throughout the canopy. No obvious or imminent hazards are noticeable. The most recent maintenance was in September of 2006. Maintenance included pruning and an aerial inspection. The health appears to be good. Recommendations: Safety Prune (See Pruning Recommendations) Tree #14 Species: Eucalyptus globulus March 2, 2010 Eric Krebs eric.krebs@cityofpaloalto.org City of Palo Alto (650) 496-6905 Public Works Managing Arborist Page - 8 - of 12 Size: DBH = 36” Height (per PWE Survey) = 87’ Canopy spread = average 40’ Past pruning was limited to the more horizontal branching. The remainder of the tree’s structure was left to grow naturally. There are branches with heavy end weights throughout the canopy. No obvious or imminent hazards are noticeable. The most recent maintenance was in September of 2006. Maintenance included pruning and an aerial inspection. The health appears to be good. Recommendations: Safety Prune (See Pruning Recommendations) Tree #15 Species: Eucalyptus globulus Size: DBH = 40” Height (per PWE Survey) = 87’ Canopy spread = average 45’ Past pruning was limited to the more horizontal branching. The remainder of the tree’s structure was left to grow naturally. Throughout the canopy many branches have heavy end weights. No obvious or imminent hazards are noticeable. The most recent maintenance was in September of 2006. Maintenance included pruning and an aerial inspection. The health appears to be good. Recommendations: Safety Prune (See Pruning Recommendations) Tree #16 Species: Eucalyptus globulus Size: DBH = 55” Height (per PWE Survey) = 112’ Canopy spread = average 50’ Past pruning was limited to the more horizontal branching. The remainder of the tree’s structure was left to grow naturally. No obvious or imminent hazards are noticeable. March 2, 2010 Eric Krebs eric.krebs@cityofpaloalto.org City of Palo Alto (650) 496-6905 Public Works Managing Arborist Page - 9 - of 12 The most recent maintenance was in September of 2006. Maintenance included pruning and an aerial inspection. The health appears to be good. Recommendations: Safety Prune (See Pruning Recommendations) Note: Special attention should be given to the limbs that are oriented towards the playground. Tree #17 (See tree # 125 on attached map) Species: Sequoia sempervirens Size: DBH = 47” Height (per PWE Survey) = 122’ Canopy spread = average 35’ This tree is in serious decline, I estimated that more than seventy percent of the canopy is dead. An inspection of the root flare indicated that 90 percent of the roots at the surface are dead and in various stages of decay. The dead limbs and the decaying roots make this a hazardous tree. The most recent maintenance was in November 2009. Maintenance included root crown inspection. Recommendations: Based on these findings my recommendation is removal. There is a plaque at the base of this tree identifying that this tree was planted by the Daughters of the American Revolution. Additional outreach is being done with that organization and the tree will not be removed until after the representatives have been consulted with and have agreed with our findings. Discussion In my opinion the risk of limb failures on these trees has a higher degree of probability than the risk of whole tree failure. The likelihood of limb failure is compounded by the type of pruning used in the past to maintain safety. My recommendations are intended to mitigate both whole tree failure and limb failure. Some of the risk can be mitigated by fencing a large portion of the area below the trees that I have recommended for retention. This fencing would also relieve some of the soil compaction that is being caused by foot and vehicle traffic. Soil compaction can negatively impact tree roots March 2, 2010 Eric Krebs eric.krebs@cityofpaloalto.org City of Palo Alto (650) 496-6905 Public Works Managing Arborist Page - 10 - of 12 and over time cause the demise of a tree. (This is a secondary recommendation and depends on Parks Department’s funding.) The most probable targets for limb failures are the areas directly under the trees including the street, parking areas, and the sidewalk. (We can not close the street parking and sidewalk but we can fence the areas between the playground and the sidewalk.) In July of 2000, many of the eucalyptus were topped and major scaffold limbs were headed off to eliminate the possibility of large branches falling into the playground area. This aggressive pruning negatively affected the health and physiology of the trees and made them vulnerable to insects, disease, and decay. The sulphur fungus (Laetiporus sulphureus) was identified on the base of many of these trees. The presence of this decay pathogen is most likely a direct result of the topping and heading cuts. All of the literature I have studied suggests that by the time the fruiting bodies of this fungus appear, the internal decay in the hosting tree is significant enough to warrant removal. My experience supports these findings. Fungicide treatment is an option I considered however it is limited to direct application to the targeted fungi. Even with the invention of systemic fungicides, there use is limited. In this specific case, the pathogen is too involved in the wood for fungicides to be effective. Additionally, given some residents concerns regarding these trees and the proximity of the children’s play area I do not recommend second guessing what is known about the pathogen. Decay in the roots and basal area of a tree increases the risk of whole tree failure. This is not an acceptable risk in a high use area such as the park. The remaining trees are generally in good shape, both in health and structure. While pruning cannot guarantee that we will not have tree failures, it does minimize the risk of retaining such large trees. The pruning that I am recommending is intended to minimize risks while maintaining tree health. With proper care these trees should be viable for many years to come. Recommendations Pruning: Use thinning cuts only. Reduce the height, spread and end weights by pruning back to lateral branches that are large enough to assume the terminal roles (at least one-third the diameter of the cut stem). Do not use heading cuts. Cuts should be limited to a maximum of six inches in diameter. At old failure sites and heading cuts, reconstructive pruning should be used to maximize the strength of the limb to remain. Care should be taken to choose structurally sound limbs. The climber will be expected to thoroughly inspect the tree’s structure and to discuss any abnormalities with the arborist before any cuts are made so that changes to the recommendations can be formulated. Removal: At this time, because of the aggressive nature of the decay pathogen found on tree numbers 2, 3, 4, 7, 8, and 10, I am recommending removal. Trees 2, 4 and 7 will be removed first as they show the greatest signs of the pathogen decay. I will personally inspect those three trees March 2, 2010 Eric Krebs eric.krebs@cityofpaloalto.org City of Palo Alto (650) 496-6905 Public Works Managing Arborist Page - 11 - of 12 as they are removed to observe the amount of decay found within the tree and use that information as another tool to validate my recommendations regarding the remaining Eucalyptus trees currently planned for removal. I will share my findings on the first three trees removed with all interested parties before any work is taken to remove the other three trees. The redwood (tree # 17) is a hazard tree. The only means of mitigation for this hazard is removal. Planting: The removal of the seven trees will create an opportunity to create a planting that will provide aesthetics, shade, and reduced risk in the play area. The Parks Department and Public Works Arborist will need to discuss the possibility of fencing the areas between the sidewalk and the playground. Once this is accomplished, we can choose suitable tree species and locate appropriate sites. Schedule for work: Timing to perform this work will be difficult because of the recent layoff notices received by several members of the Public Works Tree Crew. Public Works still plans to use in-house crews to do this work because of the large size of the trees as well as to maintain better trimming practices by using our experienced crews. No work will begin until we receive authority from the City Managers office to move forward. Once approval is received the 14-day notices posted on the removal trees will go into affect. After the 14 waiting period is over, and assuming no other issues arise to delay the work, Public Works crews would start on the trimming and removal work immediately. If approval of this project is delayed we may need to switch to using contractors to trim these trees. As we currently do not have this project in any contract scope we will need to proceed with the normal contracting process which could add 2- months for competitive bidding and possible City Council Approval depending on cost. We estimate work on