BMP - Tree Risk Assessment - iii

Table of Contents
Preface............................................................................................................1
Acknowledgments..........................................................................................4
1. Introduction ................................................................................................5
2. Risk Assessment Basics .............................................................................7
	
Basic	Definitions ...................................................................................7
Types of Risk Associated with Trees.....................................................8
	
	 Conflicts ............................................................................................8
Structural Failures .............................................................................8
Approaches to Risk Assessment............................................................9
Quantitative Risk Assessment .........................................................10
Qualitative Risk Assessment ...........................................................10
Qualitative Numeric Assessments ..................................................10
BMP Assessment Approach ............................................................11
3. Levels and Scope of Tree Risk Assessment .............................................13
Level 1: Limited Visual Assessment ...................................................13
Level 2: Basic Assessment ..................................................................16
Level 3: Advanced Assessment ...........................................................19
	
Defining	the	Scope	of	Work ................................................................20
4. Assessing Targets, Sites, and Trees ..........................................................23
Targets .................................................................................................23
Target Zone..........................................................................................24
Occupancy Rate ..................................................................................25
Site Factors ..........................................................................................26
Wind and Weather ...............................................................................27
Tree Failures ........................................................................................29
	
Tree	Species	Failure	Profiles ...............................................................30
Protection and Multiplicative Factors .................................................31
5. Tree Risk Categorization..........................................................................32
Likelihood of Failure...........................................................................32
Likelihood of Impacting a Target ........................................................34
Categorizing the Likelihood of a Tree Failure Impacting a Target .....35
Categorizing Consequences of Failure................................................36
Tree Risk Rating..................................................................................40
Risk Perception and Acceptable Risk .................................................43
6. Risk Mitigation: Preventive and Remedial Actions .................................45
Work Prioritization ..............................................................................48
Residual Risk ......................................................................................48
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BMP - Tree Risk Assessment

Table of Contents for the Digital Edition of BMP - Tree Risk Assessment
