Level 3: Advanced Techniques Many techniques can be considered for advanced risk assessment.† Some situations may be assessed with several techniques. Advanced assessment techniques include: * Aerial inspection and evaluation of structural defects in high stems and branches * visual inspection from within the tree crown or from a lift * unmanned aerial vehicle (UAV) photographic inspection * decay testing of branches * Detailed target analysis * property value * use and occupancy statistics * potential disruption of activities * Detailed site evaluation * history evaluation * soil profile inspection to estimate root depth * soil mineral and structural testing * Decay testing * * * * * * * * increment boring drilling with small-diameter bit resistance-recording drilling single-path sonic (stress) wave sonic tomography electrical impedance tomography radiation (radar, X-ray) microscopic analysis for fungal type * * * * tree ring analysis (in temperate zone trees) shoot length measurement detailed health/vigor analysis starch assessment * Health evaluation * Root inspection and evaluation * root and root collar excavation * root decay evaluation * ground-penetrating radar * Storm/wind load analysis * detailed assessment of tree exposure and protection * computer-based estimations according to engineering models * wind reaction monitoring over a defined interval * Measuring and assessing the change in trunk lean * Load testing * hand pull * measured static pull * measured tree dynamics † Inclusion of specific techniques in this list should not be considered an endorsement of that technique. 22