this project will take 3-4 weeks to complete. Conclusion Providing safety for the City of Palo Alto’s residents and visitors is always our primary objective, but we cannot guarantee that trees will be safe. We use our professional judgment and experience to manage the risks associated with living with trees. From my visual inspection of the trees mentioned in this report, I feel that the trees I recommended for retention can be reasonably managed and that my recommendation to remove seven trees is based on sound arboricultural judgment. The trees that I am recommending for retention have no obvious signs that indicate they should be removed. The recommended pruning is targeting safety issues such as heavily weighted limbs. Fencing the areas under the trees will further minimize the risk of injury due to falling limbs and provide for better tree health. The trees that I am recommending for removal are considered hazardous due to decay in the roots and basal areas. I considered other means of mitigation, but concluded that the potential for catastrophic whole tree failure is too high and that, considering the target area, it would not be prudent to maintain these trees. March 2, 2010 Eric Krebs eric.krebs@cityofpaloalto.org City of Palo Alto (650) 496-6905 Public Works Managing Arborist Page - 12 - of 12 My investigation did not include a comprehensive study to quantify the extent of the decay or the limb attachment strength to limb weight ratio. However, I believe that the evidence collected during my visual tree assessment supports my recommendations. Respectfully submitted, Eric Krebs Public Works Managing Arborist ISA Certified Arborist # WC-829 Member of American Society of Consulting Arborists From: James Keene [James.Keene@cityofpaloalto.org] Sent: Sunday, May 09, 2010 7:19 PM To: Burt, Patrick; Espinosa, Sid; Price, Gail; Shepherd, Nancy; Scharff, Greg; Schmid, Greg; Klein, Larry; Yeh, Yiaway; Holman, Karen; Burt, Patrick (external) Cc: Antil, Pamela; Emslie, Steve; Clerkson, Linda; Roberts, Glenn; Betts, Greg; Dornell, Paul Subject: Planned Tree Removal At Eleanor Pardee Park REPORT and Recommendations Importance: High Attachments: Before_and_After_Photos Final (2).doc; ATT3432353.htm; Eleanor Park Eucalyptus MAintenance and Removals (2).doc; ATT3432354.htm Mayor Burt and Council Members: Attached is the final revised report from Public Works and the City Arborist regarding the Pardee Park tree removals. You will note from the report that after several meetings with residents both in favor of keeping AND removing the trees, staff has concluded that the best approach would be to remove six (6) of the trees in phases. The report outlines specific inspection observations and recommendations for each tree. Pruning directions and recommendations for each tree are outlined in the last few pages of the report. The overriding reason for the recommended removals is the identification of an aggressive wood decay pathogen (sulphur fungus) which was observed on the six Eucalyptus trees in question. At this time staff recommends removal of six (6) Eucalyptus trees. The removal process will be to take down three of the more severely impacted trees first and evaluate the amount of damage. Staff will report to all interested parties on our findings before any further work is done. If the condition of the first three trees is as we expected we would then proceed with the other planned removals. Our Managing Arborist has considered the use of fungicides as an alternative to removal. All accredited literature that has been studied states that the presence of fruiting bodies on the external surfaces of the trees indicates that substantial internal decay is already present which can lead to whole tree failures. Fungicide treatment is limited to direct application to the targeted fungi. Even with today's improved systemic fungicides, their use is limited. In this case, the pathogen is too involved in the wood for fungicides to be effective. In addition, with regard to the gentleman’s comment at our last Council meeting about how the trees are pruned, the City Arborist has confirmed in the report that the trees had been pruned severely in the past so the report confirms that there will be no heading cuts in future prunings. The report also acknowledges the impact to some of the trees from previous pruning and the work we plan to do this year will avoid that problem. The previous trimming that was performed 10-years ago was done under the direction of a previous arborist. Also attached are before and after photographs which reflect what the park area will look like with the six Eucalyptus trees removed. It is the combined recommendation from both Community Services and Public Works Departments that we move forward with implementing the Arborists recommendations. We’d like to do that as soon as next week if possible. The staff had placed signs out a few weeks ago indicating that tree trimming and tree removal ( limited now to three trees in the first phase and a potential total of six all together) could occur within 14 days. Page 1 of 4 11/17/2010file://C:\Documents and Settings\kwhitle\Local Settings\Temporary Internet Files\OLK8... That time has come and gone. I had informed staff that no tree removal was to occur until I had issued a direct okay. As you know from email traffic and other commentary, there are a range of opinions, from taking down all trees to none. The staff recommendation presented here is the most prudent course, I believe. Unless I hear otherwise from you, we will proceed with moving forward as recommended at the end of this coming week. I will mention this fact again on May 10 during City Manager comments at the Council meeting. Again, we will take down three trees late this week. The remaining three will not be taken until there is further evaluation, and seeing how they do. I expect those will probably come down too, but the most immediate concern, I am advised, is for three of the trees. I will inform you in advance of the final three tree removal, and when that may occur. Please look at the before/after pics that show what six tree removal will be (word attachment at end of report) Please let me know if you have any questions. Jim Report From CSD and Public Works regarding Tree Trimming and six trim removal recommendation at Pardee Park (Report itself is Word attachment at end) In January of this year a resident contacted Public Works-Operations to report a fallen limb from a Eucalyptus tree at Eleanor Pardee Park. The resident also reported that he had discussed his concerns with other park users, about spontaneous tree limb failure during a significant wind storm. In the following days residents contacted both Public Works and Community Services asking for information on these trees. To address the residents' concerns, city staff held a meeting for residents on February 24th, 2010 with Managing Arborist Eric Krebs, Parks Manager Robert Ward, Community Services Director Greg Betts, Public Works Operations Manager Sean Kennedy and five residents. Staff listened to various residents' views about the sixteen Eucalyptus trees in the vicinity of the children's playground. Two residents spoke out in favor of removing all of the Eucalyptus trees, one person spoke out in favor of keeping the trees, and the other residents wanted to know what the City planned to do. Eric Krebs, Managing Arborist, said he inspected the trees and he saw no immediate hazard. He also stated that he was working on a mitigation plan to address the concerns of the residents regarding the trees. A second meeting was scheduled once the Managing Arborist had an opportunity to finish the health and viability analysis of the trees and prepare recommendations for an action plan to ensure the safety of the park, playground and adjoining sidewalks. Prior to the second meeting, outreach notifications containing the date, time and location of the follow- up meeting were sent to each person who had corresponded with city staff up to that point. Additionally, public notices were posted at numerous locations around the park, e- mails were sent to the Crescent Park and Eleanor Pardee Park neighborhood associations, and copies of the notices were sent to the City Council, City Manager, and City Communications Manager. Page 2 of 4 11/17/2010file://C:\Documents and Settings\kwhitle\Local Settings\Temporary Internet Files\OLK8... The follow-up community meeting was held on Thursday evening, March 11th, 2010 at 5:30 PM at Eleanor Pardee Park. In addition to the staff that attended the first public meeting, the second meeting was also joined by Public Works Assistant Director, Paul Dornell. Seven residents attended the second meeting in which the Managing Arborist explained his proposed plan as we walked through the area. The meeting was held after "regular" working hours but still during daylight hours to allow interested parties an opportunity to look at the trees and hear the Arborist's