San Leandro Creek Hazardous Tree Workshop

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Kerrie Byrd
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1 San Leandro Creek Hazardous Tree Workshop H U F F A V E N U E C O M M U N I T Y W O R K S H O P J U N E 2 2, B A N C R O F T M I D D L E S C H O O L

2 Introduction & Overview Hank Ackerman, Flood Program Manager, Alameda County Flood Control & Water Conservation District Introductions

3 Tonight s Agenda Community Involvement Overview of Decision Process Risk Assessment Process Individual Tree Assessment Q&A

4 Community Involvement Tonight s workshop is first in a series of three, each focused on one of the three sites along San Leandro Creek where the trees have been identified and studied (Huff Ave., Cary Drive, and St. Mary Ave.) The focus of tonight s discussion is on the trees near Huff Ave. Our objective is to explain the risk assessment process to you, and to go over the ratings for District trees at the Huff Avenue site.

5 Overview of Decision Process We will hear your issues and concerns relevant to this site We will hold two other community workshops (Cary Drive and St. Mary Avenue) After these meetings we will incorporate your input into the development of a project

6 Overview Cont d Since May 19 meeting the District has collected additional data to rate all trees 6 inches in diameter and larger at the Huff Avenue site We will provide similar data for the other locations at the upcoming workshops

7 Huff Ave. Site Map Woodland Park 524 Callan 450 Callan

8 What is Risk? What is Hazard? Risk: Likelihood that tree will fail and cause injury or damage Hazard: Tree part likely to fail and likelihood exceeds an acceptable level of risk.

9 Tree Risk Assessment Tree health Tree structure Site conditions Weather and climate Use around tree

10 Visual Assessment Structural problems that could lead to failure

11 Visual Assessment Site Conditions Site changes Drainage Slope Wind exposure Previous failures

12 Site factors influence failure Tall trees with thin trunks Wet soil + Wind

13 Tree Risk Rating Risk Failure Size of Target Rating Potential Part Rating 3 to 12 1 to 4 1 to 4 1 to 4

14 Failure Potential: = low 2 = moderate 3 = high 4 = severe

15 Failure Potential: = low 2 = moderate 3 = high 4 = severe

16 Size of Part that Would Fail 1 = Less than 6 2 = = > <6 4 = Greater than 30

17 Target Rating 1 = Occasional use 2 = Intermittent use 3 = Frequent use 4 = Constant use residences 24 hr. use, every day

18 Huff Ave. Target Ratings 1 = creek bank, no flow disruption 2 = fence, landscape 3 = street, property, creek flow disruption 4 = people, homes

19 Tree Risk Rating Risk Failure Size of Target Rating Potential Part Rating 3 to 12 1 to 4 1 to 4 1 to 4

20 What is the degree of risk? Severe 12 High Moderate Low 3

21 Basic inspection of each tree - visual, from the ground Trees at Huff Ave. Rated risk of tree failing and causing damage

22 Trees at Huff Ave Woodland Park Callan 450 Callan

23 Trees at Huff Ave. 15 trees 9 blue gum 3 boxelder 1 sycamore 1 willow 1 Canary Island palm Steep slopes Thick ivy

24 Trees at Huff Ave. 9 blue gums tall Dense ivy cover on trunks 3 trees leaning 2 trees with trunk decay Located mid and upper bank

25 Trees at Huff Ave. 9 blue gums Primary failure mode: WIND Windthrow strong winds, wet soil conditions tall trees, long lever arm Compression Tension

26 What is the degree of risk?

27 Tree #212 Blue gum Ht. 105 Risk Rating 11

28 Tree # Blue gum Ht. 114 Risk Rating 10

29 Tree # Blue gum Ht. 94 Risk Rating 9

30 Tree # Blue gum Ht. 138 Risk Rating 9

31 Tree # Blue gum Ht. 108 Risk Rating 8

32 Let s take a break

33 Trees at Huff Ave Woodland Park Callan 450 Callan

34 Tree #202 Blue gum Ht. 98 Risk Rating 8

35 Tree #205 Blue gum Ht. 106 Risk Rating 8

36 Tree #213 Boxelder Ht. 32 Risk Rating 7

37 Tree #214 Blue gum Ht. 134 Risk Rating 7

38 Tree #215 Blue gum Ht. 119 Risk Rating 7

39 Tree #207 Willow Ht. 45 Risk Rating 6

40 Tree #208 Boxelder Ht. 34 Risk Rating 6

41 Tree #209 Boxelder Ht. 27 Risk Rating 6

42 Tree #211 Sycamore Ht. 123 Risk Rating 6

43 Tree #204 Canary Island palm Ht. 22 Risk Rating 3

44 Questions?

45 Closing Remarks Dates of Upcoming Meetings Tuesday, June 29 Community Workshop #2 (Cary Dr. Focus) at Bancroft Middle School 7-9 p.m. Tuesday, July 13 Community Workshop #3 (St Mary s Avenue Focus) at Bancroft Middle School 7-9 p.m. Look for a Summary of this evening s meeting on the Public Works Department website:

Welcome to the Open House

Welcome to the Open House The Alameda County Flood Control & Water Conservation District is hosting this interactive open house to: Review the process to date Summarize key outcomes of the process Provide