1. PLANT HEALTH CARE

2. PHC
Proactive approach that manages the plant appearance, structure, and vitality
Vitality
Plants ability to deal with stress
What arborists control
Vigor
Plant’s inherent genetic capacity to resist stress
Select the right plant

3. Tree Growth Trees energy that is allocated to 4 primary functions
Maintenance
Growth
Storage
Defense
Some trees grow rapidly, reserving few resources for defense
Others do the opposite

4. Tree Defense Cellulose and lignin in tree cells are a cellular defense
Herbivores cannot digest them

5. Tree Defense Allelochemicals produced by plant to deter herbivores
Tannins and phenols
Insects tend to be host specific
Develop special enzymes to detoxify these compounds

6. Risk assessment
Evaluates likelihood that part or all of tree will fail and cause damage
Potential for tree failure
Environment that may contribute to failure
What would be damaged
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7. Risk assessment
Structural defects not always visible

8. Risk assessment Visual tree assessment (VTA) Dieback Gaps Lean
Root collar

9. Risk assessment Visual tree assessment (VTA)
Ensure trunk flares visible
Cracks
Codominant stems
Included bark

10. Risk assessment Visual tree assessment (VTA)
Structure branches should be 50% or less than trunk

11. Risk assessment Visual tree assessment (VTA)
Decay in the form of conks or mushrooms indicate internal decay

12. 3 basic types of fungal decay
White rot
Decays lignin
Lignin gives wood compressive strength and stiffness

13. 3 basic types of fungal decay
Brown rot
Decays cellulose
Leaves behind stiff lignin
Reduces bending strength
Brittle, dry and crumbly
Most common on conifers

14. 3 basic types of fungal decay
Soft rot similar to brown rot
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15. Tree rot
Trunk rot is located in upper trunk

16. Tree rot
Basal rot (butt rot) located in lower trunk and/or base of tree

17. Tree rot
Heartwood rot starts in center

18. Tree rot Sapwood rot more serious
Small fruiting bodies on bark surface

19. Tree rot Other indications of decay Carpenter ants
Cavity nesting birds
Honeybees

24. Investigating rot
Resonance testing
Sounding with hard plastic mallet

25. Investigating rot Increment borer extract core 1/8” bit
Can introduce more damage

26. Investigating rot
Resistance recording drill pushes needle into wood and measure density

31. Investigating rot Acoustic device
Measures time it takes for sound to travel between various points
Passes slower through decayed wood
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32. Treating rot Presence of decay not necessarily a reason to remove tree
Many factors affect health and stability

33. Treating rot
Mitigation is process of reducing failure potential

34. Treating rot Pruning primary recommendation
Support via cables or bracing
Fencing off area
Posting signs

35. Treating rot Filling cavities may do more harm than good
Leave cavity alone

36. Treating rot
Negligence
Arborist fails to exercise due care

37. Treating rot Liability is based on cause
Causation traced back to arborist’s action or lack thereof