presentation on the actions proposed for each tree. Of the residents that either attended the meetings or reviewed the Arborist's staff reports, three residents were in favor of complete removal of all of the Eucalyptus trees surrounding the play area, three residents said they were opposed to any removals unless absolutely necessary and six residents reviewed and approved the Arborist's plan for a blend of removals based on individual inspections and retaining and trimming the remainder of the trees. Palo Alto has a very good municipal tree program that involves rigorous inspection and pruning cycles. No tree is devoid of some small level of risk. Elimination of all risk, even a small and acceptable one, would be impossible. The City of Palo Alto does not have a policy, nor should it have one, to remove trees on the basis of their species. The City of Palo Alto has established a policy for determining when a tree is unsafe and a possible threat to the public health, safety, and welfare. The Tree Technical Manual from June 2001 identifies: "A hazardous tree is defined as a tree that possesses a structural defect that poses an imminent risk if a tree or part of a tree would fall on someone or something of value." Our practice has been to have a certified Arborist inspect and determine a recommended specific course of action based on sound arboricultural science, experience, and judgment, and then to follow those recommendations. In this case, the Arborist's report that is attached recommends specific actions for each tree which are designed to make the park safe for its continued use by the public. Taking the Arborist's report as our main source of information and listening to input from residents who met with us, we believe that the removal of the selected trees found to be in poor health and structural pruning of the majority of the trees is the proper course of action. Mr. Krebs also met on site with Dave Dockter, Managing Arborist from the Planning Division, who corroborated Mr. Krebs' findings and agreed with the recommended course of action. This location will be placed on an annual inspection schedule due to its proximity to the play area in the park as well as the residents' concerns regarding these specific trees. In addition to the Arborist's recommendations to address tree concerns, City staff has also agreed to install a split-rail type fence just behind the sidewalk to deter pedestrians from walking directly under these trees. This fencing will also prohibit vehicular traffic from compacting the soils and driving too close to the trees, which will allow for improved ground conditions. It was pointed out by a resident at one of the neighborhood meetings that several years ago the City made the decision to prohibit parking along the Channing Avenue side of the park. Residents that drive to the park now use the Center Avenue side to enter the park. By removing selected trees on the Center Avenue side and installing a split-rail fence, a new "gateway" can be constructed into the play area. We have attached before and after photographs which reflect what the park area will look like with the six Eucalyptus trees removed. We have also attached the Arborist's report which outlines specific inspection observations and recommendations for each Page 3 of 4 11/17/2010file://C:\Documents and Settings\kwhitle\Local Settings\Temporary Internet Files\OLK8... tree. Pruning directions and recommendations for each tree are outlined in the last few pages of the report. The overriding reason for the recommended removals is the identification of an aggressive wood decay pathogen (sulphur fungus) which was observed on the six Eucalyptus trees. At this time we are recommending removal of 6 Eucalyptus trees. Our removal process will be to take down three of the more severely impacted trees first and evaluate the amount of damage. We will report to all interested parties on our findings before any further work is done. If the condition of the first three trees is as we expected we would then proceed with the other planned removals. Our Managing Arborist has considered the use of fungicides as an alternative to removal. All accredited literature that has been studied states that the presence of fruiting bodies on the external surfaces of the trees indicates that substantial internal decay is already present which can lead to whole tree failures. Fungicide treatment is limited to direct application to the targeted fungi. Even with today's improved systemic fungicides, their use is limited. In this case, the pathogen is too involved in the wood for fungicides to be effective. It is the combined recommendation from both Community Services and Public Works Departments that we move forward with implementing the Arborists recommendations. Respectfully Submitted, Paul Dornell, Assistant Director- Public Works Greg Betts, Community Services Director Eric Krebs, Managing Arborist Page 4 of 4 11/17/2010file://C:\Documents and Settings\kwhitle\Local Settings\Temporary Internet Files\OLK8... /i};j. YI AD, LLC 10024·40006 EVALUATION OF TEN EUCALYPTUS TREES ,,' E le anor Pardee Park Palo Alto , C alifornia \ \ ,. \ \ ~ "" \ \ " " , " ' " " " , \ \ I ,., -, \ v / , \ I -, ,\ I I , \, \ " \ \ \ I / ,,-, \ \ \ \ \ , \ I 1\\ 1\'" I , .... " \ ' ..... 1 '" \ .... ' I " \ " \ \ \ \ ) \" \\ ... \' .... _'" Prepared For: \ \,,; Eric Krebs, Ma n a ging Arborist City of Palo Alto 3201 Eas t Bayshore Rd. Pa lo Alto CA 94303 650·496·690 5 , " -, Prepared By : Torrey Young Regi stered Consulting Arborist® 35570 Paloma res Rd . Castro VaUey CA 94552 Phone (877) 206·4001 Fax (510) 538·6001 E-mail tyoung @dryad.us Au gust 5 , 20 10 Dryad, LLC #1002440006 City of Palo Alto Eleanor Pardee Park TREE EVALUATION Table of Contents CLIENT ..................................................................................................................................................... 1 SITE ........................................................................................................................................................... 1 INSPECTION DATES ............................................................................................................................. 1 INTRODUCTION ..................................................................................................................................... I SUMMARy ............................................................................................................................................... 2 DISCUSSION ......................................................................................................................................... 3-4 MANAGEMENT RECOMMENDATIONS .......................................................................................... 5 TREE DATA & TRACE EV ALUA TIONS ......................................................................................... 6-8 TREE LOCATION DIAGRAMS ....................................................................................................... 9-10 PHOTOGRAPHS .............................................................................................................................. 11-34 CERTfFICATfON, STATEMENT & COPyRiGHT ......................................................................... 35 CONSULTANT ....................................................................................................................................... 36 ENDNOTES .......................................................................................................................................... 37-8 + + }fAD, LLC ,0 Copyr'ight 2010,Dryad, LLC + 35570 Palomares Rd . Castro Valley CA 94552 Phone Fax E-mail (877) 206-4001 (510) 538-600 1 tyoung @dryad.us August 5, 20 10 Ory ad,llC #10024-40006 C ity of Pa lo Alto Eleanor Pardee Park TREE EVALUATIONS Client(s) City of Palo Alto '/0 Eric Krebs, Managing Arborist 3201 East 8ayshore Rd . Palo Alto CA 94303 650-496-6905 Site Eleanor Pardee Park Center Dr. & Channing Ave. Palo Alto, California Inspection Dates July 14 & 16, 2010 Introduction I was contacted on June 15, 2010, by Eric Krebs , Managing Arborist for the City of Palo Alto, relative to evaluation 1 of ten Eucalyptus trees at Eleanor Pardee Park. I was subsequently retained' by the City to "Evaluate Trees at Eleanor Park, Independent Consultant for the inspection, evaluation and recommendation of 10 Eucalyptus in Eleanor Pardee Park as required by the City". The trees consist of four manna gums (Eucalyptus viminalis) and five bluegums (Eucalyptus globulus). Not included was one additional tree already scheduled for removal (no. 3). Mr. Krebs indicated that there were strong and active community groups with opposing opinions relative to preservation or elimination of the trees. A Consulting Arborist and resident of Palo Alto, David Muffly, was recently retained by an individual supporting the removal of the trees'. Mr. Krebs provided the following documents and printouts for my review. I also visited the two online sites cited below (Facebook3 and Care2') for confirmation and citation purposes. IPiSi'ifAW, LLC ~(I",p!lrjght :!OlIO, Dryad, LLC Page 1 of30 35570 Palomares Rd . Castro Valley CA 9455 2 Phone (877) 206-400 1 Fax (510) 538-6001 E-ma il tyoung @dryad .us August5,2010 Dryad , LLC #10024-40006 City of Pa lo Alto Eleanor Pardee Park 1. Eleanor Pardee Eucalyptus and Redwood Maintenance Recommendations Report, Eric Krebs, March 2, 2010 . 