PLANT HEALTH CARE
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
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
Tree Defense Cellulose and lignin in tree cells are a cellular defense Herbivores cannot digest them
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
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 https://www.youtube.com/w atch?v=EGMcso_2fK8
Risk assessment Structural defects not always visible
Risk assessment Visual tree assessment (VTA) Dieback Gaps Lean Root collar
Risk assessment Visual tree assessment (VTA) Ensure trunk flares visible Cracks Codominant stems Included bark
Risk assessment Visual tree assessment (VTA) Structure branches should be 50% or less than trunk
Risk assessment Visual tree assessment (VTA) Decay in the form of conks or mushrooms indicate internal decay
3 basic types of fungal decay White rot Decays lignin Lignin gives wood compressive strength and stiffness
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
3 basic types of fungal decay Soft rot similar to brown rot https://www.youtube.com/watch?v =_pmoKLxyJZM
Tree rot Trunk rot is located in upper trunk
Tree rot Basal rot (butt rot) located in lower trunk and/or base of tree
Tree rot Heartwood rot starts in center
Tree rot Sapwood rot more serious Small fruiting bodies on bark surface
Tree rot Other indications of decay Carpenter ants Cavity nesting birds Honeybees
Investigating rot Resonance testing Sounding with hard plastic mallet
Investigating rot Increment borer extract core 1/8” bit Can introduce more damage
Investigating rot Resistance recording drill pushes needle into wood and measure density
Investigating rot Acoustic device Measures time it takes for sound to travel between various points Passes slower through decayed wood https://www.youtube.com/wat ch?v=WyHXvP0AJAs
Treating rot Presence of decay not necessarily a reason to remove tree Many factors affect health and stability
Treating rot Mitigation is process of reducing failure potential
Treating rot Pruning primary recommendation Support via cables or bracing Fencing off area Posting signs
Treating rot Filling cavities may do more harm than good Leave cavity alone
Treating rot Negligence Arborist fails to exercise due care
Treating rot Liability is based on cause Causation traced back to arborist’s action or lack thereof