INTRODUCTION. Beau Brodbeck Alabama Cooperative Extension System

Transcription

1 Identifying Hazardous Trees; INTRODUCTION Beau Brodbeck Alabama Cooperative Extension System

2 The workshop today Part 1: Introduction to urban forestry and hazard tree identification Part 2: Introduction to the ISA Visual Guide to Risk Assessment Part 3: Tree Defects; the Roots Part 4: Tree Defects; the Trunk Part 5: Tree Defects; the Crown Part 6: Outdoor Practicum

3 Cities and Towns Happen 307,006,550 US citizens (2009) 25,375 places 106.3M developed acres 295.9B ft² of built space Alabama 4.7 M citizens 453,760 developed acres

4 Urban Trees Happen 3.82 billion urban trees 3.5% US land space Contains 75% population Average 27.1% canopy cover

5 However, all too often they collide! Diseased Trees Dead Trees Tree Failure

6 Trees can be dangerous

7 Hurricane Ivan, Brewton, AL Photo by Charles Nesbitt, Birmingham News

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10 Threaten Public Safety

11 Can some of this be prevented The answer is Yes Better Tree Placement and design Minimizing damage from construction, utilities, & poor arboriculture Regular urban tree assessments & maintenance

12 So why are trees worth the risk? Aesthetics

13 Make our communities more livable Slide by: Ed Gilman St Augustine

14 However, there is more than beauty Psychological Benefits Stress reduction Shorter hospital stays & use less meds for patients with landscape views Lower domestic violence Children witha D D have Children with A.D.D. have better behavior in green environments

15 There is more than emotion $$$ Energy Savings!!! Auburn residential study showed that 17% shade saved $10/month on power bill. Same study also showed 50% shade saved $28/month California has controversy of tree shad vs. solar panels

16 More trees = higher property values Each mature front lawn shade tree adds ~1% to home property value Shoppers purchase 12% Fairhope, AL

17 The list of tree benefits is long Water retention in canopy (28%) Trees cool by degrees C0 2 reduction (3%) Streets w/ little or no shade need re paving twice as often as those with 30% tree cover Etc

18 Most of us can agree trees are good

19 However We don t always know how to get there

20 What makes a hazardous tree? A hazard tree has a structural defect that may cause the tree or a portion of the tree to fall on someone or something else of value. (National Arborday Foundation)

21 Hazard Tree Identification Process 1. Tree Characteristics 2. Overall Tree Health 3. Site Conditions 4. Target 5. Tree Defects a) Root Defects b) Trunk Defects c) Crown Df Defects 6. Hazard rating 7. Hazard ard abatement 8. Comments

22 Tree Characteristics Collect and consider information on tree s: Species DBH Important tto know tree Height species and associated Spread growth characteristics and expected responses Crown class to wounds, maturity Pruning history,etc Special value Lafayette, Louisiana

23 Tree Health Collect and consider information on tree s: Foliage color Foliage density Woundwood development Vigor Tree healthy can be an indicator of some structural problems and should be considered when factoring tree hazards

24 Site Conditions Collect info on Site character Residence etc Landscape type Yard, curb etc Site disturbance % paved etc Obstructions Overheadandbelow and ground lines Exposure to wind Likelihood of windthrow Site conditions help evaluation by knowing: Regional weather to evaluate windthrow Degree of site change helps evaluate potentialdamage and rot likely in the roots

25 Targets the target component of a hazard rating is the people and property that would be injured or damaged should a failure occur Matheny & Clark Occupancy inspector must anticipate use of the site around trees. Sites used 24 hours a day have a higher hazard rating than those used seasonally

26 Targets; Use under tree Building Parking Traffic Pedestrian Recreation Landscape Hardscape Small feature Utility lines

27 Target; Occupancy Constant use Hazard rating increases with ih increasing use Frequent use Intermittent use Occasional use What is the probabilitythatthat a target will be present during the most likely failureevent event, before thenext evaluation

28 Targets NOT ALL TARGETS ARE CREATED EQUAL

29 Tree Defects: Root tdf defects Trunk kdf defects Crown defects df

30 Hazard Rating, Abatement & Hazard Rating. Comments Failure potential + Size of Part + Target Rating = Hazard Rating Abatement: What are you going to do about i? it? Comments: Inform your client of any special considerations

31 A few things that can help you identify hazard trees 1. Know your trees (Tree ID) 2. Know some basic tree biology 3. Understand tree structure 4. Understand tree mechanics 4. Experience

32 Helpful tools for evaluating trees Camera Diameter tape Increment borer Soil auger Chisel or surveyors

33 Resistograph

34 Tree Radar

35 Specialized arboricultural tools Airspade

36 Evaluations forms and hazard rating systems There are several systems out there and they all have pluses and minuses Basically they help remind assessors of what to look for and how to categorize their thoughts, comments and report findings

37 Tree Risk Assessment; Systematic Evaluation Process Dr. Kim D. Coder, Univ. GA 1990

38 Coder s Method

39 Bartlett Tree Research Lab E. Thomas Smiley Bruce R. Fraedrich Neil Hendrickson

40 Bartlett s Method

41 USDA Community Tree Risk Assessment Jana Albers Jana Albers Jill Pokorny Dr. Gary Joshnson

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43 Photographic Guide to the Evaluation of Hazard Trees in Urban Areas Nelda Matheny Jim Clark

44 Photographic Guide to the Evaluation of Hazard Trees in Urban Areas Why did we pick this guide for today? 1.Relatively easy to use and understand 2.Incorporates tree health into the process 3.Incorporates tree characteristics and site considerations into the process 4.It provides for good record keeping if you ever need to re visit the tree