2. Eleanor Pardee Eucalyptus and Redwood Maintenance Recommendations Report, Eric Krebs, Phase II, June 4 ,2010 . 3. Facebook , Residents for Safe Palo Alto Parks', Question and Answer pa~e by David Muffly . 4. Care2, Replace Eucalyptus Trees at Eleanor Pardee Park; online petition . 5. Eleanor Pardee Park Eucalyptus Maintenance Project documents , RFQ123456, including Section III Scope of Services . I met on site with Mr. Krebs, performed my inspection and photographed the trees on July 16, 2010. This report details and summarizes my evaluation and resulting opinions as to the condition and management of these trees. A number of trees in the vicinity had been recently removed to stumps prior to my inspection. One additional tree (no . 3) is already scheduled for removal and is therefore not addressed in this report. For identification purposes, I refer within this report to the numbers on existing aluminum tags attached to the trees. The ten trees included are nos. 1, 5, 6, 9 and 11-16. Summary The ten trees addressed in this report are very large, well-established trees. They appear to have experienced similar pruning over many years, including a recent pruning in 2010. They display a myriad of conditions worthy of concern, remarkably similar between all trees. The majority of these conditions cannot be remedied, and the extent to which they can be mitigated is minimal. There is currently a significant potential for failure of smaller limbs and branches, as well as potential for large limbs and stems eventually to fail. The presence of extensive trunk decay from sulfur fungus (Laetiporus gifbertsonii)' combined with external related signs in standing trees suggests there is also potential for whole tree failures. It is my opinion that the high·traffic nature ofthe site combined with the method and long-term impacts of previous pruning renders inevitable the need to eventually remove these trees. In consideration of that conclusion , there are only two viable management options: 1) Develop a long-term phased removal and replacement plan, including regular risk reduction pruning. Root crown excavation and inspectionS, Resistograph® testing " and mapping of basal decay should be performed on every tree before developing removal priorities. 2) Remove all ten trees, redesign the site landscape including judiciously selected shade tree species and specimens, as well as growing area culture and protection (fencing). A third option, retaining the trees indefinitely, is possible, but inconsistent with my observations and conclusions relative to the condition of these ten trees. Regular and judicious pruning could reduce but not eliminate the potential for failures and resulting damages or injury. t do not recommend indefinite retention of any of these trees. + + + LLC M!JOPVriot,t2(110 .Dryad, LLC Page 2 of38 35570 Palomares Rd. Cast ro Valley CA 94552 Phone (877) 206 -4001 Fax (510)538 -6001 E -mail tyoung @dryad .us August 5, 2010 Dryad, LLC #10024-40006 City of Palo Alto Eleanor Pardee Park Discussion These trees are very large and majestic, providing critical shade to community park and playground as well as adjacent homes and streets. Unfortunately , this very size and location also renders them a significant risk. All large landscape trees, regardless of species or condition, present some degree of risk in proximity to people , vehicles , structures and utilities . Some risk is often accepted in consideration of the dramatic aesthetic and functional benefits of living with large trees . However , this site presents multiple targets to tree failures including pedestrians and park users, adjacent utility lines and residential streets and parking as well as homes. Whole tree failure would inevitably result in catastrophic damage with a high risk for injury as well. The most serious conditions of these trees can be attributed to inherent species character combined with pruning 10 technique and enhanced by site use and conditions. Pruning: Pruning, from many years ago to the very recent, has resulted in structure" and architecture" that cannot be remedied . Pruning techniques appear to have been consistent over the years . Specifically , a combination of topping , profuse heading cuts, cuts to right-angle leaders , lion's-tailing, excessive thinning and a failure to improve structure and architecture (e .g., acute-angled attachments, preserving lateral limbs). All of these pruning methods result in an increasing potential for limb and stem failures. Heading cuts are cuts either between nodes or branches (creating stubs), or to new leaders too small to assume the terminal role. Large enough to assume the terminal roles is considered a leader of between one-half and one third the diameter of the adjacent pruning cut. Lesser proportions have an enhanced susceptibility to decay, and in species that sprout -weakly attached, dense regrowth, and thus an increased potential for failures . Some headed limbs and stems will die outright. The heading (and topping) cuts are prevalent in these ten trees . The effects of heading were enhanced by cutting to leaders with poor architecture, e.g ., wide, or right-angled attachments. Topping is the removal of the leading portion of althe primary stem 13 via a heading cut. Such cuts typically result in decay at the pruning cut and in species that sprout, poorly attached, dense regrowth subject to failure . Virtually all the trees, with the possible exception of no. 16, have suffered such cuts years ago and recently. The effect , in addition to those described for general heading cuts, is that tree architecture is permanently and seriously altered . In many cases, this effect is irreparable . Lion's-tailing consists of removing the majority of internal foliage and lateral limb architecture, leaving only a small volume of foliage at the end . Lack of foliage along the height or length of limbs and trunks reduce the ability to develop taper", which reduces strength . It also concentrates stress and weight at the end of limbs, with no lower or interior bufferinq of wind possible. The lion 's-tailing of these trees has eliminated most lateral branching and lower scaffold limbs 5 alleviating any possibility of effective crown reduction". Manna gums (#1-9) already have a natural propensity to retain few lateral limbs , character which has been enhanced by this pruning. Excessive thinning, in addition to the architectural and structural issues discussed above, removal of large volumes of foliage , reduces the tree's ability to produce carbohydrates for energy (photosynthesis). Less carbohydate production thus reduces their ability to recover from pruning and resist insects, disease, decay and environmental impacts. While the short-term effect reduces weight and wind resistance, thinning also changes the way limbs move in the wind as well as increasing exposure, thus enhancing the potential for small branch and limb failures . Most lower scaffold limbs and interior growth has been eliminated from these trees over the years, reducing the ability of the trees to buffer the stress of wind and enhancing the potential for whole tree failure. MlJl'PYJight 201 0, Dryad, llC Page 3 0138 35570 Palomares Rd . Castro Valley CA 94552 Phone (877) 206 -4001 Fax (510) 538 -6001 E-ma il tyoung @dryad.us August 5, 20 10 Dry ad, LLC #10024-40006 City of Pa lo Alto Eleanor Pardee Park Acute-angled attachments originale al a close angle to Ihe parent slem or limb , inlerfering wilh growth in Ihe area belween, where bark remains . Such attachmenls are exlremely prone to failure and should be eliminaled when very small. Sulfur fungus (Laetiporus gilbertsonii)": Exlensive decay from Ihis heart-rot fungus compromises both Irunk slrength , and supportive roots. This pathogen typically enters through large wounds, including topping and heading cuts and damaged roots, all of which are prevalent in these trees. The decay from this fungus will continue to spread and is not treatable . It is not unusual to condemn infected trees by virtue of its mere presence. In the interest of phased removals, Resistograph®'8 testing and diagramming of the results could establish a basis for prioritizing removals. The presence of vigorous ribs of reaction wood" at the base of several trees (e.g ., #5 & 6) suggests basal decay severe enough to increase stress on the remaining outer shell of the trunk. These two trees are thus particularly suspect as having the potential for whole tree failure . Resistograph ® testing is warranted . Site use and management: The soil throughout the growing area of these trees is bare of organic material (mulch) and heavily compacted . These conditions are not conducive to tree health , likely contributed to susceptibility to the decay pathogen, and reduced ability to compartmentalize large cuts . Compaction interferes with root gaseous exchange, reduces infiltration of water , and increases soil temperatures damaging existing roots and rendering new root development difficult. TRACE'· Risk Assessment: Included in this report (Data chart, pg .6) are Risk Assessment ratings developed following the Pacific Northwest Chapter ISA's Certified Tree Risk Assessor Program protocol. This information was included for informational purposes only and is not the basis of my conclusions or recommendations . This process is based upon identifying only the tree part most likely to fail soonest, rather than the largest , most serious or with the most potential for serious damage or injury . The majority of the ten trees addressed in this report have short term potential for minor failures and long-term potential for failure of large parts that could result in serious damage andlor injury . Cost Considerations: 1) A long-term phased removal plan would require substantial and continuous maintenance . The current cost of debris clean-up for a profusely-shedding species (Eucalyptus) would be reduced as trees are removed , but not eliminated. The substantial cost of removal would be experienced over a long-term duration . A slight increase in removal costs might result from the need to protect new plantings and design elements. Replanting costs and resulting maintenance would also be experienced over a long-term duration. 2) Removing all ten trees at once and promptly replanting would entail substantial cost in a short duration. The benefits of large landscape trees would also be lost for many years. The substantial cost of maintenance, including constant debris clean -up would be eliminated . The risk of these trees would be eliminated, along with any financial exposure the City of Palo Alto and its agents or contractors might experience should failing trees or tree parts result in serious damage or injury . Further, a well-planned and maintained replacement landscape results in little maintenance needs or associated costs . The asset feature of the trees would be lost, but eventually regained as a well -designed landscape takes its place , without the substantial risk represented by the existing trees . + + + ~ioPI"jgl't2010, Dryad, LLC Page4of38 35570 Palomares Rd . Castro Valley CA 94552 Phone Fax E-mail (877) 206-4001 (510) 538-6001 tyoung@dryad.us August 5 , 20 10 Dryad , llC #10024-40006 City of Pa lo Alto Elea nor Pard ee Par k Management Recommendations 1) Management recommendations for trees retained: the following are recommendations for the management of any trees to be indefinitely retained or retained over a phased removal approach . Although these efforts can enhance tree health and reduce risk , they cannot eliminate risk . Some conditions , regardless of preservation efforts, will continue to worsen and increase risk. a) Root crown excavations and inspections should be performed on all trees along with Resistograph® testing of supporting roots . Inspection should be possible around the origination area of the trunk and supporting buttress roots to a depth of at least six-twelve inches below the current grade . The intent is to determine the condition and distribution of the supporting root system . b) Resistograph® testing should be performed at the base of each trunk circumferentially and at any specific location suggesting decay or fractures , as well as vertically on significant supporting roots . Sound wood depths can be used to diagram any discovered internally decayed areas . c) Prioritize trees for removal based upon plan duration, City tolerance of risk and tree condition . d) Remove promptly any and all trees found to be at immediate risk for whole-tree failure . e) Mitigate soil compaction in the area beneath the trees, roughly from sidewalk to playground . Soil cultivation/aeration can be achieved in the least damaging manner using a radial trenching technique via an air knife tooi" (pneumatically driven). I) Mulch" the area beneath the trees, roughly from sidewalk to playground, with 3-4" (seUled depth) of organic mulch . Maintain the mulch layer permanently and enhance on a regular basis . g) Perform crown-reduction pruning, including of elimination of limbs structurally at risk, on at least a biannual basis. Allow interior and lower growth to develop, selectively leaving occasional sprouts to be nurtured into substantial lateral branches . 2) Management recommendations for removal and replacement: the following are recommendations relative to complete removal and replacement of all ten trees, or for incorporation into a long -term phased removal plan . Not included are any recommendations for construction elements, or design for aesthetics or usage beyond the selection and handling of replacement trees . a) Remove all trees to grade and grind completely all stumps and roots within approximately ten feet of the center of each trunk or anywhere visible at grade . b) Mitigate soil compaction in the area beneath the trees, roughly from sidewalk to playground . Tilling is acceptable except in the vicinity of trees or shrubs to remain . In those areas, employ radial trenching only via an air knife tool (12-18 " depth). c) Replant with native species , Native species can reduce maintenance needs while providing enhanced aesthetics and functional value. I recommend a combination of native trees and shrubs found in the area : i) California live oaks (Quercus agrifolia) plant two or three to the north and northwest , mid-way between sidewalk and playground , to allow for maximum growing space . ii) Valley oak (Quercus /obata) and/or California black oak (Quercus keloggil) plant two to four to the south and west, to provide shade in the summer and allow for sunlight penetration when leaves are lost in winter . iii) California coast redwood (Sequoia sempervirens) replace the grandeur of large trees by planting eight to twelve specimens, allowing maximum space between trees and oaks . d) Mulch the area, roughly from sidewalk to playground, with 3-4 " (settled depth) of organic mulch . Maintain the mulch layer permanently and enhance on a regular basis . Avoid planting of turf, groundcovers or any plants requiring frequent irrigation beneath trees . e) Install permanent protective fencing, sufficient to protect much of the dripline areas of trees, while allowing for use of and access to the area . I) Maintenance: i) Irrigate only during establishment (1-3 years) ii) Maintain continuously an organic mulch layer throughout the planting area . iii) Perform only minor, structural , corrective pruning of oaks and as necessary for clearance . iv) Avoid pruning of redwoods altogether. If pruning is preformed , limit to removal of dead branches and needles, structural improvements (e .g ., codominant stems) and broken limbs . LLC @C:OP!lriQlht:!0110 ,Dryad, llC Page50f38 35570 Pa lomares Rd . Cas tro Valley CA 94552 Phone Fax E-mail (877) 206·4001 (510) 538-600 1 tyoung@dryad.us August 5, 2010 Dryad , LLC #10024-40006 Ci ty of Pal o Alto Eleanor Pardee Park Tree Data & TRACE Evaluations NOTE : The TRACE Evaluation Ratings and descriptions are included only for informational purposes , and are not the basis of an y of the conclusions or recommendations included in this report. The TRACE process is based upon the single part with the most imminent potential for failure. Each of these ten trees has multiple parts with potential for failure , all of which have been considered in this report . Identification Trunk diameter TRACE Evaluation" , I Conditions and No Genus-Species DBH24 Observations Rated Defect25 Probability Part Ta r get Risk TRACE Risk (most likety part to tail) (1-5) Size Rating Rating Description" (1-3) (1-4) (1-12) (summarized ) • Codominant stems • Acute-angled attachments -6" diameter limb , Moderate 3 , Euca lyptus • Decayed pruning cuts • Topping cuts poor taper , lion's-Well defined 1 viminalis 55 • Old and recent heading cuts tailed and headed at issues -retain manna gum • Lion 's tailing (old & recent) 4 2 2 8 • Right-angled new leaders tip to opposing and monitor , • Poor taper of limbs laterals. no concern for • Limb curvature 1-2 years. • Codo minant stems 48 + 36 + 26 • Acute-angled attachments Extreme , Eucalyptus • Decayed pruning cuts -6" diameter limb , Failure is 5 viminalis (81 in. diameter • Old and recent heading cuts manna gum at 36 " abo ve • Right-angled ne w leaders poor taper , lion's-4 2 4 10 occurring - grade ) • Poor taper of limbs tailed. Immediate • Limb curvature action is • Lion's tailing (old & recent) required. • Codominant stems • Acute -angled attach ments • Decayed pruning cuts Leaning , codominant High 2 , Issues Eucalyptus • Topp ing cuts • Old and recent heading cuts stem with acute-clear - 6 viminalis 58 • Lion 's tailing (old & recent) angled attachment mitigation 4 2 4 10 manna gum • Right-angled new leaders with decay ; lion's-measures be • Poor taper of limbs & curvature tailed ; poor taper ... on a timeline for action. • Reaction wood with kino exudino at base © Copyright 20 1 0 , Dryad, LLC Page 6 of 38 August 5, 2010 Dryad, LLC #10024-40006 City of Palo Alto Eleanor Pardee Park Identi f icat i on No Genu s -Spec i es Eucalyptus 9 viminalis mann a gum Eucalyptus 11 glo b ulus blueg um Eucalyptus 12 globulus bluegu m Eu calyptus 1 3 globulus b lue gu m © Copyright 2010 , Oryad, LLC T runk d iameter DBH " 56 37 4 0 4 1 Condi t ions and Observations • Acute-angled attachments • Decayed pruning cuts • Old and recent heading cuts • Lion's taiting (old & recent) • Right-angled new leaders • Topping cuts • Poo r ta per of limbs • Limb cUivature • Reaction wood with kino exudin o at base • Codominant stem @ 30 ° over street • Acute-angled attachments • Oecayed pruning cuts • Topping cuts • Old and recen t heading cuts • Li on 's taiting (old & recent) • Right-ang led new leaders • Poor taper of li mbs • Limb curvature • Codomi nant tops • Acute-a ngl ed attachments • Old and recent heading cuts • Right-angled new leaders • Topping cuts • Poor taper of limbs • Limb curvature • Lio n's tai ling (old & recent) • Codominant stem & tops • Acute-angled attachments • Decayed pruning cuts • Topping cuts ' Old and recent head ing cuts' Lion's tailing (old & re cent) • Right-angled new leaders • Poor tape r of limbs· Limb curvature • Root dama ne/qird ling root(s) TRACE Eva l uation 23 Rated Defect 25 Probability Pa rt Ta rget Risk TRACE Ri sk (most likely part to fail) (1-5) Size Rat ing Rating Desc ri ption" (1 -3) (1 -4 ) (1-12 ) (summarized) H igh 1, Issues -6" diame ter li mb , are cl ear - poor t aper , lio n's -4 2 3 9 reta in b ut ta il ed . monitor annu all y. Mo de rate 3 , -4" d ia m eter limb, W e ll d efin ed i poor ta per, li o n's-i ss ue s -re tain 3 1 4 8 ta ile d . a nd m o nito r, no co nce rn for 1-2 y ears . High 1, Is sues -6" dia meter lim b, are cle ar- poo r t aper , li o n's -3 2 4 9 re tai n but tai le d. mo nito r annua lly. M od erat e 3 , -4 " di a meter limb , W ell de fin ed poo r tape r , lio n's-3 1 4 8 is s ues - ret ain tail e d. and monitor , no co nc ern f or 1-2 ye ars. Page 70f38 August 5, 2010 Oryad, LLC #10024-40006 City of Palo Alto Eleanor Pardee Park Identification No Genus-Species Eucalyptus 14 globulus bluegum Eucalyptus 15 globulus bluegum Eucalyptus 16 globulus bluegum © Copyright 2010, Dryad, llC Trunk diameter DBH24 36 40 55 Conditions and Observations Rated Defect25 (most likely part to fail) • Topping cuts • Old and recent heading cuts -4" diameter limb, • Lion 's tail ing (o ld & recent) poor taper , lion's-• Right-angled new leaders • Poor taper of limbs tailed. • Limb curvature • Codominant tops ; both near- horizontal • Acute-angled attachments • Decayed pruning cuts -4" diameter limb , • Topping cuts poor taper, lion's-• Old and recent heading cuts • Lion 's tailing (old & recent) tailed. • Right-angled new leaders • Poor taper of limbs • Limb curvature • Acute-angled attachments • Decayed pruning cuts • Old and recent heading cuts -4" diameter • Lion's tailing (o ld & recent) sprouts, poor taper , • Right-angled new leaders • Poor taper of limbs lion's-tailed. • Limb curvature + + + Page 8of38 TRACE Evaluation" Part Target Risk Probability TRACE Risk (1-5) Size Rating Rating Description" (1-3) (1-4) (1-12) (summarized) High 1, Issues are clear- 4 2 3 9 retain but monitor annually. High 1, Issues are clear- 4 2 3 9 retain but monitor I annually . High 1, Issues are clear- 4 2 3 9 retain but monitor annually. - AugustS, 2010 Dryad, LLC #10024-40006 City of Palo Alto Eleanor Pardee Park Tree Location Diagram (aerial photo) NOTE : Printed from GoogleEarth . /PA!IrA1l'J,LLC ~,pYI-igtlt2 ID1D, Dryad, LLC Page 9 of 38 35570 Palomares Rd. Castro Valley CA 94552 Phone Fax E-mail (877) 206-4001 (510) 538-600 1 Iyoung @dryad .us August 5,20 10 Dryad, LLC #10024-400 06 City of Palo Alto Elea nor Pa rd ee Park Tree Location Diagram NOTE: Excerpted from Eleanor Pardee Eucalyptus and Redwood Maintenance Recommendations Report, Eric Krebs, March 2, 2010. • ,~ c ~ s i I) --------- il,e;>qyr'ight2010, Dryad, LLC 0 ELEANOR PARDE Field Chan n ing Ave Page 10 of 38 35570 Pa lomares Rd. Castro Valley CA 94552 0 0 00 o~ 0 ARK 8 0 8 o o Phone (877) 206-4 001 Fax (510) 538-6001 E·mai l tyoung @dryad .us August 5. 2010 Dryad, LLC #10024-40006 City of Palo Alto Eleanor Pardee Park Photographs There are photographs on the following pages of each entire tree, followed by examples of described negative conditions . Tree No.1 photographs include numerous examples, intended to illustrate the extent of such conditions, as is typical with all the trees . The photos of subsequent trees include only a few examples each. fl..!' .. I' > "'" 1 J! ", ,;: .' .. il tJ FA D, LLC yrlght 2010, Oryad,lLC Page 11 of 38 35570 Palomares Rd . Castro Valley CA 94552 Phone Fax E·mail (877) 206 -4001 (510) 538-6001 tyoung @dryad.us Au gust 5, 2010 Drya d , LLC #100 244 0006 City of Pa lo Alto Elea no r Pa rd ee Pa rk Tree No.1: Manna LLC ,C:Q,pyr';ghlt2010, Drya d , LLC Pa ge 1 2 of 3 8 35570 Palo mares Rd. Castro Va ll e y C A 94552 Ph one Fax E -mail (877 ) 206 ·400 1 (5 10) 538·600 1 tyoung@ d ryad.us August5.2010 Dryad, LLC #10024-40006 Ci ty of Palo A lto Eleanor Pardee Park Tree No.1 (continued) /I. n _n WAD,LLC " '~y-",", • -, . \ t lij pyrlght 201 D, Dryad, LLC , . , Page 13 of 38 Old topping cuts with decay and adjacent, weakly attached, codominant acute·angle sprouts forming the new top . Heavily decayed old heading cut. 35570 Palomares Rd. Castro Valley CA 94552 Ph one Fax E·mail (877) 206·400 1 (5 10) 538·6001 Iyoung @dryad .us August 5, 20 10 Dryad. LLC #10024-40006 City of Pa lo Alto Eleanor Pardee Park Tree No.1 (continued) Codominant stems with acute angled attachments. /U WAD, LLC , -. ' . ". c, '. pyright2010, Dryad,lLC :>1' ';'; Page 14of38 " ... , " \ , I , I I I I J)ll 16 2010 Old , decayed topping cut. 35570 Palomares Rd . Cast ro Valley CA 94552 Pruning cuts to right-angled leaders. Phone (877) 206·4001 Fax (510) 538·600 1 E-mail tyoung @dryad .us August5.2010 Dryad, LLC #10024-40006 City of Pa lo Alto Eleano r Pardee Park Tree No.1 (continued) Lion's-tailed limb with poor taper, headed to opposing right-angle leaders. /Pi&rWAIJIJ; LLC iCpl~yr;ght2010. Oryad.llC JU l e: 2010 Page 15 of 38 35570 Paloma res Rd . Castro Valley CA 94552 JUL 'S 2010 Phone Fax E-mail (877) 206 ·4001 (510) 538 ·600 1 tyoung @dryad .us AugustS, 2010 Dryad, LLC #10024-40006 City of Palo Alto Eleanor Pardee Park Tree No.1 (continued) Old toping cut to right angle leader; lion's·tailing, curvature, etc. fPJj{;'}f Al,), LLC ~'\!ls)py;rigllt201 O. Dryad. LLC Page 16 of 38 35570 Palomares Rd . Castro Valley CA 94552 Phone Fax E-mai l (877) 206 ·4001 (510) 538·6001 tyoung @dryad .us Augu st 5 , 2010 Dryad, llC #10024-40006 City of Palo Alto Eleanor Pard ee Pa rk Tree No.5: Manna gum (Eucalyptus vimina/is) lPftY~J~, LLC C<>pyrlght 201 0, Dryad, lLC Page 17 of 38 35570 Palomares Rd . Caslro Valley CA 94552 Phone Fax E-mail (877 ) 206-400 1 (5 10) 538-6001 Iyoung@ dryad .us AugustS, 2010 Dryad, LLC #1002440006 City of Palo Alto Elea nor Pardee Park Tree No .5 (continued) ppp'Yriglht2010"D'l,ad.LLC Page 18 of 38 Old, decayed heading cuts, right·angle leaders, weak attachments, etc . 35570 Paloma re s Rd. Cast ro Valley CA 94552 Phone (8771206 ·4001 Fax (5 10) 538-6001 E-mai l Iyoung @dryad.us August 5,2010 Dryad, LLC #10024-40006 Ci ty of Palo Alto Eleanor P ardee Park Tree No. 6: Manna LLC ~CP'pyr'lght 2(11 O.Dryad, llC Page 19 of 38 35570 Palomares Rd . Cas tro Valley CA 94552 Phon e Fax E -mail (877) 206-4001 (5 10) 538 -6001 Iyoung@dryad.us Aug u stS, 2010 Dryad, LLC #10024-40006 City of Palo Alto Elea nor Pardee Park Old topping cuts wI codominant sprouts on left, and right-angle leader on right. fI..C WAD, LLC ,', .;-< ,> '" ." pyright 2010 , Dryad . LLC , , , < - Page 20 of 38 35570 Palomares Rd . Castro Valley CA 94552 Leaning , lion's tailed, codominant stem with weak attachment (left) Phone Fax E-mail (877) 206-4001 (510) 538-600 1 tyoung@dryad .us August 5, 2010 Dryad, lLC #10024-40006 City of Palo Alto Eleanor Pardee Park Tree NO.9: Manna gum (Eucalyptus vimina/is) ~,,,pYrliahI12010.Dryad. LLC Page 21 of 38 35570 Palomares Rd . Castro Valley CA 94552 Phone (877) 206-4001 Fa x (510) 538-6001 E-mail Iyoung@dryad .u s August 5, 2010 Dryad, LLC #10024-40006 City of Pa lo Alto Eleanor Pardee Park ,/:l.Qjpyriighlt 201 O. Dryad. LLC Old failure wound weakening acute-angle attachment of adjacent sprout. Page 22 of 38 Illustrates extremely thin canopies, lion's tailing, right-angle leaders, poor taper, acute-angle attachments, limb curvature. 35570 Palomares Rd . Castro Valley CA 94552 Phone Fax E-mai l (877) 206 ·4001 (510) 538·6001 Iyoung @dryad.us August 5, 2010 Dryad, LLC #10024-40006 City of Pa lo Alto Eleanor Pardee Park Tree No11: Bluegum (Eucalyptus globulus) fJlB,P/l JU, LLC (l.olPyriighlt2010, Dryad, LLC Page 23 of 38 35570 Palomares Rd . Castro Valley CA 94552 Phone Fax E-mail (877) 206-400 I (510) 538-600 1 tyoung @dryad.us August5.2010 Dryad, LLC 1110024·40006 City of Palo Alto Eleanor Pard ee Park LLC Acute-angle attachment of codominant stem leaning over street. ICpPY"ight2Cl10,Dryad, LLC Page 24 of 38 Tree no , 11 is much smaller and understory to surrounding trees (9 & 12) o ~ o N <D ~ 35570 Palomares Rd . Castro Valley CA 94552 Phon e Fax E ·mail (877) 206-400 1 (5 10) 538-6001 Iyoung@dryad.us August5.20 10 Dryad, LLC #10024-40006 City of Palo Alto Eleano r Pardee Park Tree No12: Bluegum (Eucalyptus globulus) LLC 11,c"py,-ighl20'1 O,Dryad, LLC Page 25 of 38 35570 Palomares Rd . Castro Valley CA 94552 Phone Fax E-mail (877) 206-4001 (510) 538 -6001 tyoung @dryad .u s A ugust 5, 20 10 Dryad, LLC #10024-40006 C ity of Pa lo A lto Eleanor Pardee Park Tree No. 12 (continued) .Co,ovrljah.j 2010 . Dryad, LLC Illustrates lion's-tailing, right-angle leaders, limb curvature, and recent removal of entire lateral limbs. Page 26 of 38 35570 Palomares Ad . Castro Valley CA 94552 Phone (877) 206-4001 Fax (510) 538·600' E-mail tyoung @dryad.us Augu st 5 , 2010 Dry a d, llC #1002440006 City of Pal o Alto Elea nor P ardee Park Tree No13: Bluegum (Eucalyptus globulus) , WA D, LLC CDpyrlght2010, Dryad,llC Page 27 of 38 35570 Palomares Rd . Castro Valley CA 94552 Phone Fax E-mail (877) 206·4001 (510) 538·6001 Iyoung@dryad.us August5.2010 Dryad, LLC #10024-40006 City of Palo Alto Eleanor Pardee Park IPAllfA JD, LLC \-Qo,pyriight2010, Dryad, LLC Page 28 of 38 Right-angle leaders, limb curvature, lion's-tailing, etc. 35570 Palomares Rd . Castro Valley CA 94552 Phone Fa, E-mail (877) 206-4001 (510)538-6001 tyoung @dryad .us Augu st 5, 2010 Dryad, lLC #10024-40006 City of Pal o Alto Eleanor P ard ee Pa rk Tree No14: Bluegum (E ucalyptus globulus) >I " ", ~ r.., • pynght2010, Dryad,LLC , Page 29 of 38 "" 35570 Palomares Rd . Cas lro Valley CA 94552 Phone (677) 206-400 1 Fax (510) 538-6001 E-mail Iy oung @dryad.us August 5, 2010 Dryad, LLC #10024·40006 City of Palo Alto Elea nor Pardee Park Tree No. 14 (continued) <'l<>pyright2010, Dryad, LLC Page 30 of 38 Right-angle attachments, lion's-tailing poor tape r , heading cuts, etc. 35570 Palomares Rd . Castro Valley CA 94552 Phone (877) 206·4001 Fax (5101538 ·6001 E·mail Iyoung @dryad.us August 5, 20 10 Oryad, LLC #10024-40006 City of Palo Alto Eleanor Pardee Park Tree No15: Bluegum IiM'l<>p,/riahI2!01(1.Dryad, llC Page 31 of 38 35570 Palomares Rd . Castro Vane y CA 94552 Phon e Fax E-mail (8771206 ·4001 (5101538 ·6001 \young @dryad.us August 5, 2010 Dryad , LLC #10024-40006 City of Pa lo Alto Eleanor Pardee Park Heading cuts, right angle leaders, old, decaying topping cut, etc. Qopyright2010,Oryad,llC Page 32 of 38 35570 Palomares Rd . Castro Valley CA 94552 Phone (877) 206 ·4001 Fax (510) 538·6001 E-mail tyoung @dryad.us August 5, 2010 Dryad, LLC #10024-40006 City of Palo Alto Eleanor Pardee Park Tree No16: Bluegum (Eucalyptus globulus) .Jj """', LLC ~jilp,pyr'ig ht 2('10, Dryad, LLC Page 330f38 35570 Palomares Rd. Castro Valley CA 94552 Phone (877) 206 -400 1 Fax (510) 538-600 1 E -mail tyoung @ dryad.us AugustS, 2010 Dryad, LLC #1002440006 City of Palo Alto Eleanor Pardee Park Tree No. 16 (continued) ~""71 L1, LLC jeJ!J~yright201 0 , Dryad. LLC Page 34 of 38 Right·angle leaders, heading, limb curvature, sprouted topping cut, etc. 35570 Palomares Rd. Castro Valley CA 94552 Phone (877)206 -4001 Fax (510)538-6001 E-mail ty oung@dryad.us August 5, 2010 Dryad, LLC #1002440006 City of Palo Alto Eleanor Pardee Park Certification, Statements and Cop~(rj'~~b1r Certification of Performance I, Torrey Young , certify that: • I have personally inspected the tree(s) and the property(ies) referred to in this report and have stated my observations and findings accurately ; • My analysis, opinions and conclusions were developed and this report prepared according to commonly accepted arboricultural practices . • The analysis , opinions and conclusions stated herein are my own and are based upon current scientific procedures, facts and my personal experience and observations. • I have no current or prospective personal or commercial interest in the vegetation or the property(ies) that is/are the subject of this report , and I have no personal interest or bias with respect to the parties involved; • My compensation is not contingent upon the result of the assessment, attaining stipulated results, the occurrence of any subsequent events , nor the reporting of a particular or predetermined conclusion that may favor the client or any other party. • That no one provided significant professional assistance to the consultant except as indicated within the report . • I am a current member of the American Society of Consulting Arborists (ASCA), an ASCA Registered Consulting Arborist (#282), a CUFC Certified Urban Forester and that I accept and aspire to adhere to the ASCA Standards of Professional Practice . I am also a current member of the International Society of Arboriculture (ISA), an ISA Board Certified Master Arborist (#WE-0131B), a Certified Urban Forester (#121) certified by the California Urban Forests Council (CUFC) and a Certified Tree Risk Assessor, (#602) certified by the Pacific Northwest Chapter of ISA. Arborist Disclosure Statement Arborists are tree specialists who use their education, knowledge training and experience to examine trees, recommend measures to enhance their health and beauty and to attempt to reduce the risk of living in the vicinity of trees. Clients may choose to accept or disregard the recommendations of the arborist or to seek additional advice . Trees and other plantlife are living , changing organisms affected by innumerable factors beyond our control. Trees fail in ways and because of conditions we do not fully understand. Arborists cannot detect or anticipate every condition or event that could possibly lead to the structural failure of a tree . Conditions are often hidden within the trees and below ground . Arborists cannot guarantee that a tree will be healthy or safe under all Circumstances, for any specific period of time or when a tree or its parts may fail. Further , remedial treatments, as with any treatment or therapy, cannot be guaranteed . Treatment, pruning, bracing and removal of trees may involve considerations beyond the scope of the arborists skills and usual services such as the boundaries of properties, property ownership , site lines, neighbor disputes and agreements and other issues. Therefore, arborists cannot consider such issues unless complete and accurate information is disclosed in a timely fashion . Then , the arborist can be expected to reasonably rely upon the completeness and accuracy of the information provided . Trees can be managed but not controlled . To live near trees , regardless of their condition , is to accept some degree of risk. The only way to eliminate all risk associated with trees is to eliminate all trees . Copyright © Copyrighl2010, Dryad, LLG. Other than a 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. + + Page 35 0138 + 35570 Palomares Rd . Castro Va lley CA 94552 Phone Fax E-mail (877) 206-4001 (510)538-6001 tyoung @dryad.us August5.2010 Dry ad, LLC #10024-40006 City of Palo Alto Eleanor Pardee Pa rk Consultant '" \ " ... \ ... ... -... .. " ... ... " , ... " ... , " '\ , \ \ , , , 'vi I , ,.. -..... ) I , , I ,,, I -," " ,,-... \~I .. ~'(,~\' \ I'" . f \ ... / , J I ( " J / \ \ lpr)ey pU 9 , 'RegiSte r~crC. sClltiP Arborist ® , \ \ I \ ... / , I " / -~ CREDENTIALS: • ASCA Registered Consulting Arborist ® No . 282 • ISA Board Certified Master Arborist No . WE-0131 B • CUFC Certified Urban Forester No. 121 • PNW-ISA Certified Tree Risk Assessor No . 602 • CA P.C. Qualified License No.: 104772 PROFFESSIONAL AFFILIATIONS • American Society of Consulting Arborists • International Society of Arboriculture • Society of Commercial Arboriculture • Tree Care Industry Association • California Arborists Association • California Urban Forests Council • California Landscape Contractors Association • California Oak Foundation • American Forests • Pesticide Applicators Professional Association • U.S . Green Building Council + + + 0, Dryad, LLC Page 36 of38 35570 Palomares Rd . Cas tro Valley CA 94552 Phone Fax E-mail (8771206 ·400 1 (510) 538-6001 tyoung @dryad .us August 5, 2010 Dryad , LLC #10024-40006 City of Pa lo A lto Eleanor Pardee Park I Evaluation: (as applied in this report) A determination and analysis of the physiological, structural and architectural condition of a tree, or selected aspects thereof. 2 City of Palo Alto Purchase Order no .: S11137608 3 Facebook is a social networking website launched in February 2004 , operated and privately owned by Facebook , Inc . 4 Care2 is a social network website that was founded by Randy Paynter in 1998 to help connect activists from around the world . The social interactions on Care2 revolve around groups that connect people who care about similar issues. Internet petitions and news articles posted by members are also frequently used. 5 Residents for Safe Palo Alto Parks; http://www.facebook.com/group .php?gid=108941109151025&ref=search 6 http://www.thepetitionsite .com/1/replace-eucalyptus-trees-at-eleanor -pa rdee-pa 1 Sulfur fungus (Laetiporus gilbertsonii): An aggressive decay fungus that causes brown rot of sapwood (heart-rot). Generally enters through large wounds or pruning or topping cuts or dead stubs . Usually infecting the lower portion of tree trunks, it can extend below ground, resulting in whole tree failures. 8 Root crown excavation and inspection: Excavation of the junction of trunk and buttress roots and immediate vicinity below grade for the purpose of inspection for biological and structural condition and/or to restore the original grade. In a mature tree, Root crown excavation should include clearing excess soil, rocks , planting containers, rocks and other debris within at least 24" of the tree base. Sufficient soil shall be removed from the tree's root crown region to expose at least 25% of the upper Circumference of each buttress root, within at least 12~ of the tree trunk. Soil should (where possible) be graded in a manner as to direct drainage away from the tree base. All such excavation should be performed by hand, with only the aid of hand tools, or via appropriate pneumatic or hydraulic excavation equipment, in such a fashion as to avoid traumatic damage to roots and trunk . Where indicated , root crown excavations should be performed prior to any other required maintenance work. In the event of discovery of significant root defects (root disease, girdling roots, concave trunk areas, etc .) in sizable trees, other maintenance work shall be postponed and such defects reported to the property owner or other proper authority. 9 Resistograph®: An instrument used to detect internal wood decay and cracks . Such defects are detected by measuring relative resistance to drilling with a 3.0 mm drilling needle. The results are simultaneously recorded on a paper graph. The Model F500S employs a needle (drill bit) capable of drilling to a depth of approximately 19 inches . The Resistograph e is manufactured by Instrument Mechanic Labor , Inc. (IML). The Resistograph® testing locations are determined dependent upon on -site testing results and observations, at the discretion of the consultant. Resistograph® testing provides information only, that is subject to interpretation, and therefore , the significance of testing results or evaluation of results cannot be anticipated or otherwise guaranteed . 10 Pruning: The removal of plant parts. Proper pruning is performed in a manner intended to achieve a specific goal while minimizing the negative effects on the plant (tree). Improper pruning is that which may not be coupled with a specific goal, may not employ techniques consistent with the identified goal, or may result in significant negative physiological and/or structural impacts on the plant. Pruning standards: The following standards were developed by a consensus of representatives from various industry professional organizations; -+ American National Standards Institute, 2008. Standard Practices for Tree, Shrub and other Woody Plant Maintenance (Pruning), American National Standards Institute (ANSI A300 Part 1-2008) -+ International Society of Arboriculture, 2002 Best Management Practices, Tree Pruning, International Society of Arboriculture + I I Structure: The nature, character, physical integrity and attachments of trees ; primarily refers to the wood in limbs, branches, stems (trunks) and roots . 12 Architecture : (as employed in this report) the arrangement of the (external) parts of a tree; primarily refers to the foliage crown including major (scaffold) limbs, lateral branches and trunks . 13 Stem: The primary portion of a plant's supportive and transportive architecture (synonymous with ·trunk'). 14 Taper: (of stems & limbs) the increase in diameter towards the base of stems (trunks) and limbs that is typical and desirable in woody plants. Degree of taper is influenced by a variety of factors including foliage , limb and branch distribution, species , location (sunlight), wind patterns, pruning, etc. InsuffiCient taper results in a concentration of stress from movement towards the base of the limb or stem, resulting in a greatly increased potential for breakage or uprooting. Pruning that removes interior lateral branches from limbs and/or lower limbs from trunks dramatically reduces taper development. 15 Scaffold limbs : Primary limbs usually originating from a (the) main stem of a tree , contributing substantially to the architecture and structure of the tree canopy. 16 Crown Reduction: A pruning standard consisting of selective thinning cuts to reduce height and/or spread ; removal of more than '/4 of the Jive foliage shall be avoided; the lateral to which a branch or stem is cut should be at least one-half the diameter of the cut being made. 17 Sulfur fungus (Laetiporus gifbertsonii): An aggressive decay fungus that causes brown rot of sapwood (heart-rot). Generally enters through large wounds or pruning or topping cuts or dead stubs . Usually infecting the lower portion of tree trunks, it can extend below ground, resulting in whole tree failures . 18 Reslstograph®: An instrument used to detect internal wood decay and cracks. Such defects are detected by measuring relative resistance to drilling with a 3.0 mm drilling needle . The results are simultaneously recorded on a paper graph . The Model F500S employs a needle (drill bit) capable of drilling to a depth of approximately 19 inches. The Resistograph ® is manufactured by Instrument Mechanic Labor, Inc. (IML). The Resistograph ® testing locations are determined dependent upon on-site testing results and observations , at the discretion of the consultant. Resistograph® testing provides information only, that is subject to interpretation , and therefore, the significance of testing results or evaluation of results cannot be anticipated or otherwise guaranteed. 19 Reaction wood : Specialized, secondary xylem (sapwood) that forms in response to mechanical stresses on limbs and trunks. Rapid changes in stress points in vigorous trees can result in large distortions of limbs and trunks from the development of such wood . Such growth may also be characterized by extensive splitting of outer bark as new bark and wood expands. Dryad, LLC Page 37 of 38 35570 Palomares Rd. Castro Valley CA 94552 Phone Fa' E-mail (877) 206-4001 (510)538-6001 Iyoung @dryad .us Augu s t5.2010 Dryad, LLC #10024-40006 City o f Pa lo Alto Eleanor Pard ee Park 20 TRACE: Tree Risk Assessment Course and Exam , developed and administraled by the Pacific Northwest Chapter of the International Society of Arboriculture. TRACE employs a 12-point evaluation and rating system to categorize the most likely and imminent tree hazards . 2 1 Pneumatic excavation : Soil excavati on performed via supersonic compressed air excavation with a tool called an air knife (spad e). This tool removes soil from roots (or pipes , wires , etc.) with little or no damage to the roots (or utilities). Soil is separated and blown away via highly focused , supersonic velocity compressed air, which separates the soil particles without penetrating rools . 22 Mulch: Organic materials (e .g ., bru sh chips , fir bark) spread upon the soil for a variety of benefits : aesthetics , retains soil moisture , moderates soil temperatures, improves soil structure and increases fertility , protects against compa ction , suppresses weeds , etc . (Note : Elsewhere, definition may include non -organic materials.) 23 TRACE evaluations are included here for informational purposes only, and are not the basis of any conclusions or recommendations . 24 D.B.H.: Diameter at Breast Height, or approximately 4.5 feet (54 inches) above grade. This expression is commonly used as a point of reference in determining tree size (synonymous with DSH, or Diameter at Standard Height). 2S This rating is based upon the part of the tree most likely to fail as deteremined at the time of inspection . There is no relatioship to the largest, most likely to result in damage, etc. 26 Rsk descriptions are summarized from descriptions in the TRACE process chart entitled The Overall Risk Rating and Actio n Thre sholds . The desciptions in this chart do not relate directly to the conclusions and recommendations of this report . + + .. 0, Dryad , LLC Page 380138 35570 Palomares Ad . Castro Valley CA 94552 Phone Fax E-mail (877) 206 ·400 1 (510) 538·6001 tyoung @dryad .us